There are some human activities in which striving for uniformity is desirable, but making forage crop species selection decisions for a livestock farm is usually not one of them. Of course, nature provides lots of diversity in pastures (including weeds in many cases), but, when it comes to development of a forage program, intentionally using a diversity of forage species offers some distinct advantages.
Adaptation - It is of basic importance to match forage species with appropriate sites. While this is nothing more than "common sense," the fact is an all-too-frequent reason for poor forage production is that someone is trying to grow a forage crop in an area where it really isn’t well adapted. On many farms, simply doing a good job of identifying which forage species will perform best on various parts of the farm and then making planting decisions accordingly will ensure a diversity of forage species will be grown.
Risk - The concept that it isn’t desirable to "have all your eggs in one basket," applies to forage programs as well as to many other aspects of life. Most diseases and many insect pests are species specific; that is, they only attack a particular species or, in some cases, certain varieties within a particular species. Also, different forage crops vary in their ability to tolerate heat, cold, drought and other climate extremes. Therefore, as more species (and to a lesser extent, more varieties) are grown on a farm, risk is lessened.
Distribution of Growth - A particularly compelling reason for striving to have a diversity of forage species on a livestock farm pertains to distribution of growth. No two forage crops have exactly the same growing season. Therefore, by having several different types of forages growing in different fields, or even growing together in the same field, the distribution of pasture forage available (and thus, the grazing season) is spread over a longer period of time. Many university studies have shown that as stored feed requirements go up, profitability generally goes down. A basic desirable objective is to provide pasture over as long a period of time as possible.
Species Compatibility - Much of this article could be interpreted as having dealt with growing different forage crops in different areas on a farm, so it should be pointed out growing forage crops in mixtures in a particular field can also offer some definite advantages. The classic example of this is the use of grass/legume mixtures. Legumes fix nitrogen used for growth by grasses, while grasses reduce the likelihood of bloat from legumes. Also, many grasses tend to ensure good forage yield, while legumes often improve forage quality as compared to grass alone.
More interesting - A final point of less importance, but worth mentioning, is it’s just more interesting to grow several different types of forages on a farm. There is a lot of truth to the old cliché; "variety is the spice of life." If you aren’t having fun doing whatever you do for a living, you probably either ought to make some changes in how you’re doing it or change careers. Using a diversity of forage species is a way to provide a little additional interest to the challenging business of being a livestock producer.
Don Ball is an Extension Forage Crop Agronomist with Auburn University.