A mechanic working on a car has a set of tools to use. The mechanic knows what each tool is capable of doing - lifting, opening, prying, pounding, pulling, turning, shaving, and so on. Often a tool, such as a screwdriver, exists in different sizes, types, and capabilities. 

Mechanic with tools

When a professional mechanic determines the problem, using the tools is automatic. Rummaging through the tool box and experimenting with each tool would be inefficient, time consuming, and frustrating. With this analogy in mind, let's study the need and procedures for selecting a forage plant.

View the various forage plant species as tools. Like the mechanic you need to know your tools to use them effectively for specific jobs. A screwdriver may work to pound something but a hammer works much more effectively and safely. Even duct tape can be used in emergencies to do certain jobs, but tools designed to do a specific job are much more worthwhile in the long run.

Learning the specific attributes of forages is important because forages can be worthwhile in two major ways; 1) economically (How can I cheaply feed 300 dairy cows so that they will produce as much milk as possible?) and 2) environmentally (What can I do to best reduce erosion?). Current agricultural focus on sustainability requires that a combination of both issues be considered in forage selection.

Worldwide a handful of field crops are grown for direct human consumption. Those crops vary considerably one from another. But selecting a forage is more difficult because there are thousands of grass and legume species. Although most are not cultivated for forages, there are still dozens of choices and even more combinations that are used as mixtures. And, these species often have dozens of cultivars plant breeders have selectively bred for better forage characteristics or better tolerance of a certain set of prevailing conditions. This process of selection for prevailing conditions is called adaptation. Legumes have a more narrow range of adaptation than grasses. This is important since grasses and legumes are often grown together in mixtures. (In the study of biology, evolutionary adaptation differs in that a specific hereditary change occurs that allows a species to better take advantage of its environment.)

Forage crop adaptation refers to grasses and legumes that have evolved or been bred to live under certain conditions. Thriving plants have developed to exploit or tolerate the following prevailing conditions:

Edaphic (soil factors)

  • pH
  • drainage/flooding
  • fertility


  • day length
  • relative humidity
  • solar radiation
  • minimum/maximum temperature
  • length of growing season
  • snow cover


  • elevation
  • aspect (slopes)

Biotic Stresses

  • insects
  • diseases
  • nematodes
  • vertebrates

Exploitation indicates that the plant makes the most of such conditions and thrives. Tolerance indicates that the plant probably will survive but it does not mean the plant will be productive. It is important to differentiate between what a species will tolerate from the optimum range for the best yield. And yield should be measured over the long run. Sometimes short-term yield is good but the long-term life of the plants needs to be considered for a realistic look at total economic yield. Selection should be based on year-round benefit which may require a mixture of species with different adaptations. This is an important difference from measuring yield of many row crops.

When given a set of conditions that describe the area to be used for growing forages, it is important to select a species that will produce abundantly with minimum inputs required to manage the plants and at the least cost. Knowing the specific adaptations of each of the major forage species is goal. Continually looking up the plant traits and adaptations from forage texts is like the mechanic rummaging through his tool box before each task. Those interested in forages need to learn the specifics about the 30 - 40 grasses, legumes, and forbs from classes like this, textbooks, seed company information, extension agents,and their materials, or consultants. This course provides forage identification material available on CD-ROM and opportunities to develop selection skills in the activities section. When plant identification and the following material on species limitations are considered, then appropriate selection can be wisely accomplished. Appropriate selection of a forage crop will greatly affect yield, quality, longevity (plant stand life), management input and, of course, profits.