Meadow Forage Production as Influenced by Fertilization in a Dry Year

Abstract

During drought years, stream flow is often insufficient to irrigate normally flooded native meadows. Herbage production of the meadow is reduced, haying operations are suspended, and the available forage is grazed by cattle. Fertilization of meadows in eastern Oregon is done in the late fall or early spring before the availability of irrigation water for the following growing season is known. This study was initiated in 1977, following a severe winter drought, to determine the effect of fertilizing meadows in a dry year. Urea fertilizer was applied at 13 rates (0 to 745 kg N/ha). Maximum forage production of 1,000 kg/ha occurred about mid-July for the check treatment. Production was not increased at fertilizer rates of 0 to 50 kg N/ha, but were increased up to 1,600 kg at fertilizer rates of 95 to 745 kg N/ha. Crude protein concentrations in the forage were similar to those measured in years of normal rainfall. Herbage NO3- N levels were considered nontoxic at fertilizer rates less than 540 kg N/ha. It appears that during years of low precipitation, with customary rates of fertilization (90-110 kg N/ha), forage production will be increased slightly, forage quality will be about normal, and the danger of nitrate poisoning will be nil.