| Tianci 19 was used as the test material in this experimentand six potash treatments(KO:0kg·hm-2,K1:60 kg·hm-2,K2:120 kg·hm-2,K3:180 kg·hm-2,K4:240 kg·hm-2;K5:300 kg·hm-2)were set under the drip irrigation water and fertilizer integration technology to explore different treatment on the growth and development of spring maize,leaf photosynthetic characteristics,potassium absorption and operation,grain starch accumulation and key enzymes of starch formation,accumulation and distribution of dry matter and yield,the best potassium fertilizer dosage in local corn high yield mode was screened,which provided a theoretical basis for the efficient use of corn and potassium fertilizer.The main results are as follows:1.Reasonable potassium fertilizer dosage can significantly improve maize uniformity and promote the improvement of plant height,stem diameter and leaf area index.Compared with K0,K1,K2,K4,and K5,the plant height of K3 treatment was increased by 6.4%,1.9%,1.6%,10.8%,and 12.9%,respectively in the tasseling period;Compared with K0,K1,K2,K3 and K4,the stem ratio of K5 treatment was increased by 15.1%,10.3%,8.1%,16.9%,and 21.1%,respectively.2.There were significant differences in chlorophyll content,net photosynthetic rate,intercellular CO2 concentration,stomatal conductance and transpiration rate of maize under different potassium application conditions,reaching the maximum at 180 kg·hm-2 at each growth stage.During the tasseling period,K3 treatment that the photosynthetic rate was 26.3%,21.4%,9.3%,13.2%,and 14.7%higher than K0,Kl,K2,K4 and K5,respectively.The potential activity of PS? photosynthesis and the initial light energy conversion efficiency of PSII reaction were the best at 180 kg·hm-2,and excessive fertilization inhibited the activity of PSII,resulting in photosynthesis decreased.3.The potassium contents in different organs of maize under different potassium treatments were as follows:stem sheath>leaf>ear.,Potassium utilization rate,potassium contribution rate,and potassium harvest index in maize leaves and stems were significantly higher than other treatments under K3 treatment.The potassium harvest index of K3 treatment was 62.8%,71.4%,23.4%,7.9%,and 9.2%higher than K0,K1,K2,K4,and K5,respectively.Compared with K1,K2,K4 and K5 treatments,the physiological utilization of potassium fertilizer in K3 treatment increased by 198.4%,9.5%,6.5%and 17.2%,respectively.Reasonable potassium application can improve the efficiency of potassium assimilation and increase the utilization rate of potassium fertilizer to some extent.4.Different potassium application treatments increased the total starch,amylose,amylopectin content and key enzyme activities of corn kernels in different degrees.The corn starch content was the highest when the potassium application rate was 180 kg·hm-2 under each treatment.The activities of ADPG-PPase,UDPG-PPase,SBE,GBSS and SSS in maize kernels reached the highest on the 30th day after anthesis.The key enzymes of corn starch synthesis were higher than other treatments when the potassium application rate was 180 kg hm-2.5.When the potassium application rate of corn reached 180 kg·hm-2,the dry matter operation rate,operation rate and contribution rate of corn leaves,stems,leaves and stems were significantly higher than other treatments.The dynamics of corn kernels meet the slow-fast-slow "S" growth curve during the filling phase.The maximum grain filling rate(Gmax),the maximum filling rate(Tmax),the duration of filling(T),and the number of active grouting days(P)of maize kernels were all optimal with K3.The yield of maize under K1,K2,K3,K4 and K5 treatments respectively increased by 24.07%,10.83%,7.1%,9.6%and 14.3%,respectively,it was more conducive to the growth of corn ear when the potassium application rate was 180 kg hm'2.,and the yield was 15883.35 kg hm'2.It is recommended that the optimal potassium application rate in this area is 168.45 kg·hm-2?180 kg?hm-2 combined with the yield regression equation. |
PDF Full Text Request