Submitted to: Forage Focus
Publication Type: Popular Publication
Publication Acceptance Date: December 1, 2009
Publication Date: December 18, 2009
Citation: Sanderson, M.A. 2008. Soil fertility levels on northeastern pastures. Forage Focus. December 2009. p. 15. Interpretive Summary: An interpretive summary is not required.
Technical Abstract: Livestock producers in the northeastern USA rely more on forages, pasture, and grazing management to reduce production costs and remain competitive. Soil nutrient levels are one indicator of the level of nutrient management on farms. Our objective was to gain some insight into the level of various soil nutrients on grazing farms across the northeastern USA. The majority of pastures sampled had optimum to high levels of soil P and K. Nearly one-half of pastures were “high” in soil P and 20% had soil P levels greater than 100 ppm. Increased levels of soil test P have been associated with an increased risk of P loss in surface water runoff; however, other risk factors such as the amount of soluble P from manure, landscape position of the pasture, and hydrologic connections must be considered as well. A well managed grazing system should maintain a dense vigorous sod in pastures and reduce the potential for soil erosion, water runoff, and nutrient losses. More than 40% of paddocks had soil K levels in the “high” category. Soil K also tended to be lower in pastures farther from the barn. Although high levels of soil K are not a water quality problem, high soil K may result in high forage K concentrations, which can cause metabolic problems in dry cows. Thus, dairy producers need to test both soils and forages in pastures to determine if specific pastures are a high risk for dry cows and if specific dietary supplements (e.g., anionic salts) may be necessary. If high K pastures are set aside for hay or silage harvest, the forage should be tested for K. Producers who have adopted intensive grazing management practices also need to monitor soil fertility and implement appropriate nutrient management practices.