Soil Nutrients Variability in Irrigated Strip-Stocked Pastures in Semiarid Condition in Northern Nevada.

The management of pasture can alter the properties of soil both in depth and distance from water or shade source. Soil samples were collected from two historical strip-stocked pastures at the University of Nevada, Reno Main Experiment Station in Reno Nevada. The grazed pastures comprised of a mixture of tall fescue (Festuca arundinacea), white clover (Trifolium repens), Kentucky bluegrass (Poa pratensis), orchardgrass (Dactylis glomerata) and timothy (Phleum pretense).  Each strip was one hectare in size and typically stocked with crossbred cattle, at a stocking density of 20 animals ha^-1 for a duration of 1- to 2-d. The objective of this study was to evaluate the effects of strip stocking on soil nutrient distribution in a semiarid environment. Soil samples were collected from three different depths (0- to 8-cm, 8- to 15-cm and 15- to 23-cm) and distances from water source (0- to 60-m [Zone 1], 60- to 120-m [Zone 2] and the rest of each strip [Zone 3]). Soil extractable P and ammonium (NH₄-N) concentrations were affected by soil depth (P < 0.0001) but not by distance from water source (P > 0.05). Both soil extractable P and NH₄-N concentrations were greater at the soil surface 0- to 8-cm compared to deeper in the soil profile. Soil nitrate-N (NO₃-N) concentration was not affected by soil depth (P = 0.385) but was affected by distance from water source (P = 0.0015). Soil NO₃-N concentration was greatest in Zone 3 followed by Zone 2 and 1 respectively. These results are preliminary and with the exception of soil NO₃-N concentrations, distance from water source did not affect soil extractable P and soil NH₄-N in strip-stocked pastures.