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ARS Home » Midwest Area » Ames, Iowa » National Laboratory for Agriculture and The Environment » Agroecosystems Management Research » Research » Publications at this Location » Publication #381989

Research Project: Sustainable and Resilient Cropping Systems for Midwestern Landscapes

Location: Agroecosystems Management Research

Title: Short-term effects of nitrogen source on soil properties and plant growth

item Wacha, Kenneth - Ken
item HATFIELD, JERRY - Retired ARS Employee
item O'Brien, Peter
item DOLD, CHRISTIAN - Agrosphere Institute

Submitted to: Agrosystems, Geosciences & Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/21/2021
Publication Date: 6/17/2021
Citation: Wacha, K.M., Hatfield, J.L., O'Brien, P.L., Dold, C. 2021. Short-term effects of nitrogen source on soil properties and plant growth. Agrosystems, Geosciences & Environment. 4(2). Article e20176.

Interpretive Summary: This manuscript focuses on the short-term impact that amendment types (organic vs inorganic) has on several metrics of soil functionality. These metrics include soil biological activity, aggregation and plant biomass production are are important in improving soil quality. We found using organic amendments did not lose any plant production when compared to inorganic, but there were notable increases in aggregate stability and biological activity. This study does not provide an answer for how long it takes to see benefits of organic amendments, but it does hint that there are plenty of short-term benefits, and it justifies further examination of these types of amendments. This research informs producers of the tradeoffs of organic N sources on soil health and production and scientists interested in alternative management practices.

Technical Abstract: A growth chamber experiment was conducted to evaluate the short-term impact of nitrogen (N) amendment type on three metrics of soil functionality, namely soil carbon dioxide (CO2) fluxes, aggregate stability and plant production (aboveground biomass). Large intact soil cores (n=6) were collected and segmented into three N source treatments; (1) organic N source (ORG-N); (2) inorganic N source (UAN-32); and (3) no N source added (no-N). The experiment was run for 130 days, representing one growing season of winter wheat (Triticum aestivum L.). Soil CO2 fluxes accumulated during the growing season (largest to smallest) found ORGN>UAN-32>no-N, with 47.1, 36.6, and 24.6 mol CO2 m-2, respectively. For plant production, both N sources had significantly more aboveground biomass produced than no-N. The wet mean weight diameter (WMWD) of stable aggregates (largest to smallest) was ORG-N > no-N > UAN-32, with 0.22, 0.19 and 0.18 mm, respectively. Significant differences among N source treatments were observed (p<0.05). This study highlights that even over a short-term study, organic N amendments can significantly increase aggregation and soil CO2 fluxes, indicating an increased capacity for several soil functions.