Mineral fertilizer and manure effects on leached inorganic nitrogen, nitrate isotopic composition, phosphorus, and dissolved organic carbon under furrow irrigation

Lentz, R.D. and Lehrsch, G.A. (2018) Mineral fertilizer and manure effects on leached inorganic nitrogen, nitrate isotopic composition, phosphorus, and dissolved organic carbon under furrow irrigation. Journal of Environmental Quality. 47(2):287-296. 8 March 2018.

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Abstract

To improve nitrogen (N) use efficiency in irrigated agriculture, a better understanding is needed of mineral fertilizer and manure effects on nutrient leaching in a furrow irrigated silt loam in southern Idaho. In this 2003-to-2006 field study, we measured deep percolation fluxes at 1.2-m depth and associated nutrient concentrations and mass losses for dairy manure-N or mineral-N (urea, sodium nitrate [NaNO3]) amended soils (372 kg available N/ha in four years) and non-amended controls, and determined the 2H-H2O and 18O-H2O isotope ratios in the leached nitrate. Flow-weighted concentration means for individual irrigations varied widely, from near zero to as much as 250 mg/L for NO3-N, 480 µg/ L for dissolved reactive phosphorus (DRP), 43 mg/L for dissolved organic C (DOC), and 390 mg/L for chloride (Cl). Relative to other treatments, mineral fertilizer increased NO3-N (3.3x) and Cl (4.4x) concentrations in deep leachate, particularly when NaNO3 was applied in 2004, and produced maximum mean season-long NO3-N and Cl losses. Manure and control treatments produced similar leachate nutrient mass losses, and for some irrigation periods, mineral fertilizer produced 85% and 97% lesser DRP losses and 2x greater Cl losses compared to manure and control treatments. Four-year cumulative losses among treatments differed only for Cl. Isotopic composition of deep leached nitrate indicate that both transformation and biologic cycling of mineral and manure N are rapid in these soils, which, with percolation volume, influence the amounts of NO3-N and DOC leached. In light of the potential negative effects associated with either fertilizer type, and because even non-amended soils produced substantial amounts of leached NO3-N (69.5 kg ha-1 Yr-1), an important management key for limiting nutrient losses in these fertilized, furrow-irrigated soils is to minimize percolation water losses.

Item Type: Article
NWISRL Publication Number: 1608
Subjects: Irrigation > Furrow irrigation
Manure
Soil > Amendments > Fertilizer
Water > Water quality
Depositing User: Michelle Wayment
Date Deposited: 12 Mar 2018 23:27
Last Modified: 12 Mar 2018 23:27
Item ID: 1651
URI: https://eprints.nwisrl.ars.usda.gov/id/eprint/1651

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