福建山地龙眼园土壤镁素状况与龙眼缺镁调控措施

Studies on Magnesium Status in Mountain Soils of Longan Orchards and on the Control Methods for Longan Magnesium Deficiency in Fujian

福建山地龙眼园土壤镁素状况因成土母质不同而异 ,玄武岩发育的土壤供镁充足 ,第四纪红壤尤其是花岗岩、凝灰岩发育的土壤供镁水平低或极低 ,这类土壤是福建山地龙眼园的主要土壤类型 ,应重视施用镁肥。土壤活性铝含量高 ,部分龙眼园土壤K Mg比值过高 ,抑制了龙眼镁素吸收 ,也是造成山地龙眼缺镁的重要原因。龙眼缺镁的调控措施是 :施用镁肥 (硝酸镁喷施结合土施钙镁磷肥 ) ;合理配施钾肥和镁肥 ;

Soils analysis data showed that magnesium status in mountain soils of longan depended to a large extent on soil parent materials.The soils derived from besalt were rich in exchangeable magnesium and had high magnesium saturation.The soils derived from quaternary period red earth,especially from granite and tuf,the main mountain soil types in Fujian province,were poor in exchangeable magnesium and had low magnesium saturation. Besides soil magnesium status, high active aluminum content and high ratio of exchangeable potassium to exchangeable magnesium were also the causes for longan magnesium deficiency.Results of two years location field experiment showed that application of magnesium fertilizers markedly increased magnesium content in the leaves and decreased the morbidity of magnesium deficiency of longan. Combined soil application of calcium magnesium phosphate with foliar spraying of magnesium nitrate was the best choice for the correction of magnesium deficiency in longan.Rational application of potassium and magnesium fertilizers, detoxification of aluminum were also effective control methods for longan's magnesium deficiency.