Effect of Phosphogypsum and CaCl\(_2\) Amendments on Reclamation of Saline-Sodic soil in Rice - Wheat Cropping Sequence

Abstract

Saline–sodic soils constitute a major limitation to agricultural productivity in coastal regions, where elevated concentrations of soluble salts and exchangeable sodium adversely affect soil physico‑chemical properties and significantly reduce crop yields. Phosphogypsum (PG) is widely utilized as a reclamation amendment; however, the integration of more soluble calcium sources such as calcium chloride (CaCl2) may enhance sodium displacement and accelerate improvements in soil quality. In order to address this, a field study was conducted at Coastal Soil Salinity Research Station, Navsari Agricultural University, Danti, Gujarat (India), to assess the impact of different PG and CaCl2 levels on the reclamation of saline-sodic soils. The field experiment was conducted over a period of three consecutive years (2021-22 to 2023-24) under a rice–wheat cropping sequence, employing a randomized block design (RBD) with four replications. The treatments consisted of seven amendment levels viz., T1: Control (no amendment), T2: 75% GR through PG, T3: 75% GR through CaCl2, T4: 37.5% GR through PG + 37.5% GR through CaCl2, T5: 18.75% GR through PG + 56.25% GR through CaCl2, T6: 56.25% GR through PG + 18.75% GR through CaCl2 and T7: 65.62% GR through PG + 9.38% GR through CaCl2 with each treatment replicated four times. The results revealed that application of 56.25% GR of PG along with 18.75% GR of CaCl2 during land preparation of kharif rice for getting higher rice-wheat yield and net income. Application of PG with CaCl2 was found to reduce soil sodicity.