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.

摘要

土壤中盐分的积累是广大地区粮食生产面临的主要挑战之一，而开垦这些土壤对边缘农民来说过于昂贵。我们评估了现有做法（EP；石膏用量为 50% 石膏需求量 (GR)，然后种植传统水稻和小麦品种）和改进做法（IP；石膏用量为 25%GR+10 Mg ha ^-1压泥）随后在印度北方邦哈多伊区的农田种植耐盐水稻和小麦品种。从 2011 年到 2014 年，对这些处理对水稻生产力和盈利能力的影响进行了为期 3 年的评估。研究地点的土壤为钠质土壤（pH 9.2 到 10.4，EC 0.67 到 2.21 dSm ^-1），估计 GR 为 8.5 到 13.6 Mg公顷^-1. 以 30 天为间隔记录的所有生长参数均显着高于 EP，秸秆和谷物产量分别高 36.5% 和 39.3%。观察到谷物和秸秆产量的钠含量×复垦实践之间的显着相互作用。在 pH 值为 9.2、9.6、10.0 和 10.4 的农田上使用 IP 可将复垦成本降低 258、309、376 和 413 美元 ha ^-1， 分别。IP 复垦处理的成本降低和产量增加相结合，导致水稻种植的回报更高。由于 IP 对产量的影响在更高的钠含量下变得更好，只有 IP 导致三个水稻季节内所有钠含量水平的净利润≥0，而在 EP 下，这仅在 pH 值水平为 9.2 和 9.6 时实现。与 EP 相比，IP 下土壤的 pH 值、EC、有机碳、可交换钠百分比 (ESP) 和阳离子和阴离子含量显着改善。因此，改进的钠质土壤复垦实践大大有助于改善土壤健康、作物生产力和农业收入。开垦土壤后，农场收入损失大幅减少，提高了盐碱地资源贫农的生计保障。