The ability of certain legume-grass mixtures to withstand grazing

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NEW MEXICO COLLEGE OF AGRICULTURE AND MECHANIC ARTS
AND AO-STCULTURAL EXPERIMENT STATION
Press Bulletin 1007
THE ABILITY OF CERTAIN LEGUME-GRASS MIXTURES TO WITHSTAND GRAZING
Most dairymen throughout the United States believe that pasture is essential
for profitable dairying. This belief is, supported by the knowledge that growing
plants supply certain essential nutritive values that are difficult and always
expensive to obtain in other feedstuffs. Furthermore, pasturing may be the most
economical method of harvesting a crop, thereby reducing the dairyman's feed costs.
Under certain conditions the economy of pasturing depends mainly upon the cost of
producing feed. This is especially true wherever the pasture land is arable and
can be used for other purposes. For example, in many parts of New Mexico the cost
of preparing the soil, seeding, and irrigating will be nearly as great for producing
pasture forage as for many other crops. In these areas permanent pastures would
reduce the cost of soil preparation and seeding by eliminating annual seeding, but
careful selection of the forage crop is necessary to obtain a high yield that would
further increase the economy of producing pasture forage.
Legumes, such as alfalfa or clover, usually produce higher yields than any of
the grasses but they present the hazard of occasionally bloating the animals.
Growing grasses with legumes has been suggested as a means of reducing the probability of bloat. This would necessitate a grass that grows well in the hot months.
Furthermore, the use of "cool season" grasses should lengtheh the pasture season by
providing forage early and late in the season when the legume is making less rapid
growth.
These assumptions formed the basis for trials of legume and legume-grass mixtures in permanent pastures' at the New Mexico Experiment Station. Four 1-acre plots
having fairly rich, medium-heavy adobe soil were used. One plot was planted with
15 pounds of alfalfa, one with 6 pounds of ladino clover, one with 5 pounds of alfalfa in a grass mixture, and the fourth with 4 pounds of ladino clover in a grass mixture. The grass mixture consisted of 3 pounds African lovegrass, 4 pounds switch-
grass, 3 pounds perennial ryegrass, 3 pounds orchardgrass, 4 pounds Dallisgrass,
and 3 pounds alta fescue. These plots were planted in late October 1942, and fairly
good stands of each were obtained. The plots have been irrigated and pastured
through two seasons, and clipped only occasionally to control the growth of weeds.
Ho fertilizing other than that obtained while pasturing, and no cultivation has
been practiced. The legume-grass mixtures and the clover made fairly firm sod, but
it was thought desirable to remove the animals whenever the ground was moist enough
that their hoofs would disturb the plant roots. This procedure allowed the forage
to attain considerable growth between pasture periods, although it seldom reached
the early b]com stage which is desired in the harvest method of pasturing.
Throughout 5 months of pasture season, both the alfalfa and ladino clover plots
have afforded good pasture with a carrying capacity equivalent to approximately one
and one-half cows per acre. In addition to this, the clover plot has afforded a
small amount of pasture for two to four yearling heifers during the winter months.
These yearling heifers also had access to dry hay and a little grain, but did obtain from the clover sufficient feed to be apparent in the general appearance of
the animals. The clover also started growing early in the spring, allowing very
light grazing during March and April before the other plots could be pastured.
The plot consisting of clover and grasses afforded approximately the same amount
of pasture as either the clover or the alfalfa plot during the usual 5-month season.
The proportion of clover stand has increased very materially while alta fescue and