Skip to main content
ARS Home » Midwest Area » Ames, Iowa » National Laboratory for Agriculture and The Environment » Agroecosystems Management Research » Research » Publications at this Location » Publication #376428
Research Project: Agroecosystem Benefits from the Development and Application of New Management Technologies in Agricultural Watersheds

Location: Agroecosystems Management Research

Title: Organic agriculture effect on water use, tile flow, and crop yield

Author
item Logsdon, Sally
item CAMBARDELLA, CINDY - Retired ARS Employee
item DELATE, KATHLEEN - Iowa State University

Submitted to: Agrosystems, Geosciences & Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/25/2021
Publication Date: 8/4/2021
Publication URL: https://handle.nal.usda.gov/10113/7709405
Citation: Logsdon, S.D., Cambardella, C.C., Delate, K. 2021. Organic agriculture effect on water use, tile flow, and crop yield. Agrosystems, Geosciences & Environment. 4(3). Article e20200. https://doi.org/10.1002/agg2.20200.
DOI: https://doi.org/10.1002/agg2.20200

Interpretive Summary: Organic agriculture often includes long-term rotations and additions of manure. This plot study showed that organic forage took up more water in the spring and fall than conventional corn-soybean rotation. A four-year rotation (corn, soybean, oat with first-year alfalfa, second year alfalfa) was intermediate in water use. The leaf area index (measurement of crop growth) did not show a consistent difference between conventional and organic corn or soybean. In the wet year of 2018, weed pressure hindered organic soybean growth. There was a good relationship between crop water use and grain yield for corn and soybean. Having crops on the land for a longer season could be beneficial in drying the soil during wet springs. This information is important for organic farmers and their advisors.

Technical Abstract: Organic agriculture usually includes long term rotations (including small grain and forages) or cover crops, which extend the growing season compared to annual crops alone. The purpose of this study is to compare organic and conventional agriculture effects on plant water use and seasonal water balance and leaf area index (LAI). We compared conventional corn (Zea mays L.)-soybean (Glycine max (L.) Merr.) rotation with a four-year rotation (corn-soybean-oat (Avena sativa L) with first year alfalfa (Medicago sativa L.)-second year alfalfa) all present each year, and mixed forage. The water component was measured for the last 3.5 yrs of an 8-yr experiment. Weather station data was combined with photographic information to determine evapotranspiration (ET) for each component crop or weed in each plot. In 2017 and 2019 from April through mid to late June, the organic forage had significantly greater ET than the four-year rotation, which had significantly greater ET than the conventional rotation. The same trend was apparent in 2017, 2018, and 2019 mid-September through October. The early season trend was not apparent in 2018 as compost was applied, and alfalfa and mixed forage were re-established. On a few mid-season dates, the conventional system had greater ET than the four-year organic rotation due to difficulty establishing first-year alfalfa, and cutting of second-year alfalfa. The significance of LAI differences between organic and conventional corn and soybean were inconsistent.