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At
present many livestock producers are talking about forage legumes. This
is a new development because in recent decades most livestock producers
have not invested much time, energy or money in growing legumes.
However, it is not unprecedented because there was a time (before World
War II) when they were widely grown in Alabama and in many other states.
Many
livestock producers presently appear to be on the brink of changing
their attitudes toward forage legumes. Obviously, decisions regarding
the forage species grown on a farm greatly affect livestock production
and profit. Therefore, the "pros" and "cons" of
growing forage grasses versus growing legumes or, as is more commonly
the case, grass/legume mixtures is worthy of a closer look.
Advantages
of Forage Grasses
Forage
grasses offer a number of important advantages. In general, they are
easier to establish than legumes, they tend to be more dependable and,
when comparing perennial grasses with legumes, usually are more
persistent. Except for rare occurrences with a succulent annual-like
ryegrass, livestock bloat is not a problem with grasses.
Grasses
respond to liming and fertilization, but many are fairly tolerant of
soil acidity and/or low levels of various nutrients. The forage yields
of many grasses are good, especially if regular applications of nitrogen
are made which is relatively easy for producers to do. Most grasses
require less overall management than legumes and leaf shatter is not a
concern if grasses are cut for hay.
Advantages
of Forage Legumes
Proponents
of legumes point to their generally superior forage quality, which can
result in significantly higher average daily gains and often better
livestock reproduction. Legumes also tend to improve soil tilth and
increase soil organic matter. In addition, the taproot-type root system
of some legumes penetrates the soil deeply and leaves root channels that
aid growth of subsequent plants. In some cases, growing legumes with
grasses will increase forage dry matter yield and/or extend the grazing
season.
Last,
but not least (and this is a big reason for the current surge in
interest), legumes have the unique ability to fix nitrogen in
association with Rhizobium bacteria that are in close proximity
to their roots. This is of great importance, because nitrogen is the
nutrient required in the large amounts for forage production and is also
the most expensive nutrient. While nitrogen fertilizer is a major cost
input in grass forage production, legumes provide their own supply and
even supply nitrogen to plants growing with or after them.
What’s
The Answer?
In
many management situations, there is actually no "right" or
"wrong" approach. It is a matter of attitude, personal
preference and a person’s perceptions regarding which approach will make
the most of the resources available. |
