Effect of Some Organic and Inorganic Soil Amendments on the Available N, P and K in Sandy and Calcareous Soils

Incubation experiment was carried out to study the effect of some soil amendments i.e. biogas manure (BM), chicken manure (CM), taffla material (T) at a rate of 2% (20 ton fed^-1), sulfur (S) at a rate of 500 kg fed^-1 and two water capture fertilizers (acidic and neutral WCF) at a rate of 40 kg fed^-1 on the available N, P and K in sandy and calcareous soils. The tested materials were used separately and in different combinations. Soil samples were taken at intervals of 7, 14, 28, 42 and 56 days where available nitrogen forms, phosphorus and potassium were determined.  Results showed that treating the soil with CM, BM, T, S and WCF increased the available nitrogen forms, phosphorus and potassium due to its effect on the soil reaction and the activities of soil organisms. The available nitrogen in sandy soil was higher in the treatment of BM than in the treatment of CM within 7, 14 and 42 days incubation, while the values after 28 and 56 days incubation were lower. The values of available –N in calcareous soil were higher with BM than with CM in all periods except after 14 days. The values of available (NH₄ +NO₃)-N were higher in the sandy soil than in calcareous one within incubation periods except after 28 days. The available P and K were higher with CM than with BM in during the incubation periods.