Effect of Aluminum Sulfate and Cover Crops on Some Chemical and Physical Properties of Degraded Soil

Abstract

Prevalence of saline and sodic soils has been increased in arid and semi-arid regions which are often depend on irrigated agriculture, and this has led to a major threat to the agricultural sustainable production and environment. An alum has been used as chemical amendments in reclamation of degraded and dispersive soils which are affected by higher sodium concentration. A field experiment was carried out during the fall season in July, 2022 at Karma District - Anbar Governorate to study the effects of aluminum sulfate (alum) and cover crops on some soil physical and chemical properties and crop indicators in silty clay degraded soil due to salinization and high sodicity. The experimental design for the study site was a split-plot design arrangement with a randomized completely plot design (RCBD. The whole plot factor included cover crops which included no cover crops (NCC), sesbania (CC1) and millet crop (Panicum miliceum L.) (CC2), and alum levels were a split-plot factor which included A0 (0 mg ha-1), A1 (1.8 mg ha-1), A2 (3.6 mg ha-1) and A3 (7.2 mg ha-1). Three replications within each treatment were used in this study design, and the total experimental treatments were 36 treatments. Sorghum was planted as main crop in this study. The results showed that the concentration of A3 has decreased adsorption sodium percentage (ESP), pH, soil bulk density and carbonate minerals by 64, 20, 21 and 35%, respectively as compared with A0. Also, the alum level of A3 had greater aggregate stability, total porosity and saturated hydraulic conductivity (Ksat) by 100, 29 and 145%, respectively. Cover crops were roughly decreased by 10, 3 and 8% for ESP, soil bulk density and carbonate minerals, respectively. The water-stable aggregates and Kat were increased by averaging 8-12% and averaging 8-29 mm hr-1, respectively for cover crop systems as compared to NCC management. The treatment of CC2A3 had the highest values for all measured soil properties as compared with the control treatment of NCCA0. In conclusion, adding alum and planting cover crops have been contributed to improved overall soil chemical and physical properties in degraded soil.