施磷和接种根瘤菌对黄河三角洲紫花苜蓿生长及品质的影响

Effect of superphosphate application and rhizobia inoculation on growth and forage quality of Medicago sativa in the Yellow River Delta

田间试验研究了施磷肥和接种根瘤菌对黄河三角洲地区紫花苜蓿生长及品质的影响。结果表明,播种前施磷肥能明显提高紫花苜蓿的出苗和成苗率,显著提高紫花苜蓿的叶茎比、叶面积指数、叶绿素含量,并提高干物质产量12.9%～85.5%。施磷肥还显著提高了紫花苜蓿地上部可溶性碳水化合物和粗蛋白质的含量,降低了中性洗涤纤维含量,使饲草体外干物质消化率增加0.73%～8.49%。播种时接种根瘤菌能显著增加紫花苜蓿单株根瘤结瘤数和平均根瘤重,并能改善苗期的生长,但对干物质产量影响不明显。试验结果显示,黄河三角洲地区种植紫花苜蓿施用过磷酸钙750kg/hm2,并接种根瘤菌可获得较好的提高产量和改善品质的效果。

This paper details the results of a field trial which was conducted in the Yellow River Delta in order to investigate the effects of the application of superphosphate fertilizer in conjunction with rhizobia inoculation on the growth and forage quality of M. sativa. Results indicated that the application of superphosphate fertilizer increased seedling emergence and the percentage of plant set significantly (P<0.05). The application of superphosphate fertilizer also significantly improved the leaf/stem ratio, leaf area index and chlorophyll content compared with the control (P<0.05), with the dry matter yield increasing from between 12.9% to 85.5%. Significant differences were shown to occur in the number and weight of root nodules between plots with and without rhizobia inoculation. Rhizobia inoculation treatments, however, had less of an effect on the dry matter yield. The content of water-soluble carbohydrate and crude protein was increased significantly (P< 0.05) in all treatments compared with the control. Although in treatments where both superphosphate fertilizer and rhizobia inoculation were used the content of neutral detergent fiber decreased. In vitro dry matter digestibility of phosphorus treatments were 0.73%-8.49% higher than the control. Results suggested that M. sativa grown in the Yellow River Delta should ideally have 750 kg/hm^2 superphosphate fertilizer applied in conjunction with rhizobia inoculation in order for the highest yield to occur.