Montana HAYWATCH: Field Prediction for Timely Alfalfa Harvest

Alfalfa is the premier hay crop in North America. Annually it contributes $250 million to Montana's economy. While most of the alfalfa produced in Montana and the Northern Great Plains is fed to beef cattle on-site, there is a growing interest in producing high quality hay for dairies or other premium markets outside the region. In many principal dairy areas of the Eastern U.S., high summer humidity and rainfall often limit the production of premium quality dry hay, increasing the demand for Western hay. There are excellent management strategies available to optimize alfalfa forage quality and yield. Yet until now, only limited practical information on the production and merits of high-quality hay has been disseminated to traditional beef cattle producers in Montana. The HAYWATCH program was initiated in 1993 to assist producers in monitoring the forage quality of standing alfalfa to determine optimum harvest schedules.

Most of Montana's hay is cut at some stage of bloom. Current recommendations for beef producers call for harvest at 10% bloom to optimize forage yield and quality. Many producers wrongly assume 10% bloom to be when 10% of the alfalfa canopy is purple or flower colored. The proper definition of 10% bloom is when 10% of the alfalfa plants in a field have at least one open floret--which occurs several days earlier. As alfalfa and other forage crops advance through growth and maturity, there is a decline in forage quality. Definitions of alfalfa growth stages such as "bud," "late bud," "10% bloom," and "mid-bloom" are useful, but imprecise. Fick and co-workers at Cornell University have developed a 10-stage scoring system that very accurately predicts concentrations of crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), and other parameters of forage quality (Fick & Mueller, 1989; Kalu & Fick, 1983). The mean stage of maturity by count (MSC) method consists of taking random, representative field samples, and scoring individual stems for stage of development. Stems in the vegetative stages are scored 0-2, bud stage 3-4, flowering 5-6, and seed production 7-9. The MSC is calculated as the weighted mean stage of all stems collected in the sample, and has been published as an accurate field tool to predict pre-harvest forage quality of standing alfalfa.

The objectives of the HAYWATCH program were to (a) adapt the MSC technique for Montana hay producers, (b) develop HAYWATCH as a timely interactive tool, and (c) use HAYWATCH to promote and educate producers about the values of improved harvest management for forage quality.

In 1993, county agricultural agents collected weekly samples at 13 sites in 10 large hay-producing counties in Montana. In 1994, the HAYWATCH program was expanded to 31 sites in 15 counties. Five random one-foot samples were clipped on consecutive Mondays, from late May through early July. Agents determined MSC at their respective sites, dried the forage sample, and then shipped it to Montana State University (MSU)-Bozeman for laboratory analysis of CP, ADF, NDF, and relative feed value (RFV) by near infrared reflectance spectroscopy (NIRS). After the samples were analyzed, the MSC and NIRS results were sent by electronic mail to all county offices each Friday afternoon. The results were also posted on radio spots, three local newspapers, and on the "Forage Update" menu of the toll-free Montana Crop Health Hotline voice-mail system. During harvest, each cooperating producer left an unharvested area for subsequent HAYWATCH samples. After harvest, bale core samples from each site were submitted by the agents to compare forage quality of the standing crop versus the hay.

The MSC technique is a very useful educational and predictive tool. In 1993, agents were able to learn the scoring system and complete their samples in less than 30 minutes per site. In 1994, several producers worked with the agents, and became competent with the MSC system. In both years, HAYWATCH provided excellent weekly dialogue among producers, agents, and several specialists on many areas of forage management including alfalfa weevil control, weed control, soil fertility, hay markets, feeding, and harvest management.

The growing seasons of 1993 and 1994 were dramatically different. 1993 was cool and wet, and most producers in Montana had difficulty harvesting hay due to frequent and high rainfall. By contrast, 1994 was warm and dry, and provided excellent haying conditions. In spite of the climatic differences in the two growing season, alfalfa maturity progressed at similar rates (Cash, 1995). For both years, the alfalfa samples progressed from the mid-vegetative stage (MSC 1.3) in late May to early flowering (MSC 4.9) in early July. Over the seven-week period each year, this represented a 38% decline in CP, and the fiber components increased by 53% (ADF) and 39% (NDF).

The HAYWATCH regression equations to predict CP, ADF, and NDF from MSC were compared to the Cornell University equations published by Fick, et al. (Fick & Mueller, 1989; Kalu & Fick 1983). Both sets of regression equations provided statistically significant predictions (R-squared of 0.55 to 0.58, p<0.01, 238 df). Although these R-squared values were not as high as desired, the HAYWATCH and Cornell predictions of CP, ADF, and NDF were highly correlated (Table 1).

The HAYWATCH data were further analyzed to determine the appropriate MSC at which "premium"-quality hay (>20% CP, <30% ADF, <40% NDF) could be cut. The HAYWATCH data demonstrated that across Montana, first cutting alfalfa must be harvested prior to MSC 3.0 (early bud stage) to assure the potential of premium quality hay (Table 2). Producers with large tracts would need to begin harvest prior to this stage to have a majority of the crop cut prior to MSC 3.0. The MSC score of 3.0 was attained at different dates across Montana. Specific target dates, according to MSC scores depending on location have been prescribed (Cash, 1995).

During 1993, rainy conditions delayed harvesting and limited the quality of alfalfa hay in Montana. In 1994, many producers used the HAYWATCH results and began first cutting of alfalfa in time to obtain premium quality hay. In 1994, 179 calls were placed to the "Forage Update" menu on the Montana Crop Health Hotline voice-mail system. Generally, most cooperators who cut at an earlier stage of growth in 1994 than typical, put up higher quality hay than expected.

At the completion of the 1994 HAYWATCH, all cooperators were provided with a summary of the results, and a survey to evaluate the program and its impacts. The participants were interviewed personally, by phone, or by mail. Eighteen (58%) responded to the 10-question survey (Table 3).

The HAYWATCH program is a good field predictor of first cutting alfalfa hay quality in Montana. Although most participants were already good producers, the survey indicated that they learned from the program and that they would put some of the information to practice. Most cooperators increased their awareness of the importance of stage of alfalfa maturity and the merits of routinely testing their hay. During 1995, four producers collected and scored their own MSC samples, and delivered them to the agents for shipment to the laboratory. Ultimately we hope that many producers will use the technique and equations to accurately predict hay quality.

The MSC technique and other "scissor-cut" field estimates of forage quality are being used in several Midwestern states to assist producers in decision-making for optimal harvest dates. Extension personnel in Washington and Idaho have regional programs similar to HAYWATCH that target producers of dairy hay. In Montana the approach has been to use statewide data to provide information to traditional beef operations as well as producers of cash hay. The weekly sampling provided excellent dialogue among producers and the Extension Service for all areas of forage management. Although HAYWATCH runs for a seven-week period each year, the information and grower interaction is used throughout the year. For example, in 1993, most first cutting hay was moldy and had poor quality due to cool, rainy weather throughout the summer. Based on the evaluations of the core samples from the HAYWATCH sites, we alerted producers to potential feeding problems and needs for winter supplementation.

The HAYWATCH program is a useful model for taking applied research to the field, and actively involving producers in the learning process. Although most of the forage quality research has been conducted in major dairy states, we have tried to efficiently adapt it to our conditions and producers. Electronic mail and the hotline voice mail systems allow timely updates to Extension Service field staff and Montana producers. As budgets become more limiting, it will become increasingly important for Extension Service specialists and agents to integrate available educational and technological resources to meet the needs of clientele.

Cash, S. D. (1995). Montana HAYWATCH program. Montana AgResearch, 12(1), 9-14.

Fick, G. W., & Mueller, S. C. (1989). Alfalfa quality, maturity, and mean stage of development (Cornell University Information Bulletin 217). (Available from Distribution Center, 7 Research Park, Cornell University, Ithaca, NY 14850)

Kalu, B. A., & Fick, G. W. (1983). Morphological stage of development as a predictor of alfalfa herbage quality. Crop Science, 23, 1167-1172.