IMPACTS OF FERTILITY PRACTICES ON SOIL AND WATER QUALITY IN KENTUCKY

Fertilizer applications are crucial for crop productivity; however, they pose a risk of nutrient runoff and water contamination, threatening water quality. In Kentucky, nutrient pollution in surface and groundwater bodies, leading to eutrophication, is significantly driven by production agriculture, particularly due to the state's heavy reliance on animals and row crop farming. This four-year study investigates the impacts of dairy manure, composted dairy manure, and synthetic fertilizer on soil and leachate water quality under Kentucky's corn/soybean cropping system. The methodology employs a Randomized Complete Block design (RCBD) in a 1.7-acre field with three treatments and four replications. Soil samples from each plot at depths of 0-10 cm and 10-20 cm were collected using bulk-density core samplers. Critical compaction depth and surface area will be measured using a penetrometer and an Autosorb surface area analyzer. Additional soil health parameters will also be assessed, including aggregate stability, pH, electrical conductivity, organic matter, and nutrient content. Leachate water samples were collected over time using suction cup lysimeters installed in the field. Water quality parameters, such as nitrate, phosphates, and potassium, were analyzed using a Dual Channel Ion Chromatograph instrument. Other water quality parameters measured included pH and electrical conductivity. Baseline soil sampling results indicated significant differences between the two depths, with higher bulk density (1.38 g/cc) at 10-20 cm depth indicating denser soil, and lower bulk density (1.17 g/cc) at 0-10 cm depth indicating loose soil. The critical compaction depth was measured at 26.7 cm. The findings aim to guide the best management practices for farmers, policymakers, and environmental agencies to reduce water pollution without sacrificing agricultural productivity