| The experiment was conducted in the high-yielding field at Qibin District of Hebi city in Henan Province during the year of 2013-2014.Zhengdan 958 and Xundan 29 were used to study stalk lodging rate,morphology,chemical content,Photosynthetic fluorescence characteristics of functional leaves,yield and nutrient absorption and utilization etc on summer maize with different Potassium Level.The lodging resistance and yield increasing with potassium fertilizer and its mechanism of the high-yield summer maize was investigated to provide a theoretical basis for the reasonable application of potassium fertilizer of summer maize with reduced lodging rate and increased yield.The main results are as follows:1.The lodging-resistant and yield of summer maize was significantly increased by applying potassium fertilzer.The lodging rate reduced by 4.16% ~ 6.28% and 3.28% ~ 6.28%,respectively.The grain number and 1000-grain Weight significantly increased,the yield of Zhengdan 958 increased by9.70%~10.23% and 6.51%~8.24% respectively for two years,Xundan 29 increased by 6.80%~12.14%and 5.63%~7.70% respectively for two years.The average potassium utilization rate were 58.50% and51.49%,the average agronomic efficiency were 8.25 and 6.72 kg/kg for two years.The lodging of Zhengdan 958 is better with K2 O 90 kg/hm2,Xundan 29 with K2 O 180 kg/hm2 can achieve the better lodging effect.Zhengdan 958 and Xundan 29 both achieved the highest yield at K2 O 180 kg/hm2,but the efficiency and agronomic efficiency of the potassium fertilizer was the higher with the potassium K2 O 90 kg/hm2.2.The function leaves photosynthetic rate,the transpiration rate,the stomatal conductance,the nitrate reductase activity,the glutamine synthetase activity,the conversion efficiency of light energy function(Fv/Fm),the actual photochemical efficiency of PS II(PS II),the photochemical quenching coefficient(q P)and the leaf electron transfer rate(ETR)of the summer maize were significantly increased by applying potassium fertilizer,the initial fluorescence intensity(F0)was lower,the non-photochemical quenching the coefficient(q N and NPQ)was significantly reduced.The indicators of Zhengdan 958 were higher at K2 O 90 kg/hm2,and Xundan29 can reach a higher level at K2O180kg/hm2.3.Lodging rate and plant height,ear height and third stem internode length of high-yield summer maize were significant or highly significant positive correlation,and the diameter of third internode stem,the thickness of stem bark,the tensile strength of the field and the chemical content of stem had a significant or highly significant negative correlation.Grain yield and the photosynthetic rate of ear leaf,transpiration rate,stomatal conductance,conversion efficiency of light energy function(Fv/Fm),the actual photochemical efficiency of PS II(? PS ?),photochemical quenching coefficient(q P)and electron transfer rate(ETR)were significant or highly significant positive correlation,and initial fluorescence intensity(F0)and non-photochemical quenching the coefficient(q N and NPQ)were significant or highly significantly negative correlation.4.The stalk cellulose,hemicellulose,lignin,the content of soluble sugar and potassium,the tensile bending strength of the summer maize were significantly increased by applying potassium fertilizer,the intensity of stalk,the thickness of stem bark,inhibition of internode elongation were also improved,the plant height,ear height,ear coefficient were declined,the tensile bending strength of the field and lodging resistance were improved.Application of potassium fertilizer can improve the function leaves of summer maize photosynthetic fluorescence characteristics and the enzyme activity of carbon and nitrogen metabolism,promote the leaf photosynthesis,enhance the carbohydrate accumulation;A moderate amount of potassium fertilizer can promote the absorption of nutrients utilization on summer maize,so as to realize the further increase of summer maize. |
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