Long-Term Leachate Water Quality Trends from a Broiler-Litter-Amended Udult in a Karst Region Abstract Subsurface water quality is an important consideration in regions with underlying karst features, especially when organic soil amendments are surface applied. We examined 8-yr trends in plant nutrient and heavy metal leaching from a pasture soil amended once a year with broiler litter. Results showed that leaching patterns for some soluble constituents take years to develop and negative water quality implications may be observed years after applications cease. Application of broiler (Gallus gallus) litter (BL) to pasturelands in karst regions like the Ozark Highlands can potentially reduce water quality due to leaching of BL-derived nutrients and trace metals. The objective of this study was to determine long-term linear trends in drainage and soil leachate water quality under natural precipitation from a silt-loam soil amended annually with BL at three application rates (0 [control], 5.6 [low], and 11.2 [high] Mg BL ha−1]. Automated equilibrium tension lysimeters were used to continuously monitor and collect leachate from an undisturbed soil profile with a history of litter applications under forage management at a depth of 0.9 m for the 8-yr period from May 2003 through April 2011. Average annual flow-weighted mean (FWM) concentrations and loads of NH4–N, As, Mn, and Ni decreased linearly (P < 0.05), while Cu and Se increased (P < 0.05) linearly during the 8 yr. Nearly all water quality parameters measured were unaffected (P > 0.05) by BL rate alone. Continued annual additions of BL linearly increased (P < 0.05) the average annual FWM leachate Na concentrations relative to the unamended control. Results indicated that pasturelands with a history of BL application may continue to release BL-derived metals, such as As and Se, at concentrations harmful to health regardless of current management practice long after litter application has ceased. Land application of nutrient- and trace-metal-containing animal wastes in regions with underlying karst features needs to be carefully managed to minimize subsoil leaching losses. - https://soils.org/publications/vzj/abstracts/13/9/vzj2014.06.0064 en.wikipedia.org/wiki/Red_junglefowl
Posted on: Mon, 22 Sep 2014 22:40:01 +0000
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