【作者】 陈述明；

【导师】 李卫军；

【作者基本信息】 新疆农业大学 ， 草业科学， 2005， 硕士

【摘要】 通过不同株、行距配比设置12种不同的种植密度,研究不同密度对二年龄苜蓿生长发育特征、冠层结构和种子产量的影响,找出不同种植密度下的苜蓿冠层发育特征、叶面积发育规律、群体透光率变化规律和种子结实特性。结果表明,在苜蓿营养生长期,密度对苜蓿的高度和生长速度影响不大,但在生殖生长期,会影响苜蓿的高度和生长速度,其中行距对其影响不显著,株距的影响有显著差异。在初花期和盛花期,随种植密度增大,苜蓿叶面积系数有增大的趋势,而在结荚期,苜蓿叶面积系数随种植密度增大有减小的趋势。在结荚期小叶面积小于初花期和盛花期的小叶面积。不同密度处理之间叶面积系数的差异是由叶片数量不同而引起的。在苜蓿生长发育前期,各处理之间土壤平均含水量没有显著差异,在苜蓿生长发育后期,不同处理土壤平均含水量出现差异,随密度增大,后期土壤平均含水量随时间下降的速度减缓,到苜蓿种子收获时高密度的处理土壤含水量较高。密度对节间数的影响大于对节间长度的影响。不同密度处理之间每个一级分枝上形成的二级分枝数有显著差异。随着株距的增加,二级分枝数呈上升的趋势,差异显著(p<0.05),而相同的株距不同的行距各处理之间二级分枝数差异不显著。在苜蓿的种子产量构成因素中,苜蓿单株的生殖枝数和种子产量具有很高的相关性(r=0.859),随着密度的增加,单位面积上的苜蓿生殖枝条数呈上升的趋势,但无效的二级分枝数也随密度的增加而增加。密度的增加不利于苜蓿单株种子产量的提高,对于二年龄的苜蓿,当株距小于20cm 时,株距对苜蓿种子产量的影响远大于行距,株距越小,种子产量越低。当株距大于20cm 时,增大行距虽然单株种子产量有所提高,但群体产量开始下降。更多还原

【Abstract】 Through different planting density treatments of different row space and plant space, we study on the change of row space and plant space and the relationships between two-year-alfalfa growth, fructification, colony development traits, light pass thought ratio, the change of soil water content, the change of LAI and seed yield component. Planting density lever designed: row space of 60cm, 80cm, 100cm and plant space of 2cm, 10cm, 20cm, 30cm, its add up to 12 treatments. Results showed that planting density has littler influence on height and growth speed at vegetable stage, but planting density has significance influence on height and growth speed at budding stage and flower stage. At flower stage, LAI increased when planting density was increased, while it fall down at pod stage. Leaves area at pod stage was less than it at initiation flower stage and full-blown stage. No significant difference was fled on leaf area between all treatments. At the early stage, No significance difference was fled on average soil water content between all treatments, but at harvesting stage, the average soil water content of high-planting-density treatments was higher than low-planting-density treatments. Effect of planting density on the amount of nods was more than it on the length of nodes. Significance difference was fled on the first grade valid branch and the second grade valid branch between higher-plant-space treatments and lower-plant-space treatments. With the increasing of plant space, the amount of the second grade valid branch was increasing. The correlation coefficients were very high between the amount of fertile branch and seed yield (r=0.859). The amount of fertile branch per square meter increased when enlarged planting density. Results show that the influence of plant space upon alfalfa seed yield was far larger than row space, when plant space less than 20 cm, the lessen the plant space, the lower seed yield we got.更多还原