Research Of Plant Density And Mixed Planting Of Silage Corn In The Second Accumulated Temperature Zone Of Heilongjiang

Silage corn (Zea mays L.) is an indispensablely basic feed of stockbreeding. Dairy industry developes rapidly in the second accumulated temperature zone of Heilongjiang province, and in recent years plant area of silage corns is growing quickly,reached to 400000 hm2 in 2007.But low plant density has serious effect on potential productivity of silage corn and reduces yield. In this field experiment, the effects of three plant densities (62000,79500 and 97500 plants/ha) on yield and forage value and neutral detergent fiber in vitro digestibility were studied on 7 silage corn varieties of all over using in the second accumulated temperature zone of Heilongjiang at present.The experiment was to find out suitable plant densities of 7 varieties.At the same time,the mixed planting experiment were studied.The studying results showed as follows:1,In silage corn plant density experiment,the feasible density of the highest fresh yield and dry yield of Zhongyuandan32,Dongqing1,and Gaoyou106 was 79500 plants/ha.The feasible density of the highest crude protein yield, and dry-matter milk production of per mass was 79500 plants/ha. The feasible density of the highest crude protein content,starch content and the lowest NDF content,ADF content was 62000 plants/ha.The feasible density of the optimal comprehensive evaluation of these varieties was 79500 plants/ha.2,The feasible density of the highest fresh yield and dry yield of Jisi9 was 79500 plants/ha.The feasible density of the highest crude protein yield and starch yield dry-matter milk production of per mass was 79500 plants/ha.The feasible density of the highest crude protein content,starch content,dry-matter milk production of per mass and the lowest NDF content,ADF content was 62000 plants/ha.The feasible density of the optimal comprehensive evaluation of these varieties was 79500 plants/ha.3,The feasible density of the highest fresh yield and dry yield, the best forage value and the optimal comprehensive evaluation of Jidan4011 and Tieji11 was 62000 plants/ha.4,In silage corn plant density experiment,according to Milk2000 index comprehensive evaluation, the optimal treatment was Jisi9 in 79500 plants/ha,and the second is Yangguang1in 79500 plants/ha.5,With the density increased,fresh yield and dry yield of Jidan4011 and Tieji11 were decreased,the others were increased firstly and then decreased; crude protein content and starch content of all varieties showed trendency of decrease,and NDF content and ADF content showed trendency of increase.6,In silage corn mixed planting experiment,the difference of yield,NDF content, starch content and ash content between 2 mixed planting combinations and single planting was not significant;the crude protein content and ether extract content of combination 1(Zhongyuandan 32+Jisi9+ Dongqing1) was higher than the other treatments,and feasible density of crude protein content and ether extract content of combination 1 was 79500 plants/ha.