The Effects of Conservation Agriculture Practices on the Population Density of Fungivorous and Free-Living Nematodes in Different Crop Rotation Patterns

Conservation agriculture (CA) has been widely adopted in many regions of the world; however, the effect of CA practices on non-plant pathogenic nematodes is not well understood.This study was carried out to determine the effect of CA on population density of fungivorous (Aphelenchus avenae) and free-living nematodes under four crop rotation patterns.The experiment was arranged as a split plot in randomized complete block design with three tillage systems (conventional tillage, minimum tillage and no-tillage) as the main plots and three level of crop residue retention (no-residue, 30%, and 60% of residue retention) as the subplots that replicated three times during five consecutive cropping seasons.The results showed that fungivorous and free living nematodes exhibited differential responses to tillage and residue retention under different rotation patterns.Analysis of variance showed that the effect of tillage, residue retention and their interaction effect on population of fungivorous and free-living nematodes in the 1 st (wheat, barley, cotton, wheat) and the 2 nd (wheat, sugar beet, wheat, sugar beet and wheat) rotation patterns were not statistically significant.In the 3 th rotation pattern (wheat, maize, wheat, melon and wheat) interaction of tillage × residue retention had a significant effect on the population of fungivorous and free-living nematodes.In the 4 th rotation pattern (wheat, canola, wheat, Persian clover, tomato and wheat), tillage intensity influenced the population density of fungivorous and free-living nematodes significantly.Long-term experiments are necessary to determine the capacity of non-pathogenic nematodes in suppression of soil-borne pathogens including the fungal and pathogenic nematodes.