Abstract: To obtain alfalfa hay with high yield and good quality,the effects of N,P,K mixed fertilizing on yield and nutrition of alfalfa (Medicago sativa L. ‘zhongmu No.3’) were studied in Cangzhou of Huang-Huai-Hai area using 3414 quadratic regression optimum design from 2016 to 2017. The results showed that the order of effects on alfalfa hay yield were phosphorus > potassium > nitrogen. The highest yield of 23 657.9 kg·hm^-2 was obtained by treatment 3 (N₁P₂K₂),the combination of N 5.00 kg·hm^-2,P₂O₅ 60.00 kg·hm^-2 and K₂O 180.00 kg·hm^-2. Of the 14 treatments,treatment 7 (N₂P₃K₂) had the highest crude protein content (22.45%),while treatment 6 (N₂P₂K₂) had the lowest crude protein content (16.87%). The lowest content of acid detergent fiber and neutral detergent fiber were from treatment 3 (N₁P₂K₂) and treatment 7 (N₂P₃K₂),respectively. Treatment 7 (N₂P₃K₂) had the highest RFV values (111.36). Comprehensive analysis showed that the nutritional value of treatment 7 (N₂P₃K₂) was high during early flowering period of Zhongmu No.3. Based on the yield model analysis,the maximum yield of 23 918.2 kg·hm^-2 could be obtained by applying N 4.10 kg·hm^-2,P₂O₅ 48.47 kg·hm^-2 and K₂O 270.00 kg·hm^-2 for Zhongmu No.3 alfalfa.

Key words: Alfalfa, Fertilizer, Yield, Quality, Huang-Huai-Hai Area

摘要： 为高产优质苜蓿草地施肥提供科学依据，2016-2017年选择黄淮海地区苜蓿生产的典型区域沧州为试验点，以该地区当家苜蓿品种中苜3号（Medicago sativa L.‘zhongmu No.3’）为试验材料，采用"3414"二次回归最优设计试验方案，研究N，P，K肥配施对紫花苜蓿当年干草产量和营养成分的影响。结果表明，影响中苜3号苜蓿干草产量高低顺序为磷肥>钾肥>氮肥。处理3（N₁P₂K₂）即施N 5.00 kg·hm^-2，施P₂O₅ 60.00 kg·hm^-2，施K₂O 180.00 kg·hm^-2时获得最高产量23 657.9 kg·hm^-2。14个处理组合中，处理7（N₂P₃K₂）粗蛋白含量最高，为22.45%，处理6（N₂P₂K₂）粗蛋白含量最低，为16.87%。酸性洗涤纤维含量最低的处理3（N₁P₂K₂），为34.14%，中性洗涤纤维的含量最低的处理7（N₂P₃K₂），为51.27%。处理7（N₂P₃K₂）相对饲用价值最高，为111.36。综合分析，处理7（N₂P₃K₂）的初花期营养价值较高。根据产量模型分析，中苜3号苜蓿施N 4.10 kg·hm^-2，施P₂O₅ 48.47 kg·hm^-2，施K₂O 270.00 kg·hm^-2时可获得最高产量23 918.2 kg·hm^-2。

关键词: 紫花苜蓿, 施肥, 产量, 品质, 黄淮海地区