Abstract: The present experiment was conducted in 1988-1991 in Ping-he County of south Fujian to study the effects of soil application of calcium magnesium phosphate and magnesium sulphate on the correction of Mg deficiency in Guanxi Honey Pomelo (Citrus grandis) trees during full fruit period. The experimental design consisted of seven treatments with soil application rate of calxium magnesium phosphate and magnesium sulphate, i.e. MgO at 0.16, 0.32 and 0.48 kg·tree^-1·year^-1, respectively, and the control (no Mg fertilizer). The application of two magnesium fertilizers to the soil had a der-tain effect on the increasing amount of available Mg and the decreasing ratio of K/Mg, Ca/Mg in the soil, as well as the increasing content of Mg, Chlorophyll and the decreasing rafio of K/Mg, Ca/Mg in the leaf. In addition,the soil application of Mg fertilizers resulted in an increase of the growth of spring shoots and fruit yield. It was found from our study that both medium and high level of Mg fertilizer application induced good effect on correcting Mg deficiency. Moreover, there was a definite tendency of a better influence of the calcium magnesium phosphate than that of the magnesium sulphate.The authors recommend that the optimum amount of calcium magnesium phosphate in red soil pomelo orchard is 1.5-2.0kg·tree^-1·year^-1.

Key words: Guanxi Honey Pomelo, Magnesium deficiency, Soil application of magnesium fertilizer, Calcium magnesium phosphate, Effect of correction

摘要： 本文探讨钙镁磷和硫酸镁的三种土壤施用量对矫治盛果期琯溪蜜柚缺镁的效应。试验结果表明,两种镁肥的土壤施用,对提高土壤有效镁和植株镁含量以及改善土壤和植株钾、钙与镁之间的平衡有一定的作用,从而不同程度地矫治了缺镁,并促进植林的生长与结果。试验结果还表明,施用钙镁磷的效果优于硫酸镁。作者推荐,盛果期每年株施钙镁磷1.5~2.0 kg较为适宜。

关键词: 琯溪蜜柚, 缺镁, 土壤施镁, 钙镁磷, 矫治效应