USE OF ANNUAL PLANTS IN CALIFORNIA FOOTHILLS 41 



it did show that only in the closely grazed pasture was mature herbage 

 production greatly influenced by degree of grazing. 



In these studies high herbage yields were obtained on all sites under 

 light grazing. But this degree of grazing left considerable unused herbage 

 on the ground that might well be grazed by livestock. Grazing to a 

 moderate degree will give efficient livestock production, and it will leave 

 sufficient unused vegetation to maintain satisfactory soil-surface condi- 

 tion and sustained herbage production. It is clearly more efficient use 

 of the available forage. 



Although yields of each major plant species on slopes, such as soft 

 chess, foxtail fescue, filaree, and clover, were less in the closely grazed 

 pasture, the percentage of each major species in the herbaceous cover on 

 slopes was not greatly different in pastures that had been grazed at 

 different degrees (table 10). For example, the yield of soft chess in 

 closely grazed pasture 3 was 391 pounds per acre as an average for 1943-45, 

 and the yield in lightly grazed pasture 2 was 614 pounds, the percent of 

 total yield being 31 and 33 respectively in pastures 3 and 2. In pasture 1, 

 grazed at an intermediate degree, soft chess composed 27 percent. Fox- 

 tail fescue produced about 12 to 13 percent of the yield in each pasture. 

 The differences in proportion of major species on slopes that did occur 

 between pastures — for example, the greater percentage of filaree in 

 pasture 1 — were present at the start of the experiment. Density estimates 

 showed these differences occurred in 1936 and remained until 1943 when 

 yield measurements were started. Measurements in 1948 showed that 

 at the end of the experiment each of the major species composed about 

 the same proportion of the herbage on slope soils in pasture 3 as in pasture 

 2. 



There were, however, noticeable differences in the abundance of species 

 ordinarily dominant on swale soils. The closely grazed pasture had a 

 much lower yield and a lower percentage of Mediterranean barley and a 

 greater amount of foxtail fescue than the more lightly grazed pastures 

 (table 10). This is not a desirable change because Mediterranean barley 

 in the swales starts growing earlier and dries later than foxtail fescue. 

 In the pasture grazed moderate to close, the amount of Mediterranean 

 barley in the swales was considered adequate even though the yield and 

 percentage were less than in the lightly grazed pasture. 



Both yields and proportions of some minor species in the herbage were 

 changed by degree of grazing on both slopes and swales. Two tall-growing 

 grasses (slender oat and ripgut brome) increased slightly but gradually 

 from 1936 to 1943 in lightly grazed pasture 2. During the period 1943-45, 

 the combined average yield of these species in that pasture was 102 pounds 

 per acre of slope soil. Present in this amount, the two grasses are desirable 

 additions to the winter forage. 



Minor forbs of low forage value (particularly smooth cats-ear and 

 windmill pink on slopes and pogogyne in swales) increased under close 

 grazing (table 10). Smooth cats-ear increased in pasture 3 after 1941; 

 by 1944 it made up 12 percent of the total plant density in that pasture. 

 Because of the wide leaved, rosette form of smooth cats-ear (similar to 

 the form of dandelion), its greater abundance under close grazing was 

 very apparent even though it produced only 31 pounds per acre in pasture 

 3 as an average for 1943-45. The species was not conspicuous in the 

 plant cover on the other pastures. 



