Goat Urine and Limestone Affect Nitrogen and Cation Distributions in an Acidic Grassland

Abstract

Prior surface application of limestone may influence soil changes resulting from high rates of urine deposition occurring where goats (Capra aegagrus hircus L.) congregate. A quantity of limestone equivalent to 0 and 6720 kg ha−1 was surface applied to vegetated 45‐cm‐deep columns of a Typic Hapludult soil collected from an abandoned Fescue spp. grassland in southern West Virginia. Eighteen weeks after lime application, one, two, or three applications of urine supplying a total of 36, 98, or 177 g m−2 of N, respectively, were made. One and two applications of urine increased vegetative growth and decreased the amount of water leaching through the column, but the third addition damaged plants. The three‐addition treatment reduced the amount of N taken up by the plants, decreased transpiration, increased leachate volume, and resulted in a 12‐fold increase in the amount of N leached from the columns compared with the one‐application treatment. Leachate Ca, Mg, and K were increased by urine. Soil pH and extractable Ca and Mg were decreased by urine and increased by limestone, and extractable Al was increased by urine and decreased by limestone applications. Net amounts of N recovered as NH3 gas released to the atmosphere, N taken up into aboveground plant material, NH4+ and NO3− extracted from soil, and NH4+ and NO3− in drainage water ranged from 49 to 77% of the amount added. Surface application of limestone alleviated some of the detrimental effects of high rates of urine addition by increasing levels of pH, Ca, and Mg and reducing Al as deep as 28 cm in the profile.