Abstract: To lay a theoretical basis for alfalfa soil testing and fertilizer recommendation on the Inner Mongolia Plateau of China,the method of scattered experimental data integration and the method of nutrient balance and target yield minus soil fertility yield were employed to study the rich-lack index (RLI) of soil available P and the recommended phosphate fertilizer application rates (RPFAR) for alfalfa on the Inner Mongolia Plateau of China. The results showed that the RLIs of soil Olsen-P for alfalfa on the Inner Mongolia Plateau for the 1^st to 11^th level were ≥39,22~39,12~22,6.7~12,3.7~6.7,2.1~3.7,1.2~2.1,0.7~1.2,0.4~0.7,0.2~0.4 and<0.2 mg·kg^-1,separately. When the phosphate fertilizer use efficiency was 20% and the target yield was 9~18 t·hm^-2,the RPFAR for the alfalfa soil available P rich-lack level 1~11 from high to low were 0~0,27~54,54~108,81~162,108~216,135~270,162~324,189~378,216~432,243~486 and 270~540 kg·hm^-2,separately. This research established a recommended fertilization system of rich-lack index of soil available P for alfalfa,and laid a theoretical foundation for alfalfa soil testing and fertilizer recommendation on the Inner Mongolia Plateau of China.

Key words: Alfalfa, Soil available P, Rich-lack index, Fertilization index, Rate of fertilizer application

摘要： 为了给内蒙古高原紫花苜蓿（Medicago sativa L.）测土施肥奠定理论基础，本试验采用养分平衡—地力差减法和零散试验数据整合法，开展了内蒙古高原紫花苜蓿土壤有效磷丰缺指标和推荐施磷量研究。试验结果表明，内蒙古高原紫花苜蓿土壤有效磷第1~11级指标依次为≥39，22~39，12~22，6.7~12，3.7~6.7，2.1~3.7，1.2~2.1，0.7~1.2，0.4~0.7，0.2~0.4和<0.2 mg·kg^-1；当目标产量为9~18 t·hm^-2、磷肥利用率为20%时，丰缺级别第1~11级的紫花苜蓿推荐施磷量范围依次为0~0，27~54，54~108，81~162，108~216，135~270，162~324，189~378，216~432，243~486和270~540 kg·hm^-2。本研究建立了内蒙古高原紫花苜蓿土壤有效磷丰缺指标推荐施肥系统，为内蒙古高原紫花苜蓿测土施肥奠定了理论基础。

关键词: 紫花苜蓿, 土壤有效磷, 丰缺指标, 施肥指标, 施肥量