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Abstract

Climate change has altered global rainfall amounts and seasonality. Rainfed crops are particularly dependent on foreseeable rainfall, thus yields of maize, wheat and sorghum have decreased globally. Rainfed maize is the cornerstone of the agriculture in Mexico and the nutrition base of as many as twenty million people. Despite its relevance, the risk that climate change represents for this economic activity has not been studied in our country. We evaluated the link between rainfall variability and maize yields in Mexico across three different time periods: the present, the past 30 years and the remainder of this century (future) with RCPs scenarios. We found that rainfed agriculture was distributed as a function of the dry-season length, occurring in areas with a 4–9 months dry season, thus climate change may alter not only agricultural yields, but also the spatial distribution of land uses. There was a linear correlation (r = 0.45) between mean annual precipitation and rainfed maize production nationally for the period 1980–2012. The correlation was stronger (r = 0.91) during 2005–2012 when high-resolution data were available for the analysis. Correlation values were not homogeneously distributed within the country, although the minimum correlation was 0.35. In the future scenarios, yields were predicted to either not change or to decrease by as much as 10%. The strongest negative impacts were predicted across the Northeast and the South of the country, where yields declined by up to 30% in all scenarios.

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... In the last six-year period (2013-2018) with the MasAgro program, national production increased through the use of native maize varieties (MAGR, 3.07%) with small-scale producers [32]. Despite all these efforts, grain maize production in Mexico is insufficient to guarantee food security of a population in continuous growth [33]. The agrifood policy in Mexico in the six-year period of 1983-1988 caused the MAGR of this period to be negative (−3.59%), since imports were prioritized over the programs to strengthen the farmland [30]. ...
... In the last six-year period (2013-2018) with the MasAgro program, national production increased through the use of native maize varieties (MAGR, 3.07%) with small-scale producers [32]. Despite all these efforts, grain maize production in Mexico is insufficient to guarantee food security of a population in continuous growth [33]. ...
... The growing trend in the production of grain maize for the SS-Rainfed cycle can be reverted in the short term, as consequence of the reduction of the surface planted since the year 2000 and a null growth of field yields in the same cycle ( Figure 2). In this regard, [33] considers that the constant production of grain maize that Mexico has maintained in the last decade is due to the increase in productive efficiency, particularly in the irrigation areas, which compensates the low productivity per surface planted in the rainfed areas. ...
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Mexico depends on maize imports to satisfy its national demand. The use of native maize varieties among subsistence farmers can help to reduce the cereal’s imports. However, the agricultural policy in Mexico to improve the productivity per hectare has centered on the use of improved varieties; among them, the transgenic variety. In this study, the maize productivity in Mexico from 1983 to 2018 was analyzed to determine the influence of agricultural policies in the sector, and the factors that condition the adoption of transgenic maize. It was found that the agricultural policy improved the productivity of those regions with irrigation; however, for rainfed regions, the expected technological changes were not achieved because the ancestral tradition in cultivation, associated with the greater variety of native maize and to a larger indigenous population, was stronger. The adoption of transgenic maize also had low significance in the rainfed regions, since the increase in field yields is not economically profitable with regards to the increase in production costs. Therefore, the agricultural policy to increase productivity ought to be directed at the protection of subsistence farmers, revaluing the use of native varieties that have shown higher resilience to technological and environmental changes.
... Such studies use biophysical crop models that provide gross estimates of changing yields (Howden et al., 2007;De Salvo et al., 2013;Rosenzweig et al., 2014). Climate change scientists have analyzed the impacts of climatic variables over rainfed maize in Mexico (Murray-Tortarolo et al., 2018;Ureta et al., 2020), while others have explored the linkage between institutions, climate risk, and vulnerability of maize production (Eakin et al., 2018). Although these studies are useful to identify coarse trends and impacts of climate change on maize production, they do not consider the diversity of the socio-ecological contexts which can affect their risk. ...
... The general overall climatic ranges for maize included 0 to 2,900 m altitude, 11.3 • to 26.6 • C annual mean temperature, 12.0 • to 29.1 • C growing season mean temperature, and 426-4245 mm annual rainfall (Ruiz-Corral et al., 2008). However, it seems that rainfed maize are strongly correlated to annual precipitation and precipitation seasonality (Challenger, 1998;Murray-Tortarolo et al., 2018). The RF models identified that annual precipitation was the second most important predictor in rainfed maize yields (Supplementary Figure 3). ...
... low yields (<3.0 ton/ha) which will reduce by climate change (Murray-Tortarolo et al., 2018). To overcome the climatic challenges for the agricultural sector in the north of Mexico, farmers have implemented irrigation management to grow animal feed crops such as sorghum and wheat, leaving staple foods production to the southern and central Mexico (Eakin et al., 2014b). ...
Article
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Evidence suggests that climate change could drastically reduce Mexico's agricultural productivity with severe socio-ecological consequences. Population growth and the increasing demand of resources will exacerbate these impacts. Focusing on rainfed maize production, we evaluate the socio-ecological risk that municipalities currently face and how climate change could modify it. Municipalities were classified based on their biophysical and socioeconomic traits like temperature, precipitation, population, gross domestic product, marginalization, and agricultural subsidies. The study identifies municipalities that would face higher risk under climate change conditions, and it evaluates whether increases in agricultural subsidies could be effective for reducing the farmers' future risk. Our results show that during the 2010's, 36.8% of the municipalities and 15% of the population were at very high and high risk, respectively. By 2070, under a high-warming scenario these figures increase to 56.5 and 18.5%. We find that a generalized augment in agricultural subsidies is not enough to compensate for the effects of climate change on the socio-ecological risk of rainfed maize producers. We suggest that transformative adaptation is required for managing the agricultural risk that socio-ecological systems experience under climate change conditions. Such adaptation strategies should include poverty alleviation, promotion of resistant and native varieties of crops, capacity building to improve management and water use, sustainable technification, and soil restoration.
... Moreover, global warming and the irrational use of natural resources has an impact on food security (Saccon, 2018;Azadi et al., 2018). For example, one problem associated with global warming is drought, which affects agricultural production systems and, consequently, food-bearing plants for human consumption (Ali et al., 2020;Murray-Tortarolo et al., 2018;Mardero et al., 2018). Likewise, water stress promoted by drought in plants leads to reactive oxygen species (ROS) production, generating wilting in leaves, oxidative damage to proteins and cell membrane instability . ...
... Also, climate change has generated alterations in hydrological patterns, which has led to a higher incidence of droughts and flooding which has affected the production of temporary crops (Ali et al., 2020;Arreguin et al., 2019;Murray-Tortarolo et al., 2018). Furthermore, the climatic phenomenon has generated changes in the behaviour of the agricultural system, which are manifesting themselves in the form of erosion, salinization, and a general decline in soil quality, leading to the abandonment of farmland. ...
... At present, Mexico is experiencing changes in temperature and precipitation, resulting in a 25% decrease in crop yields such as corn production. Comparable data have reported a decrease (100 mm year -1 ) and an increase (2000 mm/year), in precipitation in the north and south of the country respectively, during the period of 1901-2009(Murray-Tortarolo et al., 2018. Additionally, significant losses of 45 and 83 mln t of corn and soybeans have also been reported in the United States due to severe drought during 2012 (Rodríguez-Calzada et al., 2019). ...
Article
Drought stress has serious repercussions for agriculture, affecting crop growth with low yield effects concerning food production and food security. The main objective of this research is to conduct a scientific literature review of the physical methods used to generate tolerance to water stress in crops. (i) The most widely applied physical method to counteract the effects of drought stress is UV radiation, magnetic field application (18%), He-Ne and CO2 laser (18%), gamma radiation (9%) and plasma (6%). (ii) Treatments with ultraviolet light and magnetic fields have been applied mainly in cereals, vegetables, legumes, medicinal plants, and trees. Also, He-Ne, CO2 laser, and plasma in seeds in cereals and medicinal plants in the pre-sowing stage to seed level. Finally, gamma radiation has been applied to plants and seeds (grass, flowers, sugar plant). (iii) The reported physical methods can increase or decrease the biochemical variables under water stress depending on the physical method and radiation parameters applied, as well as the crop, level of drought and the environment in which the plants develop. Thus, UV radiation, magnetic fields, gamma radiation, and He-Ne and CO2 lasers are physical methods that produce seed and plant improvement effects
... Such studies use biophysical crop models that provide gross estimates of changing yields (Howden et al., 2007;De Salvo et al., 2013;Rosenzweig et al., 2014). Climate change scientists have analyzed the impacts of climatic variables over rainfed maize in Mexico (Murray-Tortarolo et al., 2018;Ureta et al., 2020), while others have explored the linkage between institutions, climate risk, and vulnerability of maize production (Eakin et al., 2018). Although these studies are useful to identify coarse trends and impacts of climate change on maize production, they do not consider the diversity of the socio-ecological contexts which can affect their risk. ...
... The general overall climatic ranges for maize included 0 to 2,900 m altitude, 11.3 • to 26.6 • C annual mean temperature, 12.0 • to 29.1 • C growing season mean temperature, and 426-4245 mm annual rainfall (Ruiz-Corral et al., 2008). However, it seems that rainfed maize are strongly correlated to annual precipitation and precipitation seasonality (Challenger, 1998;Murray-Tortarolo et al., 2018). The RF models identified that annual precipitation was the second most important predictor in rainfed maize yields (Supplementary Figure 3). ...
... low yields (<3.0 ton/ha) which will reduce by climate change (Murray-Tortarolo et al., 2018). To overcome the climatic challenges for the agricultural sector in the north of Mexico, farmers have implemented irrigation management to grow animal feed crops such as sorghum and wheat, leaving staple foods production to the southern and central Mexico (Eakin et al., 2014b). ...
Article
Full-text available
Evidence suggests that climate change could drastically reduce Mexico's agricultural productivity with severe socio-ecological consequences. Population growth and the increasing demand of resources will exacerbate these impacts. Focusing on rainfed maize production, we evaluate the socio-ecological risk that municipalities currently face and how climate change could modify it. Municipalities were classified based on their biophysical and socioeconomic traits like temperature, precipitation, population, gross domestic product, marginalization, and agricultural subsidies. The study identifies municipalities that would face higher risk under climate change conditions, and it evaluates whether increases in agricultural subsidies could be effective for reducing the farmers' future risk. Our results show that during the 2010's, 36.8% of the municipalities and 15% of the population were at very high and high risk, respectively. By 2070, under a high-warming scenario these figures increase to 56.5 and 18.5%. We find that a generalized augment in agricultural subsidies is not enough to compensate for the effects of climate change on the socio-ecological risk of rainfed maize producers. We suggest that transformative adaptation is required for managing the agricultural risk that socio-ecological systems experience under climate change conditions. Such adaptation strategies should include poverty alleviation, promotion of resistant and native varieties of crops, capacity building to improve management and water use, sustainable technification, and soil restoration.
... Una constante en los resultados es considerar el maíz como recurso indispensable para la seguridad alimentaria mexicana (Donnet, Becerril, Black, & Hellin, 2017;Langner et al., 2019;Murray-Tortarolo, Jaramillo, & Larsen, 2018;Novotny et al., 2021). Mientras que otros se enfocan en la producción pecuaria como solución a la falta de seguridad alimentaria en el país (Ibarra, Sánchez Vargas, & Martínez López, 2013;Nicholson et al., 2021;Velázquez, 2017). ...
... Así mismo, considerar el cambio climático en temas de seguridad alimentaria es indispensable, ya que gran parte de la producción de alimentos depende enteramente de los cultivos de secano, que a su vez dependen de la variabilidad de las precipitaciones y cambios en las temperaturas (Bee, 2014;González-Marín, Moreno-Casasola, Castro-Luna, & Castillo, 2017;Murray-Tortarolo et al., 2018); Munang, Thiaw, & Rivington, 2011). ...
... Moreover, rainfed agriculture is closely related to food security in developing countries such as India, where 70% of the population depends on such agriculture (Ramirez-Cabral et al., 2017;Reddy & Syme, 2014). In Mexico, 59% of the rainfed agricultural land is devoted to maize, and at least 50% of this area is for self-consumption providing the main nutritional base for about 20 million people (Murray-Tortarolo et al., 2018). Observed trends in climate during the period 1980-2008 have already produced decreases of approximately 5% in maize and wheat production at the global scale, while the global rice production has remained stable because regional decreases and increases largely offset each other (Lobell et al., 2011). ...
... While the literature has shown that endogenous economic responses to climate change effects on agricultural productivity and the availability of new harvest areas can limit changes in consumption and yield loss, prices can significantly increases in response to yield reductions which negatively affects consumer welfare . Moreover, the large spatial heterogeneity in the effects of climate change on agriculture revealed by the results, in combination with the socioeconomic conditions in some countries, could affect food security at the local and country level scales (Murray-Tortarolo et al., 2018;Ramirez-Cabral et al., 2017;Schlenker & Lobell, 2010). ...
Article
A main channel through which climate change is expected to affect the economy is the agricultural sector. Large spatial variability in these impacts and high levels of uncertainty in climate change projections create methodological challenges for assessing the consequences this sector could face. Crop emulators based on econometric fixed-effects models that can closely reproduce biophysical models are estimated. With these reduced form crop emulators, we develop AIRCCA, a user-friendly software for the assessment of impacts and risks of climate change on agriculture, that allows stakeholders to make a rapid global assessment of the effects of climate change on maize, wheat and rice yields. AIRCCA produces spatially explicit probabilistic impact scenarios and user-defined risk metrics for the main four Intergovernmental Panel on Climate Change’s (IPCC) emissions scenarios.
... The lateral acceleration can be expressed using Newton's second law in terms of the lateral tire forces: = 1 ( , ( , , ) + , ( , )) (8) Lateral force can be defined using the well-known magic formula [30]: ...
... Lateral force can be defined using the well-known magic formula [30]: ...
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In this study, a low-cost proposed platform for training dynamics (PPTD) is proposed based on operational amplifiers to understand the dynamics and variables of the agricultural tractor John Deere tractor model 4430 to gain autonomy and analyze the behavior of control algorithms proposed in real time by state feedback. The proposed platform uses commercial sensors and interacts with the Arduino Uno and/or Daq-6009 board from National Instruments. A mobile application (APP) was also developed for real-time monitoring of autonomous control signals, the local reference system, and physical and dynamic variables in the tractor; this platform can be used as a mobile alternative applied to a tractor in physically installed form. In the presented case, the PPTD was mounted on a John Deere tractor to test its behavior; moreover, it may be used on other tractor models similarly as established here. The established results of this platform were compared with models established in MATLAB, validating the proposal. All simulations and developments are shared through a web-link as open-source files so that anyone with basic knowledge of electronics and modeling of vehicles can reproduce the proposed platform.
... * * * Water, too much of it and especially not enough of it, embodies the climate threat to Mexican maize production. The drought conditions caused by the El Nino of 1998 knocked a quarter of the annual harvest, while the wetter more humid years of 1991 to 1993 provided bumper crops [15]. The region of Chiapas and its indigenous farmers in southern Mexico are no strangers to such variability. ...
... However with further growth in global emissions, and warming of 4 degrees Celsius or more [19], most states are predicted to experience much drier conditions and precipitous drops in maize yields. For some, including Chiapas, it would spell disaster-yields there could drop by a famine-inducing 80 per cent [15]. ...
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In the US alone, over 85 million maize tortillas are eaten each year in everything from wraps and sandwiches to pizzas and lasagnes, and that’s before all our snacking on tortilla chips is added in. While Central America is its birthplace, the US, China and Brazil are now the big maize producers—together they produce two-thirds of the global harvest. One snack bag of tortilla chips has a climate footprint of around 50 grams of greenhouse gas emissions. Even with transatlantic shipping, this footprint largely comes from growing the maize in the first place. In the UK each year we throw away an estimated 23,000 tonnes of savoury snacks, including tortilla chips. Water, too much of it and especially not enough of it, embodies the climate threat to maize production. Attack by pests and diseases may increase, with a particular concern being a rise in fungal toxins, like aflatoxin, in human and livestock food. Improved plant health through soil water management, irrigation and new varieties can each give greater resilience. Supporting maize types and cultivation practices that are specifically aligned with local contexts emerges as a core requirement of climate-smart practice.
... This is particularly the case in Mexico and Mesoamerica, where maize is the basis of human nutrition, and approximately 78.4 % of maize cropping depends on rainfall as the main source of water (SIAP 2019). Cropping practices may mitigate the impact of climate change on food security, however, few studies have analysed how variations in agricultural practices influence microclimate within the crop area, and thereby the physiological performance of the maize plant (Murray-Tortarolo et al. 2018). Such studies are necessary for a better understanding of the ecological and functional dynamics within regional maize crop systems. ...
... There is therefore scope for a better understanding of the physiological response of maize to microclimatic variations as a result of different agricultural management systems. Studies in this regard are useful for designing strategies that contribute to reducing the negative effects of climate change on maize yield (Xu et al. 2017) in small-scale management systems, particularly in rainfed conditions, and whose food security is severely threatened by climate modifications (Nigh & Diemont 2013, Murray-Tortarolo et al. 2018. ...
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Background: Maize is cultivated under different agricultural management systems, which influence the ecological dynamics of the crop, and therefore the physiology of the plant. Questions: What is the effect of different agricultural management on the microclimate and the physiology of maize plants? Studied species: Zea mays L. Study site and dates: Nacajuca, Tabasco, Mexico; January to April 2017. Methods: Physiological performance of maize plants and microclimatic variation in the crop area was characterized under three management systems: maize monoculture, maize-bean, and maize-bean-squash intercropping. Each treatment was established in three 100 m2 plots (300 m2 per treatment). Four measurements were taken between days 33 and 99 after maize sowing, to characterize five microclimatic parameters (relative air humidity, air and soil temperature, vapor-pressure deficit and soil volumetric water content) and nine physiological parameters (photosynthesis, transpiration, water use efficiency, stomatal conductance, electron transport rate, quantum efficiency of photosystem II, non- photochemical quenching, foliar water potential and chlorophyll content). Results: Maximum soil temperature was up to 4.4 ºC less in the maize-bean system than in the monoculture at 15:00 h; soil in the maize-bean-squash intercropping retained up to 45 % more water than the monoculture throughout the day. Photosynthesis and electron transport rate in the maize-bean intercropping was up to 32 % higher than in the monoculture. The highest non-photochemical quenching and transpiration rate were observed in the maize-bean-squash system. Conclusions: The maize-bean and maize-bean-squash combination provides maize plants with lower soil temperature and higher water availability, allowing them better physiological performance compared to monoculture.
... The findings of lower consumption of unprocessed foods associated with decreases in rainfall may be driven at least in part by lower production of grains at lower precipitations. Rainfall is one of the most important factors for the growth of cereals, as already observed in studies in Mexico and other countries (25)(26)(27)(28)(29). Specifically, rainfed corn is a fundamental component of agriculture in Mexico and a staple food among Mexicans (11,28,30); corn tortilla, a minimally processed food, represented 20% of TEI among adults in 2012 (11). ...
... The findings of lower consumption of unprocessed foods associated with decreases in rainfall may be driven at least in part by lower production of grains at lower precipitations. Rainfall is one of the most important factors for the growth of cereals, as already observed in studies in Mexico and other countries (25)(26)(27)(28)(29). Specifically, rainfed corn is a fundamental component of agriculture in Mexico and a staple food among Mexicans (11,28,30); corn tortilla, a minimally processed food, represented 20% of TEI among adults in 2012 (11). Lower production of grains, such as corn, can, in turn, lead to lower availability and higher food prices and, therefore, lower consumption of these types of unprocessed or minimally processed foods (31,32). ...
Article
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Background: Little is known about the potential impact of climate change on food systems and diet. We aimed to estimate the association of changes in rainfall and temperatures with consumption of unprocessed and processed foods among residents of Mexican cities by climate region. Methods: We analyzed 3,312 participants of the 2012 Mexican National Health and Nutrition Survey with dietary intake and sociodemographic information linked to historical rainfall and temperature data collected by the Mexican National Weather Service. We classified foods as unprocessed, processed, or ultra-processed. We performed multilevel linear regression to estimate the association of annual change in rainfalls (for each 0.5 mm decrease) and temperatures (for each 0.1 • C increase) at municipality level over the past 5 years with consumption of processed and unprocessed foods measured as the contribution to total energy intake. We investigated whether associations differed by climate region (tropical, temperate, and arid). Results: Each 0.5 mm annual decrease in precipitation was associated with lower consumption of unprocessed foods and higher consumption of ultra-processed foods [mean differences in percent contribution to total energy intake −0.009% (95% CI: −0.019, < −0.001) and 0.011% (95% CI: 0.001, 0.021), respectively]. Each 0.1 degree Celsius annual increase in temperature was also associated with lower consumption of unprocessed and higher consumption of ultra-processed foods [mean differences in percent contribution to total energy intake was −0.03 (95% CI: −0.05, −0.01) and 0.03% (95% CI: <0.01, 0.05)]. When stratified by climate region these associations were only observed in tropical regions. Conclusions: Decreases in rainfalls and increases in temperature were associated with lower consumption of unprocessed foods but higher consumption of ultra-processed foods, especially in tropical regions. Previous studies have established how food López-Olmedo et al. Climate Trends and Food Consumption production affects the climate, our study suggests that climate change could, in turn, reinforce modern food production, closing a vicious circle with clear negative implications for planetary health.
... The impact of droughts will have a disproportionate impact on low-income, marginalized groups, who also have limited capacity to fund climate adaptation initiatives. For example, maize, a staple crop for small farms in Central America, is generally grown under rain-fed conditions and is therefore highly vulnerable to changes in precipitation ; rainfed maize production is closely correlated with precipitation (Murray-Tortarolo et al., 2018). In northeast Mexico, agricultural yield is predicted to decrease by 30% under some emissions scenarios (Murray-Tortarolo et al., 2018). ...
... For example, maize, a staple crop for small farms in Central America, is generally grown under rain-fed conditions and is therefore highly vulnerable to changes in precipitation ; rainfed maize production is closely correlated with precipitation (Murray-Tortarolo et al., 2018). In northeast Mexico, agricultural yield is predicted to decrease by 30% under some emissions scenarios (Murray-Tortarolo et al., 2018). It is important to prepare for droughts and prevent land degradation, which is more cost-effective than responding to extreme events and restoring land after it has degraded (Mirzabaev et al., 2019). ...
... In terms of water availability, worldwide climate change generates alterations of global hydrological patterns (Murray-Tortaloro et al. 2018), modifying rainfall amounts, river discharges, drought frequency, and intensity and increasing the dry season length. Hence, Mutiibwa et al. (2018) described that warming air temperature, water availability, and elevated CO 2 emissions are negative projections in current and future yields in agriculture and cattle. ...
Article
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Global warming has produced negative effects in all life aspects around the world. Particularly, in terms of agriculture, the rainfall variability causes lower water availability, having unfavorable yield effects in all the crops. Temperature increases and rainfall reduction have resulting decreases in agricultural production and infertility. These issues, combined with the constant population growth, predict a severe food security problem for the next decades. In recent years, natural disasters are more frequent and dangerous as the result of global warming. Droughts, freezing, and flooding are the problems with the highest impact on the food supply chain, particularly in low-income communities, increasing the lack of access to food and undernourished problems, resulting in human casualties. This paper presents a response analysis of the food supply chain network in 14 municipalities of the state of Michoacán in Mexico; these municipalities are the ones with the lowest human development index values, joined to malnutrition problems. Natural disasters such as freezing, flood, and drought were considered and used to measure their impact on the food network through a mathematic optimization model, obtaining food system behavior to these difficulties. In the addressed case study, as a consequence of natural disasters, the total cost of the food network increases fifteen times to obtain a resilient system. The proposed approach is general, and this can be applied to other cases.
... Over extraction of groundwater, which comprises about one-third of all irrigation water, and low irrigation use efficiency is a widespread problem (Sun et al., 2016). Still, while access to irrigation expanded in some areas during the last decade of the twentieth century (Eakin, 2003), most Mexican smallholders lack access to irrigation and depend exclusively on precipitation-based, rainfed systems (Cohen et al., 2014;Murray-Tortarolo et al., 2018;Spring, 2011). At the same time, larger farms in Mexico's extensive northern irrigation districts frequently receive water from both surface and subterranean sources (Lobell et al., 2005;Wilder, 2010). ...
Article
Farmland size is a key factor in debates over agricultural land use, food security, agrochemical pollution, and the future of smallholder systems. This paper examines relationships between farmland size, chemical fertilizers and irrigation management, and maize and wheat yield in Mexico. We used agricultural census data to estimate the mean farmland areas and crop yields of 5.5 million farms and nine million agricultural plots in 2,455 Mexican municipalities. We also derived indices of socio-environmental and management factors to examine relationships with yield. Using multiple regression models, we found that although mean farmland area positively relates to maize and wheat yield, the relationships depend critically on the management contexts of chemical fertilizers and irrigation, which vary widely across farm size gradients. Smallholder yield gaps were associated with deficits in irrigation, rather than chemical inputs. Findings highlight the growing need for expanded irrigation access and/or water management assistance for smaller farms.
... 400). CC will reduce the yields and productions of the main staple crops such as rice (Akinbile et al., 2015;van Oort & Zwart, 2018), wheat (Trnka et al., 2019) and maize (Davenport et al., 2018;Freduah et al., 2019;Murray-Tortarolo et al., 2018;Waha et al., 2013), CC is also predicted to affect livestock productivity (Godber & Wall, 2014;Mare et al., 2018;Naah & Braun, 2019). Ramasamy (2010) put that "Rising temperatures, more intense droughts, floods, and greater weather variability all mean productivity losses to crops and livestock" (p. ...
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Climate change is one of the most pressing challenges facing humanity in the Anthropocene era. It is widely admitted that climate change will have far-reaching impacts including on food security. Therefore, this review paper analyses the multifaceted relations between climate change and food security. In particular, the paper explores the impacts of climate change on the four dimensions of food security (i.e. food availability, food access, food utilization, stability). It draws upon a review of scholarly literature indexed in the Web of Science. The analysis of the literature shows that there is a dual relationship between climate change and food security; on the one hand, climate change affects all the dimensions of food security and, on the other hand, the quest for food security has implications in terms of climate change. As for food availability and supply, climate change is widely believed to reduce crop yields and livestock productivity especially in the countries of the Global South. Effects on food production and availability as well as the impacts of extreme climate events affect both food physical and economic accessibility. The changes in production systems induced by climate change may induce changes in dietary patterns and food utilization. Climate change will also affect the stability and resilience of food systems with consequences in terms of long-term food security. Moreover, the quest for food security, through agricultural intensification and agricultural land expansion, increases greenhouse gas emissions from deforestation and land use changes. The intricate relation between climate change and food security makes the case for integrated policies that maximise co-benefits while addressing trade-offs. That is fundamental to make sure that ‘climate action’ will not jeopardize the achievement of ‘zero hunger’ and vice-versa.
... In a previous study, we established a positive relationship between the rainfall anomalies and changes in maize yields in Mexico (Murray-Tortarolo et al. 2018); however, to our knowledge, the risk that extreme weather events pose to cattle and other forms of freeranging livestock in the country has not been assessed. An example of a recent extreme weather event in Mexico was the 2011-2012 drought, one of the worst in the past 70 years. ...
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Extreme weather events represent a large risk to food production systems. In this study, we evaluated the impacts of the 2011–2012 drought in Mexico, the worst in the last 70 years, on free-ranged livestock populations to link extreme weather events and production. We also considered the potential prevalence of recurring droughts under two contrasting future climate scenarios to examine what could happen over this century. Our results showed that cattle and goat stocks decreased about 3% in response to the drought countrywide. Regionally, the changes in cattle and goat populations generally mimicked the precipitation anomaly, with the strongest reductions across the driest areas in central and northern Mexico. Our work showed that the biophysical and management components of livestock production interact depending on the regions and the type of livestock, leading to a mosaic of spatial responses. It seems that the management of large herds limits the economic viability of drought crisis management options such as the importation of fodder and water, or by moving the animals to other pastures. Sheep herds were much less affected since more than 50% of the total sheep stock is raised in wetter states, which showed a relatively small (~ − 10%) precipitation anomaly during the drought. Under the severe climate change scenario, a greater frequency of extremely dry years (once every 3 years) would have negative impacts on livestock production regionally. Climate change together with already existing trends in overgrazing and soil erosion could further increase the sensitivity of livestock production across the country. Graphical abstract
... The current literature provides some evidence on the potential impacts that climate change and extreme weather events can have for human populations in Mexico. Climate change has the potential to reduce agricultural production (Conde et al. 2006;Guerrero 2013;Murray-Tortarolo et al. 2018) and land values (Mendelsohn et al. 2010). It could also reduce local employment, increase migration from rural areas (Jessoe et al. 2017), and negatively affect human health (Guerrero 2013). ...
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Climate change could increase the frequency and duration of droughts that affect Mexico. This is particularly worrisome because many agricultural communities in the country are poor and with limited capacities for adaptation. This study estimated the impact of droughts on rural households’ wellbeing in Mexico, specifically on per capita earnings, poverty, and children’s school attendance. To do this, we focused our empirical analysis on the effects of the 2011 drought, one of the worst droughts that have affected Mexico in the past 70 years. Our results provide clear evidence that droughts have a negative impact on rural households’ wellbeing. Households that experienced a drought had lower per capita earnings and were almost 5 percentage points more likely to be poor after the drought than their counterparts. Furthermore, droughts reduced female employment and male school attendance in almost three percentage points. Our results also provide indirect evidence showing that households that are less familiar with relative water scarcity are the ones that are hit hardest during droughts. Droughts are poised to become an additional threat to the wellbeing of rural Mexican households.
... Our findings on the negative impact of climate change (assessed based on the dynamics of the representative CWB index and of its constituting parameters P and ETo) on agricultural systems (maize crops) in Romania are consistent with international studies that confirm, either directly or indirectly, the vulnerability of numerous major agricultural crops to climate change across the globe. Thus, there are various specialized studies that addressed the negative impact of climate change (assessed based on a wide series of climatic parameters and indices) on maize agrosystems in various countries around the world, such as Argentina (Verón et al., 2015), Mexico (Murray-Tortarolo et al., 2018), United States (Basche et al., 2016), South Africa (Adisa et al., 2018, Iran (Karandish et al., 2017), India (Tesfaye et al., 2017) or China . In Europe, the impact of climate trends on agriculture indicated, over the past decades, a large heterogeneity across the countries of the continent, with yields reduction (maize and other major crops) in the Mediterranean area and increased yields in northern areas (Moore and Lobell, 2015). ...
... In spite of the contribution to the environment, this way of farming has the disadvantage of being completely dependent on consistent rainfall, temperate weather, and predictable season cycles (Henderson, 2019). For this reason, since 1981 (the first report of CLR), coffee growers along with the government have been working together with the aim to adapt arabica cultivars (Murray-Tortarolo et al., 2018); however, it is becoming increasingly difficult since the optimal germination temperature of HV is above 24°C and the optimal cultivation temperature of Coffee arabica ranges between 18 and 21°C. This rapid adaptability has made useless the efforts to control the epidemic and production losses of at least 30% are becoming more frequent (Medina-Meléndez et al., 2016). ...
Article
Coffee is one of the most important commercial traded commodities in the international market, as well as the most popular beverage around the world. In Mexico, organic coffee cultivation (specifically, Arabica coffee crops) is a highly demanded that generates up to 500,000 employments in 14 federal entities. Among various coffee producers, Chiapas, Veracruz, and Oaxaca are responsible of 80% of the total coffee production in the country. Currently, Mexico is the leading producer of organic coffee in the world. However, there have been a slow recovery due to the large production losses since 2012, caused by earlier and highly aggressive outbreaks of coffee leaf rust (CLR), in the country, where the infectious agent is known as Hemileia vastatrix (HV). This phenomenon is becoming frequent, and climate change effects could be the main contributors. This spontaneous proliferation was generated in Mexico, due to the precipitation and temperature variability, during the last decade. As result, in Mexico, the biological interaction between coffee crops and their environment has been harmed and crucial characteristics, as crop yield and quality, are particularly being affected, directly by the negative effects of the greenhouse phenomenon, and indirectly, through diseases as CLR. Therefore, this review discusses the contribution of climate change effects in the early development of CLR in Mexico. The focus is also given on possible schemes and actions taken around the world as control measures to adapt the vulnerable coffee varieties to tackle this challenging issue.
... Historical information shows that this vegetation had altitudinal or geographical shifts as a result of the climatic fluctuations occurred in the Southern and Northern hemispheres during the Quaternary (Betancourt et al., 1990;Markgraf et al., 1995), which emphasize its vulnerability to the increase of temperatures and the intensity and duration of droughts. Currently, an increase of severe droughts in Mexico has been documented for the last two decades (Cruz, 2011;Neri and Magaña, 2016;Murray-Tortarola et al., 2018). ...
... It therefore plays an important role in meeting the needs of a growing population and ensuring food security (Biradar et al., 2009;Doll and Siebert, 2002;Postel et al., 1996). Climate change impacts are predicted to be harmful for rainfed agriculture in regions such as Mexico, China, India, Thailand, Spain, and other regions, which will face future yield reductions of up to 30% (Hernandez-Ochoa et al., 2018;Murray-Tortarolo et al., 2018;Valverde et al., 2015). Intercropping is a traditional sustainable planting system having advantages of increased production (Gao et al., 2009;Gou et al., 2017a;Miao et al., 2016) and improved yield stability (Raseduzzaman and Jensen, 2017). ...
... Narrowly focused productivity-centered policies and programs have led to the prevalence of agricultural practices that favor soil loss, lower the percentage of soil organic matter and reduce overall soil quality in the long term (Ceccon, 2008;SEMARNAT, 2008;FAO, 2015). In turn, this compromises the resilience of rainfed maize production in the face of increasingly long canicule periods (Ruiz-Vega and Silva Rivera, 1999;Murray-Tortarolo et al., 2018). ...
Article
Green manures are a promising alternative for achieving the sustainable production of maize in the face of low soil fertility and increasingly long canicule periods, particularly in rainfed systems associated with the reproduction of local agrobiodiversity. However, it is necessary to investigate what are the advantages and disadvantages associated with different species of native and exotic pulse, as well as their overall contribution to the sustainable production of maize landraces. In order to do so, we followed the MESMIS method to assess five species of pulse (three native and two exotic) grown with maize in two plots with different soil conditions. This was done in the seasons of 2017 and 2018 the municipality of Villa de Zaachila, Oaxaca, a site with remarkable biological, agricultural and cultural diversity. A fully randomized complete block design was implemented with 11 treatments and three repetitions in the two plots. The output variables of the experiment were: land equivalence ratio, interspecific aggressiveness, content of soil organic matter, decomposition rate, plant survival rate and plant dry biomass. We also evaluated quantitative or qualitative indicators of cost, adaptability and contribution to food security. For all the possible maize-pulse combinations, except for one, polyculture outperformed maize and pulse monocultures. Exotic pulses ( Crotalaria junscens spp. and Dolicho lablab ) had a better performance in biomass, reincorporation of organic matter and possible nitrogen fixation, as well as greater resistance to drought in the second cycle. The native pulses ( Phaseolus vulgaris and Phaseolus coccineus ), however, had a greater acceptance and economic output and are important for the food security in our study site. Our results provide quantitative and qualitative elements to design combined schemes of green manures associated with maize that would help tackle current challenges regarding maize productivity, food security and response to climate change.
... Tradeoffs as a result of adaptation responses appear in the form of maladaptation and limitations, which potentially increase risks in the adaptation of another sector or exacerbate vulnerabilities. In Africa, Asia, and Latin America, maladaptation associated with the FEW nexus has been reported in response to climate-induced droughts resulting in intensive cultivation of marginal lands for food (Afriyie et al., 2018;Hummel et al., 2018;Olivares et al., 2017;Singh et al., 2018), decreased yields from rainfed-dependent agriculture (Murray-Tortarolo et al., 2018;Singh et al., 2018), poor irrigation schemes (Ticehurst & Curtis, 2018), and risks to the loss of livelihoods (Bele et al., 2014;Kronik & Verner, 2010;Villamayor-Tomas & García-López, 2017). On the other hand, adaptation synergies include co-benefits or opportunities that aid risk reduction in other areas or even address multiple vulnerabilities at once. ...
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Food-energy-water (FEW) systems are increasingly vulnerable to natural hazards and climate change risks, yet humans depend on these systems for their daily needs, wellbeing, and survival. We investigate how adaptations related to food, energy, and water vulnerabilities are occurring and what the global community can learn about the interactions across these adaptations. We conducted a global analysis of a dataset derived from scientific literature to present the first large scale assessment (n=1,204) of evidence-based FEW-related climate adaptations. We found that the most frequently reported adaptation to FEW vulnerabilities by continent occurred in Africa (n=495) and Asia (n=492). Adaptations targeting food security are more robustly documented than those relevant to water and energy security, suggesting a greater global demand to address food security. Determining statistically significant associations, we found a network of connections between variables characterizing FEW-related adaptations and showed interconnectedness between a variety of natural hazards, exposures, sectors, actors, cross-cutting topics and geographic locations. Connectivity was found between the vulnerabilities food security, water, community sustainability and response to sea-level rise across cities, settlements, & key infrastructure sectors. Additionally, generalized linear regression models revealed potential synergies and tradeoffs among FEW adaptations, such as a necessity to synergistically adapt systems to protect food and water security and tradeoffs when simultaneously addressing exposures to consumption & production versus poverty. Results from qualitative thematic coding showcased that adaptations documented as targeting multiple exposures are still limited in considering interconnectivity of systems or applying a nexus approach in their response. These results suggest that adopting a nexus approach to future FEW-related adaptations can have profound benefits in the management of scarce resources and with financial constraints.
... Our findings on the negative impact of climate change (assessed based on the dynamics of the representative CWB index and of its constituting parameters P and ETo) on agricultural systems (maize crops) in Romania are consistent with international studies that confirm, either directly or indirectly, the vulnerability of numerous major agricultural crops to climate change across the globe. Thus, there are various specialized studies that addressed the negative impact of climate change (assessed based on a wide series of climatic parameters and indices) on maize agrosystems in various countries around the world, such as Argentina (Verón et al., 2015), Mexico (Murray-Tortarolo et al., 2018), United States (Basche et al., 2016), South Africa (Adisa et al., 2018, Iran (Karandish et al., 2017), India (Tesfaye et al., 2017) or China . In Europe, the impact of climate trends on agriculture indicated, over the past decades, a large heterogeneity across the countries of the continent, with yields reduction (maize and other major crops) in the Mediterranean area and increased yields in northern areas (Moore and Lobell, 2015). ...
... In Mexico, given the high diversity of landraces, many maizes are grown close to their optimum environments. Climate change scenarios anticipate important changes in temperatures and precipitation throughout the country, especially for central Mexico, where the maizes considered in the present study were obtained (Diffenbaugh et al. 2015; de la Barrera and Orozco-Mart ınez 2016; Zhao et al. 2017;Murray-Tortarolo et al. 2018). This is an important threat for the conservation of such unique landraces adapted to specific conditions (Tollenaar et al. 1979). ...
Article
Maize is one of the most important crops in the world, particularly in Mexico where it was domesticated and is central to traditional cultures. The fall armyworm (Spodoptera frugiperda [J.E. Smith]), is a major pest that can greatly reduce production of this crop. Climate change also threatens maize production, as projections estimate an increase of fall armyworm outbreaks. For these reasons, (1) we assessed the changes in the S. frugiperda life cycle along a temperature gradient ranging from 23 °C to 31 °C, and (2) assessed the development of larvae feeding on two Mexican landraces and the responses of each landrace to herbivory under current and predicted climatic conditions; both assessments were conducted under laboratory conditions. Development was faster and each life cycle stage was shorter at higher temperatures. The effect of herbivory differed between the landraces; herbivory was more harmful for White Ranchero than for Yellow. As warmer and drier conditions are expected during this century, sowing appropriate maize landraces that can cope with herbivores under climate change could mitigate potential economic losses.
... The negative associations of temperature (<0.0001) and the slope of the terrain (0.045), as well as the positive association of precipitation (0.001), indicate that lower rainfall, high temperatures, and steep slopes constrain the area planted with maize. Given that under climate change temperature is expected to increase and precipitation to become more erratic, though not necessarily decrease, this indicates that maize production in Mexico could be heavily and negatively impacted by climate change (Murray-Tortarolo et al. 2018;Ureta et al. 2011Ureta et al. , 2020). The capacity of campesinos to adapt to these changes in temperature and precipitation will depend to a great extent on the genetic diversity present in their native varieties and their response to these new conditions (Bellon and van Etten 2014;Mercer and Perales 2010). ...
Article
Mexico is the center of domestication and a center for diversity of maize. Area planted with maize is the country’s largest agricultural land use, mostly planted by smallholder family farmers known as campesinos. They generally plant native varieties, saving and sharing seed by and among themselves, enabling the evolutionary processes that sustain and generate crop genetic diversity to continue today. Campesinos have been viewed as largely subsistence farmers generating limited maize surpluses. Here, we show that subsistence production is insufficient for explaining the quantity of maize they produce and the extent of the area they plant across Mexico. Our hypothesis is that beyond supplying their own consumption needs, campesinos collectively produce maize to respond to the demand of non-maize producing local consumers. We quantify the extent of subsistence versus surplus production among campesinos, showing that they produce more maize than would be needed to feed themselves and generate substantial surpluses. We test statistically the association between the area campesinos plant with maize across the country with socioeconomic variables that link their production to the demand by other consumers, and examine the implications of the results for the supply and conservation of native maize in the country. Our results suggest that maize trading linking campesinos to other consumers may be important and widespread, contributing to create additional incentives beyond self-consumption to plant native varieties from saved seed. We conclude that there are important opportunities for maintaining maize evolution under domestication at large scale by strengthening local maize markets.
... Not surprisingly, according to Appendini and Liverman [89] about 90% of total agricultural losses in the country are related to drought. The sensitivity of crop production to drought in Mexico has been further corroborated by a series of studies that found that rainfall variability is strongly correlated with aggregate production of maize-the most important crop of the country in terms of production and the staple of most rural and urban diets (see [90,91] for national scales, [92] for Oaxaca, and [93] for central Mexico). Although agriculture admittedly accounts for less than five percent of Mexico's Gross National Product, its high susceptibility to drought is a matter of social and political concern since it employs almost a fifth of the national workforce [6,94]. ...
Article
Drought is one of the most disruptive climatic extremes in Mexico. The country is particularly exposed to this phenomenon given its location in the tropics and subtropics. Furthermore, much of the population is highly vulnerable to drought effects. Enhancing drought preparedness in Mexico demands a holistic understanding of this climatic extreme. Here we review the causes, impacts, responses to, and future trends of drought in the country. Our work synthesizes both physical and social perspectives, focusing primarily on climatological and geographical research. Three overarching messages emerge from the existing knowledge: (1) drought has been a recurrent event in Mexico and is predicted to become more severe in coming decades as a consequence of global warming; (2) pervasive socioeconomic inequality in the country has produced a stark differentiation in drought impacts, with the smallholder sector being one of the most affected; and (3) the institutional framework focused on mitigating drought impacts remains highly fragmented and overall prioritizes alleviating rather than preventing disasters. Based on the review, we propose a set of general guidelines to steer public policy towards a more integrated management of drought risk, in which enhancing local adaptive capacities is considered essential.
... The negative associations of temperature (<0.0001) and the slope of the terrain (<0.0001) indicate that high temperatures and steep slopes constraint the area planted with maize, but not precipitation (0.777). Given that under climate change temperature is expected to increase and precipitation to become more erratic, though not necessarily decrease, indicate that maize production in Mexico could be heavily and negatively impacted by climate change (Murray-Tortarolo et al. 2018;Ureta et al. 2011Ureta et al. , 2020). The capacity of campesinos to adapt to these changes in temperature and precipitation will depend to a great extent on the genetic diversity present on their native varieties and their response to these new conditions Mercer & Perales 2010) which highlights the importance of maintaining maize evolution under domestication as an adaptive mechanism for campesinos to face climate change. ...
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Mexico is the center of domestication and a center for diversity of maize. Area planted with maize is the country’s largest agricultural land use, mostly planted by smallholder family farmers known as campesinos. Due to the large area they plant with saved seed from native varieties in a wide variety of environments across the country, maize evolution under domestication continues today at a very large scale and under a multiplicity of selection pressures. Campesinos have been considered mainly subsistence farmers. Here we show that subsistence production is insufficient for explaining the scale of the area they plant with maize and on which its contemporary evolution under domestication depends. Our hypothesis is that beyond supplying their own consumption needs, campesinos across Mexico collectively produce maize to respond to the demand of non-maize producing local consumers. Here we quantify the extent of subsistence versus surplus production among campesinos, showing that subsistence production cannot explain the scale of their maize cultivation. Then, we test statistically the association between the scale of maize cultivation and socioeconomic variables that link campesino production to the demand by other consumers and examine the implications of the results for the supply and conservation of native maize in the country. Our results suggest that maize trading linking campesinos to other consumers may be important and widespread. We conclude that there are important opportunities for maintaining maize evolution under domestication at large scale by strengthening local maize markets.
... Future climate projections predict a general decrease in precipitation across Mexico (Colorado-Ruiz et al. 2018), which could lead to new migratory peaks over the XXI century (Feng et al. 2010). Drought is expected to increase in intensity and recurrence, which could potentially impact crop yields and livestock populations (Murray-Tortarolo et al. 2018;Murray-Tortarolo and Jaramillo 2019), impoverishing the livelihood of many rural farmers across the country. Particularly, attention should be given to low-income farmers, to create a farming system capable of maintaining-or increasing-their living conditions while dealing with drought. ...
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Emigration from Mexico to the USA represents one of the largest current socioeconomic phenomena in the world. Climate, and particularly drought, has been identified as a key driver of peak migratory flows between the two nations. However, current existing studies are constrained by a reduced spatial scale (e.g., a single community or municipality) or a short time-window (e.g. <10 years), which limits our long-term nationwide understanding of the climate-migration relationship. To tackle this, we employed high-resolution (municipal-level) and long-term databases (1970–2009), which included nation-level interviews, border patrol apprehensions, and high-resolution precipitation. Our results showed that the decadal and maximum migratory fluxes in these four decades corresponded to years with low precipitation. In particular, the migration of low-income rural farmers tripled during drought, representing as much as a third of all historical migration. It is very likely that rural people were pushed to leave their lands as the result of strongly diminished rainfed agriculture and pastureland production, their main livelihood. Our results suggest that policy oriented to reduce the negative impacts of drought (such as livestock drought insurances and the provisioning of drought-resistant seeds), particularly to marginal farmers in arid ecosystems, could be an effective way to reduce current and future migratory peaks between Mexico and the USA. Graphical abstract
... In recent studies, Ray et al. (2019) and Gomez-Zavaglia et al. (2020) have stated that agriculture production is highly sensitive to climate change. Some other research studies have also arrived at the conclusion that climate change affects food production negatively (Fanzo et al. 2018;Murray-Tortarolo et al. 2018;Arora 2019;Aryal et al. 2019;Kehrberger and Holzschuh 2019). ...
Article
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Food production as global public goods depends upon many factors. This poses a risk to food safety as well as food prices. One of the most prominent factors that affects food production is climate change, which is mainly caused by carbon emissions. The knowledge of the impact of climate change on food production is important in terms of food policies and awareness regarding the issue. The purpose of this study was to empirically investigate the way in which climate change impacts edible food production in 12 selected countries as they had the highest carbon emissions during the 1995–2014 period. Unlike previous studies in the literature, we employ a food production index as an indicator of food production that does not include products such as coffee and tea, which are not nutritious. Further, we investigate the effects of climate change both statically and dynamically. We also do not focus on any specific country or food, as done by many studies in the literature. The results revealed that climate change adversely affects food production, with the production of edible food decreasing with the increase of climate change/carbon emissions.
... Narrowly focused productivity-centered policies and programs have led to the prevalence of agricultural practices that favor soil loss, lower the percentage of soil organic matter and reduce overall soil quality in the long term (Ceccon, 2008;SEMARNAT, 2008;FAO, 2015). In turn, this compromises the resilience of rainfed maize production in the face of increasingly long canicule periods (Ruiz-Vega and Silva Rivera, 1999;Murray-Tortarolo et al., 2018). ...
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In agricultural landscapes, management practices and other environmental and social factors shape complex agroecological matrices. In turn, the structure of such matrices impacts both agricultural activities and biodiversity conservation, for instance, by mediating wildlife migration between agricultural and habitat patches. One way to characterize a matrix, its potential role in biodiversity conservation, and how its descriptors change across different spatial scales, is characterizing heterogeneity metrics and systematically examining how such metrics change with grain size and landscape extent. However, these methods have rarely been applied to tropical, peasant-managed landscapes, even though this type of landscape occupies most of the agricultural surface in or near biodiversity hotspots. We focus on a peasant-managed agricultural landscape in Oaxaca, Mexico, for which we mapped and quantified the land-use classes and evaluated heterogeneity metrics. We also examined the response of heterogeneity metrics to changes in grain and extent scales. This allowed us to further understand the structure and conservation potential of the agroecological matrix in this type of landscape, to broadly compare this landscape with other agricultural landscapes in North America, and to recommend specific landscape metrics for different types of studies involving agricultural matrices. We conclude that this type of agricultural matrix is ideal to pursue joint agricultural and conservation strategies in an integrated landscape.
... These physiological traits make these plants particularly vulnerable to suffer significant physiological and structural damages, and even plant mortality, under increasing temperatures and hydric stress [88]. In addition, the Mexical vegetation is highly sensitive to long drought episodes, which are expected to increase in duration and intensity, as documented in Mexico in the last two decades [89][90][91]. This vulnerability becomes especially relevant where the Mexical occupies the top of the mountains, unable to shift its distributional range upwards tracking more favorable conditions. ...
Article
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‘Mexical’ scrubland is a sclerophyllous evergreen Mediterranean-like vegetation occurring in the leeward slopes of the main Mexican mountain ranges, under tropical climate. This biome occupies an elevational range approximately from 1900 to 2600 meters above sea level, which frequently is the upper-most part of the mountains range. This puts it at risk of extinction in a scenario of global warming in which an upward retraction of this type of vegetation is expected. The Mexical remains one of the least studied ecosystems in Mexico. For instance, nothing is known about pollinator fauna of this vegetation. Our main objective is to make a first insight into the taxonomic identity of the bee fauna that inhabits this biome, and to study how it is distributed along the elevational gradient that it occupies. Our results highlight that elevation gradient negatively affects bee species richness and that this relationship is strongly mediated by temperature. Bee abundance had no significant pattern along elevational gradient, but shows a significant relationship with flower density. Interestingly, and contrary to previous works, we obtained a different pattern for bee richness and bee abundance. Bee community composition changed strongly along elevation gradient, mainly in relation to temperature and flower density. In a global warming scenario, as temperatures increases, species with cold preferences, occupying the highest part of the elevation gradient, are likely to suffer negative consequences (even extinction risk), if they are not flexible enough to adjust their physiology and/or some life-story traits to warmer conditions. Species occupying mid and lower elevations are likely to extend their range of elevational distribution towards higher ranges. This will foreseeably cause a new composition of species and a new scenario of interactions, the adjustment of which still leaves many unknowns to solve.
... Maize production in the rainfed regions of the world is projected to decline by 33.3% under drought conditions . Based on the global climate change scenario, many researchers are working on to validate the crop model and find out the suitable land for maize production (Ramirez-Cabral et al. 2017;Murray-Tortarolo et al. 2018). On drought escape, manipulation of planting date is a low-cost solution to address this issue depending on the precipitation forecasting during the rainy season (Kucharik 2008;Moradi et al. 2013;Baum et al. 2020). ...
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Drought has been identified as a major factor restricting maize productivity worldwide, especially in the rainfed areas. The objective of the present study was to investigate the physiological adaptation strategies and sugar-related gene expression levels in three maize (Zea mays L.) genotypes with different drought tolerance abilities (Suwan4452, drought tolerant as a positive check; S7328, drought susceptible as a negative check; Pac339, drought susceptible) at the seedling stage. Ten-day old seedlings of maize genotypes were subjected to (i) well-watered (WW) or control and (ii) water-deficit (WD) conditions. Leaf osmotic potential of cv. S7328 under WD was significantly decreased by 1.35–1.45 folds compared with cv. Pac339 under WW, whereas it was retained in cv. Suwan4452, which utilized total soluble sugars as the major osmolytes for maintaining leaf greenness, Fv/Fm, ΦPSII, and stomatal function (Pn, net photosynthetic rate; gs, stomatal conductance; and E, transpiration rate). Interestingly, sucrose degradation (65% over the control) in cv. Pac339 under WD was evident in relation to the downregulation of the ZmSPS1 level, whereas glucose enrichment (1.65 folds over the control) was observed in relation to the upregulation of ZmSPS1 and ZmSUS1. Moreover, CWSI (crop water stress index), calculated from leaf temperature of stressed plants, was negatively correlated with E, gs, and Pn. Overall, growth characteristics, aboveground and belowground parts, in the drought-susceptible cv. Pac339 and cv. S7328, were significantly decreased (> 25% over the control), whereas these parameters in the drought-tolerant cv. Suwan4452 were unaffected. The study validates the use of leaf temperature, CWSI, Pn, gs, and E as sensitive parameters and overall growth characters as effective indices for drought tolerance screening in maize genotypes at the seedling stage. However, further experiments are required to validate the results observed in this study under field conditions.
... Furthermore, studies have revealed that farmers in the neighbouring south Asian countries largely depend on monsoon rain for meeting their irrigation water requirements (Prasanna 2014;Bhatta and Aggarwal 2015). Apart from Asia (Singh et al. 2014;Lassa et al. 2015;Loo et al. 2015), farmers in sub-Saharan Africa (Shimeles et al. 2018) and Latin America (Prager et al. 2016;Murray-Tortarolo et al. 2018) are also quite dependent on monsoon rains for farming. It has been reported that farmers in the developing countries of South Asia and Latin America are particularly vulnerable to the impacts of climate change due to their heavy reliance on agriculture for livelihood (Jat et al. 2016). ...
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Variability of rainfall pattern and its resulting issue of water shortage is a growing concern in Bhutan’s agricultural system. To assess the rainfall anomalies and the extent of farmers’ dependency on rainwater for farming, a semi-structured questionnaire survey was conducted in six districts of the country, covering low-, mid- and high-altitude agro-ecosystems. A point score analysis showed that most farmers (50% or more) depended on rainwater for farming activities. The extent of farmers’ dependency on rainfall across the districts was as high as 51%, except for Paro which had a lower dependency level of 10–20%. However, an overwhelming 40–80% of respondents had perception of decreased rain over the years, and the rainfall data for 20 years (1997–2017) showed a decreasing trend, reinforcing the survey findings. Moreover, up to 75% of respondents had perceptions of rain being untimely and unpredictable, including fewer incidences of short spells of high intensity or occasional prolonged periods of rains. The consequences of these issues were perceived to have caused (1) drying of water sources; (2) delay in planting; (3) erosion and infrastructure damage; and (4) work disruption. To overcome these issues, there is a need to overhaul Bhutan’s irrigation system, in terms of both infrastructure development and methods as aspired by farmers. The need of the hour for Bhutan is to reduce dependency on rains with state-of-the-art irrigation technologies to buffer against the changing patterns of rain and to improve farmers’ resilience to the impact of climate change.
... From the group of conical landraces of maize from the highlands of central Mexico, characterized by conical or pyramidal ears, the "conical cobs'' landrace, with semi-floury grains of reddish to purple or black coloration, has been used by generations for the preparation of traditional dishes and production of pigments (Jiménez-Pérez et al. 2015;Mora-Rochin et al. 2016). Frequently the production of maize in Mexico is affected by biotic and abiotic factors, such as, annual precipitation, frosts, use of agrochemicals (poor nutrient soils), pests and pathogen microorganisms (Murray-Tortarolo et al. 2018). ...
Article
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Mexican maize landraces, produced for local consumption, are adapted to different environmental conditions, and their yield is affected by abiotic and biotic factors, including the use of agrochemicals. The search for sustainable alternatives to agrochemicals includes the study of the culturable microbial communities. In this study, the fungal communities associated with 2 Mexican maize landraces reddish and bluish "conical cobs" were found to be comprised of Ascomycota fungi, represented by 89 strains within 6 orders (Pleosporales, Hypocreales, Onygenales, Capnodiales, Helotiales, and Eurotiales) and 16 genera. Cellulases and metallophores production were the primary enzymatic products and plant growth-promoting activities were detected among the isolates. Penicillium, Didymella, and Fusarium strains had the most active enzymatic and plant growth promoting activities, however, Aspergillus sp. HES2-2.2, Talaromyces sp. RS1-7, and Penicillium sp. HFS3-3 showed antagonistic activity against the four phytopathogenic Fusarium strains Fusarium oxysporum, Fusarium sambucinum, Fusarium fujikuroi and Fusarium incarnatum-equiseti and also a high and diverse production of enzymatic and plant growth promoting activities; here we identified fungal strains as candidates to promote maize growth.
... Between May and December, maize (Zea mays L.) is generally grown, and this may receive 1 or 2 furrow irrigations depending on the amount of rainfall in the particular growing season. Precipitation is projected to decrease under all climate change scenarios, which will increase the need for irrigation to maize production in the region (Murray-Tortarolo et al., 2018). There are several options for reducing water use in this barley-maize production system. ...
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The Mexican Bajío region is the country's main barley ( Hordeum vulgare ) producing area. Barley is commonly produced during the dry autumn–winter season using furrow irrigation with ground water, following which rainfed maize ( Zea mays ) is grown in the spring–summer season using supplementary irrigation. Ground water levels in the region are steadily dropping, and the introduction of water-saving technologies in agriculture is urgently required. Drip irrigation can reduce water use but is costly. Conservation agriculture—the combination of minimal tillage, permanent soil cover and crop diversification—might reduce water use, but studies in irrigated systems are scarce. We compared water use and grain yield in tillage-based conventional agriculture and conservation agriculture, both with furrow irrigation and drip irrigation, in a 3-year (six growing seasons) barley-maize field experiment. Additionally, side-by-side demonstrations of conventional and conservation agriculture were installed simultaneously in farmers' fields and yields, water use and fuel use were recorded. In the field experiment, yields did not differ significantly between production systems, but irrigation water use was on average 17% lower in conservation agriculture than in conventional agriculture, ~36% lower with drip irrigation compared with furrow irrigation in conventional tillage, and 40% lower with drip irrigation and conservation agriculture combined compared with conventional agriculture with furrow irrigation. Water use reductions differed strongly between years, depending on weather. The water saving through conservation agriculture in farmers' fields was similar to the water saving in the controlled experiment with about 17%. Additionally, in farmer's fields conservation agriculture reduced greenhouse gas emissions by 192 kg CO 2 ha ⁻¹ and improved soil health. The implementation of conservation agriculture would be a cost-effective method to reduce water use in the barley-maize production system in the Mexican Bajío, while simultaneously reducing greenhouse gas emissions.
... Maize occupies a prominent place among cereals and there is no other cereal that has such immense potential [2]. In terms of world-wide area, Brazil stands next to the USA, India, China and Mexico, while it ranks second to the US when it relates to production [3]. ...
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Conservation systems for less soil movement and when associated with previous crops may reduce the effects of soil compaction. The objective of this work was to evaluate soil mechanical resistance penetration (MRP) in different cropping systems associated with previous corn crop after fifteen years. The experimental design was composed of experimental strips with subdivided plots, combining three soils management systems: CC- conventional cultivation, MC- minimum cultivation and NT- no-tillage, and four species of crops antecedent to maize for the production of commercial ears of green corn. In the determination of soil MRP, the electronic penetrometer (FALKER model SoloTrack PLG 5200) was used, with readings up to a depth of 400 mm. The results showed that there was a significant effect on the MRP values of the soil when submitted to the different cropping systems and previous crops at the end of fifteen years. The lowest MRP values were located in the superficial layers in the CC and MC. The NT cultivar system showed higher MRP values, at depth 0-100 mm. At conditions of tableland, after fifteen years, it was observed that the NT system provides better corn productivity levels combined with lower MRP values along the profile.
... In Tamazulapam in 2017 or Teopoxco in 2019, the trees bore fruit in spring whereas the main crop failed in summer. Climate change is likely to increase the frequency of such growing seasons, especially in the south of Mexico maize yields are expected to decline under most climate change scenarios (Murray-Tortarolo et al., 2018;Ureta et al., 2020). Crop diversification would improve resilience of smallholder production under climate change and reduce the risk of overall crop failure (Donatti et al., 2019). ...
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The effects of climate change on crop and terrestrial food production are evident in several regions of the world (high confidence). Negative impacts of climate trends have been more common than positive ones. {Figures 7-2, 7-7} Positive trends are evident in some highlatitude regions (high confidence). Since AR4, there have been several periods of rapid food and cereal price increases following climate extremes in key producing regions, indicating a sensitivity of current markets to climate extremes, among other factors. {Figure 7-3, Table 18-3} Several of these climate extremes were made more likely as the result of anthropogenic emissions (medium confidence). {Table 18-3}.
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