Study on the effect of different application rate of beef cattle feces on yields and nutrients level of dwarf elephant grass and on the degradation rate of dry matter

Chinese. 阐明不同牛粪施用量对矮象草产量、营养物质含量及干物质降解率的影响，旨在通过合理施用牛粪提高矮象草的营养价值、降低牛粪中氮、铁、锌和铜等物质对环境的污染。试验设置不施牛粪（0 kg鲜牛粪/10 kg土）、低量牛粪（3 kg鲜牛粪/10 kg土）和高量牛粪（6 kg鲜牛粪/10 kg土）3组处理，采用盆栽试验和肉牛瘤胃降解试验测定了在不同牛粪施用量下矮象草的产草量、营养物质含量及营养物质降解率的变化。施用低量和高量牛粪均能极显著的（P＜0.01）提高矮象草的茎和叶干物质产量，其中茎干物质产量分别比不施牛粪提高45.5%和54.5%，叶干物质产量分别提高85.7%和121.4%；施用低量和高量牛粪矮象草叶蛋白质含量和中性洗涤纤维含量也显著地（P＜0.05）高于不施牛粪，其中叶蛋白质含量分别提高13.3%和20.9%。矮象草植株中锌和铜累积能力均表现为：根＞叶＞茎。有机物在瘤胃内尼龙袋中的降解率随牛粪施用量的增加和在瘤胃内的停留时间的延长而增加。增加牛粪施用量可提高矮象草的产草量、营养物质含量及干物质在瘤胃内的降解率，从而提高矮象草的饲用价值，减少日粮中蛋白质饲料和微量元素添加剂的使用量，但牛粪的适宜施用量还有待于进一步深入研究。

English. An experiment was conducted to study the effect of different application rate of fresh cattle feces on dwarf elephant grass yield, nutrients content and dry matter degradation rate in order to find a measure to increase nutritive values of dwarf elephant grass and decrease the pollution of nitrogen, ferrus, zinc and copper of feces on environment by the way of reasonable application with cattle feces. Dwarf elephant grass was treated with fresh beef cattle feces at three application rates: control, low application rate (3 kg fresh cattle feces/10 kg soil) and high application rate (6 kg fresh cattle feces/10 kg soil), respectively. The effect of cattle feces on yield, nutrients content and dry matter degradation rate of dwarf elephant grass was studied, the trial of planting dwarf elephant grass was carried out with plastic pot and the trial of degrading dry matter in rumen with nylon bag. These results indicated that low and high application rates of fresh cattle feces significantly (P＜0.01) increased the dry matter yield of stem and leaf, the yield of stem dry matter was 45.5% and 54.5% higher than that of control, the yield of leaf dry matter was 87.5% and 121.4% higher than the control, respectively. Low and high application rates of fresh cattle feces significantly (P＜0.05) increased the level of leaf protein and neutral detergent fibre of dwarf elephant grass, the content of leaf protein in two application rates was 13.3% and 20.9% higher than that of control, respectively. The ability of accumulating Zn and Cu ranked as follows: root＞leaf＞stem. Degradation rate of dry matter increased with the increase of application rate of feces and duration of sample in rumen. The yield, nutrient contents and dry matter degradation rate of dwarf elephant grass increased with the application rate of feces increased, much more works are still needed to be done for the optimum application rate of feces used for planting dwarf elephant grass. To plant dwarf elephant grass with cattle feces is a good method of increasing the level of N, Zn and Cu of dwarf elephant grass and alleviating pollution of feces to environment.