Document Type

Technical Report

Publication Date

6-1-1993

Keywords

Pesticides, Water quality, Poultry manure, Surface runoff, Solute Transport, Cryomazine

Abstract

In Arkansas, much of the environmental concern related to water quality has focused on the high volume of poultry fecal waste spread on the surf ace of local pastures to fertilize forage grass. Cyromazine (N-cyclopropyl-1,3,5-triazine-2,4,6- triamine), a feed-through larvicide used to control house flies (Musca domestica), is often a component of caged-layer manure. Cyromazine is quite soluble and stable in water, and previous research has shown that it can be readily washed from pasture plots by intense rainfall. Therefore, a study was conducted to evaluate increased drying time as a best management practice technique for reducing cyromazine runoff losses from pasture fertilized with caged-layer manure. The objective of this study was to compare cyromaz ine runoff losses from plots with different drying intervals between the manure application and first rainfall event. Fescue plots with uniform slope and dimensions were used to simulate pasture. Each plot had a runoff collector and borders to isolate plot runoff. Manure was analyzed for cyromazine content, applied to the plot surface at 3. 76 Mg/ha, and allowed to dry for 1 or 7 days. Simulated rain was then applied at 50 mm/h to generate 30 min of runoff from each plot. Plots with manure that dried for 7 days had significantly less runoff than both the control plots that dried for 7 days and manure plots that dried for only 1 day. Analyses of runoff samples indicated that increased drying time following manure application reduced the amount of surf ace runoff and reduced the concentration of cyromazine in the runoff. The resulting decrease in cyromazine runoff loss implies that increased drying time may serve as an effective best management practice for reducing cyromazine losses in runoff from pastures fertilized with caged-layer manure.

Report Number

PUB 162

Page

30

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