Distribution and population dynamics of nematodes in a rice field and pasture in India
Mishra, C.C.; Dash, M.C.
Journal of Nematology 13(4): 538-543
1981
ISSN/ISBN: 0022-300X PMID: 19300801 Document Number: 172761
Ecological studies on soil nematodes [Hirschmanniella mucronata and Orientylus orientylis] were made in a tropical rice field and pasture. Parasitic species were more diversified in the pasture than in the rice field. Of total nematodes 86% and 60% occurred in the top 10 cm in rice field and pasture, respectively. Nematodes were not randomly or uniformly dispersed but aggregated. Parasitic forms were most abundant and correlated with root biomass in the 0-15 cm soil layer, the greatest number usually occurring at the 10-15 cm depth at both sites. In summer, they were densest at the 15-30 cm depth. Microbivores were most frequent in the top 5 cm of both sites. Miscellaneous feeders (food sources uncertain) usually occurred in highest densities at the 15-30 cm depth. Predators showed no distinct depth preference. Temperature and moisture of the soil apparently played an important role in regulating nematode population. Peak densities of 31.3 .times. 104/m2 and 21.6 .times. 104/m2 at a 30 cm depth occurred in Jan., while minimum densities of 5.0-5.3 .times. 104/m2 and 4.1 .+-. 104/m2 occurred in July-Oct. and April in rice field and pasture, respectively. Monthly mean biomass of nematodes was 23.8 .+-. 4.5 mg/m2 in rice field and 11.5 .+-. 1.5 mg/m2 in pasture.