The Nutrient Dynamic And Feeding Value Of Corn As Forage

In the ecotone between agriculture and animal husbandry in Northeast China, grassland degradation was serious, because animal husbandry production depended excessively on grassland, which has resulted in the acute contradictions between forage and livestock. Corn was a major crop, resource of corn straw was abundant in this region. So we can use the corn stover to alleviate the feed-animal imbalance.The aims of this paper: First, the change of nutrient of every organ was researched with different height in reproductive period. Second, the effects of different methods of topping and defoliation were compared on the yield of seed, nutrient of seed, and the nutrient value of high quality green feed. Third, the nutrient value of dry corn stover and dry Leymus chinensis were compared. And the conclusions were drawn from the above work.The nutrient value of stover was rapidly decreasing with the extent of growth period of corn, but the seed was gradual mature and the decrease of whole plant nutrient value was slower than the stover(straw). The yield and the nutrient value were equally important when the whole plant was considered. The best harvest time should base on the trade-off the yield and nutrient value. In the present research, the total crude protein per unit area was maximal on Sep 9, 2007 (the 121th days after sowning), while the digestible dry matter yield and total metabolism amount per unit area was maximal on Sep 4, 2007 (the 117th days after sowning). According to these three factors, when the whole plant was used as feed, the best harvest time should be from Sep 4 to Sep 9. However, when the stover was applied as the feed and the yield of seed was not affect, the best harvest time should be Sep 24. If the crude protein content was more than 4%, the top of stover can be used as the feed, and the bottom of stover can be applied as fuel.When the corns were topped and defoliated in reproductive period, the unaffected seed yield and the abundant high quality stover feed can be achieved at the same time, and sometimes, the seed yield may be improved. Compared with the CK, the treatment of topping and defoliation can decrease the crude protein content and improve the crude fat content, but the effect on the crude protein content was smaller than the effect on the crude fat content.In contrast to Leymus chinensis, the crude protein content of corn was lower, while the digestibility and total metabolism amount was higher. Ammoniated method or mixed with legume forage was considered as a way of compensating lack of nitrogen content.