TWN Info Service on Sustainable Agriculture
30 January 2024
Third World Network
www.twn.my
Dear Friends and Colleagues
Diversified Cropping Systems Yield Multiple Benefits
Scientists have demonstrated the multiple benefits of diversified cropping systems. They showed that diversifying traditional cereal monoculture (wheat–maize) with cash crops (sweet potato) and legumes (peanut and soybean) improved grain and protein yields, soil health and livelihoods, while reducing greenhouse gas (GHG) emissions.
The 6-year (2016–2022) field study was conducted in the North China Plain—the food basket of China—where crop production is dominated by simple winter wheat and summer maize double cropping. Empirical evidence showed that wheat and maize yields could increase by 32%, if planted following alternative crops such as sweet potato, soybean or peanuts; this would make about 36.1 million tonnes of additional straw biomass available annually for alternative uses, such as feed, bioenergy, or enhancing soil carbon stocks. Farmers could benefit from 20% increases in annual net income, equivalent to US$11.6 billion in total.
At the same time, net CO2-eq emissions could be reduced by 106.8±31.7 million tonnes annually. Diversified rotations with sweet potato, soybean, and peanut significantly reduced net GHG emissions by 75–92% compared to less diversified systems. The legume-based rotations significantly reduced N2O emissions by 30–42% compared to the conventional wheat–maize rotation because they required 37% less synthetic fertilizer than conventional rotations, yet significantly increased system productivity. Including legumes in crop rotations was found to stimulate soil microbial activities, increase soil organic carbon stocks by 8%, and enhance soil health by 45%.
The novelty of this study is its highly diversified crop rotations, with cash crops and legumes replacing cereal monocultures, together with rotating shallow-rooted crops with deep-rooted crops. The authors recommend diversified cropping systems as a comprehensive systems approach in agricultural policy setting and as a top priority for on-farm decision-making, in order to achieve long-term food production resilience and ensure environmental sustainability.
With best wishes,
Third World Network
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DIVERSIFYING CROP ROTATION INCREASES FOOD PRODUCTION, REDUCES NET GREENHOUSE GAS EMISSIONS AND IMPROVES SOIL HEALTH
Yang, X., Xiong, J., Du, T. et al.
Nat Commun 15, 198 (2024).
https://doi.org/10.1038/s41467-023-44464-9
https://www.nature.com/articles/s41467-023-44464-9
3 January 2024
Abstract
Global food production faces challenges in balancing the need for increased yields with environmental sustainability. This study presents a six-year field experiment in the North China Plain, demonstrating the benefits of diversifying traditional cereal monoculture (wheat–maize) with cash crops (sweet potato) and legumes (peanut and soybean). The diversified rotations increase equivalent yield by up to 38%, reduce N2O emissions by 39%, and improve the system’s greenhouse gas balance by 88%. Furthermore, including legumes in crop rotations stimulates soil microbial activities, increases soil organic carbon stocks by 8%, and enhances soil health (indexed with the selected soil physiochemical and biological properties) by 45%. The large-scale adoption of diversified cropping systems in the North China Plain could increase cereal production by 32% when wheat–maize follows alternative crops in rotation and farmer income by 20% while benefiting the environment. This study provides an example of sustainable food production practices, emphasizing the significance of crop diversification for long-term agricultural resilience and soil health.