The Effects Of Population Density And Nitrogen Fertilizer On The Growth And Yield Of Maize Under Mulched Drip Irrigation

The study was conducted directly against the ecological characteristics of west semiarid area with the condition of existing well-organized mulch trickle irrigation of maize in Jilin Province.The experiment studied the effects of different population density and nitrogen level morphological characteristics,accumulation of dry matter,photosynthetic characteristics,main physiological index and yield of maize,this study analyzed intrinsic mechanism of yield difference compared with the condition of non-mulch trickle irrigation,and discussed the optimal fertilization amount and planting density in condition of mulch trickle irrigation,the goal of the study is to provide theoretical and practical basis of high and stable yield for maize in west semiarid region of Jilin province.The main conclusions are as follows:1、Acording to the research results of the population density effects on growth and yield of corn conducted by mulchied drip irrigation have showed that: in the coventional non-mulch drip irrigation planting mode,the maximum value of plant height,leaf area index LAI,maize ear unit internode dry weight and grain yield were all appeared in 65 thousand strains every hectare.In the mulched drip irrigation planting mode,the maximum value of the best density index was higher than that of the control.As the density increasing,the two modes of the weight of the group dry materials on the ground increased firstly,and then these would decreased,the maximum value were all appeared in the 80 thousand strains every hectare.Under the same density,in the early incubation stage（within 30⁷5 days after emergence）,the weight of group dry materials conducted by mulched drip irrigation was significantly higher than that in the control,in the late incubation stage（105 days and 130 days after emergence）,the control conducted by non-mulch drip irrigation has incentive the weight of group dry materials rapidly,there was no significant difference with mulchined drip irrigation treatments.2、The effects of population density on the growth and yield of maize under mulch trickle irrigation were studied and the results showed that: The chlorophyll content,net photosynthetic rate,transpiration rate,water use efficiency（WUE）,stomatal conductance of leaves,which of the mulch trickle irrigation treatments were higher than non-mulch trickle irrigation treatments under the condition of the same density in 20 days after flowering and the results were opposite in 40-50 days after flowering.All the physiological indexes of 65 thousand strains treatment（M-6.5）were higher than others among different treatments.The leaves PEP carboxyl enzyme activity of M-6.5 was highest among different treatments and leaves PEP carboxyl enzyme activity of M-5.0 and M-6.5 were not significant difference,but which were higher than other treatments,especially were significant in late growth stage in the condition of non-mulch trickle irrigation.The leaves SPS activity of M-6.5 was highest among different treatments in filling stage.SPS activity of mulch trickle irrigation treatments began to fall after 30 days of flowering with prolong of the time after flowering in the density of M-6.5,but the control treatments began to fall after 20 days.3、Acording to the research results of the effect of the same nitrogen nutrient level to the yield of plant and growth of the maize conducted by mulchined drip irrigation have shown:the value of plant height,the maximum dry material weight and the dry materials weight of the organs conducted by the mulchined drip irrigation were higher than those of the non-mulchined drip irrigation treatment.With the increase of nitrogen fertilization application rate,the dry materials of each organ was increased firstly and then decreased,and the maximum dry materials and maturial dry materials weight of leaf,sheath,stem and tassel reached the highest value at 300 kg hm^-2 of nitrogen fertilization application rate.The nitrogen accumulation of maize was increased firstly and then decreased as the increase of the density.the highest nitrogen accumulation of corn conducted by the mulchined drip irragtion appeared at 200 kg hm^-2 of nitrogen fertilization application in 45-75 days after emergence.But the max nitrogen accumulation of MN300 was appeared in 90-120 days,and the max nitrogen accumulation of the all growth processing of the maize conducted by non-mulchined drip irrigation was appeared at 300 kg hm^-2.in the mulchined drip irrigation mode,the max production of the corn appeared at the 200 kg hm^-2 of nitrogen application rate,and there was no significant difference of the yield of maize between 300 kg hm^-2 and 300 kg hm^-2.The yield of maize under non-molchined drip irrigation was the highest Is 300 kg hm^-2.4、Acording to the research results of the effects of nitrogen nutrition level on photosynthetic and physiological characteristics of maize leaves conducted by mulchined drip irrigation:appropriate amount of nitrogen fertilizer can significantly improve the photosynthetic properties of leaves,With the increase of nitrogen application rate,leaves gas exchange parameters also increased gradually,When the nitrogen fertiliziation exceeded 300 kg /hm2,the every indexes began to decline;In the fluorescence induction kinetic parameters,The max photochemical efficiency（Fv/Fm）was more sensitive to the change of cropping patterns,The mean Fv/Fm of each treatment under mulch drip irrigation was significantly higher than that in the same field,Fv / Fm also increased with the increase of nitrogen application rate,In the two treatments with high nitrogen(300 and 400 kg hm^-2),There was no significant difference in Fv / Fm.In both modes,the activities of PEP and RUBP carboxylase,nitrate reductase（NR）and glutamine synthetase（GS）in the ears of maize were increased by applying nitrogen fertilizer,and decreased the activity of endopeptidase and aminopeptidase in leaves.To sum up,in semi-arid region in the West of Jilin province,under the condition of drip i rrigation under plastic film,corn planting density may reach 80,000 plants every hectare,although the photosynthetic characteristics and key enzyme activity is not optimal,dry matter accumulation and transcription of grain dry matter is high,and have higher yields.When the nitrogen fertilizer application amout is 300 kg hm^-2,the light collection,and nitrogen metabolism enzyme of synthesis and the nitrogen accumulation were higher than others,but there was no significantly differences between N200 and N300.So,in actual production,we can apply low nitrogen fertilizer in the early growth,and apply much more nitrogen fertilizer in later growth to avoid late appeared leaves premature phenomenon.