A field experiment was executed on wheat (Triticum aestivum, cv. Sakha 93) at Belbees district, Sharkia Governorate, Egypt during 2004/2005 winter growing season. The purpose of this study was to investigate the effect of application of increasing rates of either raw (rock phosphate) or manufactured (Ca-superphosphate) mineral phosphate fertilizers with and without inoculation of wheat grains by P-biofertilizer with a trade name of Phosphorien on grain and straw yields as well as N, P and K concentration and content in grains and straw. Grain quality, agronomic P efficiency and available P in soil after harvest were also studied. A randomized complete blocks design with three replicates was used. The experiment included 18 treatments. Nine treatments were assigned to four P fertilization rates (3.25, 6.50, 9.75 and 13.00 kg P/fad), two sources of P (ordinary calcium superphosphate, 6.50 % P = 15 % P2O5 and rock phosphate, 3.25 % P = 7.50 % P2O5) and control treatment (without P application). The same nine treatments were replicated with inoculation wheat grains using Phosphorien.
The results show that treated wheat grains with Phosphorien as a P- biofertilizer significantly increased grain and straw yields as well as N, P and K concentration and their content in grains and straw and both grain quality parameters, i.e. protein percentage and protein yield. Also, inoculation with Phosphorien gave higher values of agronomic P efficiency and available P in soil after harvest. Generally, all P rates applied as super-P or rock-P increased all the aforementioned parameters and super-P was more effective in enhancing them than rock-P at all P rates used. At all P rates, inoculation with Phosphorien under super-P gave, in general, higher values than those obtained at inoculation under rock-P or under both P fertilizers without inoculation. The highest values were obtained by inoculation + application of super-P fertilizer at the rate of 9.75 and 13.00kg P/fad and inoculation + application of rock-P fertilizer at the rate of 13.00kg P/ fad.
Results indicated that treating wheat grains before planting with Phosphorien combined with applying 9.75kg P/fad as super-P or 13.00kg P/ fad as rock-P may be recommended to obtain the maximum yield and nutrient uptake. With Phosphorien inoculation there is a chance of reducing amount of P-fertilizer in the form of super-P or replacing entire super-P with rock-P, which is economically cheaper and it is abundant in Egypt. This would help in reducing production costs of wheat and pollution of environment.