Submitted to: Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/17/2021
Publication Date: 6/2/2021
Citation: Adeli, A., Brooks, J.P., Feng, G.G., Mozaffari, M., Jenkins, J.N. 2021. Integration of pelleted biosolids with cover crops for improving soil properties. Soil Science. 44(18); 2677-2690. https://doi.org/10.1002/saj2.20341.
Interpretive Summary: The interest of using soil organic amendments such as poultry litter and biosolids for sustainable agricultural production is expanding. Long-term application of these organic by-products result in significant increase in soil C, increase soil N and P availability and reduce the demand for synthetic fertilizers. The role of carbon content in bio-solids for enhancing soil organic matter and improving soil quality has been gaining popularity in the last decades. Keeping soils in a healthy condition is important to ensure satisfactory crop growth and yield. Application of bio-solids to agricultural lands increases soil organic matter, results in general enhancement of soil biological activity, and enhances crop growth and development. Despite beneficial effects of bio-solids on crop production, a very small percentage of total amount of bio-solids produced in the US is currently utilized as soil amendment for crop production due to difficulties in transport, handling and field application. In recent years, bio-solids have been turned into heat-dried pelleted forms to increase the economic feasibility of transportation and handling. Pelletized organic materials generally have higher bulk density, more stable nutrient easy to transport and land-apply compared to non-pelletized organic materials. Information on the effects of pelleted form of organic by-products, such as pelletized bio-solids, on soil quality parameters is limited, particularly in sub-humid southeastern US ecosystems. Since pelleted bio-solid contains a considerable amount of organic matter, it should have favorable effects on soil physical conditions and tilth. More information is needed regarding the long-term effects of heat-dried pelleted bio-solids on soil quality for enhanced agroecosystem services. The hypothesis of our study was that application of pelleted bio-solids would result consistent positive changes in soil biological, chemical, and physical properties. The objective of the study was to evaluate the impact of repeated application of heat-dried pelleted bio-solids relative to inorganic fertilizer N to row crops on soil chemical, physical and biological properties all in the presence/ absence of winter cover crop residues under Mississippi agro-ecosystem.
Technical Abstract: Investing in soil health is an adaptive strategy to improve soil productivity and sustainable agriculture. A field study was conducted on a Marietta loam soil at the Plant Science Center at Mississippi State to determine the effects of pelleted bio-solids relative to poultry litter and inorganic fertilizer N applied to corn and cotton in the presence or absence of cover crop residues on soil chemical, physical and biological properties. Fertilization treatments included pelleted bio-solids at high and poultry litter at agronomic rate, pelleted bio-solids as a onetime single application at the high rate, inorganic fertilizer N and unfertilized control. Three years after applications, soil samples were collected and analyzed for post-harvest major soil health indicators. The presence of cover crop residue significantly reduced bulk density, penetration resistance, pre-planting and post-harvest residual soil NO3-N, and increased soil total C, aggregate stability and infiltration rate. Relative to inorganic fertilizer, application of pelleted bio-solids at agronomic rate significantly reduced bulk density and penetration resistance by 3 and 20 % and increased soil total C, water stable aggregate and infiltration by 28, 15 and 45%, respectively. One time single application of pelleted bio-solids at the high rate resulted in significant NO3-N concentration below 30 cm soil depth and substantial P accumulations at the top 15 cm, increasing the potential for pollution of water bodies.