Soil Phosphatases Activity in Soil From Long-Term Plow Tillage and No-Tillage Systems.

The conversion of phosphorus from organic forms to inorganic forms is essential for uptake by plants, and phosphatases play a major role in this process. However, the product of their reaction, which is phosphate, inhibits the activity of most phosphatases in soils. No-tillage practices lead to increased soluble and available P levels at the soil surface. Gypsum precipitates this phosphate and thus decreases the amount of phosphates available to inhibit soil phosphatases. We hypothesize, therefore, that gypsum will reduce the phosphate-induced inhibition of phosphatase enzymes. In this project, the activity of soil phosphatases affected by tillage, crop rotation and gypsum additions was measured. This research was conducted on soil from the long-term (i.e. 49 years) tillage and rotation plots located near Wooster and Hoytville, Ohio. Treatments were tillage (no-tillage and plow tillage), crop rotation (continuous corn or corn after soybean) and different rates of gypsum (0, 30, 300 and 3000 ppm). Soil from the continuous corn rotation plot had higher phosphatase activities compared with plots where corn was grown after soybean. No significance difference in the activities of phosphatases was observed relative to application of gypsum treatments. We conclude that application of gypsum to long-term no-tillage soils has no effect on the amount of inorganic and plant available phosphorus released from soil organic matter and that the available phosphorus concentrations are not changed enough to affect phosphatase activity.