The comparison of some bio and chemical P- fertilizers in corn.

In order to examine the effect of phosphorous release microorganisms in corn production and compare them with phosphorous chemical fertilizers, a field experiment was conducted in corn fields of Fars, Khozestan (Dezful), Varamin and Karaj during the 2003-2006. The experiment was performed in the form of Randomized Complete Block Design with 4 treatments and three replications. The treatments were a) control (without phosphorous application), b) application of phosphorous as microbial phosphate source (organic fertilizer), c) application of phosphorous as Golden Bio-phosphate source (organic fertilizer) and d) application of phosphorous as triple super phosphate (chemical fertilizer). Scince there was some organic matter, sulphur, and zinc in the organic fertilizers, the calculated amount of these elements was also applied to other treatments. Results of statistical analysis in Fars area showed that the effect of different treatments on total yield and grain yield was significant at P0.01 or P0.05. The maximum yield of grain (9559 kg.ha-1) was obtained from the treatment in which triple super phosphate was used as phosphate resource. There was significant difference between the control treatments and treatments in which P was applied for grain yield, while the difference between the treatments in which P was applied was not significant for grain yield. Results of the experiment conducted in Khoozestan (Dezful) showed that P application from the triple super phosphate source can be recommended for P requirements of corn. But application of super phosphate can be replaced by organic fertilizers such as microbial phosphate and or Golden Biophosphate sources when use in super phosphate is not economic. Results of experiments performance in Karaj showed that application of phosphorus had a significant effect on grain yield (p 0.01). The highest grain yield (with 14% moisture content) was obtained through the application of P microbial and lowest was obtain from the control treatment. Based on the results obtained in Karaj, P microbial source was recommended for corn production in Karaj area. Result of Varamine experiments showed that there was no significant difference between phosphorous sources but application of fertilizers containing P had significant effect on grain yield compared to control. In other words, corn needs P fertilizers. There was no difference between organic and chemical sources. In general, based on the results of this experiment in different parts of the country, there was a positive and significant effect of P application on grain yield. Triple super phosphate was better than other sources. Microbial phosphate was in the second place. Although, Golden bio-phosphate showed positive effect on grain yield in Varamin, but in Fars and some other area there was no significant difference between control and Golden bio-phosphate source. In general, application of microbial phosphate can be recommended instead of triple super phosphate especially from the economical view point but using Golden bio-phosphate source in corn fields is not recommended.