中国三大自然区域紫花苜蓿土壤速效钾丰缺指标和推荐施钾量

为给内蒙古高原区、黄土高原区和西北荒漠绿洲区紫花苜蓿测土施肥奠定科学基础,采用零散实验数据整合法以及养分平衡-地力差减法,开展了三大自然区域紫花苜蓿土壤速效钾丰缺指标和推荐施钾量研究。结果表明,内蒙古高原区紫花苜蓿土壤速效钾第1~4级指标依次为≥342mg/kg、89~342mg/kg、24~89mg/kg和<24mg/kg,黄土高原区第1~6级指标依次为≥171mg/kg、96~171mg/kg、54~96mg/kg、30~54mg/kg、17~30mg/kg和<17mg/kg,西北荒漠绿洲区第1~4级指标依次为≥303mg/kg、140~303mg/kg、65~140mg/kg和<65mg/kg;当目标产量9~27t/hm²、钾肥利用率50%时,第1~6级土壤的推荐施钾量分别为0、54~162kg/hm²、108~324kg/hm²、162~486kg/hm²、216~648kg/hm²和270~810kg/hm²。

Study on Available Potassium Rich-lack Index and Recommended Potassium Application Rate of Alfalfa Soil in Three Natural Regions of China

In order to lay a theoretical basis for soil testing and fertilization of alfalfa in the Inner Mongolia plateau,the Loess plateau and the northwest desert oasis region,the scattered experimental data integration method and the nutrient balance-soil fertility difference subtraction method were employed to study the rich-lack index(RLI)of soil available potassium(SAK)and the recommended potassium fertilizer application rates(RPFAR)for alfalfa in the three great natural regions of China.The results showed that the RLI of SAK for alfalfa in the Inner Mongolia plateau for the 1^st to 4^th level were≥342mg/kg,89~342mg/kg,24~89mg/kg and<24mg/kg.The RLI of SAK for alfalfa in the Loess plateau for the 1^stto 6^th level were≥171mg/kg,96~171mg/kg,54~96mg/kg,30~54mg/kg,17~30mg/kg and<17mg/kg.The RLI of SAK for alfalfa in the northwest desert oasis for the 1^st to 4^th level were≥303mg/kg,140~303mg/kg,65~140mg/kg and<65mg/kg.When the potassium fertilizer use efficiency was 50%and the target yield was 9~27t/hm²,the RPFAR for the 1^st to 6^th level soil from high to low were 0,54~162kg/hm²,108~324kg/hm²,162~486kg/hm²,216~648kg/hm²and 270~810kg/hm²,respectively.