The Effect of Organic Waste Addition on Biochemical Factors and Availability of Phosphorus in Desert Soils

Abstract

Phosphorus is an essential nutrient. In spite of its wide distribution in nature, P is a limited resource and it is deficient in most soils. This study is aimed to evaluate availability of phosphorus in desert soil with a sandy texture, treated with organic waste (dung of sheep) at rates of different additions (amount applied at 30, 60, 90 & 120 tons. ha-1) over 12 weeks, to find out the effect of pH on soil rates mineralization at various applications. Used soil samples were collected from the surface layer (0-30cm) of arable soils. Available phosphorus determinate as stated in Olsen. It was appreciated colorometrically according to Murphy and Riley. Soil pH measure of extracts 1:1 (soil/solution ratio) according to Jackson. The results showed that the soil pH changed in range 7.5 to 7.8 which increased the phosphorus concentration in the soil. So there were significant changes in biochemical soil factors due to bacterial groups and phosphatase activities which were responsible for mineralization. The results show that available phosphorus improved at rate of 254.47-301.01ppm in fourth week for all applications, which refers to increase of biological activity of soils by adding organic waste and led to a significant increase in available phosphorus concentration.

Keywords: Effect, Phosphorus, Desert soils, Organic waste, Mineralization, pH, Biochemical factors, Microbial groups.