Effects of the supply of citric acid and citric soluble phosphatic fertilizers on yield of wheat genotypes with high phosphorus efficiency

Under greenhouse condition, a pot experiment with citric acid, citric soluble and acid soluble phosphorus fertilizers applied to study the effects of various treatments on wheat growth and development was carried out. The results indicated that, among the treatments, citric acid accompanied with citric soluble phosphorus fertilizer could increase the yield most significantly, at the corresponding rates supplied, the average increase of P highly efficient genotype Lofflin was 94%, while that of low efficient 80-55 was 83.1%. Citric acid supplied alone could also increase the yields, for example, Lofflin had a increasing yield of 63.3%, 80-55 had that of 28.8%, showing a significant difference between highly efficient and low efficient genotypes. Little effect was found by application of rock phosphate alone or accompanied with citric acid. The main reason is the high pH value in calcareous soil in which the rock phosphate could not provide enough available phosphorus for crop growth.Furthermore, it showed that the acidification in the rhizosphere was limited by citric acid and the application of rock phosphate could also decrease the acidification through the dilution effect which resulted in a little effect of yield improvement for both of highly and low efficient genotypes.