Evaluating the USDA-NRCS pasture condition score system with weighted indicators

• The pasture condition score system is used by USDA to assess pastureland for cost-share programs.
• A modified system uses weighted indicators but it is not known how weights affect scores.
• The weighing methods tended to shift aggregate scores higher compared with the standard system.
• There is a need for a standard reference or classification to account for differences in site type.

The pasture condition score (PCS) system is a monitoring and assessment tool for pastureland in the USA. The original system has been modified to address specific variations in vegetation and soils by assigning weights to the individual indicators to emphasize or de-emphasize particular attributes. We compared the effects of different weighting systems on aggregate PCSs and their distribution among five management recommendation categories. Five regional weighting systems were used to compute aggregate PCSs from a data set of 178 observations of pasture condition indicators measured on 39 farms. Distributions of PCSs from the five systems were compared with those obtained from using the original system. In modifications of the original system, plant vigor was the most heavily weighted indicator, whereas plant residue was the least weighted. The various weighting methods tended to increase aggregate scores compared with nonweighted scores, which resulted in different management recommendations. The median score for the original system was 31 compared with a range of 33 to 36 for the weighted systems. Alterations of the PCS system to include weighted indicators attempt to adjust for different environments and site types and suggest the need for some form of standard reference site or classification to account for differences in site type.