Abstract: In order to investigate the effects of fertilizing amount on alfalfa growth and yield in Horqin sandy land, the paper detected the relevant indexes, including fresh grass yield, shoot length, stem diameter, number of branches and plant height of alfalfa in Horqin sandy land under different fertilization levels, and also calculated the growth rate, ratio of stem to leaf, ratio of root to shoot, and ratio of dry weight to fresh weight. The results showed that: ① The branch length of the first stolon, stem thickness and ratio of root to shoot of the second stolon firstly increased along with the increase of fertilizing amount, then decreased. The branch number of the second stolon increased with the increase of fertilizing amount. While, that of the third stolon decreased with the increase of fertilizer application. ② Correlation analysis showed that the order of contribution to alfalfa hay yield was stem diameter > branch number > branch length. ③ The changing growth rate of alfalfa first stolon was relatively stable, and the second and third stolon alfalfa all showed the law of rapid growth in the early stage, then slowed down in the later period. ④ The total yield of alfalfa hay increased first and then decreased with the increase of fertilizing amount, following the law of diminishing return. The total yield of alfalfa hay reached 17 218.9 kg/hm2 when the total fertilizing amount was 656.25 kg/hm2. Therefore, it is recommended that the fertilizing amount was 375 kg/hm2(N 60 kg/hm2, P2O5 56.25 kg/hm2, K2O 56.25 kg/hm2) in period of seedling establishment, 131.25kg/hm2(N 21 kg/hm2, P2O5 19.687 5 kg/hm2, K2O 19.687 5 kg/hm2) after the first cutting, 150 kg/hm2(N 24 kg/hm2, P2O5 22.5 kg/hm2, K2O 22.5 kg/hm2) after the second cutting. And the total fertilizing amount was 656.25 kg/hm2(N 105 kg/hm2, P2O5 98.437 5 kg/hm2, K2O 98.437 5 kg/hm2). The results have provided basis for rational alfalfa fertilizer management in Horqin sandy land.

Key words: grassland 3 alfalfa, forage, fertilization, growth, grass yield

摘要： 为探讨施肥量对科尔沁沙地苜蓿生长及产量的影响，对不同施肥水平下科尔沁沙地的苜蓿干鲜草产量、枝条长度、茎粗、枝条数、株高等相关指标进行检测，并计算生长速率、茎叶比、根冠比、干鲜比。结果表明：①第一茬枝条长度、第二茬茎粗和根冠比均随施肥量的增加呈先升高后降低的趋势，第二茬枝条数随施肥量的增加而增加，第三茬枝条数则随施肥量的增加而降低。②通过相关性分析表明，对苜蓿干草产量贡献大小的指标排序依次为茎粗＞枝条数＞枝条长度。③第一茬紫花苜蓿生长速率变化较为平稳，第二、三茬苜蓿均呈现前期生长迅速后期减慢的规律。④苜蓿干草总产量随施肥量的增加而呈现先增后减的趋势，遵循报酬递减规律，在总施肥量为656.25 kg/hm2时苜蓿干草总产量最高，达到17 218.9 kg/hm2。因此，建议施肥量为返青施肥375 kg/hm2(N 60 kg/hm2、P2O5 56.25 kg/hm2、K2O 56.25 kg/hm2)，第一次刈割施肥131.25 kg/hm2(N 21 kg/hm2、P2O5 19.687 5 kg/hm2、K2O 19.687 5 kg/hm2)，第二次刈割施肥150 kg/hm2(N 24 kg/hm2、P2O5 22.5 kg/hm2、K2O 22.5 kg/hm2)，施肥总量656.25 kg/hm2(N 105 kg/hm2、P2O5 98.437 5 kg/hm2、K2O 98.437 5 kg/hm2)。结果为科尔沁沙地苜蓿合理施肥管理提供依据。

关键词: 草原3号苜蓿, 牧草, 施肥, 生长, 产草量