The Relationship Between Cultural Practices and Atbuscular Mycorrhizal ( Activity in Orchards Under Diiiferent Management Systems AM )

It has been demonstratecl that soil disturbance, excessive feTtilization a d the use of some agrochemicals affect the survival hnd function of arbuscular mycorrhizal (AM) fungi, To clarify the effect of different cultural practices on mycorrhizal activity in orchards, spore population dynamics, soil and plant mineral content and mycorrhizal infection were surveyed monthly from May to October, 2ooO in kiwifruit, Japanese chestnut, Iyo tangor, satsuma mandarin, Japanese peTsimmon, apple, peach, Japanese plum and grape plantings, subjected to different management Tegimes, In intensively managed orchards, levels of major elements in the soil weTe generally high, owing to periodic feTtilization; consequently, the content of these elements in the leaves was within the recommendcd range for normal growth and function. High levels of AM infection were maintained throughout the season in the apple orchard that received no fertilizer o fungicide. The infection levels on roots of kiwifruit vines decTeased in July and August afteT three fungicide sprays in June; it also decreased in Iyo tangor in July following fouT fungicide applications in May