Location: Soil Dynamics ResearchTitle: Economics of cover crop nutrient accumulation as biomass increases
|HAYMAKER, JOSEPH - Virginia Tech|
|REITER, MARK - Virginia Tech|
|STEWART, RYAN - Virginia Tech|
|STEPHENSON, KURT - Virginia Tech|
|LIPFORD, MARY MICHAEL - Virginia Tech|
Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 9/12/2022
Publication Date: 11/7/2022
Citation: Haymaker, J., Reiter, M., Stewart, R., Stephenson, K., Balkcom, K.S., Lipford, M. 2022. Economics of cover crop nutrient accumulation as biomass increases [abstract]. ASA-CSSA-SSSA Annual Meeting Abstracts. Baltimore, MD. Nov. 6-9, 2022.
Technical Abstract: On the coastal plain of Virginia, sandy loam soils are generally prone to subsurface losses of nutrients, such as nitrogen (N) and potassium (K). Furthermore, drastic increases in fertilizer prices have severely affected the profitability of grain production. This project’s overall goal is to increase soil organic matter and scavenge leached nutrients from deep within the soil profile by using various cover crop species in both monoculture and diverse mixes. The long-term study was initiated in fall 2014 to observe the effects of 12 different crop rotations on soil health and cash crop yields. After corn harvest in 2020, cover crops were planted in six rotations with cover crop biomass and nutrient accumulation being assessed multiple times, over the course of the following spring, until termination just prior to cash crop planting. At termination, the average dry biomass was 5004 kg ha-1, which was a 211% and 364% increase in biomass in 5 weeks and 9 weeks before termination, respectively. While the average N accumulation was 101 kg N ha-1 and average K accumulation was 121 kg K ha-1, valued at $227 and $262 ha-1, respectively. The highest N accumulation was seen in monoculture hairy vetch at 171 kg N ha-1 ($383 ha-1) and highest K accumulation was seen in a 3-species mix of spring oats, radish, and crimson clover, which had accumulated 154 kg K ha-1 ($332 ha-1). Overall, low C:N species (e.g. hairy vetch) and mid C:N cover crop mixes accumulated the highest amounts of N and K. In conclusion, utilizing cover crops that can scavenge excess leached nutrients and/or fixate nitrogen can greatly reduce the amount of fertilizer needed, which can significantly improve the profitability of grain production in the coastal plains.