Effect of .Manure and Soil-Carbonates on the Availability and Uptake of Superphosphate-Phosphorus by Wheat Plants Under Greenhouse Conditions

Abstract

A greenhouse experiment was conducted on medium textured, calcareous surface soil (Typic calciorthids) collected from the Agricultural Farms of the Al-Fateh University. Tripoli. The study consisted of two parts.

in one experiment 2 mm sieved and unsieved soil samples were treated with 100 ppm P as superphosphate and manure separately and in combination. The amount of manure applied was double that the amount of superphosphate fertilizer needed for lOOppmP. In the second experiment the same levels of P and manure were applied separately and in combination to the sieved soil treated with 5°o ofc 1 mm and <6> 1 mm size fractions of soil-carbonates collected by soil sieving. Sidi Misri variety of wheat (Triticum aestivum L.) was grown to study the effect of treatments on plant uptake of P. Soil samples from all treated pots were analysed for NaHCO3 extractable P to observe the effect on P availability.

Results indicated a strong effect of soil sieving on NaHCO3-P in soil and uptake of P by plants in all treatments. The use of 5 mm sieved soils for greenhouse experiments is suggested for studies where results are to be extrapolated for immediate field applications, especially when interactions of a soil-added chemical element/compound with soil components are vital in controlling its availability for plant uptake. Addition of manure with P increased its availability and uptake by plants. Availability and uptake of applied P was inversely related to soil-carbonate particle size w hich could be enhanced by adding manure.