Growing a cover crop in summer in Brigalow, and in other locations that experience enough rainfall during the usual fallow period could increase SOC in two ways: i it would increase the C biomass inputs and ii keep the soil drier by plant water uptake, and hence decrease C mineralization. Cover crops in Wubin and to a larger extent in semi-arid climates are not likely to have these SOC benefits because of a lack of water for crop growth during the fallow.
The use of cover crops is encouraged in several publications Sanderman et al. There is an additional benefit of growing a cover crop in summer under Brigalow and regions with similar rainfall patterns. However, cover crops could lead to insufficient soil water content for the following crop. In addition to this, by covering the soil surface, they could also limit soil water evaporation and consequently could promote N 2 O emissions.
Studying the influence of cover crops on soil water content and examining which of the limited soil water evaporation and water uptake during cover cropping has a stronger effect on soil water content and on N 2 O emissions could be topics of future modeling research. Through APSIM simulations combining contrasting soils, climates, and farming practices, we showed that the initial soil C content had the largest impact on SOC over years, followed by the climate and fertilization practices.
Tillage and stubble managements had a lower impact compared to the soil, climate, and other farming practices. Furthermore, the inclusion of a chickpea phase in a wheat-chickpea rotation had a negative impact on SOC when fertilizer was applied. By going beyond the boundary of existing soil and climate patterns, the transposition of contrasting soils and climates revealed the importance of the climate constraints on SOC. The study raised the question of cover crops potential in Brigalow, and other regions with sufficient rainfall during the fallow period, to increase SOC as well as to limit N 2 O emissions.
The impact of climate on the SOC balance requires further investigation considering the importance of the climate influence highlighted in this study and the actual context of climate change. Moreover, further research on crop cover use potential in tropical and sub-tropical climates and on concomitant management of SOC and N 2 O emissions in agro-ecosystems are needed.
CMG: Conceived and designed the study, performed the experiments, analyzed the data and wrote the paper. PJT: Contributed to the design, analyses and paper redaction.
What is Agroecology?
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The authors acknowledge the Liebe Group for assisting with accessing the results of the Buntine experiment and Dr. National Center for Biotechnology Information , U. Journal List Front Plant Sci v. Front Plant Sci. Published online May Thorburn , Jody S. Biggs , and Elizabeth A.
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Isaac, University of Toronto, Canada. Godde, ua. Received Jan 12; Accepted Apr The use, distribution or reproduction in other forums is permitted, provided the original author s or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice.
No use, distribution or reproduction is permitted which does not comply with these terms. This article has been cited by other articles in PMC. Abstract Carbon sequestration in agricultural soils has the capacity to mitigate greenhouse gas emissions, as well as to improve soil biological, physical, and chemical properties.
Keywords: agricultural practices, APSIM model, climate, conservation practices, crop management, greenhouse gases, nitrous oxide emissions, soil organic matter. Introduction Soils can act as a net source or sink of atmospheric carbon dioxide CO 2 and thus influence the process of global climate change. Open in a separate window. Harvest index Literature dryland crop Unkovich et al. Results We studied the relative contribution of the variables soil, climate, and farming practices to SOC variations for the first and last 10 years simulated, as well as the relative contribution of farming practices when the soil and climate are fixed.
- What is Agroecology?.
- Global meta-analysis of the relationship between soil organic matter and crop yields?
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Table 6 Influence of the types of soils, climates and management practices on the rate of SOC loss over the 90 years simulated — Effects of Fertilization on SOC and the Environment To increase wheat yields and SOC for a particular combination of soil and climate, the most efficient way was to increase fertilization. Discussion Impacts of Soil, Climate, Management Practices, and Their Interactions on SOC In this study, SOC was impacted differently by the different combinations of soils, climates and farming practices and can be managed to some degree via simple changes in agronomic practice.
Cover Crops Impacts on SOC and the Environment As the Brigalow summer fallow period is wet and hot, there is a higher C mineralization during that period, compared to the drier summer at Wubin. Conclusion Through APSIM simulations combining contrasting soils, climates, and farming practices, we showed that the initial soil C content had the largest impact on SOC over years, followed by the climate and fertilization practices.
Author Contributions CMG: Conceived and designed the study, performed the experiments, analyzed the data and wrote the paper. Conflict of Interest Statement The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Acknowledgments The authors acknowledge the Liebe Group for assisting with accessing the results of the Buntine experiment and Dr. Footnotes Funding.
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Global meta-analysis of the relationship between soil organic matter and crop yields
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Soil Organic Matter in Sustainable Agriculture
London: Imperial College Press; 9— Dordrecht: Springer; — Soil properties, nutrient uptake and crop growth in an irrigated Vertisol after nine years of minimum tillage. Impacts of fertilisers and legumes on N 2 O and CO 2 emissions from soils in subtropical agricultural systems: a simulation study. Using spatial interpolation to construct a comprehensive archive of Australian climate data. London: Imperial College Press; — Soil carbon sequestration in India. Change 65 — Potential soil organic carbon stock and its uncertainty under various cropping systems in Australian cropland.
Meta-modeling soil organic carbon sequestration potential and its application at regional scale. The future of sustainable agriculture is through integrated nutrient management that ensures soil health and increased productivity. We need to find the right balance on intensification that reduces use of chemicals, reduce soil compaction and maintain soil health. Soil erosion also has a direct link to declining soil fertility. Fertiliser application cannot prevent soil erosion, but agroecological soil health management systems can.
Agricultural sustainability requires effective management of the soil, water and crop. Soil biodiversity plays a central role in maintaining soil organic matter, soil fertility and soil health dynamics. These soil micro and macro fauna improve soil physicochemical properties through the decomposing of organic residues, soil aeration, and storage of water, reduce erosion, break down of organic matter and increase plant nutrition. Soil biodiversity can also suppress disease-causing soil organisms, soil-borne plant pathogens , thereby contributing to production of healthy crops.
Sustainable soil management practices that conserve the ecological processes, reduce the use of external inputs and their negative environmental impacts should be promoted and scaled up. This article advocates a transformative change in agricultural production and food systems in both developing and developed countries.
Below are a few key elements that can guide a global strategy and policy that will help to sustainably produce food and address the declining soil fertility problem.
This requires putting agroecological innovations to practice, in a way that combines the nutrients that are available in nature with inorganic supplement. These will help reduce fossil fuels and cut on the cost and requirement of chemical fertilisers. Nonetheless, fertilisers are still crucial for smallholder farmers to achieve higher yields of crops, what is unnecessary is the high rate of fertiliser use. The future of agriculture will depend on a healthy balance of combining mineral fertilisers with organic, mainly biological nutrient sources.
In order for food and agricultural systems to be sustainable, they must equally and simultaneously address the social, economic and environmental dimensions—the three bottom-line. Neglecting any one aspect jeopardises the attainment of sustainability in the other dimensions.