Ecological agriculture proves beneficial for farmers in Africa

An international team of scientists has found that environmentally friendly practices such as growing a range of crops, including legumes like beans or pigeon peas, and adding plant residues or manure to soils can increase food crop yields in places like rural Africa, where smallholder farmers cannot apply much nitrogen fertilizer.

Published in the scientific journal Nature Sustainability and examining data from 30 long-term field experiments involving staple crops – wheat, maize, oats, barley, sugar beet or potato – in Europe and Africa, the study is the first to compare agricultural practices that work with nature to increase yields and explore how they interact with fertilizer use and tillage.

“Agriculture is one of the main causes of global environmental change, but it is also highly vulnerable to this change,” said Chloe MacLaren, plant ecologist at Rothamsted Research, UK, and lead author of the article.

“Using state-of-the-art statistical methods to distill strong conclusions from divergent data from field experiments, we have found combinations of farming methods that boost harvests while reducing the overuse of synthetic fertilizers and other environmentally harmful practices.”

Recognizing that humanity must intensify production on current arable land to feed its growing numbers, the paper advances the concept of “ecological intensification,” that is, agricultural methods that enhance ecosystem services and complement or replace man-made inputs, such as chemical fertilizers, to maintain or increase yields.

The dataset included the results of six long-term field experiments in southern Africa conducted by the International Maize and Wheat Improvement Center (CIMMYT).

African farming systems receive an average of only 17 kilograms of fertilizer per hectare, compared to more than 180 kilograms per hectare in Europe or nearly 600 in China, according to Christian Thierfelder, cropping systems agronomist at CIMMYT and co-author of the ‘study.

“In places where farmers’ access to fertilizers is limited, such as in sub-Saharan Africa or the highlands of Central America, ecological intensification can supplement scarce fertilizer resources to increase crop yields, raise incomes household and food security,” explained Thierfelder. “We believe that these practices act to increase nitrogen supply to crops, which explains their value in low-input agriculture.”

CIMMYT’s long-term experiments were conducted under “climate-smart” conservation agriculture practices, which include reduced or no tillage, leaving some crop residue on the soil and (again ) cultivation of a range of crops.

“These maize-based cropping systems have shown considerable resilience in the face of climate effects that increasingly threaten smallholders in the Global South,” Thierfelder added.

In addition to increasing crop yields, ecological intensification can reduce the environmental and economic costs of productive agriculture, according to MacLaren.

“Crop diversification with legumes can increase profits and reduce nitrogen pollution by reducing the fertilizer requirements of an entire crop rotation, while providing high-value supplemental foods, such as beans,” said explained MacLaren.

“Crop diversity can also confer resilience to climate variability, increase biodiversity and suppress weeds, crop pests and pathogens; this is essential if farmers are to improve maize production in places like Africa.

Thierfelder warned that widespread adoption of ecological intensification will require strong support from policy makers and society, including the establishment of functioning markets for legume seeds and for marketing farmers’ produce, among other political improvements.

“Serious and worsening global challenges – climate change, land degradation and declining fertility, and freshwater scarcity – threaten the very survival of humanity,” Thierfelder said. “Renovating agricultural systems and bringing us back to a space environment is of the utmost importance.”

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Since 1991, Martin Industries has designed, manufactured and sold advanced agricultural equipment in the United States and Canada. Known for Martin-Till planter accessories, the company has grown to include a five stage planting system, closing wheel systems, twist pull chains, fertilizer openers and more in their line. Their durable and reliable planter accessories allow more and more farmers to plant in higher residue levels.

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