Effects Of Different Nitrogen Forms And Film Mulching Methods On Nitrogen Metabolism And Yield Formation Of Spring Maize

Different nitrogen forms and cultivation patterns are key factors exerting influence on crop growth,metabolism and yield formation.In this study,the effects of nitrogen ratio(ammonium nitrate ratio 1:0,1:1,1:3,3:1,0:1)on the growth and development of maize,the activity of nitrogen metabolism key enzyme and its products and yield were studied.The suitable nitrogen form ratio for high-yield corn in dryland was selected.This study aims to provide relevant theoretical basis and technical guidance for the film mulching cultivation of dryland maize.The main results are as follows:1.Compared with the treatment of full film flat sowing,the full film mulching and double ridge planting pattern could increase the plant height,the stem diameter and the leaf area index of maize.The plant height,stem height and leaf area index were increased by10.35 cm,3.5% and 0.21,respectivly.The difference was significant except the seedling stage.The treatments of two forms nitrogen could significantly increase the plant height,stem diameter and leaf area index of maize.It was the most favorable for the growth of maize when the ratio of nitrogen was 1:1 and 3:1.2.Compared with the full film mulching and flat planting,the full film mulching and double ridge furrow planting significantly promoted the chlorophyll SPAD value and dry matter accumulation of maize.The treatments of two forms nitrogen could significantly improved the chlorophyll SPAD value and dry matter accumulation of maize.The chlorophyll SPAD value and the increase of dry matter increased with the ammonium nitrogen ratio increasing in the seedling stage and the nitrate nitrogen ratio increasing in the later period of maize respectively.The nitrogen ratio of 1: 1 and 3:1 were helpful to maize chlorophyll SPAD value and increase the dry matter accumulation.3.Compared with the full film mulching and flat planting,the full film mulching and double ridge furrow planting mode significantly increased the activities of key enzymes of nitrogen metabolism(NR,NiR,GS and GOGAT)in maize.The combination of two forms of nitrogen was more beneficial to improve the activity of nitrogen metabolism key enzymes in maize leaves compared with the treatment of single form nitrogen.It was the best when the ratio of nitrate and ammonium nitrogen was 3:1.4.The full film mulching and double furrow sowing cultivation mode is beneficial to increase the leaf soluble protein and free amino acid content of maize.Under the same cultivation mode,the content of soluble protein and free amino acid in maize leaves were significant different under two different nitrogen ratios.The content of soluble protein and free amino acid in maize leaves increased with increasing of the ratio of nitrate nitrogen and were largest when the ratio of nitrate and ammonium nitrogen was 3:1.5.Different nitrogen forms and film mulching methods significantly affected grain yield and harvest index of spring maize.Compared with the full film flat sowing,the ear length under the full film mulching and double ridge furrow planting increased by 3.67%~13.76%,the ear diameter increased by1.42%~12.74%,the number of rows increased by 6.9%~30.61%,the grain number and the 100 grain weight increased by 10.9%~37.06% and 1.42%~9.06%,respectively.The grain yield was significantly increased by 12.81%.The combination of two forms of nitrogen was more beneficial to increase the grain yield and harvest index of maize than the single form nitrogen.The ratio of nitrate and ammonium nitrogen of 1:1 and 3:1were more beneficial to increase the grain yield and the harvest index.