| One-time application of new fertilizer is an important cultivation measure to improve maize yield,nitrogen use efficiency and save labor cost simultaneously.In spring maize production,low temperature induced slow growth rate and less dry matter accumulation,and the long growth period caused large run off loss of fertilizers if fertilization was conducted at sowing time.In the present study,two maize varieties,namely,Suyu30(SY30)and Jiangyu877(JY877),which were widely planted in Jiangsu Province,were selected as test materials.Under field conditions,405 kg N/hm2 of amino acid compound fertilizer(N-P2O5-K2O=27%-9%-9%)was one-time applicated at sowing stage(SF-0),3-leaf stage(SF-3)and 6-leaf stage(SF-6).No fertilizer(F0)and conventional fertilizer 405 kg N/hm2(CF)(basal application of common compound fertilizer 135 kg N/hm2(N-P2O5-K2O=15%-15%-15%),topdressing urea(N=46%)225 kg N/hm2 at jointing stage,and 45 kg N/hm2 at flowering stage)were used as controls.The effects of different fertilization treatments on the growth and development of maize plants,physichemical properties of maize leaves,roots and soil at the silking stage(R1),milk-stage(R3)and maturity(R6)were studied.The physiological mechanism involved in the grain yield,dry mater accumulation,transport and distribution as well as nitrogen absorption and utilization of spring maize were clarified.The main results were as follows:1.Compared with conventional fertilization mode,one-time application of amino acid compound fertilizer could significantly increase grain number per ear,1000-grain weight and yield of spring maize.Compared with CF,the grain yields(mean of three years)of SF-0,SF-3 and SF-6 were increased by 8.1%,11.6%and 17.2%in SY30,and by 6.2%,6.5%and 16.0%in JY877.The grain yield in 3 years was the highest under SF-6 treatment,and the average yield of SY30 and JY877 was 10863 and 11536 kg/hm2,respectively.2.Compared with conventional fertilization mode,the application of amino acid compound fertilizer could efficiently improve the post-silking dry matter accumulation,ultimately increasing the total dry matter accumulation.Under the same fertilization rate,compared with CF,the dry matter accumulation of SF-0,SF-3 and SF-6 was increased by 3.7%,8.7%and 11.4%in SY30,and 11.9%,10.5%and 18.6%in JY877 The total dry matter accumulation under SF-6 treatment was the largest,and the average annual dry matter accumulation of SY30 and JY877 was 23058 and 23912 kg/hm2,respectively.Compared with conventional fertilization mode,one-time application of amino acid compound fertilizer significantly increased the dry matter transition amount,but unaffected the transition rate,contribution rate,and harvest indexof both varieties.3.Compared with conventional fertilization mode,the application of amino acid compound fertilizer could effectively improve the nitrogen absorption and utilization of spring maize.In comparison to CF,the average annual increase of nitrogen accumulation in SF-0,SF-3 and SF-6 was increased by 10.8%.17.0%and 24.2%in SY30,and by 9.1%,10.6%and 19.4%in JY877.The total nitrogen accumulation was the largest under SF-6 treatment,and the average annual nitrogen accumulation was 292 kg/hm2 for SY30 and 296 kg/hm2 for JY877,respectively.Compared with CF,the average annual NUE of SF-0,SF-3 and SF-6 was increased by 6.1%.9.6%and 13.8%in SY30,and by 5.5%,6.5%and 11.8%in JY877.Compared with conventional fertilization mode,one-time application of amino acid compound fertilizer significantly increased the nitrogen transition amout of SY30 and JY877,and the PEP,AE and NUE increased,and the increase was the highest under SF-6.The fertilization modes unaffected the nitrogen transition rate,nitrogen contribution rate and harvest index.4.Compared with the conventional fertilization mode,the application of amino acid compound fertilizer significantly increased the activities of metabolic enzymes in soil,roots and leaves of spring maize,increased the contents of organic matter,total nitrogen and inorganic nitrogen in soil at the later growth stage,and ultimately improved the photosynthetic productivity.The contents of soil organic matter,total nitrogen,inorganic nitrogen and the enzymatic activities of ASPD,GAD,TDC,TSA,LS,TGS,NR,DHO,POD,CAT,PHO,Ure,Inv and Pro were all the highest in SF-6 than those in other treatments.The activities of NR,GS,GOGAT,SOD,POD,CAT and root activity after silking were higher than those of other treatments,while the content of MDA in root was the lowest.Leaf SPAD,net photosynthetic rate,LAI,soluble protein content,soluble sugar content and enzymatic activities of NR,GS,GOGAT,RuBPCase,PEPCase,SOD,POD,CAT,SS and SPS were all higher than those of other treatments,while MDA content was lowest after silking.5.The results of the three years experiments showed that one-time application of amino acid compound fertilizer at the 6-leaf stage could improve the soil enzyme activity,increase soil nutrients,promote the carbon and nitrogen metabolism of leaves,delay the senescence of leaves and roots,enhance the root activity and leaf photosynthetic capacity of plants,and promote the dry matter and nitrogen accumulation,ultimately increase the grain yield of spring maize.In spring maize production in Jiangsu Province,the application of 405 kg/hm2 of amino acid compound fertilizer at the 6-leaf stage was beneficial to the high-yield and high-efficiency cultivation. |
