Effects Of Different Phosphorus Contents In Soil And Phosphorus Application Amount On Grain Yield And Quality In Wheat Yangmai 15

The effects of different available phosphorus contents in soil and phosphorus application amount on the characteristics of phosphorus absorption, protein synthesis and starch accumulation in grains, grain milling quality, SPAD value and MDA content in flag leaves in weak-gluten wheat Yangmai15 were studied on the field of Crop Cultivation and Physiology Key Laboratory of Jiangsu Province, Yangzhou University in 2006-2008. The experiments divided soil available phosphorus contents into three groups, ie.low-P level (available phosphorus content in soil < 10mg/kg), medium-P level (available phosphorus content in soil between 18 mg/kg and 20mg/kg) and high-P level (available phosphorus content in soil >30mg/kg ) The main results were as follows.1. The effects of phosphorus (P) on dry matter production and yield formation in Yangmai 15The high available P content in soil and applying P fertilizer in a certain extent was beneficial to the increase of photosynthetic area, the amount of dry matter accumulation, the number of tillers, the rate of eared tillers, spike number, grain number per ear and grain weight. The above-mentioned indicators declined when the P application amount was more than the appropriate amount. Available phosphorus content of different soils had different suitable P application amount. The experiments showed that the tiller number of plants, earing percentage of main stems and tillers, amount of dry matter accumulation, SPAD value of flag leaf after anthesis, yield and its components increased monotonically, while the MDA content in flag leaf declined with the increasing of P application rate in the appropriate range. Under this experiment, the treatment of applying 180 kg P₂O₅ hm^-2 in low-P level field, the treatment of applying 108 kg P₂O₅ hm^-2 in medium P level field, the treatment of applying 36⁷2 kg P₂O₅ hm^-2 in high P level field would get the highest yield.2 Effects of P on grain quality in Yangmai 15Grain protein content and protein accumulation amount of Yangmai 15 in low-P field would raise with the increasing of P application at the range of 0 144 kg P₂O₅ hm^-2, and in medium P level field at the range of 36 108 kg P₂O₅ hm^-2, while the regulation effects would weaken in high-P level field. According to GB/T17893-1999 Wheat quality requirements (protein content (%)≤11.5), applying P fertilizer at the range of 0 144 kg P₂O₅ hm^-2 in low-P level field, 0 108 kg P₂O₅ hm^-2 in medium-P level field, 0 72 kg P₂O₅ hm^-2 in high-P level field could reach the standard. The wet gluten content, dough stability time, damaged starch content was the lowest for the treatment of 108¹44 kg P₂O₅ hm^-2 application amount in low-P field, 72¹08 kg P₂O₅ hm^-2 in medium-P field, 36⁷2 kg P₂O₅ hm^-2 in high-P field, while the total starch content, amylose content was the highest. Based on the results obtained, when the available phosphorus was lower than 10 mg/kg, the phosphate fertilizer should range from 108 kg P₂O₅ hm^-2 to 144 kg P₂O₅ hm^-2. When the available phosphorus ranged from 18 mg/kg to 20mg/kg, the phosphorus applied should be from 72 kg P₂O₅ hm^-2 to 108 kg P₂O₅ hm^-2. When the available phosphorus was more than 30 mg/kg, the phosphorus should be from 0 kg P₂O₅ hm^-2 to 72 kg P₂O₅ hm^-2.3 Effects of the content of available P in soil and P application amount on phosphorus efficiency in wheat Yangmai 15The effects of the content of available P in soil and P application amount on phosphorus efficiency in wheat Yangmai 15 were slightly different. The stimulation effect of applying P was obvious when the available phosphorus content in soil was relatively low, the yield-increasing effect decreased while applying phosphate fertilizer in the field which available phosphorus content in soil was relatively high, excessive phosphorus even had negative effects. In soil with the same available phosphorus content, the fertilizer agronomic utilization efficiency decreased with the increasing of phosphorus application amount, the fertilizer agronomic utilization efficiency in low-P field was higher than that in medium P field, and far more than that in high-P field. In the fields with different available phosphorus contents, the suitable amount of phosphorus application was helpful to the utilization of phosphorus for this season, even in low-phosphorus fields, the excess phosphorus would lead to a decline in the utilization of phosphorus. The efficiency of phosphate fertilizer production decreased with the increasing of phosphorus application, the more content of available P in soil, the greater the decrease of the efficiency of phosphate fertilizer production.