LABORATORY APPARATUS TO APPLY AND SAMPLE ANHYDROUS AMMONIA IN BANDS

To describe how soil properties effect anhydrous ammonia (NH//3) retention, more accurate laboratory methods are needed to apply anhydrous NH//3 in a line source (band) and sample the resulting NH//3 retention zone. We developed and tested a line-source NH//3 applicator and a method for sampling the resulting NH//3 retention zone. The applicator has a system of flow control valves and a flow meter to regulate the rate of NH//3 flow to an injection needle. The soil sampling method was to sequentially remove concentric cylindrical cores of increasing radii centered around the line of NH//3 injection. Ammonia was applied to two soils with different NH//3 retention capacities and the resulting NH//3 retention zones were sampled. The applicator and soil sampling method proved to be both accurate and precise for studying NH//3 retention zones in soil.