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Transition from conventional to low-input agriculture changes soil fertility and biology
Abstract and Figures
Growers converting from conventional to low-input and organic farming systems must
rely on organic sources for adequate soil fertility. At the Sustainable Agriculture
Farming Systems (SAFS) project at UC Davis, we measured soil fertility and biological
parameters in four farming systems. By the end of the first 4 years, pH and percent
nitrogen were consistently higher in organic and low-input than conventional plots
for all crops. Levels of organic matter, phosphorus and potassium were significantly
higher in the organic than conventional 2-year plots. Microbial biomass levels were
consistently higher in organic and low-input systems, while plant parasitic nematode
numbers were consistently lower. Nitrogen deficiency appeared to be a problem in organic
tomatoes during the transition period. More research is needed into the dynamics of
soil nutrient availability in low-input systems. For instance, we may need to develop
new methods of assessing soil fertility in organically fertilized systems.
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... Earlier research on low-input production systems, was especially focused on agronomic aspects, often targeting organic production techniques. For example, to assess the sustainability of low-input practices some studies investigated into the soil biology and its microbial composition (e.g., Clark et al., 1998;Kong et al., 2011;Mäder et al., 2000;Scow et al., 1994) and others looked at the impact in terms of yields (e.g., (e.g., Clark et al., 1999;Liebhardt et al., 1989;Seufert, Ramankutty, and Foley, 2012). Economic research in this field addresses the differences between the low-input and high-input agriculture in terms of production and production risks (e.g., Gardebroek, 2006;Gardebroek, Chavez, and Lansink, 2010;Serra, Zilberman, and Gil, 2008), efficiency and performance (e.g., Acs et al., 2007;Lansink, Pietola, and Bäckman, 2002) as well as trade-offs with respect to the environmental performance (e.g., Seufert and Ramankutty, 2017;Seufert, Ramankutty, and Foley, 2012). ...
... The impact of low-input production practices on production and the environment is multifaceted. Low-input systems tend to be associated with higher levels of organic carbon, soluble phosphorus, exchangeable potassium and potentially mineralizable nitrogen as well as a higher soil pH (Clark et al., 1998;Scow et al., 1994) and also impact the soil microbial mass (Mäder et al., 2000;Scow et al., 1994). Such changes in soil composition and biology are critical for long-term fertility maintainance and allow for a reduction in chemical input use. ...
... The impact of low-input production practices on production and the environment is multifaceted. Low-input systems tend to be associated with higher levels of organic carbon, soluble phosphorus, exchangeable potassium and potentially mineralizable nitrogen as well as a higher soil pH (Clark et al., 1998;Scow et al., 1994) and also impact the soil microbial mass (Mäder et al., 2000;Scow et al., 1994). Such changes in soil composition and biology are critical for long-term fertility maintainance and allow for a reduction in chemical input use. ...
Cropping management practices is an agronomic notion grasping the interdependence between targeted yield and input use levels. Subsequently, one can legitimately assume that different cropping management practices are associated to different production functions. T o better understand pesticide dependence – a key point to encourage more sustainable practices – one have to consider modelling cropping management practices specific production functions.Because of the inherent interdependence between those practices and their associated yield and input use levels, we need to consider endogenous regime switching models. When unobserved, the sequence of cropping management practices choices is considered as a Markovian process. From this modelling framework we can derive the cropping management choices, their dynamics, their associated yield and input use levels. When observed, we consider primal production functions to see how yield responds differently to input uses based on the different cropping management practices. Thus, we can assess jointly the effect of a public policy on input use and yield levels.In a nutshell, in this PhD we are aiming at giving some tools to evaluate the differentiated effect of agri-environmental public policies on production choices and on the associated yield and input use levels.
... The role of the global soil for carbon emission and sequestration processes, in particular, are a key unknown factor in this global C balance (Lal et al., 2007) [12] . Carbon sequester is a stable process that has no effect on atmospheric chemistry, and absorbs ambient carbon dioxide (Miller et al., 2002) [13] . The discovery of viable sinks is therefore a top priority in order to sequestrate various passive C pools with a long residence period. ...
... The role of the global soil for carbon emission and sequestration processes, in particular, are a key unknown factor in this global C balance (Lal et al., 2007) [12] . Carbon sequester is a stable process that has no effect on atmospheric chemistry, and absorbs ambient carbon dioxide (Miller et al., 2002) [13] . The discovery of viable sinks is therefore a top priority in order to sequestrate various passive C pools with a long residence period. ...
... Another survey indicated that there was a significant increase in soil fauna diversity in fields under organic or "low-input" agriculture (El Titi and Landes 2020). A study conducted by Scow et al. (1994) on the impact of the agricultural strategy on soil pathogens and root rot showed an inferior density of R. solani in tomato (Solanum lycopersicum) plots that were grown organically in comparison to conventional fields receiving large amounts of inputs. ...
Sugar beet is an important sugar crop that supplies approximately 35% of the sugar in the world. Sugar beet root rot, caused by fungal pathogens, significantly reduces yield, juice purity, and sugar concentration. Studies have revealed that sugar beet root rot (SBRR) is mainly caused by soil fungi like Rhizoctonia solani, Sclerotium rolfsii, Fusarium spp., Macrophomina phaseolina, Aphanomyces cochlioides and Phytophthora spp. Given the wide host spectrum, the great influence by environmental conditions, and the resistant structures of fungi causing SBRR, the management of this disease which begins with invisible symptoms remains a difficult task. Therefore, further studies are needed to correctly identify the causative agents and to understand more about conditions and factors favoring disease incidence. This will greatly contribute to designing and adopting appropriate control methods to manage this economically important disease. Hence, this review concentrates on key symptoms and current advances in morphological and molecular means used for the precise designation of the fungus associated with SBRR, and control procedures designed to manage this disease in recent years. This work also exposes the new alternative approaches exploited to manage root rot in the context of sustainable sugar beet production.
... It is possible to encounter yield losses because, during this period, the use of chemicals and fertilizers is prohibited and the production system has just changed (İlbaş, 2009;Akgün, 2011). In their studies, researchers found that organic tomato growers faced some problems throughout the transition period due to nitrogen deficiency, that yield losses were encountered during the period due to nutritional deficiency and fight against plant diseases, and that wheat yield decreased by 23-65% in the transition period (Scow et al., 1994;Bruggen and Termorshuizen, 2003;Gopinath et al., 2008). Ünal et al. (2016) reported that, in Kocaeli in 2014, 4 of 12 growers in transition period ceased their activities and did not go into organic agricultural production. ...
Globally, agriculture is frequently impacted by climate change. Choosing the optimum cropping system and related farming techniques is crucial to implementing an agricultural production system that is both economical and environmentally friendly. One of the main agricultural systems and industries in the nation that has the potential to significantly sequester CO is coconut farming and the coconut agro-ecosystem. Only one state produces 2.11, 3.10, 2 and 3.96 tons per acre per year, which is Tamil Nadu. In Vellore district, coconut trees aged five, ten, fifteen, twenty, and twenty-five could sequester 1.48, 1.37, 1.78, 2.42, and 4.63 tons per acre per 365 days, respectively. The C-capture potential of a 10-year- old tall or dwarf coconut tree was roughly 18 to 28 kilograms per tree per year. The Vellore district's tall and dwarf coconut plantations, which spanned fifteen years from 2003–2004 to 2017–18, removed 1.15 million tons of carbon dioxide from the environment. This research mainly contributes to the utilization of carbon in increasing yield of coconut trees.
Growth in demand for organic small grains, coupled with persistently low prices in the conventional small grains market, has increased interest in producing certified organic crops in the semiarid Western U.S. The region is well-suited for organic small grains production due to the strong demand for organic food products exists on the U.S.’s West Coast, the climatic conditions that tend to produce high quality grains relative to wetter, more humid areas, and the benefits that certified organic practices can have for soil and environmental conservation in a region at high risk of damage from degradative conventional farming practices coupled with climate change. However, many producers encounter significant and persistent challenges with weed control and especially maintaining adequate nitrogen fertility due to poor legume performance and low access to manure-based organic amendments. In this paper, we present a review of the newly growing body of research literature working to expand certified organic agriculture in the semiarid West where small grains are the predominant cash crop, irrigation is rare, and soils are fertile but highly susceptible to erosion and degradation. We highlight progress made on market development; identification of crop rotations, fertility, and weed management practices that optimize productivity; and finally, highlighting pioneering work on new ecological management systems, including semiarid organic reduced tillage methods and intercropping. Our review reinforces the environmental- and economic-based need to grow organic small grains production in the semiarid West, while also identifying remaining challenges and research/development priorities.
The functioning of well-studied key groups of soil microorganisms depends on the microbial ecosystem in which they function in interaction with species belonging to other ecological groups. An analysis of the composition of the soil microbiota, and the possibility of analyzing the number of representatives of specific species, remains an urgent task of soil microbiology. Such analysis could be performed using modern and expensive methods such as metagenomics and mass-spectrometry, but some questions could also be answered using real-time PCR. This well-known approach is rather cheap for massive analysis and is ready to present reproducible results for practical agricultural applications. Understanding the variability of the primary structure of 16S rRNA is key to the reliable identification of bacterial species and provides an opportunity to choose the optimal pathways for their detection by PCR. In this work, analysis of the sequences of 16S rRNA of two species of soil bacteria, Acinetobacter lwoffii and Paenibacillus taichungensis is carried out. The most variable and most conservative areas on the level of species are detected. It was proved that conventional variable and conservative areas of the gene have on average nearly the same level of variability on the intraspecies level.
Sustainable alternative agricultural practices like organic farming have evinced interests due to public consciousness about food safety, environmental pollution, soil quality and human health. The study aimed to evaluate the productivity, soil quality, energetic and economic aspects under organic vs conventional management in cassava (Manihot esculenta Crantz). Field experiments were conducted over a three year period at ICAR-Central Tuber Crops Research Institute, Thiruvananthapuram, India in split plot design with three varieties of cassava, H-165, Sree Vijaya and Vellayani Hraswa, in main plots and five production systems, traditional, conventional, integrated and two types of organic (without and with microbial inoculants) in sub plots. Organic management (without microbial inoculants) (27.26 t ha⁻¹) produced insignificant yield increase (+2.40%) over conventional system (26.62 t ha⁻¹). The industrial (H-165) as well as domestic varieties (Sree Vijaya, Vellayani Hraswa) of cassava exhibited similar performance under the different production systems. At the end of the third crop, soil chemical properties like pH and organic C were significantly enhanced by 1.15 unit and 22.58% under organic (with microbial inoculants) over conventional system, whereas the soil porosity, cation exchange capacity and exchangeable Ca were significantly higher by 9.36, 27.32 and 29.10% in the organic (without microbial inoculants) over conventional. Besides, biological improvement of the soil with higher counts of bacteria, fungi and actinomycetes and greater activity of soil enzymes like acid phosphatase and dehydrogenase were also observed under organic (with microbial inoculants) system. Both the organic practices (without and with microbial inoculants) scored higher soil quality index (SQI) over the rest, but similarly (0.98 and 0.94 respectively). The soil pH, exchangeable Ca, dehydrogenase enzyme activity and porosity were the decisive factors that governed SQI in the present study. Organic system (without microbial inoculants) proved to be the most energy efficient as evidenced from the highest energy output (152.63 × 10³MJ ha⁻¹), net energy (143.55 × 10³MJ ha⁻¹), energy use efficiency (16.80) and energy productivity (3.00 kg MJ⁻¹). Organic system generated the highest net income (US $ 4977.57 ha⁻¹) statistically similar to conventional (US $ 4833.10 ha⁻¹) and organic with microbial inoculants (US $ 4720.69 ha⁻¹). Hence organic practices can be recommended for sustainable cassava production.
Conventional agriculture can lead to reduced soil organic matter and depletion in soil fertility. For that reason, Food and Agriculture Organization of the United Nations (FAO) recommends organic matter incorporation to soils to increase their agronomic quality. This work studies the effect of the transition to organic farming on chemical and biochemical properties of a loam soil (Xerofluvent), through a succession of five crops cycles over a 3‐yr period. Two mature composts (vegetal and animal compost) were used for the organic fertilization. Soil chemical and biological status was evaluated by measuring total organic carbon (TOC), humic acids, bicarbonate‐extractable P (Olsen‐P), ammonium acetate extractable‐potassium (AAE‐K), Kjeldahl‐N, microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), enzymatic activities (dehydrogenase, protease, glucosidase, alkaline phosphatase), soil respiration, MBC/TOC, and MBC/MBN ratios. At the end of the study, the organically fertilized soils showed an increase in quantity (TOC) and quality (humic acids) of organic matter compared to inorganically fertilized soils. Nutrient content (Kjeldahl‐N, Olsen‐P, and AAE‐K) also increased in organically fertilized soils. In general animal compost improved chemical and biological properties more than vegetal compost. Soil respiration was highly influenced by seasonal variability, and the highest values were found in summer. The MBC/TOC values indicated that microorganisms converted C to MBC more efficiently in conventionally fertilized soil. Protease and phosphatase activities differed between treatments after the third crop cycle, and the highest values were observed in organically fertilized soil. The TOC and nutrient content were correlated ( P < 0.001) with microbial biomass and enzymatic activities. Extracellular enzyme activities (protease, glucosidase, alkaline phosphatase) were found to be significantly and positively correlated with MBC and MBN.
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