施肥和播种量对扬州地区苜蓿生长特性和产草量的影响

Effects of Fertilizers and Sowing Rates on Growth Characteristics and Forage Yields of Alfalfa in Yangzhou Region

用裂区试验设计研究扬州地区苜蓿(Medicago sativa)不同播种量和施肥水平对产草量及生产性能的影响。结果表明:江淮地区苜蓿推荐播种量为18.75kg·hm-2,氮、磷、钾推荐施用量分别为23,113,68kg·hm-2时,此时苜蓿的理论产草量可达22858.25kg·hm-2。单独施用氮、磷、钾肥时,在一定范围内对苜蓿产草量有促进作用,但当超过最大施用量时,对苜蓿的生长反而造成抑制。建议氮肥施用量不超过30kg·hm-2,磷肥施用量不超过130kg·hm-2。氮、磷、钾共同施用时苜蓿产草量才能达到最大值;氮肥在苗期、分枝期和初花期对苜蓿植株生长均有一定的促进作用;磷肥促进苜蓿主枝数的增加,氮钾肥有利于苜蓿侧枝数的生长。

The optimum application rates of nitrogen（N）,phosphorus（P）,potassium（K） and sowing rates on forage yield of alfalfa（Medicago sativa L.） were determined in this study.A randomized spilt-plot was designed with three replications.Results indicated that a maximum yield（22858.25 kg·hm-2） was obtained with N 23,P 113,K 68 kg·hm-2 fertilizers and 18.75 kg·hm-2 sowing rate in the field experiment of Yangzhou.Forage yields were improved by applying N,P,K fertilizer separately within proper application rates.N,P,K over-application was a negative influence on the forage quality of alfalfa.The limited levels of N and P fertilizers were 30 and 130 kg·hm-2.N fertilizer promoted plant growth at sowing stage,branching stage and initial flowering stage.P increased the number of branch.K increased the number of sub-branch.