Reclaiming sodic soils for wheat production by Prosopis juliflora (Swartz) DC afforestation in India.
A greenhouse pot trial was conducted to assess the impact of afforestation with Prosopis juliflora on the productivity and fertility of degraded sodic soils in Haryana, India. Wheat (Triticum aestivum, cultivar HD 2329) plants were grown from seed on top soils collected from a chronosequence of 0-, 5-, 7-, and 30-yr-old P. juliflora plantations established on highly sodic soils and a non-sodic reference soil collected from a local farm. Afforestation improved physical and chemical properties of surface soils by decreasing pH, electrical conductivity and exchangeable Na levels, and increasing infiltration capacity, organic C, total N, available P, and exchangeable Ca, Mg, and, K levels. The ameliorative effect of the trees on top soil increased with plantation age. Soil nutrient status under the 30-yr-old plantation was higher than that of the non-sodic farm soil. The reduced soil sodicity and improved fertility contributed to higher germination, survival, growth, and grain yield of wheat grown on the P. juliflora soils, even surpassing the yield attained on the farm soil in the case of 30-yr-old plantation soil. Sodium accumulation in the crop declined while N, P, K, Ca, and Mg uptake increased with soil plantation age, reflecting the changing nutrient status of the rooting zone due to afforestation. Results confirmed that successful tree planting may restore the productivity and fertility of highly degraded sodic soils.