Soil‐Climate Effects on Nitrate Leaching from Cattle Excreta

Abstract

AbstractManagement intensive grazing (MIG) is a grazing system in which animals at a high stocking density are rotated through several paddocks at short time intervals (12–24 h) so that animal performance is maximized. Although MIG has the potential to increase dairy farm profitability in the northeast USA, recent work in this region has shown that a substantial amount of N recycled through urine is leached below the root zone. How soil properties, particularly water‐holding capacity, can affect NO3‐N leaching from beneath urine and feces spots under the climatic conditions of the northeast USA is not known. We conducted a field study to measure NO3‐N leaching loss from spring‐, summer‐, and fall‐applied urine and summer applied feces beneath N‐fertilized orchardgrass (Dactyls glomerata L., cv. Pennlate) using large drainage lysimeters installed in two soils that differed greatly in soil water storage capacity. The study sites were located in central Pennsylvania on a Hagerstown silt loam soil (fine, mixed, mesic Typic Hapludalf) and a Hartleton channery silt loam (loamy‐skeletal, mixed, mesic Typic Hapludult). Compared to the Hagerstown soil, the Hartleton soil provided an 85% decrease in plant N uptake, a 52% increase in leachate volume, but no significant increase in NO3‐N leaching beneath urine spots. However, the lower soil water‐holding capacity of the Hartleton soil caused the NO3‐N leaching losses to be more evenly distributed over the year.