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Picturing present and potential pasture production

By Roger Gates
Whitfield County CEC

“Taking stock” is a phrase that means to “think carefully about a situation… so that you can decide what to do.” Historically, the phrase came from a farmer’s practice of counting the number
of animals on the farm.

Periodic livestock inventories provide important and useful records. Creating and maintaining an inventory of pasture resources is not as straightforward as counting bulls, cows and young stock… but is probably equally important and useful. Monitoring pasture conditions at the conclusion of the growing season is a logical “management appointment.” Two ingredients for forage production, temperature and day length, are decreasing, so pasture growth is also slowing. Fall pasture conditions also reflect the consequences of decisions about fertilization, weed control and especially grazing management.

Keep in mind that “taking stock” is an effort to acquire information that will guide future decisions. Having records that reflect past management decisions is necessary to interpretation of current pasture assessment.

Perhaps the factor having the greatest impact on the present condition of pasture plants is rainfall. A rain gauge and consistent recording of precipitation are essential to understanding records of pasture conditions. Although very simple to record, pasture grazing records are too often avoided, or, if available, ignored when developing future grazing plans. Knowing when and how long a pasture is grazed, by how many animals of know size, is the best way to estimate pasture yield, most often described as carrying capacity. A simple, but extremely valuable addition to records of occupation would be a measurement of pasture availability before and after grazing. That can be as simple as average vegetation height, measured with a grazing stick.

There are several useful approaches to evaluating condition of pasture plants and soils. Determining the “energy status” of pastures is, in some ways, similar to body condition scoring assigned to the cowherd. Vegetation and landscape conditions at the end of the growing season indicate what happened during the grazing season. End of season status provides more than recent history; it also can serve as a leading indicator of future productivity.

On one extreme, pasture defoliated by severe, season long grazing is easy to “condition score” and will be less productive during the following year. On the other extreme and perhaps almost as easy to evaluate are pastures that remained ungrazed, receiving a full growing season deferment. These pastures will be more productive during the coming growing season. Parenthetically, the parallel to excessively fat cows might be those pastures that have remained ungrazed for several consecutive years. While periodic rest benefits pasture vegetation, excessive rest is “abnormal” and compromises overall productivity and composition of the vegetation community.

Just as fat cover serves as an accurate indicator of a cow’s energy status, residual vegetation reflects the “energy status” of pasture plants. Sunlight is the energy source for green plants. Grasses and forbs have an adequate opportunity to display their leaves in order to develop energy reserves. Sunlight “harvested” during the growing season is converted into plant tissue, providing for growth and grazable feed. Particularly at the end of the growing season, plants that are in a positive energy balance are able to partition energy to storage organs such as stem bases, stolons, rhizomes and roots. Stored nutrients are critical to spring recovery and initial growth.

For many cool-season grasses, new tillers initiated from buds in the fall establish the threshold for potential production beginning the following spring. Residual vegetation or stubble height reflects the opportunity pasture plants have had to establish and maintain a positive energy budget and therefore is a suitable leading indicator for next year’s production.

Spending time to evaluate grazing resources this fall, pasture by pasture, is an important step in developing appropriate grazing plans for the next growing season. Pastures with limited residual vegetation should be given the opportunity for plants to develop and display their leaves for the longest period at the beginning of next season. Conversely, those pastures where residual vegetation displays the most positive energy status are likely to be most productive and could be grazed carefully this winter or earliest next year.

One tool that can be extremely helpful in evaluating pasture condition is the “Pasture Scorecard” developed by, and available from, the Natural Resources Conservation Service. Pastures are scored from 1 (poor) to 5 (excellent) for 10 different categories including: Percent desirable species, plant cover, plant diversity, plant residue, plant vigor, percent legume, uniformity of use, livestock concentration areas, soil compaction, and erosion. High average scores for any pasture would confirm past management strategies. Low scores would indicate that management changes are needed. Identifying which characteristics are deficient provides further guidance about which future management approaches might be appropriate. Low plant residue and evidence of erosion would indicate that stocking rates should be reduced. Low percentages of desirable plants might indicate weed management is needed. Low legume percentages would suggest that seeding clover would be beneficial.

Both the pasture condition scorecard https://fyi.extension.wisc.edu/forage/files/2014/01/NRCS-Pasture-Condition-Score-Sheet-2001.pdf and a guide to pasture scoring https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb1044239.pdf can be accessed online.

A second tool that will be helpful is the establishment and use of “photo points.” It is human nature to trust that we will be able to recall accurately the appearance of a landscape and know whether it has improved or degraded. It is equally true that a photographic record is more trustworthy that even the best memory. Photo points are locations established so that photos can be taken from the same location repeatedly. Both landscape views and “straight down” views of the vegetation canopy can be instructive.

Mobile devices with continually improving image resolution will make recording photo points convenient and useful. An additional convenience is available by using an app for smart phones or tablets called GrassSnap. This app was developed and is supported by UNL (Nebraska) Extension. The app is free and available in both iOS and Android formats.

There can be issues, like getting the same landscape view between years, ensuring the pictures have been stored in an easily downloaded and useable manner, and that written comments are tied to the correct image. This app assists producers in grabbing repeatable photo-monitoring data, and saving it on their smart device in an orderly fashion so it can be downloaded to the home computer to study.

Features of Grass Snap include:
• “Overlay” or ghost image allows a user to capture the same “look out” photograph, by laying the original landscape view over the screen. Silhouettes of the hills will easily line up year after year.
• Photo-stamps each photograph with the pasture name, GPS location (in decimal degrees), and date. Comments, such as rainfall amounts, grazing records, or other events, can also be recorded.
• Organizes photographs and data in in a separate folder for each pasture, which can be uploaded to a home computer.

More information can be found at: http://go.unl.edu/GrassSnap. The website has videos there to help with setup, a user guide, and downloading instructions of photographs.

In addition to evaluation of short-term management impacts, the end of the growing season is a prime opportunity to commit time to longer-term monitoring. The best “return on investment” is likely to come from establishing photo points. The objective of long-term monitoring is to provide a record of landscape change. Our memories are not sufficient to provide the kind of recall that is needed to evaluate long-term change. Precise and quantitative procedures are available to monitor change, particularly the species composition of pastures that will reflect long-term grazing trends. However, photo points can provide an extremely valuable qualitative record of landscape conditions. Without a permanent record, evaluating the long-term impact of grazing management decisions is much more difficult and reduces the confidence with which future plans can be developed.