Despite doubling of yields of major grain crops since the 1950s, more than one in seven people suffer from malnutrition (1). Global population is growing; demand for food, especially meat, is increasing; much land most suitable for annual crops is already in use; and production of nonfood goods (e.g., biofuels) increasingly competes with food production for land (2). The best lands have soils at low or moderate risk of degradation under annual grain production but make up only 12.6% of global land area (16.5 million km²) (3). Supporting more than 50% of world population is another 43.7 million km² of marginal lands (33.5% of global land area), at high risk of degradation under annual grain production but otherwise capable of producing crops (3). Global food security depends on annual grains—cereals, oilseeds, and legumes—planted on almost 70% of croplands, which combined supply a similar portion of human calories (4, 5). Annual grain production, though, often compromises essential ecosystem services, pushing some beyond sustainable boundaries (5). To ensure food and ecosystem security, farmers need more options to produce grains under different, generally less favorable circumstances than those under which increases in food security were achieved this past century. Development of perennial versions of important grain crops could expand options.

The Asian green revolution trebled grain yields through agrochemical intensification of monocultures. Associated environmental costs have subsequently emerged. A rapidly changing world necessitates sustainability principles be developed to reinvent these technologies and test them at scale. The need is particularly urgent in Africa, where ecosystems are degrading and crop yields have stagnated. An unprecedented opportunity to reverse this trend is unfolding in Malawi, where a 90% subsidy has ensured access to fertilization and improved maize seed, with substantive gains in productivity for millions of farmers. To test if economic and ecological sustainability could be improved, we preformed manipulative experimentation with crop diversity in a countrywide trial ( n = 991) and at adaptive, local scales through a decade of participatory research ( n = 146). Spatial and temporal treatments compared monoculture maize with legume-diversified maize that included annual and semiperennial (SP) growth habits in temporal and spatial combinations, including rotation, SP rotation, intercrop, and SP intercrop systems. Modest fertilizer intensification doubled grain yield compared with monoculture maize. Biodiversity improved ecosystem function further: SP rotation systems at half-fertilizer rates produced equivalent quantities of grain, on a more stable basis (yield variability reduced from 22% to 13%) compared with monoculture. Across sites, profitability and farmer preference matched: SP rotations provided twofold superior returns, whereas diversification of maize with annual legumes provided more modest returns. In this study, we provide evidence that in Africa, crop diversification can be effective at a countrywide scale, and that shrubby, grain legumes can enhance environmental and food security.

The importance of legumes in sustainable cropping systems has been studied extensively. Among legumes, common beans (Phaseolus vulgaris L.) are a rich world resource of biodiversity with two centers of domestication (Andes and Central America) and over 10 major market classes cultivated globally. Common beans are recognized as a nutrient‐dense, healthy food source due to their high protein, dietary fiber, and minerals content and also being a rich source of resistant and slowly digestible starch, which elicits a lower glycemic response. Some bioactive compounds present in beans are reported to mitigate cardiovascular diseases, hypertension, hyper‐cholesterolemia, and cancer. Dry bean production systems provide unique advantages that support sustainability, including a low carbon footprint and short growth cycle, which facilitates crop diversification and cover crop integration. Symbiotic nitrogen fixation (SNF), a unique characteristic of legumes, promotes environmentally friendly production through modest fertilizer use. Advances to improve the upright plant architecture of beans during the last two decades have enhanced options for direct harvest thereby reducing the number of equipment passes required. Overall, the sustainability implications of diversifying crop rotation using beans result in reduced requirements for environmentally unfriendly inputs and buffering of crop productivity under variable weather conditions. This review article covers common beans' role in agricultural sustainability (biodiversity, SNF, rotational diversity, harvest management) and as a sustainable source of nutrition and food security. Further discussion includes measures to enhance dry beans sustainability through breeding and crop management practices by addressing biotic and abiotic stresses (diseases, drought, high temperature, waterlogging, conservation tillage).