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In this experiment, silage corn combination CAU 1027 as test material , respectively, of the 5 kinds of density and nitrogen levels of silage corn yield and forage quality ; yield and forage quality under different harvest periods and harvesting height the comparison . Obtain the following results : ( 1 ) with increasing density , leaf area index of corn silage significantly increased ; ear leaf chlorophyll content and group production first increased and then decreased , 120,000 / hm2 density of corn silage available highest chlorophyll content and biomass yield ; of silage corn organs crude protein content decreased gradually , NDF , ADF and ADL content increased gradually ; ear leaf nitrate reductase activity decreased . The whole growth period , whole plant dry matter crude protein content and density was negatively correlated ; NDF content and ADL content and density is positively correlated ; big mouth and milk stages , a positive correlation between the ADF content and density in the silking stage. and filling stage , and the density was quadratic parabola regression relationship . 2 jointing stage to Shi 135kg/hm2 nitrogen , leaf area index of corn silage and whole plant biomass of the highest yield ; same amount of nitrogen do the base fertilizer likened jointing fertilizer , cellulose and lignin can reduce the whole plant dry matter ; appropriate to increase the jointing fertilizer , can improve the CP content of the silage corn ; jointing stage once adequate facilities nitrogen fertilizer applied the same amount of nitrogen fertilizer jointing - big mouth , and obtain higher biological yield and forage quality . With the harvest height increases, the protein yield and dry matter yield decreased in varying degrees , but gradually increased corn silage forage quality , with the extension of the harvest period , rising corn silage dry matter yield , moisture content and CP content decreased gradually , NDF and ADF content increased at first and then decreased ADL content did not change significantly . Low-density ( 120,000 / hm2 ) in the whole growth period , low water content , dry matter production rose faster ; higher water content of the high-density ( 120,000 / hm2 ) , early dry matter yield increased rapidly , post - production rises slowly .
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