How Do I Determine Actual Forage Production? A rancher can never see exactly how much forage has been or is being produced because it is constantly growing and continuously being consumed by livestock or lost to other causes. However, if he can quantify the amount of forage on the land at any given time, he can project how much of it will need to be reserved as residue and how much can be used. Naturally, this is an on-going process and the rancher must make these evaluations often. How does a rancher determine the quantity of forage he has and is likely to produce in coming months? There are three approaches to this problem. The rancher can conduct periodic range condition surveys to compare current species composition with known ratings in the Soil Conservation Service Technical Site Guides. These provide a guideline for establishing an annual stocking rate (McGinty and White, 1991). Most ranchers are unable to project how long their current forage will last by simply observing animal and pasture conditions. But with photo guides they can better quantify forage supplies and then (with a planned stocking rate and grazing plan) estimate the amount of forage needed for consumption from each pasture and from the whole ranch (forage demand) so that seasonal adjustments can be made (White and Richardson, 1989). A second approach to quantifying forage production is to monitor the disappearance of range forage by comparing grazed areas with small, fenced areas which are left ungrazed (Figure 7). These exclosures allow the rancher to visualize how much forage has been produced and how much has been consumed or lost. The cages should be moved periodically so that the impact of grazing on forage growth can be determined, and many exclosures are needed for an accurate assessment. With this method, the rancher measures the rate of forage disappearance at frequent intervals, which allows him to predict forage shortfalls or excesses, The minimal unit days of grazing for the pasture since the last observation, divided into the amount of forage disappearance, provide an estimated daily disappearance rate (forage eaten by livestock plus natural disappearance). For example, if an exclosure was established on July 1 and on August 1 (31 days later) the difference in forage supply between the grazed area and the exclosure equalled 75 pounds per acre, the disappearance would equal 2.4 pounds per day. If the remaining grazable forage (amount above desired residue) equaled 90 pounds per acre, then approximately 38 days of grazing would remain at the current stocking rate. A third approach uses computer software to help with stocking rate decisions. APSAT (Annual Planning Stock Adjustment Templates) uses pasture utilization ratings and actual versus expected growing conditions to project needed stocking rate adjustments (Kothmann and Hinnant, 1990). The software will warn of potentially heavy use early enough so that adjustments in stock numbers can be made before overgrazing occurs. Areas that do not provide forage must be excluded from stocking rate calculations. The use of stocking rate guidelines to determine the number of animal units a pasture can carry often results in overstocking unless the ungrazable area is taken into account. The process of estimating annual forage production becomes easier if a rancher gathers historical data and pays attention to trends. A useful practice is to take photographs at several set locations on the ranch three or four times each year. When these photographs are compared for several consecutive years, the rancher will be able to see trends in forage production over time. Authors: Larry D. White, Allan McGinty