Recent Advances in the Agronomy of Food Legumes

Sustainable production of grain legumes can ensure global food and protein security. Grain legumes contribute 33% of the global protein requirement of the human diet. Most grain legume crops are grown in rainfed and arid environments. Compared with cereals, few studies have focused on the yield improvement of food legumes. Over the decades, breeding approaches to resist abiotic and biotic stresses in grain legumes have advanced, but then a substantial list of agronomic advances follows. The major reasons for the low productivity of food legumes are lack of quality seed, being grown on marginal lands, no or imbalanced use of fertilizers, monocropping, extreme rainfall events, and threats of biotic factors. Advances in the agronomy of grain legumes to cope with these issues include (1) seed enhancements (agronomic ways, seed priming, seed coating/pelleting, and biopriming, or genetic approaches, early-maturing cultivars) to ensure proper crop stands and early crop emergence to avoid suboptimal conditions; (2) improved water use efficiency and irrigation management through early planting, changes in planting geometry, direct seeding in the stubble of previous crops, rainwater harvesting, and planting on raised beds; (3) integrated nutrient management including biochar application, green manuring, residue retention, and the use of beneficial microbes (mycorrhizae and plant growth-promoting bacteria) which help plants to cope with stresses and increase solubilization and nutrient uptake (4); integrated insect-pest management, including mixed cropping, crop rotation, canopy adjustment, pesticide application, and fungicidal seed treatments; (55) development of production systems with better productivity, such as conservation agriculture, relay planting/intercropping, and diversification of cropping systems to break the cycles of diseases, insect pests, and weeds and to ensure better and quality produce (moreover, such systems provide ecosystem services by increasing soil organic carbon, organic nitrogen, organic matter, microbial biomass, microbial population, and macro-and micronutrients); and (6) adoption of integrated crop management that includes all of the above packages to save resources and the environment and increase the productivity and profitability of farmers.