engleski

Structure of nematode communities in different agroecosystems

Nematode community structure was analyzed in four different agroecosystems in order to determine how differences between crops and tillage treatment can influence nematode communities. The nematodes from four different treatments were analyzed: I. Winter wheat; II. Alfalfa; III. Corn in monoculture and IV. Sugar beet. Sampling was done in 1997 and 1998 year, two times per year, in four replicates, at depth of 20 cm, using sonda with internal diameter Ć2 cm. The data were analyzed statistically. The greatest total number of nematodes (1175 nematodes/100 ccm of soil – average for 1997; 1690 nematodes/100 ccm of soil – average for 1998) and greatest number of genera (24 – average for 1997; 22 – average for 1998) occurred in alfalfa. Significant differences in total number of nematodes occurred just in alfalfa compared to other three treatments, and very significant differences in number of genera, also just in alfalfa. The lowest total number of nematodes (326 nematodes /100 ccm of soil – average for 1997; 403 nematodes/ 100ccm of soil - average for 1998.) and the lowest number of genera (13,5 – average of 1997 and 16,5 – average of 1998) were determined in sugar beet. Trophic structure was similar in all treatments – dominated by bacterivorous and plant parasitic nematodes. Predators was the least present group in all treatments. Maturity index, Plant parasitic index and PPI/MI were calculated and there weren’t any significant differences between MI and PPI/MI between the treatments. The statistically significant differences occurred for PPI in sugar beet compared to other treatments. We can conclude that nematode community structure was most disturbed in sugar beet and in corn, which are both row crops with considerable impact of tillage on nematode communities. The lowest influence of tillage was in alfalfa, which is perennial crop where the nematode communities were less disturbed.

nematode communities; different agroecosystems; Maturity index; Plant parasitic index

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