Improvement of degraded physical properties of a saline-sodic soil by reclamation with kallar grass (Leptochloa fusca)

Abstract

A field experiment was conducted to evaluate the effectiveness of growing salt tolerant plants to improve the physical characteristics of a saline-sodic soil. Kallar grass [Leptochloa fusca (L.) Kunth], a species tolerant to salinity, sodicity and alkalinity, was irrigated for five years with poor quality ground water (EC = 0.14 S m−1, SARadj=19.3, RSC = 9.7 meq L−1). The soil physical properties of plant available water, saturated hydraulic conductivity, structural stability, bulk density and porosity were determined at the end of each year. The growth of kallar grass for three years significantly improved the physical properties of the soil and these were maintained with further growth of grass up to five years. Kallar grass significantly increased plant available water with time (r=0.97**). The available water was highly correlated (r=0.92**) with increases in soil organic matter content, porosity (r=0.99**) and other physical properties. Soil hydraulic conductivity increased substantially with time from 0.035 to 55.6 mm d−1 in the topsoil (0–20 cm) in five years and was significantly correlated with porosity, water retention, structural stability and organic matter content of soil. The soil structural stability index improved significantly from 32 to 151 with kallar grass and showed greater increases in the surface soil than at depth. The cropping of kallar grass resulted in a linear increase of soil organic matter content (r=0.92**) which improved porosity and other soil physical properties (r≤0.82*). This study confirmed that kallar grass is effective for rehabilitation and restoration of soil fertility in saline-sodic areas on a sustainable basis.