【作者】 李富宽；

【导师】 沈益新；

【作者基本信息】 南京农业大学 ， 动物营养与饲料科学， 2004， 硕士

【摘要】 紫花苜蓿(Medicago sativa L．)是著名的多年生优质豆科牧草，具有广泛适应能力，近年在山东省逐步普及种植。针对山东省紫花苜蓿种植区土壤肥力低，除速效钾含量相对丰富外，有机质、全氮及全磷含量均不能满足植物的正常生长需要的情况，田间试验研究了施磷和接种根瘤菌对紫花苜蓿生长及品质的影响。 试验结果表明，基施磷肥显著改善了紫花苜蓿根瘤的结瘤。施磷后，紫花苜蓿结瘤率明显提高，单株根瘤数和根瘤重均显著增加(p＜0.05)。因单株根瘤数和根瘤重与共生固氮强度明显正相关，说明施磷肥明显提高了根瘤共生固氮的效果。基施磷肥对紫花苜蓿的出苗、立苗及生长均有显著的改善和促进效应，并显著提高了紫花苜蓿的干物质产量。施磷后，紫花苜蓿出苗率、成苗率、越冬成活率(秋播)及单位面积植株数均显著提高，单株分枝数增多，叶面积指数上升，所有这些构成了紫花苜蓿干物质产量提高的重要因素。追施磷肥对紫花苜蓿的促生长效应同基施磷肥。 试验结果还表明，基施磷肥改善了紫花苜蓿的饲草品质。施磷后，紫花苜蓿叶绿素含量提高，光合生产能力增加，水溶性碳水化合物含量上井；叶面积指数提高，叶量增加，干物质体外消化率增加。追施磷肥对紫花苜蓿还具有显著降低饲草中性洗涤纤维含量的作用(p＜0.05)，但追施磷肥对第2茬饲草品质影响不大。这可能与施肥时间过长磷肥肥效降低有关。 比较各种施磷肥量的效应，黄河三角洲地区种植紫花苜蓿以基施磷肥750kg/hm2效果较好；德州地区以种植中牧1号施磷肥750kg/hm2产量较高(基施或追施)，以种植金皇后施磷肥1175kg/hm2营养品质较好(基施或追施)。 接种根瘤菌也显著提高了紫花苜蓿的结瘤。与未接种根瘤菌小区相比，接种根瘤菌后结瘤率平均提高3～20％。同时，单株根瘤重和根瘤数均显著增加(p＜0.05)。接种根瘤菌也显著促进了紫花苜蓿生长。试验结果表明，接种根瘤菌后，紫花苜蓿出苗率、越冬成活率(秋播)及单位面积成苗数明显增加，生长加快。接种根瘤菌虽然也有提高干物质产量及改善饲草品质的倾向，但不如施磷效果显著。更多还原

【Abstract】 Alfalfa (Medicago sativa L.) is a famous species for the production of high-quality forage in Shandong area. But it is susceptible to a variety of stresses that can combine to reduce dry matter yield and forage quality. A field trial was carried out in Shandong area in order to investigate the effects of a superphosphate fertilizer application and inoculation with rhizobia on growth and forage quality of alfalfa.The results showed that basic phosphorus fertilizer application increased significantly (p<0.05) nodulation rate, root nodule number and weight per plant. Beacause biological nitrogen fixation (BNF) was closely associated with root nodule number and weight per plant; phosphorus fertilizer application could significantly improve BNF of alfalfa. After application, germination rate, percentage of plant set, overwinter survival, plant No. per sq.m, branch number, plant height, stem diameter and leaf area index of alfalfa were all dramatically increased (p<0.05). All these factors resulted in remarkably increasing of dry matter yield. Applying additional phosphorus fertilizer also improved significantly growth situation of alfalfa. And the factors that resulted in increases of dry matter yield are the same as above-mentioned.Phosphorus fertilizer had a very marked effect on forage quality of alfalfa. After application, photosynthesis and water-soluble carbohydrate of alfalfa were all significantly (p<0.05) increased with the increasing of chlorophyll content of leaf, and in vitro dry matter digestibility was increased markedly result from the increasing of leaf yield after phosphorus treatment. But P-topdress had less effect on forage quality of the 2nd cut of alfalfa because it was too long to be effective after application probably.It is concluded from the results that alfalfa grown in the Yellow River Delta should be applied 750kg/hm2 basic superphosphate fertilizer (to Zhongmu No.1), and in Dezhou area should be applied 750kg/hm2 superphosphate fertilizer (basic or top application) to Zhongmu No. 1 or 1175kg/hm2 superphosphate fertilizer (basic or top application) to Gold empress, among which Zhongmu No.1 had the highest yields and Gold empress had the best quality forage.Inoculation with rhizobia could also significantly (p<0.05) improve nodulation situation of alfalfa. After inoculation, nodulation rate was increased 3~20% higher thanthat in un-inoculation plot. Root nodule number and weight per plant were all increased significantly (p<0.05) too. Rhizobia inoculation also had better effect on growth and forage quality of alfalfa. The results showed that rhizobia inoculation significantly (p<0.05) increased germination rate and plant No. per unit, then improved growth situation and dry matter yield. But the effects of inoculation were less significant than that of superphosphate fertilizer application.更多还原