Effects of phosphorus application on dry matter production and phosphorus uptake in wheat (Triticum aestivum L.)

Phosphorus(P) is one of the essential nutrient elements to maintain wheat growth.Phosphorus deficiency in the soils is constraint to the yield and quality of wheat.So increasing phosphorus application under phosphorus-deficient soils has biological and economic benefits.This experiment is to examine the effects of phosphorus application on dry matter production and phosphorus uptake in wheat in low phosphorus soils.It would be useful for improving wheat yield and quality under phosphorus-deficient conditions.The wheat cultivars tested were Yangmai 9(YM9)with weak-gluten and Yangmai 12(YM12) with medium-gluten.Phosphorus application was applied at six levels(P2O5 0,36,72,108,144 and 180 kg/ha,respectively) on a sandy loam soil(4.95(mg/kg) available phosphorus).A randomized complete block design with three replicates was adapted in this study.Dry matter production and phosphorus uptake were determined.The results showed that phosphorus uptake,uptake rate and accumulation increased with increasing of P application rate within the range of P2O5 0180 kg/ha.Leaf area index,number of main stems and tillers per plant,rate of harvested spikes,accumulation of dry matter,dry matter accumulation after anthesis and grian yield reached their climax when phosphorus application was P2O5 108 kg/ha while those declined when phosphorus application was more than P2O5108 kg/ha, indicating that there existed an optimistic phosphorus application rate even in low-phosphorus soil.The results in this experiment also suggested that there existed two phosphorus uptake peaks during wheat growth.The first peak occurred from emerging to wintering,the second appeared from jointing to booting.About 70%75% phosphorus uptake occurred after the jointing,which suggested that phosphorus application at jointing stage was critical for the growth of winter wheat.