Overcoming cereal fatigue:

Why vegetables and legumes can offer farmers, soils, and consumers a boost

Diversifying rice-based farming with vegetables and legumes offers a powerful opportunity to boost incomes, restore soil health, and improve nutrition for millions across Asia and Africa, according to a new paper from the World Vegetable Center.

With over half the world depending on rice as a staple, the crop dominates farming landscapes, especially in Asia. But challenges such as soil degradation, declining yields, rising input costs, and increasing vulnerability to climate change are putting pressure on farmers and policymakers alike.

Rice – legumes intercropping

Writing the journal Crops, Ramasamy Srinivasan, leader of the WorldVeg Safe and Sustainable Value Chains Flagship Program, explores how introducing crops like improved mungbean and soybean has helped transform rice farms into more productive, profitable, and sustainable systems.

“The evidence strongly suggests that diversifying rice systems with vegetables and legumes is not just a smart option – it’s fast becoming a necessity in Asia and Africa,” said Srinivasan. “It can address climate risks, soil health, poor nutrition, and low farm incomes all at once.”

The paper points to a number of studies documenting the introduction of vegetables into rice-based systems. These include the use of WorldVeg-improved mungbean in rice-wheat systems of the Indo-Gangetic Plains, which improved soil health and helped break the fatigue caused by repeated cereal rotations. As well as providing a source of dietary protein and iron, mungbean helped boost rice yields and farmers’ incomes, especially when combined with conservation agriculture practices.

The paper also notes successful diversification in the low and mid-altitudes of Jharkhand, India – areas usually dominated by rice. There, the introduction of improved soybean, tomato, eggplant, okra, garden pea, cowpea, and bottle gourd, along with good agronomic practices, boosted farm productivity by 200–350% and helped support diverse and nutritious diets in an area that continues to struggle with malnutrition.

Rice and legumes intercropping

Africa also stands to benefit. Though rice cultivation is expanding across the continent, yields remain low, and many countries are reliant on imports. The study points to strong potential for vegetable diversification, with early success stories emerging from countries like Benin, where maize intercropped with chili or mungbean produced higher returns. However, adoption of improved mungbean varieties remains limited—just 2% of the area compared to 61% in Southeast Asia.

To build on these successes, the paper calls for stronger policy support and greater investment in agricultural research and development. In addition, it notes that expanding the use of improved varieties – especially in under-served regions like sub-Saharan Africa – will require targeted efforts across the entire seed system, from breeding and testing to multiplication and distribution.