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A Protocol for Collecting and Constructing Soil Core Lysimeters
Published on: June 6, 2016
Inputs and losses by surface runoff and subsurface leaching for pastures managed by continuous or rotational stocking
L B Owens1, D J Barker, S C Loerch
1USDA-ARS, Coshocton, OH 43812, USA. lloyd.owens.ars@gmail.com
Journal of Environmental Quality
|January 6, 2012
Summary
Pasture stocking methods like continuous and rotational grazing had no significant impact on nitrate leaching. Precipitation levels, not grazing practices, were the primary driver of nitrate transport in subsurface water.
Area of Science:
- Agricultural Science
- Environmental Science
- Hydrology
Background:
- Pasture management influences water quality, forage, and animal production.
- Nitrate (NO(3)-N) leaching from pastures is a key environmental concern.
- Understanding the impact of grazing on water quality is crucial for sustainable agriculture.
Purpose of the Study:
- To compare the effects of continuous and frequent rotational grazing on water quantity and quality.
- To assess nitrate (NO(3)-N) transport in surface and subsurface water under different pasture management systems.
- To determine the influence of grazing intensity and precipitation on nitrogen losses.
Main Methods:
- A 5-year study at the North Appalachian Experimental Watershed compared continuous and frequent rotational stocking.
- Four instrumented watersheds received consistent nitrogen (N) fertilization and stocking rates.
- Surface runoff and subsurface flow (springs) were monitored for water quantity and nitrate (NO(3)-N) concentration.
Main Results:
- Nitrate (NO(3)-N) losses in surface runoff were minimal across all treatments.
- Subsurface flow and nitrate (NO(3)-N) transport were significantly influenced by seasonal precipitation variability.
- Average annual nitrate (NO(3)-N) transport in subsurface flow ranged from 11.3 to 22.7 kg N ha(-1), comparable to or less than precipitation inputs.
- Flow-weighted seasonal nitrate (NO(3)-N) concentrations in subsurface flow remained below 7 mg L(-1).
Conclusions:
- Grazing practices (continuous, weekly rotational, frequent rotational) did not significantly affect nitrate (NO(3)-N) leaching.
- Precipitation patterns, rather than specific grazing methods, were the primary determinant of nitrate (NO(3)-N) transport in subsurface flow.
- Sustainable pasture management should consider the significant role of hydrological variability in nutrient loss.
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