The most dependable results, it was found, can be had by seeding 15 to 20 pounds of oats and 40 to 50 pounds of vetch. This rate of seeding provided enough oats to support the vetch and produced hay of which approximately half was legume.
This mixture is also grown in some places in the Sacramento and San Joaquin Valleys, especially where, because of disease or some other unfavorable condition, alfalfa cannot be grown. In the Valleys, the mixture is grown mostly on irrigated land. In fact, to be sure of a good crop, irrigation is necessary. In these areas the late fall and winter is somewhat colder than along the coast. If seeding is delayed until the fall rains have moistened the soil, perhaps in late November or early December, the soil may be so cold that the vetch does not germinate and only oats are obtained. Therefore, seeding is on pre-irrigated land, preferably in late October when a good stand of vetch, as well as oats, can be obtained and the plants, once established, survive the winter.
Kanota oats, rather than California Red, are used in mixture with legumes. It has a stiffer straw, is less inclined to lodge, and provides a better support for the legume. Purple vetch is the legume commonly employed in mixture, mainly because of its greater dependability and higher yield. Common vetch, Canadian field peas, and Austrian Winter peas are also used sometimes. Hairy vetch and Tangier peas have given excellent results under a wide variety of conditions, but the scarcity of seed and its high price has kept them from general use.
Some barley and wheat are also cut for hay, for the most part incidentally to the production of grain; if the season is favorable for the grain, the crop is allowed to mature and is harvested for grain. But if conditions for growth and maturity are unfavorable, the crop is cut for hay. As a rule, these crops are allowed to become quite mature before being cut, and the quality of hay is often rather poor.
Other crops grown, to a limited extent, for hay include red clover and alsike clover in mixture with timothy or other grasses, and sorghum or Sudangrass, which is fed on the farm where it is grown and is used mainly to supplement insufficient supplies of alfalfa.
Both perennial and annual irrigated pastures are- important feed crops in California.
The use of perennial irrigated pastures, as known today, dates from the late 1920's, when it was demonstrated that Ladino clover would produce excellent yields of forage on our shallow hardpan soil if properly watered or managed. The use of perennial irrigated pastures since that time has grown rapidly. The present acreage is estimated at about 450,000; it seems likely that within the next score of years it will become our most important forage crop. Irrigated pasture provides forage of high quality at a low cost and produces it on land unsuited to alfalfa.
Ladino clover is still the leading irrigated-pasture plant, but it has limitations: It is shallow rooted; because for continued growth it requires frequent irrigation, especially in summer, it is limited to areas having plenty of water and retentive soil; it cannot stand high temperatures. Ladino is grown on irrigated pastures in a number of districts, but most of the acreage in Ladino is located in the Sacramento and San Joaquin Valleys, where favorable conditions prevail.
We still have much to learn about proper mixtures for the different areas and the best management practices, but now enough experience has been gained to suggest some rather definite procedures.
To get maximum production and a better balanced feed, most of the pasture consists of clover or other legumes with various grasses. In the Sacramento Valley and in other localities in the North, a popular mixture contains Ladino clover, annual and perennial ryegrass, tall fescue, and orchardgrass. In the San Joaquin Valley the same mixture is used although Dallisgrass is commonly added to it or substituted for the orchardgrass. Some alfalfa is sometimes added to get more legumes during the summer when heat depresses the growth of the clover.
Because the pasture must be irrigated every 10 to 14 days during the warmer months, the field is divided into four or more pastures and grazed in rotation. Opinions differ as to how close the pastures should be grazed, but observation indicates that most pastures are grazed too close, so that recovery is retarded and production lowered.
Ladino clover draws heavily on the mineral nutrients, and many pastures containing it must be fertilized with phosphorus, and sometimes sulfur, for best growth.
The most serious weeds in irrigated pastures are apt to be buckhorn, dock, and various sedges. Partial control may be effected by mowing the pastures after they have been pastured to prevent the plants from seeding and to reduce spreading. Mowing also prevents some of the bunch grasses, particularly orchardgrass and Dallisgrass, from taking over. When pastures become very weedy, the only means of eradication known is rotation with other crops.
Great interest has developed lately in birdsfoot trefoil as a pasture legume. It is a deep-rooted perennial; it is not adapted to the shallow hardpan land, but does well on the deeper, more porous soils. It tolerates more alkali and requires less frequent irrigation than Ladino. It tolerates more heat and is used with excellent results in the Imperial Valley in mixtures with ryegrass, Dallisgrass, Rhodesgrass, and other grasses. Elsewhere it is grown with the same grass mixture as Ladino is. The use of birdsfoot trefoil may greatly extend the area of irrigated pastures, but it should not be considered a substitute for Ladino in areas where the latter can be grown. While no direct comparisons are available, the birdsfoot trefoil does not recover so rapidly after grazing as Ladino, and observation indicates that it produces somewhat less feed.
One-half to two-thirds of the perennial irrigated pasture is grazed by dairy cattle, and provides succulent feed through a large part of the year. The remaining acreage is grazed by beef cattle and sheep. An important use is to finish lambs for market. The general trend appears to be to use ranges primarily to produce feeders to be finished on pasture and concentrates.
The most important annual irrigated-pasture crop, Sudangrass, is used in all of the warmer parts of the State. It is seeded in April or June after a winter hay crop is removed. Sudangrass pasture will produce more feed than any other crop available during the warm summer months. Its principal use is on small dairy farms, where maximum production of feed is required. Some sweet sorghums are used in the same way, but they do not lend themselves so well to pasturing.
Some other forms of forage are produced in limited quantities in some places. For silage, primarily for dairy cattle, various plants are grown in different localities. Corn is the most popular. In the warmer sections the sweet sorghums are grown. On the coast, oats and vetch are used; in some sections farmers put the first cutting of alfalfa, which is usually mixed with foxtail and weeds, in the silo. Silage will continue to be important in some areas, but perennial irrigated pastures, which produce an acceptable substitute at a much lower cost, have reduced its use in other districts.