Submitted to: Lancaster Farming
Publication Type: Popular Publication
Publication Acceptance Date: April 12, 2007
Publication Date: April 14, 2007
Citation: Sanderson, M.A., Goslee, S.C., Stout, R.C., Gonet, J.M. 2007. Pasture Condition Scoring at the Whole-Farm Scale. Lancaster Farming 52(5)E17. Interpretive Summary: An interpretive summary is not required.
Technical Abstract: Producers need monitoring and assessment tools to aid in pasture management. One such tool, the pasture condition score system, has been developed by the USDA-NRCS for use as a pasture monitoring and management tool. Ten key indicators (percent desirable plants, plant cover, plant diversity, plant residue, plant vigor, percent legume, uniformity of use, livestock concentration areas, soil compaction, and soil erosion) of pasture status are evaluated along with causative factors explaining reasons for low condition scores. Each of the ten indicators is rated from 1 (poor) to 5 (excellent). The individual scores are added to find the overall rating of the pasture. Overall scores are divided into classes describing their condition and need for management interventions. In a recently completed on-farm research project, we found that pasture condition scores vary among and within grazing seasons mainly in response to weather. Scores also vary widely within farms primarily because of management differences among pastures used for different classes of livestock. In the study, we applied the pasture condition score system on two farms in Pennsylvania (one beef, one dairy), two farms in New York (both grazing dairies), and one farm in Maryland (an organic dairy). All pastures on each farm were evaluated according to the published methods for the pasture condition score system in spring, summer, and fall of 2004, 2005, and 2006. In 2004, average pasture condition scores for most farms remained stable or increased slightly from spring to fall. Average pasture condition scores in 2005, however, decreased dramatically from spring to fall because of hot and dry weather that affected a large area of the mid-Atlantic region during mid to late summer. Scores were in or near the category where immediate changes to pasture management were necessary to prevent further degradation. In 2006, with greater rainfall during the grazing season, the patterns and categories of pasture condition scores were stable and similar to 2004. The indicators for legume content and forage diversity scored lowest on all farms in all years (scores of 1 to 2 on a 1 to 5 scale). An indicator score of 1 means that the legume content is 10% or less of the sward dry matter and an indicator value of 2 means that the legume component is 11 to 19% of the sward dry matter. Our previous surveys of pasture condition on northeastern farms showed that the legume and forage diversity indicators scored lowest regionally The legume component of grazed swards can be affected by soil pH and phosphorus (P) along with grazing management. Soil pH on many of the pastures was 6.0 or below, which may have limited legume persistence. Soil P was mostly at or above agronomic sufficiency levels and probably did not limit legume persistence. From interviews with the producers and from visual observation we noted that producers often struggled with managing the rapid spring growth of pastures. This often led to accumulation of tall, over-mature forage, which may have shaded legumes and reduced their persistence. We grouped the pastures into four broad types based on their primary use or age to examine management effects on pasture condition within a farm: i) pastures used for the main herd, ii) pastures used for heifers or dry cows, iii) pastures used mostly for hay and aftermath grazing, and iv) young (< 5 years old) pastures. Pastures used for heifers and dry cows or for wintering livestock had lower pasture condition scores than other pastures. Typically, livestock on these pastures were stocked at higher densities and grazing periods were longer than on other pastures. This resulted in less plant cover and more bare soil along with greater soil compaction. On some farms, these pastures were on less productive soils, which may have affected scores. Our results suggest that a strategy of assessing pasture condition at the start of the grazing season in spring, during stressful growing conditions (typically mid summer) and near the end of the season would provide timely information for making pasture management decisions. Grouping pastures managed and used for different classes of cattle (e.g., heifer, dry cow, or holding pastures) and monitoring representative subsets of these pastures would reduce the monitoring work load.