Long-term impacts of drain spacing, crop management, and weather on nitrate leaching to subsurface drains.

Autor: Kladivko EJ; Dep. of Agronomy, Purdue Univ., 915 W. State St., West Lafayette, IN, 47907, USA., Bowling LC; Dep. of Agronomy, Purdue Univ., 915 W. State St., West Lafayette, IN, 47907, USA.
Jazyk: angličtina
Zdroj: Journal of environmental quality [J Environ Qual] 2021 May; Vol. 50 (3), pp. 627-638. Date of Electronic Publication: 2021 May 05.
DOI: 10.1002/jeq2.20215
Abstrakt: Subsurface drainage is an essential water management practice for many poorly drained soils in the U.S. Midwest, but this practice also contributes nitrate-N loads to surface waters. This paper summarizes results from Years 16-31 of a long-term drainage research project in southeastern Indiana and compares results with the first 15 yr of the study. The study compared three drain spacings (5, 10, and 20 m) managed with a no-till corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] rotation, with cover crops in about half of the years. Drainflow and nitrate-N losses per unit area were greatest for the 5-m spacing and lowest for the 20-m spacing. Nitrate-N concentrations did not vary with drain spacing and were generally in the range of 4-9 mg L -1 . Annual nitrate-N loads were linearly correlated with annual flow volumes, reflecting the relatively constant concentrations over the 16-yr period. Whereas nitrate-N concentrations were relatively constant throughout the year, short-term concentration spikes occurred for nitrate-N during June-July of corn years. About 70% of annual drainflow and N loads occurred during the fallow season of November-April. The results underscore the interacting effects of drainage design, crop management, and weather in determining the magnitude of N loss from drained agricultural fields.
(© 2021 The Authors. Journal of Environmental Quality published by Wiley Periodicals LLC on behalf of American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.)
Databáze: MEDLINE
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