Improving Soil Health and Human Protein Nutrition by Pulses-Based Cropping Systems

Abstract

Low crop yields and poor nutritional quality of the produce, aggravated by soil degradation and climate change, are exacerbating food and nutritional insecurity especially in developing countries of Africa, South Asia, the Caribbean, etc. Pulses, food legumes harvested as dry seeds which are rich in protein and essential minerals, have an important role to play in addressing the food and nutritional insecurity. Thus, U.N. declared 2016 as the International Year of Pulses. An average per capita daily intake of 100–125 g of pulses to provide 25–30 g of protein would require increase in global production of pulses (106 Mg per year) from 70 in 2015 to 370 in 2030, 440 in 2050, and more than 500 in 2100. Therefore, the land area (106 ha) and agronomic yield (Mg/ha) would have to be increased, respectively, from 85.6 and 0.70 in 2015 to 296 and 1.25 in 2030, 248 and 1.50 in 2050, and 238 and 2.15 in 2100. While the increasing trend in agronomic yield of pulses since 1961 is encouraging, the rate of growth must be much higher. Being legumes, incorporation of pulses in the rotation cycle can also improve soil fertility and benefit the productivity of the following cereals. Restoration of soil health through biological N fixation is especially pertinent to Africa where the average rate of input of chemical fertilizers is ~ 15 kg/ha on continental basis. Annual input of biological N fixation is estimated at ~ 3 Tg for the pulses and 18.5 Tg for the oilseed legumes. Increase in soil N content also enhances soil organic carbon concentration and improves the overall soil health. Therefore, incorporation of pulses in cropping/farming systems is important to enhancing soil and human health. With sustainable intensification of agroecosystems, cropland area of 500 Mha under cereals and 250 Mha under pulses/food legumes would be adequate to provide nutritious food to the present and future world population.