中文摘要：

采用“3414”最优设计试验方案，在土默特左旗地区研究了施肥对中苜2号（紫花苜蓿）品种茎叶比和干鲜比的影响。结果表明，14个处理组合中，P2K2N0是试验获得茎叶比最小的组合，为1．236，P2K3N2是实验获得干鲜比最大的组合，为0．354；苜蓿的茎叶比随着氮肥的添加而增大，较高水平施氮量显著提高苜蓿茎叶比（P〈0．05），氮肥对苜蓿干鲜比没有显著影响；单施磷肥能够显著降低苜蓿茎叶比（P〈0．05），对其干鲜比没有显著影响；钾肥对苜蓿茎叶比的变化作用不明显，但过量钾肥可以提高苜蓿干鲜比；氮钾肥混施能显著改变苜蓿茎叶比（P〈0．05），磷钾肥混施能显著改变苜蓿干鲜比（P〈0．05）。因此，今后在土默特左旗地区种植苜蓿应不施或少施氮肥，适量增加磷肥和钾肥。

英文摘要：

The study was conducted in Tumotezuoqi, Inner Mongolia, the effect of fertilization on stem/leaf ratio （SLR） and dry/fresh ratio （DFR） of alfalfa zhongmu No. 2 （Medicago sativa L） were tested by the theory of 3414 regression optimum design. The results showed that the treatment of P2K2N0had the lower SLR, which is1. 236, and the treatment of P2K3N2 hadthe higher DFR,which is 0. 354;With the increase of N fertilizer, the SLR of alfalfa was increased, high N application can significantly increasethe SLR of alfalfa（P〈0.05）;P fertilizer decreased the SLR significantly（P〈0. 05） but no effect on DFR; And K fertilizer has no significant effect on SLR,but superfluousP can increase DWR of alfalfa; Nfertilizer mixed with K fertilizer can dramaticallychange the SLR of alfalfa（P〈0.05）, the same as the P fertilizer mixed with K fertilizer to the DFR of alfalfa. So, no or less N, and right amount increase P and K should he addition on planting alfalfa in Tumotezuoqi, Inner Mongolia.