坝上地区紫花苜蓿氮、磷、钾肥料效应与推荐施肥量

采用"3414"试验设计,进行田间试验,研究了坝上地区紫花苜蓿氮、磷、钾肥料效应及推荐施肥量。结果表明:在偏干旱条件下,施氮提高紫花苜蓿产量8%～25%,施磷增产率在122%～172%之间,施钾降低紫花苜蓿产量0～12%;与无肥处理相比,缺磷处理减产38.24%,其余处理增产26%～68%,高磷处理增产率最高(67.94%);氮钾互作效应降低紫花苜蓿产草量,而磷钾和磷氮互作效应为提高;缺氮、缺磷和缺钾处理的相对产量分别为75.02%、36.78%和91.60%,土壤速效氮、速效磷和速效钾的丰缺状况依次为中等、极缺和丰富。结合肥料效应函数法和养分丰缺指标法,得出坝上地区旱作条件下紫花苜蓿推荐年施氮(N)、磷(P2O5)和钾(K2O)量分别为80、50和60kg/hm2。

Effects of N, P and K Fertilizer on Alfalfa and Recommended Fertilizer Rate in Bashang Area

The effects of N,P and K fertilizer on alfalfa were studied in field using "3414" design in Bashang area and fertilizer rate for alfalfa was recommended in order to provide the scientific basis for alfalfa fertilization.The results showed that the yields of alfalfa under drought conditions in the partial increased by 8%～25% by applying N fertilizer,while increased by 122%～172% by applying P fertilizer,but reduced by 0%～12% by applying K fertilizer;compared with no fertilizer treatment the yields was reduced by 38.24% under phosphate fertilizer deficiency treatment,yields were increased by 26%～68% under all other treatments,and the increase rate under phosphate fertilizer abundance treatment was the highest(67.94%);the alfalfa yields were increased by interaction effects between P and K and between N and P,but reduced by interaction effects between N and K;the relative yields of alfalfa under nitrogen fertilizer deficiency treatment,phosphate fertilizer deficiency treatment and potassium fertilizer deficiency treatment was 75.02%,36.78% and 91.60% respectively;the abundance and deficiency condition of available nitrogen,available phosphorus and potassium were medium,serious deficiency and great abundance.By the method of fertilizer effect function and abundance and deficiency index of nutrient,the proper amount of N for alfalfa was 80 kg/ hm2 every year,the proper amount of P2O5 was 50 kg/ hm2,and the proper amount of K2O was 60 kg/ hm2 in Bashang area.