不同播期对紫花苜蓿生长性状及越冬性的影响研究

Effects of Sowing Dates on Alfalfa Productivity and Winter Ability

采用随机试验设计方法,在宁南旱作农业区进行了不同播期对紫花苜蓿出苗率、生长发育、越冬率和产草量影响的研究。结果表明,在宁南地区人工种植紫花苜蓿的出苗率与播期温度存在极显著正相关关系,而不同播期土壤耕层含水量变化率较小,且基本能满足苜蓿萌发与生长的需要;播期越早,根颈越粗,入土越深,但4月份前播种,出苗率低,群体小且易形成"小老苗";7月份以后播种,由于生长期短,植株根颈细嫩,越冬率很低或完全冻死。综合不同播期出苗率、产草量和越冬率等因素,认为在宁南地区紫花苜蓿的适宜播种期应在4月30日～6月30日。

A randomized block design was adopted to study growing characteristics,winter-survival rate and hay yield of alfalfa sown in dryland-farming regions of southern Ningxia province on different dates.The results showed that the emergence rate of alfalfa seedling had an extremely significantly correlation with the temperatures on the sowing dates in high and cold regions of southern Ningxia province and that the contents of topsoil water on different sowing dates very slightly differed so that they were capable of meeting with the requirements of alfalfa germination and growth;the earlier alfalfa was sown,the thicker and deeper its crowns grew;and when it was sown before April,it had a very low seedling-emergence rate and a small population,and tended liable to form stunted seedlings.When it was sown after July,it formed thin and tender crowns due to its short growth period and thus survived in winter at a very low rate,even frozen to death in winter.In terms of such traits as hay yield and winter survival,it was held that the optimal sowing time of alfalfa should be between April 30 and June 30.