Organic amendments and nutrient leaching in soil columns

Authors: Adeli, Ardeshir; Read, John; Feng, Gary; Jenkins, Johnie

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/12/2017
Publication Date: 6/1/2017
Publication URL: https://handle.nal.usda.gov/10113/5729152
Citation: Adeli, A., Read, J.J., Feng, G.G., Jenkins, J.N. 2017. Organic amendments and nutrient leaching in soil columns. Journal of Environmental Quality. 109:1294-1302.

Interpretive Summary: Surface coal mining negatively impacts soil physical, chemical, and biological properties and results in the breaking of soil aggregates and exposure of soil C fraction to microbial breakdown. One of the most consistent impacts of disturbance associated with surface coal mining is loss of soil organic matter. The most common practice for reclaimed soil, is adding lime and NPK fertilizer followed by seeding grass and planting pine trees for vegetation establishment. This common practice does not build up nutrients and not supply any organic C to the soil. Low soil organic matter levels in coal mine soils limit microbial activity, reduce nutrient holding capacity, increases the risk of nutrient leaching beyond the plant root zoon, inhibits restoration soil productivity. Any management practice that affects nutrient built up and enhance soil organic C can encourage the development of self sustaining plant communities, one of the main goal in restoring these lands. Organic amendments have the potential to improve fertility and restore the quality of reclaimed coal mine soil. Poultry manure is one of the most promising organic amendment source, however, the application of fresh poultry manure with low C/N ratio and large quantities of readily mineralizable N, is highly susceptible to leaching to ground water. Composting manure with higher C: N ratio than fresh manure is one approach to stabilizing manure-derived nutrients and reducing nutrient loss potential in reclaimed mine soil. The objective of this study was to determine the effect of composted poultry manure relative to fresh poultry manure on productivity, physical property, litter derived-nutrient cycling and biomass production.

Technical Abstract: The lack of nutrient build up in reclaimed coal mine soils would therefore require additional inputs to maintain plant productivity and establishment of a healthy ecosystem. In a greenhouse experiment, reclaimed coal mine soil were amended with fresh and composted poultry manure at the rates based on N needs of the established bermudagrass. The columns were intentionally leached every week and leachate were collected for nutrient analysis.. Despite approximate equivalent total N inputs with fresh (193 mg column-1) and composted poultry manure (181 mg column-1), NO3–N content in leachate was significantly lower for composted poultry manure than the fresh manure treatment. Total organic C in the leachate was 58% less in the compost than fresh poultry manure (2.27 vs. 5.45 mg column-1). Phosphorous content in leachate was also significantly lower for compost than fresh poultry manure (1.90 vs. 3.15 mg column-1), demonstrating that compost can be applied to soil with almost no risk of N and P leaching from the soil. Addition of FGD gypsum to fresh and composted poultry manure significantly reduced P content in leachate by 67 and 43%, respectively, as compared with untreated manure. Application of composted and fresh poultry manure to reclaimed coal mine soil increased total soil C as compared to the control and the magnitude of soil C was significantly lower with fresh poultry manure than the composted manure. Addition of composted poultry manure to reclaimed coal mine soil could improve soil productivity and promote a more sustainable agro ecosystem.