EFFECT OF MYCORRHIZAL INOCULATION ON INSOLUBLE PHOSPHATE ABSORB BY CITRUS SEEDLING IN RED EARTH
Tang Zhengyao Cheng Annjou ( Citrus Research Institute, ( Agricultural Bureau of Dou Chinese Academy of Agricultural Prefecture, Hunan Province ) Science )
The purpose of the present experiment was to assess the effect of endomycorrhizal fungus on utilization of phosphate rock by citrus root-stock seedlings in red earth. Seedlings of three species. Rangpur lime ( Citrus limonia ) ,sour orange ( Citrus aurantium L. ) and trifoliata orange ( Poncirus trifoliata L. Raf. ) were grown in pots with fumigated soil of red earth under outdoor and similar cultural conditions for six-teen months. Experiment was designed four treatments : 1 ) phosphate rock applied as a p source, 2 ) inoculating with the vesicular arbuscular mycorrhizal fungus C C- 1 ( Glomus citricolum ) , 3 ) mycorrhizal inocu-lation added p fertilizer as both above, 4 ) control without mycorrhizas and P applied. Among these four treatments the best effect on plant growth response and concentration of P in tissue was treatment 3 , In this treatment, the fresh and dry weight of mycorrhizal rangpur lime plant upper prat were significantly greater 94% and 91% respectively than those of non-mycorrhizal plant applied P alone. The fresh weight of sour orange and trifoliata plants upper parts in treatment 3 incleased 48% and 31% res-pectively of those in treatment 1 . The results indicate that for mycorrhizal citrus seedling, phosphate rock can be directly used in red earth as a P fertilizer.