Effects Of Soil Moisture And Phosphorus Application Rate On Tiller Occurrence And Spike Formation And Yield Of Wheat

In order to clarify the physiological mechanism of wheat tiller formation and grain yield of different stems and tillers in response to phosphorus application under the condition of water saving and high yield,and to explore the appropriate amount of phosphorus fertilizer.A field experiment was conducted in wenyangtian modern agricultural industrial park,Shandong Agricultural University,Tai’an City,Shandong Province during the wheat growing season from 2020 to 2021.Taking Jimai 22 wheat variety as the test material,The split zone design is adopted.The main area is soil moisture and the sub area is phosphorus application.The two soil water treatments were W70（the relative soil water content of 0～40 cm soil layer was supplemented to 70%in jointing stage and flowering stage）and W0（no irrigation in the whole growth stage）;The four phosphorus application treatments were P₂O₅0（P0）,90（P1）,135（P2）and 180 kg（P3）per hectare,with a total of 8 treatments repeated for 3 times.The effects of different tillers and tillers on photosynthetic senescence and grain yield of wheat were studied.The results are as follows:1 Effects of soil moisture and phosphorus application rate on tillering and spike formation of wheatUnder the condition of W70,compared with P0 and P1,P2 significantly increased the tiller node area and trans zeatin content of wheat.The net photosynthetic rate,stomatal conductance and transpiration rate of the uppermost expanded leaves of the main stem at the overwintering stage and the turning green stage promoted the occurrence of tillers,increased the tillers of III and I_Pat the overwintering stage,and the number of I_P,IV and other tillers at the jointing stage.The total number of tillers per plant at the two growth stages increased by0.77 and 0.28,1.93 and 0.65 compared with P0 and P1,respectively.The photosynthetic parameters and ¹³C assimilate distribution of the uppermost expanded leaves of stems and tillers in P2 jointing stage were higher than those in P0 and P1,and the number of spikes per plant increased by 0.51 and 0.36 compared with P0 and P1,respectively.When the amount of phosphorus application increased to P3,the number of tillers increased at overwintering stage and jointing stage,but the number of spikes of tillers II and III decreased,and the number of spikes per plant decreased by 0.18 compared with P2.Under W0 condition,the number of spikes per plant in P2 increased by 0.45,0.34 and 0.14 compared with P0,P1 and P3,respectively.The number of spikes per tiller and spike per plant of W70 were higher than that of W0 under each phosphorus application rate.Under the condition of W70,the number of spikes per plant treated with P2 was the highest.2 Effects of soil moisture and phosphorus application on photosynthetic and senescence characteristics and yield of flag leaves of different stems and tillers of wheatUnder the condition of W70,the relative chlorophyll content,net photosynthetic rate,sucrose content,sucrose phosphate synthase activity,superoxide dismutase activity,soluble protein content and panicle grain weight of P2 were significantly higher than those of P0 and P1,but there was no significant difference between P2 and P3;P2 obtained higher grain yield per plant by increasing the grain yield of main stem,I,II and III tillers than P0 and P1,and by increasing the grain yield of II and III tillers than P3.Under the condition of W0,the relative content of chlorophyll,net photosynthetic rate,sucrose content,sucrose phosphate synthase activity,superoxide dismutase activity,soluble protein content and spike grain weight of P2were significantly higher than those of P0 and P1,but there was no significant difference between P2 and P3;P2 increased the grain yield of main stem,tillers I and II than P0 and P1,and increased the grain yield of tiller II than P3.Under each phosphorus application rate,the grain weight of main stem,tillers I and II and grain yield per plant of W70 were higher than those of W0.Under the condition of W70,the grain yield per plant of P2 treatment was the highest,which was 41.1%,29.2%and 6.4%higher than P0,P1 and P3 respectively.3 Effects of soil moisture and phosphorus application on grain yield,water use efficiency and phosphorus agronomy efficiency per hectare of wheatUnder the condition of W70,compared with P0,P1 and P3,the grain yield of P2 hectare was 40.3%,13.2%and 6.0%higher,and the water use efficiency was 33.1%,16.9%and 8.0%higher,respectively.Compared with P1 and P3,the phosphorus agronomy efficiency of P2was 93.5%and 66.2%higher,respectively.Under W0 condition,the grain yield,water use efficiency and phosphorus agronomy efficiency per hectare of P2 were significantly higher than those of P0,P1 and P3 treatments.The grain yield,water use efficiency and phosphorus agronomy efficiency in W70 were higher than those in W0.Under W70 condition,P2treatment had the highest grain yield,water use efficiency and phosphorus agronomy efficiency,which was the best treatment for water-saving and high-yield cultivation in this experiment.