Regaining the Agricultural Potential of Sodic Soils and Improved Smallholder Food Security through Integration of Gypsum, Pressmud and Salt Tolerant Varieties

Abstract

ABSTRACT Accumulation of salts in soils is one of the major challenges for food production in vast areas, and reclamation of these soils is too expensive for marginal farmers. We evaluated the existing practice (EP; gypsum application at 50% gypsum requirement (GR) followed by the cultivation of traditional varieties of rice and wheat) and the improved practice (IP; gypsum application at 25%GR+10 Mg ha−1 pressmud followedby the cultivation of salt-tolerant varieties of rice and wheat) at farmers’ fields in Hardoi district of Uttar Pradesh, India. Effects of these treatments on rice productivity and profitability were evaluated over 3 years from 2011 to 2014. The soils at the study site were sodic (pH 9.2 to 10.4, EC 0.67 to 2.21 dSm−1) with an estimated GR of 8.5 to 13.6 Mg ha−1. All growth parameters recorded at 30-day intervals were significantly higher for IP than for EP, with 36.5% and 39.3% higher straw and grain yields, respectively. Significant interactions between sodicity levels × reclamation practices for grain and straw yields were observed. The use of IP on farmers’ fields with pH values of 9.2, 9.6, 10.0, and 10.4 reduced reclamation costs by 258, 309, 376, and 413 US $ ha−1, respectively. The combination of reduced costs and increased yields in the IP reclamation treatment led to higher returns from rice farming. Because IP effects on yield became better at higher sodicity, only IP led to net profits ≥0 on all sodicity levels within three rice seasons, whereas under EP, this was achieved only for pH levels of 9.2 and 9.6. Soil properties such as pH, EC, organic carbon, and exchangeable sodium percentage (ESP) and contents of cations and anions were improved significantly under IP than under EP. Thus, the improved practice of sodic soil reclamation has contributed substantially to improve the soil health, crop productivity, and farm income. Farm income losses reduced substantially after reclamation of soil and improved the livelihood security of resource poor farmers having salt-affected soils. This study suggested that a large part of agricultural land is being abandoned worldwide due to salinity or sodicity and need to be reclaimed on priority basis to improve the land productivity and farm income of resource-poor farmers.