Twenty 6 x 6 m plots were established with a 3 m buffer between plots. Five plots were randomly assigned to one of four treatments: (1) chlordane amendment 100ml AI (active ingredients) per 10,000 ml) to exclude microarthropods, (2) sprinkler irrigation (6 mm per week), (3) sprinkler irrigation (6 mm/week) plus chlordate amendment (as above), (4) control (no treatment). Measurements are taken on Erioneuron pulchellum at monthly intervals. Three randomly located subsamples are collected from each plot. Data set contains plant diameters, mites soil weight, root weight, nematode soil weight, root total nitrogen, and nematode number.