【摘要】 以多年生的豆科牧草柱花草和禾本科牧草扭黄茅和孔颖草为试验材料，通过田间实验研究不同氮磷水平下3种牧草的生长量、总生物量、不同深层根系的生物量。试验结果表明，与未施氮磷对比，P1水平扭黄茅10～20 cm根层生物量有显著差异（p<0.05）外，氮磷的施用对3种牧草地上部生长和地下部生物量和3个根层的生物量没有显著差异(p>0.05)。N1(120 kg/hm~2）水平下均能提高3种牧草生物量，N2(240 kg/hm~2）水平下对3种牧草生物量影响不大，说明适量施氮有利3种牧草的生长。与未施氮（N0）对比，除了N2(240 kg/hm~2）水平柱花草0～10 cm根层生物量减少外，3种牧草0～10 cm和10～20 cm根层生物量均为增加趋势。2个氮水平均能提高柱花草在0～10 cm根层生物量的比例，而扭黄茅和孔颖草在10～20 cm根层生物量的比例增加。与未施磷（P0）对比，P1(37.5 kg/hm~2）水平可以促进3种牧草的生长，3种牧草的生物量及0～10 cm和10～20 cm根层生物量有增加趋势，P2(75 kg/hm~2）水平影响不大。表明适量氮磷的添加有利3种牧草的生长，即种植当年氮的推荐施用量120 kg/hm~2，磷的施用量37.5 kg/hm~2。更多还原

【Abstract】 In a field experiment three species of perennial forages,Stylosanthes guianensis （leguminous forage）,and Heteropogon contortus and Bothriochloa pertusa （gramineous forages）,were treated with nitrogen fertilizer and phosphorus fertilizer at three levels,and their growth,total biomass,and root biomass at different soil layers were determined and analyzed.The results showed that as compared with the control without nitrogen fertilizer and phosphorus fertilizer,the phosphorus fertilizer treatment （P1） had a significant effect （p<0.05） on the root biomass of the three forage species at the 10-20 cm soil layer,while the nitrogen fertilizer and phosphorus fertilizer had no significant effect on the plant growth and total root biomass of the three forage species and root biomass at three different soil layers （p>0.05）.The nitrogen fertilizer treatment N1(120 kg·ha^–1) increased the biomass of the three forage species,while the treatment N2(240 kg·ha^–1) had little influence on the biomass of the three forage species,indicating application of nitrogen fertilizer at an adequate rate is conducive to the growth of the forages.Compared with the control without nitrogen application （N0）,the nitrogen treatments N1 and N2 tended to increase the root biomass of the three forage species at the0-10 cm and 10-20 cm soil layers except the root biomass at the 0-10 cm soil layer under the treatment N2(240 kg·ha^–1) which was decreased.The nitrogen treatments N1(120 kg·ha^–1) and N2(240 kg·ha^–1) increased the proportion of S.guianensis root biomass at the 0-10 cm soil layer,and enhanced the proportion of root biomass of H.contortus and B.pertusa at the 10-20 cm soil layer.Compared with the control without phosphorus fertilizer （P0）,the phosphorus treatment P1(37.5 kg·ha^–1) promoted the growth and biomass of the three forage species and their root biomass at the 0-10 cm and 10-20 cm soil layers,while the treatment P2(75 kg·ha^–1) had little influence.All these results suggest that application of nitrogen and phosphorus fertilizers at an appropriate rate is beneficial to the growth of the three forage species.These three forage species are recommended to apply with nitrogen fertilizer at 120 kg·ha^–1 and phosphorus fertilizer at 37.5 kg·ha^–1 in the same year of planting.更多还原