Production Data for 1954-1971 for USFS Study FSRM 1706-12

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.本数据集包含美国林务局（U.S. Forest Service，简称USFS）研究项目FSRM 1706-12中多年生与一年生草本植物的净地上生物量数据，研究方案副本可从官方网站下载。研究在5个牧场中各选取20条随机布设的永久性100英尺样线开展数据采集，该5个牧场自1915年起便由母牛-犊牛群全年放牧，放牧利用率介于47%至60%之间。研究启动时实施了两项放牧管理调整：其一，将放牧利用率目标下调至40%；其二，2个牧场自1958年起实施隔年夏季休牧（7月至9月），另外2个牧场则于1959年开始该休牧模式。牧场9维持全年放牧模式，并于1963年至1966年开展采样以作为对照，但其数据未纳入已发表的分析结果中。1954年至1957年间，研究人员使用柴油灭杀了牧场1和牧场7中的绒毛牧豆树（*Prosopis velutina*），而牧场8、9、10中的牧豆树未做处理。1957年至1966年的每年秋季，研究人员均采用双采样法对草本生物量进行估算，精度精确至1克：在5个永久性9.6英尺×1英尺样方以及每条样线的1个临时样方中估算野外鲜重，剪下临时样方中的草本植物并称重以计算目视估算结果的校正系数，剪下的草本植物干重则用于计算湿度校正系数。永久性样方的野外鲜重会被转换为每96平方英尺样方的克数，再通过上述校正系数转换为每英亩风干磅数，精度保留至小数点后1位。本数据集中，每英亩风干磅数会截断小数部分，但0.1至0.9的数值会被记为1磅/英亩；由于存在截断处理，从本数据集数值计算得到的总和通常会低于基于原始野外数据计算的总和。多数情况下，研究人员会按物种水平分别记录植物类群，部分情况下仅记录至属水平；代码OTHERPG代表未鉴定的多年生草本植物类群，ANNGRASS则代表所有一年生草本植物类群。本数据集的数据来源为原始野外记录表，以下情况除外：牧场1在1958年与1959年的每英亩风干磅数未被预先计算，因此研究人员通过将校正系数应用于该牧场5个永久性样方的野外数据总和，推算得到了这两年的对应数值。数据字段中出现-9999代表该日期未进行采样，无对应数据。