New Kentucky State research offers early field data on how fertility practices influence soil health and water movement

FRANKFORT, Ky. — A cornfield does not end at the edge of a row.

What farmers apply to the soil can move through it, shaping not only crop production but also the quality of water that eventually leaves the field. New peer-reviewed research from Kentucky State University takes that movement seriously, offering early Kentucky-based field data on how different nutrient-management practices affect soil health and leachate water quality in a corn agroecosystem.

Published May 7 in Frontiers in Soil Science, the study, “Effects of nutrient management on soil health and leachate water quality in a corn agroecosystem,” compared dairy manure, composted dairy manure, and synthetic fertilizer at Kentucky State University’s Harold R. Benson Research and Demonstration Farm.

For Kentucky producers, the question is practical: How can nutrients be managed in ways that support crop production while reducing the risk of nutrient loss into water systems?

Kentucky State’s research team included lead author Sandeep Airee and Asmita Bhandari, both recent graduates of the University’s Environmental Science and Technology (M.S.) program who are now pursuing doctoral studies in the Department of Crop and Soil Sciences at Washington State University.

Faculty co-authors from Kentucky State included Dr. Anuj Chiluwal, assistant professor of agronomy, and Dr. Maheteme Gebremedhin, chair of the School of Agriculture and Natural Resources. The publication also included Dr. Atanu Mukherjee, a former Kentucky State faculty member who served as a corresponding author on the study. Their findings showed that manure and compost improved selected soil health indicators during the first growing season, while synthetic fertilizer resulted in significantly higher nitrate concentrations in leachate water samples.

Across a 1.77-acre research field, three treatments were applied with four replications: dairy manure, composted dairy manure, and synthetic fertilizer. Soil and water samples were collected during the growing season from 10- and 20-centimeter depths, allowing researchers to examine both changes in soil properties and the movement of nutrients through water.

Manure significantly increased soil aggregation and organic matter compared with fertilizer treatment. Compost improved the soil’s specific surface area compared with manure and fertilizer. Those changes matter because soil structure, organic matter, and nutrient retention are central to long-term soil productivity.

Water-quality results showed a sharper short-term contrast. Leachate water under fertilizer treatment showed significantly higher nitrate concentrations at both sampling depths compared with manure and compost. Researchers also observed higher phosphate leaching under fertilizer treatment during parts of the sampling period.

Nitrate proved especially mobile. According to the study, nitrate concentrations in leachate water were far greater than phosphate and potassium concentrations, underscoring the need for careful nitrogen management in row-crop systems.

Although manure and compost showed promise, researchers cautioned against drawing long-term conclusions from a single growing season. Soil systems often require several years to fully respond to management changes, particularly when measuring properties such as organic matter, water-holding capacity, compaction, and aggregation.

That long-term view is built into the research. This publication represents initial findings from a four-year field-based study designed to examine how fertility practices influence both soil health and water quality in Kentucky cropping systems.

Rather than presenting a simple choice between organic and synthetic nutrient sources, the study provides field-based evidence to help producers, Extension professionals, and researchers better understand the tradeoffs among nutrient availability, soil improvement, and water-quality risk.

For Kentucky State, the work reflects the University’s 1890 land-grant mission: applied research that responds directly to the needs of producers, communities, and the Commonwealth. Conducted at the Benson Farm and supported through USDA Evans-Allen funding, the study adds Kentucky-specific data to a broader agricultural challenge with economic and environmental consequences.

As producers continue balancing productivity, input costs, soil stewardship, and environmental protection, research like this helps move the conversation from assumption to evidence — one field, one season, and one sample at a time.

This study was funded by USDA NIFA Research Capacity Fund (Evans-Allen), project number: KYX 10-23-78P, accession number: 7004945.