The PpossibleEvaluation Mmodification of Aabsorbable Pphosphorus of ability of Phosphate Ssolubilityles Change underinIn CcCalcareus SsSoils, and it's EeEffects on Yyyield Pproduction inof Corncorn

Alkalinity in of soils in many that cultivated areas of corn in Iran corn in Iran prevents the accessability of nutrients, particularly phosphore (P), lead to reduce nutrient access, especialy P by the plant. Application of solphur (S) and its subsequent oOxidation which is usually accompayning with a reduction of soil PH of solphur will enhance the absorbability of in soil increase P and most micronutrient solubilitysolubles in the soil., because of reducing pH. Today, lLow price of phosphorus sources such az as aApatite and composts can be taken into consideration is considered as phosphorus fertilizers for plant nutrients in agriculture. This These sources sources could increase promote absorbable phosphors in the alkaline soils and later on takenP uptake byand yield of the plantcrops, and promote availability of P in alkaline soils. However, we studied effects of changing PH and increasing phosphorus solubles in the soil on yield production of a corn single cross 0. The experiment was a factorial based on a randomized complete block design with three replications and carried out at the rResearch sStation of Soil and Water Research Institute, Karaj, Iran, in 005. The experiment consisted of four factors, each at two levels such as: Thus this experiment was conducted to evaluate the effects of urban compost (0 and 0 t/ha), PSB (Phosphate-solubilizing microorganisms (PSB)) as check and bacteria, apatite (0 and t/ha) and phosphor (P) inoculated with oxidative Thiobacillus bacteria (0 and t/ha). whit S on pH, solouble P of soil and yield of Corn. Four factors: -apatite -urban compost -Bacillus megaterium -Sulphur inoculated whit Thibacillus sp. were factorially applied in two levels in Complete Randomized Block Design with three replication in research farm of soil and water research institute, Karaj, Iran, in 005. The results showed that the highest most grain yield (9600 kg/ha) was obtaind forby the application of compost and Bacillus megaterium treatment. For the factors in which only apatites was used, yielded the lowest value (697 kg/ha) as compared to the check (7700 kg/ha). Indeed, interaction effects of compost and Bacillus megaterium on yield of maize iswas significant (P <0/.05) for yield). Application of apatite in alkality soils not only did not increase phosphorus solubles, but had a negative effect on the soil characteristics and plant growth. These treatments increase yield of corn. Plots with apatite produced significant lower yield (697 kg/ha) than control plots (7700 kg/ha). It is suggested that application of compost and Bacillus megaterium promote the accessability of plant to nutrients like phosphor and consequently will increase yield production of corn in the field. Because of high pH (8/8), apatite has reverse effect on solouble P and corn yield in calcorous soils