Abstract:

Low temperature in early spring and drought are the main factors limiting the high yield of alfalfa in the northwest desert irrigation area. The planting technology of film mulching can improve the soil ecological environment and crop growth status, and it has become an important measure to promote crop yield and quality in arid and semiarid areas of northwest China. In this paper, film mulching(FM) as treatment, without film mulching as control(CK), the effects of FM on agronomic characteristics and nutritional value of alfalfa were studied at initial flowering stage of two-year, three-year and four-year alfalfa. The results showed that compared with CK treatment, FM significantly increased plant height of the first cutting, the second cutting, the fourth cutting of two-year alfalfa, and improved dry yield of the second cutting (340.19 kg·亩^-1)and dry-fresh ratio of the third cutting of two-year alfalfa. The plant height and dry yield(257.18 kg·亩^-1,250.68 kg·亩^-1) of the second cutting and the third cutting of three-year alfalfa in FM treatment were significantly increased. FM significantly enhanced plant height and dry-fresh ratio of the second cutting and dry-fresh ratio of four-year alfalfa. Meanwhile, FM significantly decreased neutral detergent fibre content and acid detergent fibre content of fourth-year alfalfa, respectively, compared with that in CK. The ether extract content of each cutting of fourth-year alfalfa in FM were significantly improved. To a certain but statistically in significant degree, FM significantly increased calcium and phosphorus content in different years and in different cuttings of alfalfa. As a whole, the total dry yield(1053.06 kg·亩^-1,946.97 kg·亩^-1,1045.50 kg·亩^-1)of alfalfa in different years in FM treatment were increased, and were 11.81%,17.48%,0.43% higher than those in CK.

Key words: Alfalfa, Film mulching, Plant height, Dry yield, Neutral detergent fibre, Acid detergent fibre

摘要：

早春低温及干旱是限制西北荒漠灌区苜蓿高产的主要因子。覆膜种植技术可改善土壤的生态环境及作物生长状况，已成为西北干旱半干旱地区提高作物产量和品质的重要措施。本试验以覆膜（FM）为处理，不覆膜（CK）为对照，研究FM对2龄、3龄及4龄‘三得利’紫花苜蓿（Madicago sativa L.‘Sanditi’）每茬初花期农艺性状及营养价值的影响。结果表明：与CK相比，FM提高了2龄苜蓿第1、2和第4茬草的株高（P<0.05），第2茬草的干草产量（P<0.05，340.19 kg·亩^-1）和第3茬的干鲜比（P<0.05）；提高了3龄苜蓿第2、3茬草的株高（P<0.05）和干草产量（P<0.05，257.18 kg·亩^-1，250.68 kg·亩^-1）；提高了4龄苜蓿第2茬草的株高及鲜干比（P<0.05）。同时，在一定程度上FM显著增加了不同年份不同茬次苜蓿的Ca含量和P含量（P<0.05）。总体而言，FM使苜蓿年总产量比CK分别提高11.81%，17.48%及0.43%，分别达到1 053.06 kg·亩^-1，946.97 kg·亩^-1，1 045.50 kg·亩^-1。

关键词: 紫花苜蓿, 覆膜, 株高, 干草产量, 中洗纤维, 酸洗纤维