Managing agricultural soils of Pakistan for food and climate

Abstract

Pakistan; a predominantly arid land region; has a large, growing, urbanizing and increasingly affluent population. Soil and water resources are finite, with per capita arable land area of 0.10 ha by 2050, and prone to degradation by inappropriate management, harsh environments and changing climate. Nonetheless, agriculture productivity increased strongly between 1960 and 2016. Whereas, the population of Pakistan increased by a factor of 4.5 between 1960 and 2018 (from 45 to 201 million), total cereal grain production increased by a factor of 6.5 (from 6.6 to 43.0 million ton). Despite the impressive gains in agricultural production since the Green Revolution era, there is no cause for complacency because even greater challenges lie ahead. Total food production may have to be doubled between 2015 and 2050 because of the growth in population along with rapidly urbanizing and increasingly affluent lifestyle. The national agronomic crop yield (2.8 Mg/ha for wheat, 3.8 Mg/ha for rice, and 4.6 Mg/ha for maize) may have to be increased drastically, and that too in a changing and uncertain climate. Important among the challenges are the growing incidence of drought stress and heatwave, and increasing risks of soil degradation and desertification. Further, soil resources must also be managed to advance the Sustainable Development Goals (SDGs) of the UN; achieve Land Degradation Neutrality proposed by the UNCCD; implement the “4 per Thousand” program of soil carbon sequestration initiated at COP21 in Paris in 2015; and fulfil the aspirations of better lifestyle for the people of Pakistan. The strategy is to restore degraded soils and desertified ecosystems through sustainable intensification. The goal is to produce more from less by reducing losses (i.e., water, nutrients, soil) and enhancing eco-efficiency of inputs (i.e., fertilizer, irrigation water, energy). Vertical increase in agronomic yield, by restoring soil health and adopting best management practices (BMPs), is the only viable option because there is no scope for any horizontal expansion. Site/regional specific BMPs may include conservation agriculture along with retention of crop residue mulch and without any in-field burning of biomass; incorporation of a cover crop (forages) in the rotation cycle; and use of integrated nutrient management (INM) involving a judicious combination of organic (compost, manure, biofertilizers) and inorganic sources of nutrients, and integration of crops with livestock and trees. Further, the flood irrigation must be replaced by drip sub-irrigation system. Chosen BMPs must create a positive soil ecosystem C budget, and restore the soil organic carbon stock.