EFFECT OF ORGANIC AND INORGANIC PHOSPHORUS APPLICATION ON SOME CHEMICAL PROPERTIES AND SOIL PHOSPHORUS FRACTIONS

Two successive cultivation seasons (winter season 2006/2007 and summer season 2007) were conducted in field experiments on silty clay loam soil at El-Gemmeiza Agricultural Research Station, El-Gharbia Governorate. The experiment was designed using a randomized complete block design with three replicates to study                the effect and residual effects of organic and inorganic phosphorus using farmyard manure (FYM) as a source of organic phosphorus, rock phosphate (RP) and supper phosphate (SP)  as a source of inorganic phosphorus on some soil chemical properties and phosphorus fractions. Furthermore, economical analysis was done by calculating the net income. The obtained results can be summarized as follows:- 1-The use of organic and inorganic phosphorus lead to a slightly decreases in soil reaction (pH) and progressive increases in soil salinity (EC), soluble ions (Ca, Mg, Na, HCO3, Cl and SO4), total soluble salts (TSS) and sodium adsorption ratio (SAR). 2-The mean values in the two seasons showed that the effect of organic phosphorus (FYM) on soil chemical properties was more pronounced than the effect of inorganic phosphorus additions (rock phosphate and supper phosphate). 3-The distribution values of inorganic P, i.e., easily soluble P (labile-P fraction), Al-P fraction, Fe-P fraction and Ca-P fraction were increased with increasing the addition of OP with RP and SP. Also, the labile-P fraction, Al-P fraction and Fe-P fraction as a percent of the total P were increased by increasing all added treatments, except the Ca-P fraction as a percent of total P which was decreased with increasing all added treatments. 4-The mean values of total P of soil were increased with increasing all added treatments. The highest values were recorded by addition of 30 m3/fed OM with 200 Kg/fed RP and 150 Kg/fed SP which gave 12.63 and 14.93 µg/g soil, comparing with the control which recorded 4.54 and 4.66 µg/g soil in the first and second seasons, respectively. 5-Economical analysis indicate that the addition of 30 m3/fed. OM with 200 Kg/fed RP and 150 Kg/fed SP was the most valuables compared with the other treatments. Also, it gave the highest net income (8263.96 LE/fed) as compared with the control which gave the lowest value (4798.86 LE/fed.). 6-Results reveal that it is useful to use the treatments of organic and inorganic phosphorus represented by (OM, RP and SP) to get a markedly improvement in soil chemical properties which reflect on higher yield incorporated with high net income under silty clay loam soils.