Farmers in Argentina, Brazil, India, Indonesia, Kenya and Uruguay are increasing crop yields and enhancing the fertility and quality of the soil in an environmentally friendly, cost-effective way – thanks to the results of an IAEA coordinated research project recently concluded in collaboration with the Food and Agriculture Organization of the United Nations (FAO).
“We are making the most of our resources while addressing the challenges posed by food scarcity and climate change,” said Setiyo Hadi Waluyo, a scientist at the National Nuclear Energy Agency (BATAN) in Indonesia.
The work is based on a simple concept: that crop yields can be maximized through an integrated cropping-livestock production system that recycles the nutrients present in both animal manure and crop residues. This reduces the need for synthetic fertilizers that release large quantities of greenhouse gases and thereby contribute to climate change. Isotopic techniques are used to measure the amount of fertilizer in the soil and therefore the effectiveness of the concept (see The Science box).
Commercial farming operations are often based on monoculture practices, in which the same crop is grown on the same plot year after year. Monoculture over time results in lower so fertility, so excessive amounts of synthetic fertilizer are required to replenish the nutrients taken up and used by the crops.
In integrated cropping-livestock systems, which have been increasingly used over the last five years, livestock may either graze the field crops directly or may be fed the crop after harvesting. Farmers then collect the manure from the livestock and use it as fertilizer, thereby returning many of the nutrients to the soil.
“This process enriches the soil with carbon and other essential plant nutrients, drastically reducing the need for synthetic fertilizers,” said Mohammad Zaman, a soil scientist at the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture. “They also improve the soil’s structure, so its capacity to absorb water and conserve nutrients increases, leading to higher crop yields and to reduced greenhouse gas emissions at the same time.”
In Brazil, scientists are looking for ways to maximize land use efficiency, and research into the effectiveness of using an integrated cropping-livestock system has brought positive results. Around 5% of farms use this method, with a total of 10.6 million hectares under cultivation. “We are moving towards the implementation of conservation agriculture, and we have seen the feasibility of such an approach involving integrated cropping-livestock systems,” said Jeferson Dieckow, a soil scientist from the Federal University of Paraná in Brazil. As a result, greenhouse gas emissions from urine and dung have been reduced by 89%.
Likewise, scientists in Argentina have found that the integrated cropping-livestock system makes cultivated crops more resilient to the effects of climate change. “We have benefited from this project by improving our agricultural soils through crop rotation,” said Juan Cruz Colazo, a scientist at Argentina’s National Institute of Agricultural Technology. “We have observed a 50% increase in organic carbon content in the soil, which enhances the resilience of the cropping system to climate variations that may otherwise impede crop yields.”
In Indonesia, the population is rapidly growing and the government is working to ensure an adequate food supply. At the same time, it is committed to reducing greenhouse gas emissions by 30-40 % by 2030. “Conservation agriculture increases crop yields due to a reduction in tillage and by applying crop residues as mulch, resulting in a significant improvement in soil quality,” said Hadi Waluyo. “We are planning to establish these methods on 1000 farms by 2019.”
The use of integrated cropping-livestock systems, enhanced through this coordinated research project, is likely to extend far beyond the countries that participate in this project.
“What is especially encouraging about integrated crop-livestock practices is that they are not limited to certain geographical areas or climates. If land is suitable for crop cultivation, it’s suitable for integrated crop-livestock practices,” Zaman said.
