内蒙古高原和黄土高原紫花苜蓿土壤有效磷和速效钾丰缺指标与适宜施肥量研究

Study on abundance-deficiency index of soil available P and K and appropriate fertilizer application rates for alfalfa in the Inner Mongolia Plateau and Loess Plateau of China

为了给内蒙古高原和黄土高原紫花苜蓿测土施肥提供科学依据,采用土壤养分含量与缺素处理相对产量回归方程法、土壤养分丰缺分级改良方案和＂养分平衡-地力差减法＂确定适宜施肥量新应用公式,开展了内蒙古高原和黄土高原紫花苜蓿土壤有效磷（Olsen-P）和速效钾（NH_4OAc-K）丰缺指标与适宜施肥量研究。结果表明：内蒙古高原和黄土高原紫花苜蓿土壤有效磷第1～11级丰缺指标依次为≥40,39～22,21～12,11～6,5.9～3.2,3.1～1.7,1.6～1.0,0.9～0.5,0.49～0.30,0.29～0.15,〈0.15 mg/kg;速效钾第1～6级丰缺指标依次为≥204,203～100,99～49,48～24,23～12,〈12 mg/kg。当磷肥当季利用率为20%、目标产量为9.0～22.5 t/hm2时,紫花苜蓿土壤有效磷丰缺级别第1～11级的适宜施磷量范围依次为0～0,27～68,54～135,81～203,108～270,135～338,162～405,189～473,216～540,243～608,270～675 kg/hm2;当钾肥当季利用率为50%、目标产量为9.0～22.5 t/hm2时,紫花苜蓿土壤速效钾丰缺级别第1～6级的适宜施钾量范围依次为0～0,54～135,108～270,162～405,216～540和270～675 kg/hm2 。

To provide a scientific basis for alfalfa soil testing and fertilizer recommendation in the Inner Mongolia Plateau and Loess Plateau（IMP-LP） of China,the method of regression equation between soil nutrient content and relative yield of the treatment with complete nutrients except one,the improved scheme for the grading of soil nutrients abundance-deficiency,and the new applied formula based on ＂nutrient balance and projected yield minus soil fertility yield＂ for determining the appropriate fertilizer application rates were employed to study the abundance-deficiency index（ADI） of soil available P and K and appropriate fertilizer application rates（AFAR） for alfalfa in the IMP-LP. The results showed that the ADI of soil available P for alfalfa in the IMP-LP for the first to eleventh level were ≥40,39-22,21-12,11-6,5.9-3.2,3.1-1.7,1.6-1.0,0.9-0.5,0.49-0.30,0.29-0.15,〈 0.15 mg/kg, respectively. The ADI of soil available K for alfalfa in the IMP-LP for the first to sixth level were ≥204,203-100,99-49,48-24,23-12,〈12 mg/kg, respectively. The AFAR of P for the alfalfa soil available P abundance-deficiency level 1～11 from low to high were 0-0,27-68,54-135,81-203,108-270,135-338,162-405,189-473,216-540,243-608和270-675 kg/hm2,respectively, when the fertilizer use efficiency in current season（FUEICS） of P was 20%, and the target yield was 9.0-22.5 t/hm2. The AFAR of K for the alfalfa soil available K abundance-deficiency level 1～6 from low to high were 0-0,54-135,108-270,162-405,216-540和270-675 kg/hm2,respectively, when the FUEICS of K was 50% and the target yield was 9.0-22.5 t/hm2,