Accumulation,Distribution and Utilization Characteristics of Phosphorus in Super-high Yield Wheat Population under Rice Stubble in Middle and Lower Reaches of the Yangtze River

Phosphorus is one of the essential nutrients for wheat production.It is very important to figure out what are the definite characteristics of accumulation,distribution and utilization of phosphorus in different wheat varieties,ecological environments,soil types or yield level populations,which have much theoretical and practical meaning to agricultural production.Using the medium gluten wheat Yangmai 20 as the material,a field experiment with different combinations of fertilizer and plant population was carried to investigate the accumulation,distribution and utilization characteristics of phosphorus in super-high yield(9 000 kg·hm-2) wheat population in rice-wheat cropping system.The main results were as follows: the phosphorus accumulation amount dynamics under different yield levels population could be modeled using Richards equation.In super-high yield wheat population,phosphorus accumulation amount(PAA) at the stages from jointing to anthesis and from anthesis to maturity,at anthesis and at maturity were significantly higher than that in high yield wheat population.For super-high yield wheat,the corresponding population PAA was 28 kg hm-2 from jointing to anthesis,22 kg·hm-2 from anthesis to maturity,46 kg·hm-2 at anthesis and 68 kg·hm-2 at maturity or above,respectively.The period with the highest phosphorus absorption of super-high yield wheat population was from jointing to anthesis,and then from anthesis to maturity.PAA in stem and spike at anthesis,and in rachis and hull and grain at maturity were linear correlation with grain yield.PAA was 28 kg·hm-2 in stem and 8 kg·hm-2 in spike at anthesis,and 9 kg·hm-2 in rachis and hull and 45 kg·hm-2 in grain at maturity or above,respectively,which was better to realize the super-high yield.The phosphorus translocation amount from leaf to grain was negatively correlated with grain yield.The phosphorus translocation amount from stem to grain was positively correlated with grain yield.The phosphorus translocation amount was below 9 kg·hm-2 from leaf and above 15 kg·hm-2 from stem,respectively,which was better to realize the super-high yield.For super-high yield wheat population,the phosphorus amount to produce 100 kg of grain,phosphorus use efficiency and phosphorus harvest index was 0.84~0.88 kg,113.60~118.93 kg·kg-1 and 0.64~0.67,respectively.