Agricultural Systems

Description

Impact factor 2.50

  • 5-year impact
    2.84
  • Cited half-life
    8.00
  • Immediacy index
    0.52
  • Eigenfactor
    0.01
  • Article influence
    0.87
  • ISSN
    1873-2267

Publications in this journal

  • [Show abstract] [Hide abstract]
    ABSTRACT: New Zealand dairy farms are responsible for a large proportion of this nation's greenhouse gas emissions (GHG-e), arising mainly from enteric methane and urinary nitrogen deposition on pasture. De-intensification and the use of specific mitigation strategies can reduce GHG-e from dairy farms, but are generally costly. In this study, a farm-level model is used to analyse the cost of GHG-e mitigation strategies in medium- (10–20% imported feed) and high-input (20–40% imported feed) systems in the two major dairy regions of New Zealand (Waikato and Canterbury). Production intensity is measured solely in terms of feed importation, in accordance with standard practice in this nation. The focus of the study is to assess the cost-effectiveness of a variety of de-intensification and mitigation strategies aimed at reducing the negative impact of emissions constraints (reductions of 10, 20, and 30%) on farm profit. De-intensification options include changes in stocking rate, nitrogen fertiliser application, and supplement quantity. Mitigation options include feeding crops, improved reproductive management, use of feed pads, use of stand-off pads, and use of nitrification inhibitors. The model showed that a combination of reduced N fertiliser application and lower stocking rates were the larger changes experienced in the systems studied when GHG-e reductions were introduced. Nitrification inhibitors were only useful for mitigation once the GHG-e reductions required were so stringent that their cost was warranted to offset the significant costs associated with de-intensification in the high-input systems. Stand-off and feed pads were too expensive to warrant their use when not already available. Overall, de-intensification of the farming system proved to be more profitable than the use of specific mitigation practices when reduction of GHG-e was required. Maintaining a given intake of imported feed reduces the degree to which de-intensification may be used for abatement, thus inflating the cost of mitigation strategies on high-input farms.
    Agricultural Systems 05/2015; 135.
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    ABSTRACT: The cropping sector in Australia contributes 2.5% of national greenhouse gas emissions, not accounting for the historical loss of soil carbon. The Australian Government is developing policy initiatives targeted at farmers to encourage changes in management practices that aim to reduce emissions from the agricultural sector. The main policy proposal being developed is a market-based mechanism to pay farmers from an Emissions Reduction Fund using methodologies specified under the Australian Carbon Farming Initiative. The adoption of conservation agriculture practices in the dryland grain sector in Australia shows the potential to achieve emissions reductions in the order of three million tCO2e annually. This paper presents a series of systems models that describe the process of how Australian dryland grain farmers decide to change and adopt conservation agriculture practices. Results indicate that a number of economic and social factors drive the rate of practice change, and change seems to be motivated mostly by the pursuit of productivity benefits rather than environmental benefits. We postulate that it may be more effective for climate policy to directly target the adoption of conservation agriculture practices amongst Australian dryland grain farmers by promoting the crop productivity benefits likely to be achieved by such practices, rather than attempting to develop a market-based mechanism for carbon payments. Under this approach, emissions reduction outcomes and carbon payments would not be the primary driver for changing farming practices, but rather a concurrent benefit.
    Agricultural Systems 05/2015; 135.
  • Sophie Huysveld, Veerle Van linden, Steven De Meester, Nico Peiren, Hilde Muylle, Ludwig Lauwers, Jo Dewulf
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    ABSTRACT: Despite the great pressure on global natural resources, few LCA studies focus on total resource consumption and the efficiency of the use of those resources. Moreover, a total resource use assessment for agricultural systems is highly relevant because many of these systems have become high input/high output systems in order to achieve higher productivity. In this study, we propose a framework to evaluate total resource consumption of agricultural systems at the process level using an Exergy Analysis (EA) and at the life cycle level using an Exergetic Life Cycle Assessment (ELCA). We evaluate the applicability and usefulness of this approach based on a case study of an intensive confinement-based dairy farm in the region of Flanders, Belgium. The EA showed that more than half of the resources consumed by the dairy farm's herd was irreversibly lost, as a consequence of the second law of thermodynamics. The remaining went for almost two-thirds to manure (54%) and methane emissions (9%), while only one-third flowed to end-products, i.e. milk (32%) and the animals awaiting slaughter (2%). The ELCA identified the feed supply as the most demanding part of the dairy production chain by far, representing 93% of the resource footprint. Overall, concentrates were on average 2.5 times more resource-intensive per kg dry matter than roughages, while wet by-products were 34% and 73% less resource-intensive than roughages and concentrates, respectively. Mainly land (77%) and fossil resources (17%) were required throughout the life cycle. About 36% of the occupied land (in terms of m2*year) was located off-farm. Slightly less than one-quarter of the fossil resources were used on-farm as fuel and electricity. The on-farm use of groundwater accounted for about half of the total blue water use across the life cycle. With this paper, we show the usefulness of the proposed framework to evaluate total resource consumption of dairy farms and to identify on-farm and off-farm improvement opportunities. This framework has potential to support research on whole-farm improvement strategies such as pasture-based systems and low-input farming, and to compare populations of contrasting milk production systems.
    Agricultural Systems 05/2015; 135:77-89.
  • Agricultural Systems 12/2014;
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    ABSTRACT: Researchers advocate using conservation agriculture as a tool to improve farmer livelihoods, with crop residue retention being an integral component of conservation agriculture. Crop residues are used for mulch, livestock feed, and fuel material in crop-livestock farming systems. In this article, we conducted long-term simulation modelling to compare the economic effects of different crop residue retention practices for a crop-livestock agricultural household in semi-arid China. We calculated the average profit and net present value (and associated variability) of different crop residue retention practices using planning horizons of 3, 6, 10, and 20 years. Crop residue retention increased grain production, reduced forage production leading to smaller livestock flock sizes, and increased family heating and cooking costs. The net effect was that retaining minimal crop residues gave the highest profits using the three year planning horizon.
    Agricultural Systems 12/2014;
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    ABSTRACT: The annual net primary production (ANPP) of temperate grasslands and production of livestock industries is predicted to decrease in southern Australia with future climate change. By using biophysical modelling, we address productivity and profitability of grazing systems while considering systemic combination of grassland management and animal genetic improvement options. Single incremental adaptations will not completely avert declines in productivity and profitability; hence, combinations of adaptations are needed. The synergistic effects of these adaptations could potentially offset decreasing production and profit in 2030 over the majority of southern Australia, but not in some drier regions after 2030. These results demonstrate the need for changes in strategies over time with greater complexity of adaptations in drier regions. Upscaling over all southern Australia, financially optimal systemic combination (fully enhanced systems) could increase profit by 68.61%, 68.63% and 50.81% in 2030, 2050, and 2070, compared to the production of the historical period with current farm system management. Financially-motivated changes to grazing systems will result in improvement in grassland health, soil environment, and water use efficiency. However, full adaption of systemic adaptation will lead to greater ruminant CH4 emission from 70 kg ha−1 yr−1 in baseline (1970–1999) to 84, 83, and 75 kg ha−1 yr−1 in 2030, 2050, and 2070. Higher rates of CH4 emissions may affect profitability depending on future emissions pricing. In most of the drier regions, greater input intensity and management complexity may be required which requirement is likely to increase over time. However some of the drier regions would still require transformative adaptations.
    Agricultural Systems 12/2014; In press.
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    ABSTRACT: Information on irrigation indicators is needed to improve irrigation management. The objective of this paper is to assess the irrigation performance of the Gezira Scheme, Sudan. Data on climatic elements, irrigation water supply and crop yield for the period 1961–2010 integrated with remote sensing data from 2000 to 2014 are used. Crop evapotranspirations (ETc) are determined by FAO 56 reference evapotranspiration (ETo) with derived crop coefficients (kc) and the actual evapotranspiration (ETa) is estimated using FAO 33. Irrigation efficiency indicators, Relative Irrigation Supply (RIS) and Relative Water Supply (RWS), are calculated. Potential rainwater supply to crop is tested based on Moisture Availability Index (MAI) and Ratio of Moisture Availability (RMA). Furthermore, Water Use Efficiency (WUE) is used to assess the water productivity. For the spatial drought assessment, a modified Vegetation Condition Index (MVCI) derived from remotely-sensed data is used. The results of RIS and RWS show respectively that the irrigation efficiency has decreased since 1993/1994 from 1.40 and 1.70 to 2.23 and 2.60, respectively. MAI for cotton and sorghum presents moderate deficit values (0.4 to 0.68) in July and August. RMA has an average value of 0.67, 0.49 and 0.46 in July for cotton, groundnut and sorghum, respectively, indicating a promising rainfall contribution to irrigation. The Gezira Scheme achieves low WUE in comparison to many irrigation schemes of the globe. Based on the MVCI analysis, the northern part of the scheme experiences characteristic drought during the summer crop season whereas irrigation water is abundantly available during the winter. In conclusion, the overall water availability is higher than the demand; most likely the rain is not considered in irrigation scheduling. Low productivity is mainly due to poor distribution and irrigation mismanagement. Rain and drained irrigation water harvesting could be addressed in the scheme for balancing the demand and supply.
    Agricultural Systems 11/2014;
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    ABSTRACT: Over the past three decades major changes have occurred in Australia's beef industry, affecting productivity and potentially the amount of resources used and environmental impacts from production. Using a life cycle assessment (LCA) approach with a ‘cradle-to-farm gate’ boundary the changes in greenhouse gas (GHG) emission intensity and key resource use efficiency factors (water use, fossil fuel energy demand and land occupation) are reported for the 30 years from 1981 to 2010, for the Australian beef industry. The analysis showed that over the three decades since 1981 there has been a decrease in GHG emission intensity (excluding land use change emissions) of 14% from 15.3 to 13.1 kg CO2-e/kg liveweight (LW). The improvement was largely due to efficiency gains through heavier slaughter weights, increases in growth rates in grass-fed cattle, improved survival rates and greater numbers of cattle being finished on grain. However, the increase in supplement and grain use on farms, and the increase in feedlot finishing, resulted in a twofold increase in fossil fuel energy demand for beef production over the same time. Fresh water consumption for beef production dropped to almost a third from 1465 L/kg LW in 1981 to 515 L/kg LW in 2010. Three contributing factors for this dramatic reduction in water use were: (i)an increase in the competitive demand for irrigation water, resulting in a transfer away from pasture for cattle to higher value industries such as horticulture, (ii) an initiative to cap free flowing artesian bores in the rangelands, and (iii) an overall decline in water available for agriculture compared to industrial and domestic uses. While there was higher uncertainty relating to estimates of land occupation and emissions from land use (LU) and direct land use change (dLUC), an inventory of land occupation indicated a decline in non-arable land occupation of about 19%, but a sevenfold increase in land occupation for feed production, albeit from a low base in 1981. GHG emissions associated with LU and dLUC for grazing were estimated to have declined by around 42% since 1981, due largely to legislated restrictions on broad-scale deforestation which were introduced progressively between 1996 and 2006. This paper discusses the prospects and challenges for further gains in resource use efficiency and reductions in greenhouse gas intensity for Australian beef production.
    Agricultural Systems 11/2014;
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    ABSTRACT: The objective of this work was to evaluate the efficiency and stability of cow–calf, fattening and whole cycle beef cattle agro-ecosystems from the subtropical region of Argentina. For this purpose, an agro-ecosystem model consisting of a production and a management system was developed. Flexible management rules were incorporated. This simulation-based study compared potential trends of different agro-ecosystems under different animal body sizes and several management options traditionally applied in the region. The experiment aimed at estimating productive, energetic and economic efficiency and stability. The results showed that whole cycle and cow–calf systems were more stable but less productive than fattening systems. Within each agro-ecosystem, as body size increased, energetic and economic efficiency and stability decreased. Systems dynamics and multi-criteria approaches allowed recognizing tradeoffs among indicators, and main differences between agro-ecosystems. Further investigation is required to generalize these findings to other system structures, particularly when economic aspects are taken into account in decision making processes.
    Agricultural Systems 11/2014;
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    ABSTRACT: A framework for interpreting profit–environmental trade-offs in pastoral agriculture is introduced, drawing on the concepts of economic and environmental efficiency. The approach provides insights into appropriate policy mechanisms to address the environmental footprint of agricultural production. The framework is applied in the context of nitrogen leaching from pasture-based New Zealand dairy farms. This application identifies that the economic and environmental efficiency of these farms is mainly driven by imported supplement use. Grass-only farming is environmentally-efficient, with greater supplementation generating higher nutrient outflows to waterways. However, profits increase with higher supplementation within a critical range of intensification. Economic efficiency requires low use of supplement to promote herbage utilisation and reduce pasture senescence at low stocking rates, combined with high use of supplement to fill critical feed deficits at high stocking rates. Model output suggests that there exists scope for win/win solutions for private/public agents through improving the conversion of supplement to milk on New Zealand dairy farms. However, the scope to achieve such gains may be restricted in reality, given incentives for intensification, the potential cost of intensive farm planning, and personal barriers to behaviour change.
    Agricultural Systems 11/2014;
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    ABSTRACT: Crop residues have several uses in smallholder mixed crop-livestock systems. This paper examines determinants of households’ maize stover use as livestock feed, fuel and soil amendment in maize-based systems in Ethiopia. In these systems maize stover is primarily used as feed (56% of biomass) and fuel (31%), with the feed use share negatively associated with maize production potential. We develop a Seemingly Unrelated Regression model to capture the interdependence of crop residue uses. Results show extension training on crop residue retention in the field results in more residue use for soil amendment and less for feed. Farmers with more livestock tend to use more residues for feed and less for soil mulch. Cropping pattern, farm size, agro-ecology and crop residue production also influence crop residue utilization. Conservation agriculture interventions have implications for crop residue use and need to consider access to information, cropping patterns, resources endowments and other socio-economic factors in their development and targeting.
    Agricultural Systems 11/2014;
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    ABSTRACT: In Brazil, local agricultural research agendas are increasingly challenged by the search for sustainable biodiesel crop options for family farmers, especially under semi-arid conditions. The aim of this paper is to explore the suitability of different biodiesel crops (i.e. soybean, castor bean and sunflower) through a set of environmental and socioeconomic indicators in a semi-arid (Montes Claros) and a more humid (Chapada Gaúcha) municipality in the state of Minas Gerais, southeast Brazil. A technical coefficient generator (TechnoGIN) was used to assess current (maize, beans, soybean and grass seed) and alternative (castor bean and sunflower) crops grown with current and alternative production techniques. The quantification of the inputs and outputs was based on farm surveys, expert knowledge, literature and field experiments. Although castor bean and sunflower are economically competitive with maize in Montes Claros, feed and labour requirements may hinder farmers' adoption. In Chapada Gaúcha, the double cropping system soybean/sunflower presented small economic gains when compared to soybean; it also increased nitrogen losses and biocide residues. We conclude that the scope for alternative and sustainable biodiesel crops on family farms is limited. Their economic benefits are small or absent, while their introduction can lead to higher environmental impacts and there may be trade-offs with food and feed availability at the farm level.
    Agricultural Systems 11/2014;
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    ABSTRACT: Cotton yields in Mali have fallen during the past 15 years while maize yields have risen. The objective of this study is to examine key changes in the agricultural system to understand how these changes might have influenced the production of these key crops. In particular, this study seeks to understand the causes of the drop in cotton yields in southern Mali and to question the hypotheses that rapid extensification of agriculture or soil fertility loss caused the decline. The study puts forth an alternative hypothesis that fertilizer shifting – whereby farmers apply fertilizers designated for cotton to grain crops – was an important and under-recognized factor in the decline in cotton and simultaneous rise in grain yields.The study uses a mixed method approach which combines satellite image analysis with a household survey from the main cotton growing region in Mali and in-depth interviews with farmers for two key cotton growing areas to determine the causes of agricultural change.The study uses satellite image analysis to document agricultural expansion and intensification over a 35 year period (1975–2010). It uses a household survey from nine villages in three cotton growing areas to document changes in the agricultural system and in production and yields for key crops including maize, cotton and other grains. It uses in-depth interviews with farmers from 15 villages in two cotton growing areas to study farmer decision-making in terms of farming inputs for crops.The image analysis finds no evidence of rapid expansion of agriculture during the period of interest. These findings are supported by those from a household-level farm survey which finds that the major change in the agricultural system has been the increase in the area of intensively farmed crops along with a significant rise in maize yields. Finally, in-depth interviews with farmers growing cotton and maize find that the constraints on accessing fertilizer are a major determinant of farmer decision making.We conclude that the past 15 years of agricultural change in southern Mali can best be described as one where agriculture expanded slowly with gradual intensification of grain farming centered on maize production and simultaneous disintensification of cotton production as farmers shifted resources from cotton to maize resulting in a decline in cotton yields.
    Agricultural Systems 11/2014;