施用农用氢氧化镁对白菜、晚稻产量及土壤镁素的影响

闽清县耕地土壤有78.3%属缺镁水平。为探索施镁肥对农作物增产效果，以农用氢氧化镁为供试肥料，选用本地区种植面积较大、对镁元素敏感的白菜、晚稻两作物进行田间试验，分别按镁肥用量不同设5个水平，氢氧化镁肥全部采用全层基施。结果表明，施用镁肥均不同程度提高了水稻分蘖期与齐穗期叶绿素含量。适宜用量范围内，施用氢氧化镁均提高了白菜、晚稻产量，其中白菜、晚稻分别以氢氧化镁用量225、120kg/hm²增产效果最佳，分别增幅12.7%与9.1%，经济效益分别增效12423.9、1410元/hm²。但晚稻用量超过120kg/hm²，产量显著下降。在最高产量下的施镁肥水平，与CK相比，种植白菜与晚稻田块土壤有效镁分别增加14.3与11.3mg/kg。在土壤有效镁基本相当条件下，晚稻对镁肥较白菜表现敏感，过多反而减产。总之，闽清县在白菜与晚稻上施用氢氧化镁，既增产增收又能提高土壤有效镁的含量，促进耕地养分平衡，但需掌握合理用量。

Effect of Applying Agriculture-used Magnesium Hydroxide on the Yield of Cabbage, Late Rice and Content of Soil Magnesium

Deficiency of magnesium in arable land is serious in Minqing county.In order to study the increasing yield effect of combined application of magnesium fertilizer,the field experiment applying agriculture-used magnesium hydroxide to cabbage and late rice were implemented. The results show that applying magnesium hydroxide all improve the yield of cabbage and late rice.The most significant effects are found in the level of 225kg/hm₂ for cabbage and 120 kg/hm₂ late rice,increased 5749.5 kg/hm₂and 510 kg/hm₂,and improved 12423.9 yuan/hm₂and 1410 yuan/hm₂,respectively.Applying magnesium hydroxide also improve the content of soil exchangeable magnesium.