不同施肥组合对苜蓿阴阳离子平衡的影响

试验采用二次回归正交旋转组合设计,研究了硫酸钾、氯化铵、过磷酸钙和氧化镁对苜蓿阴阳离子平衡(CAB)的影响。结果表明,苜蓿株体中K⁺含量最高,变化范围为2.40%～4.01%,其次为Cl^-、S^2-,变化范围分别为0.84%～1.09%和0.35%～0.58%,Na⁺的含量最低,其变化范围为0.09%～0.22%;CAB值范围为155～501 mEq/kg DM。对苜蓿CAB值有显著影响的因子为硫酸钾和氧化镁,二者和苜蓿CAB值间存在显著的负效应;氯化铵和过磷酸钙单因子对苜蓿CAB值影响不显著,但氯化铵与过磷酸钙、氯化铵与氧化镁之间的交互作用可以显著影响苜蓿CAB值。单施一种肥料可使苜蓿CAB值最低降到216.55 mEq/kg DM,效果不显著,而组合施用可降到80.55 mEq/kg DM。在本试验条件下,苜蓿CAB值最低的施肥组合为:硫酸钾50 kg/hm²,氯化铵275 kg/hm²,过磷酸钙1 000 kg/hm²,氧化镁55 kg/hm²。

Effects of fertilizer combinations on the cation-anion balance of alfalfa

The effects of fertilizer combinations on the cation-anion balance of alfalfa were analysed using a quadratic regression orthogonal rotating combination design. The most common cation in alfalfa was K⁺, which ranged from 2.40% to 4.01%, followed by Cl^- (0.84%-1.09%) and S^2- (0.35%-0.58%), while the lowest was Na⁺, 0.09%-0.22%. The cation-anion balance ranged from 155 to 501 mEq/kg DM. The factors that had a significant negative impact on the cation-anion balance in alfalfa were potassium sulfate and magnesium oxide. Even though the effects of ammonium chloride and superphosphate on the cation-anion balance were not significant, the interactions between ammonium chloride, superphosphate, and magnesium oxide significantly affected the balance. All of the fertilizers lowered the balance to 216.55 mEq/kg DM, which was not significant. However, the combination of fertilizers lowered the balance to 80.55 mEq/kg DM. The fertilizer combination which retained the lowest balance was 50 kg/ha potassium sulfate, 275 kg/ha ammonium chloride, 1 000 kg/ha superphosphate, and 55 kg/ha magnesium oxide.