Effect of manure and chemical amelioration on crop yields and soil biological activities in saline soils of semiarid Indo-Gangetic alluvium (Typic ustrochrepts) type in India

Abstract

Reclamation of saline-alkali soils will require both leaching to remove soluble salts and application of amendments to lower ESP. The effects of these amelioration techniques on soil salinity were examined in terms of the yield performance of wheat (Triticum aestivum L.) and pearl millet (Pennisetum glaucum L.R Br.) and the soil biochemical properties. Grain yield reduction was significantly higher for bajra and wheat at 40 sodium adsorption ratio (SAR) than at 30 SAR. In the 015 cm soil layer, dehydrogenase activity (DHA) increased by 31.6 % at an electrical conductivity (ECe) of 691 μs/m than at an EC of 2241 μs/m. A decrease in microbial biomass carbon (MBC) was evident at EC of 2241 μs/m and 2181 μs/m in the 0-15 cm and 15-30 cm soil layers, respectively. The average pH (1:2) of the saline soil dropped from 8.9 to 8.0 and the average ESP was reduced from 28.5 to 16.1. Higher concentrations of C pools (soil MBC (SMBC), water-soluble C (WSC) and acid-hydrolyzable carbohydrates (AHC)) were observed in the surface layers (0-15 cm) than in the deeper layer (15-30 cm). MBC was 23 % greater after the gypsum treatments (250 mg/kg soil) than after FYM treatments (203 mg/kg soil). This suggests that gypsum application, followed by organic amendments, is a better option in salt-affected soil in terms of crop productivity as well as soil biological activities.