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ARS Home » Pacific West Area » Kimberly, Idaho » Northwest Irrigation and Soils Research » Research » Publications at this Location » Publication #413395

Research Project: Developing Resilient Irrigated Cropping Systems in Concentrated Dairy Production Areas of the Semi-arid West

Location: Northwest Irrigation and Soils Research

Title: Short-term effects of a heavy dairy manure application on soil chemical and biological indicators in an irrigated semiarid cropping system

Author
item Dungan, Robert
item Lehman, Richard
item Manter, Daniel
item Mikha, Maysoon
item Reardon, Catherine
item Veum, Kristen
item Weyers, Sharon
item White Jr, Paul
item Tarkalson, David
item Acosta Martinez, Veronica

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/13/2024
Publication Date: 12/9/2024
Citation: Dungan, R.S., Lehman, R.M., Manter, D.K., Mikha, M.M., Reardon, C.L., Veum, K.S., Weyers, S.L., White Jr, P.M., Tarkalson, D.D., Acosta Martinez, V. 2024. Short-term effects of a heavy dairy manure application on soil chemical and biological indicators in an irrigated semiarid cropping system. Agronomy Journal. 117(1):1-19. https://doi.org/10.1002/agj2.21737.
DOI: https://doi.org/10.1002/agj2.21737

Interpretive Summary: Intensive dairy production in southern Idaho is often associated with the annual application of manure to cropland soils. However, a one-time heavy application of manure could alternatively be used as a means to improve soil fertility and health for many years or even decades. To determine if this practice would negatively affect soil health in the short-term, we monitored biological and chemical properties for two years after manure incorporation. This research demonstrated that incorporating a high rate of dairy manure (with or without fertilizer) into a semiarid soil significantly influenced most biological and chemical indicators in the first two years after manure application. These effects were observed in both the topsoil and subsoil, but the responses were greatest in the subsoil, which was attributed to deep tillage of the manure. Since a single heavy application of dairy manure did not adversely impact soil properties it can be advised as a management strategy despite significantly lower corn yields compared to synthetic fertilizer in the first year after application.

Technical Abstract: Intensive dairy production in semiarid southern Idaho, USA, is often associated with the annual application of manure to cropland soils. However, a one-time heavy application of manure could alternatively be used as a means to improve soil fertility and health for many years or even decades, circumventing the need for frequent applications. To determine if this practice would negatively affect soil health in the short-term, we monitored biological and chemical properties for two years after incorporation of dairy manure solids at a rate of 103 Mg/ha (dry wt.). Soil properties measured were pH, electrical conductivity, extractable nitrogen (N) and phosphorus, total carbon (C) and N, enzyme activities, mineralizable N, soil organic C, soil protein, active C, ammonia oxidation potential, and particulate organic matter. Manure (with and without synthetic fertilizer) was found to significantly affect biological and chemical indicators in both topsoil (0-15 cm) and subsoil (15-30 cm), but the responses were greatest in the subsoil. This can be attributed to the fact that manure was incorporated to approximately 30 cm via moldboard plow. All indicators responded positively to manure, except in the case of pH, which decreased slightly in the subsoil in the first year after application. Principal components analysis of soil biological and chemical properties, across all years and depths, showed that the first two components explained 62% and 8.5% of the variance. While soil properties were not adversely affected by manure, silage corn yields in year one were significantly lower in manured plots, though in year two, barley grain yields were statistically similar among manure and fertilizer plots. Despite lower corn yields, a single heavy application of dairy manure can likely be recommended as a management strategy, but long-term affects on soil health do require evaluation.