File: prod12.xls The file contains net aboveground production data for perennial and annual grasses for USFS Study FSRM 1706-12. A copy of the Study Plan may be downloaded from the web site. Measurements were taken along 20 randomly located permanent 100-ft. line transects in each of five pastures. The pastures had been grazed yearlong by cow-calf herds since 1915; utilization ranged from 47-60%. Two changes in grazing management were instituted at the start of the study period: 1) The utilization objective was lowered to 40%, and 2) Summer deferment (July-Sept) in alternate years began in 1958 in two pastures and in 1959 in the other two. Pasture 9 continued to be grazed yearlong and was measured in 1963-1966 for comparative purposes. Data from pasture 9 were not included in published analyses. Mesquites (Prosopis velutina) in pastures 1 and 7 were killed with diesel oil between 1954 and 1957. Mesquites in pastures 8, 9, and 10 were left untreated. Herbage production was estimated to the nearest gram each autumn from 1957-1966 using double-sampling. Field weights were estimated on five permanent 9.6x1 ft. plots and on one temporary plot per transect. Herbage on temporary plots was clipped and weighed to calculate a factor for adjusting ocular estimates. Dry weights of clipped herbage provided a moisture correction factor. Field weights from the permanent plots were converted to grams per 96 sq. ft. plot. Grams per 96 sq. ft. plot were converted to the nearest 0.1 air-dry pound per acre by applying the factors. In this file air-dry pounds per acre amounts are truncated at the decimal point except for amounts of 0.1-0.9, which are recorded as one pound per acre. Totals calculated from file values will generally be lower than ones calculated from field data due to truncation. Taxa were recorded separately to the species level in most cases and sometimes to the genus level only. The OTHERPG code refers to unidentified perennial grass species; ANNGRASS to all annual grass species. Sources of data were the original field data sheets except: Air-dry pounds per acre had not been calculated for pasture 1 in 1958 and 1959, so these amounts were calculated by applying the factors to the field data totals for the five permanent plots. A value of -9999 in a field means that no data were available because a reading was not made for that date. prd12notes.txt 26 October 2001