An ion exchange resin bag technique (Binkley 1984, Lajtha 1988) was used to determine N availability in the rhizosphere of fluffgrass. Ion exchange resin bags were used to determine NO3. 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). 8 AN-bags were placed in the rhizosphere of a fluffgrass in each plot. Bags were left in the field 3 months, collected, brought to the lab and analyzed for NO3.