Effect of drying and rainfall intensity on cyromazine loss from surface-applied caged-layer manure.
1994
Pote D.H. | Daniel T.C. | Edwards D.R. | Mattice J.D. | Wickliff D.B.
Most poultry manure is surface-applied as pasture fertilizer, 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 manure component in caged-layer (Gallus gallus domesticus) systems. Since cyromazine is quite soluble and stable in water, the objective of this study was to quantify cyromazine in runoff and soil water from pasture treated with caged-layer manure. Plots of uniform slope were bordered to isolate runoff and planted in fescue (Festuca arundinacea Schreb). Manure was analyzed for cyromazine content and applied at 0, 4.4, and 17.7 Mg ha-1 (dry basis). Rain was applied by simulator at 50 and 100 mm h-1. Runoff was analyzed for cyromazine and its metabolite, melamine (1,3,5-triazine-2,4,6-triamine). A high manure application rate increased runoff volume and cyromazine concentration. High rain intensity increased total cyromazine runoff loss but provided enough runoff volume to reduce the concentration. Mean cyromazine concentration in runoff was as high as 101 micrograms L-1, and mean cyromazine loss was as high as 23.7%. Pan lysimeters monitored soil water in the vadose zone for 1 yr after the manure application, but cyromazine and melamine were not detected. In a follow-up study, plots received manure at 3.76 Mg ha-1, were allowed to dry for either 1 or 7 d, and then received rain at 50 mm h-1 for 30 min of runoff. The 7-d drying time decreased cyromazine loss, apparently by reducing both runoff volume and cyromazine concentration in the runoff.
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