USE OF ANNUAL PLANTS IN CALIFORNIA FOOTHILLS O 



Studies of range fertilization, range reseeding, range rodents, and other 

 subjects were made in portions of several pastures. The effects on 

 vegetation of complete exclusion of livestock grazing were studied in an 

 ungrazed "natural area." 



Ninety head of breeding cows were used in the grazing-intensity 

 studies. From approximately August 1 to February 1 they were divided 

 into two equal herds. One, the supplemented "A" herd, receiving con- 

 centrate feeds in addition to natural forage, was grazed in pastures 10 

 and 12. The second, the unsupplemented "B" herd, was grazed in 

 pasture 14- with access only to the natural forage. During the remainder 

 of the year, from approximately February 1 to August 1, none of the 

 cows received supplements; 15 cows with their calves were placed in each 

 of the grazing-intensity pastures 1 to 6. Pastures 1, 2, and 4 each held 8 

 cows from the "A" herd and 7 from the "B" herd; pastures 3, 5, and 6 

 each held 7 cows from the "A" herd and 8 from the "B" herd. A bull 

 was with each group of cows from January 1 until May 1. 



Approximate rates of stocking in the six grazing-intensity pastures 

 were: 10 acres per cow in pastures 1 (154 acres) and 3 (155 acres), 

 15 acres per cow in pastures 2 (230 acres) and 5 (250 acres), and 20 

 acres per cow in pastures 4 (309 acres) and 6 (316 acres). The cows 

 were placed in all six pastures in late winter at the time when new green 

 forage over most of the range was judged adequate to maintain a cow 

 with a calf for the remainder of the winter. They remained in these six 

 pastures until after the herbage was mature and dry and were removed 

 when the heaviest-used pasture was judged closely grazed. 



Measurements were made each spring to determine (1) the plants 

 that make up the forage, and (2) how herbage production varies with 

 grazing intensity and year-to-year differences in weather. The percent 

 of the ground covered by herbaceous vegetation, plant density, and the 

 percent of the cover made up by each plant species in each of the six 

 grazing-intensity units were estimated on square-foot quadrats: 300 

 quadrats per experimental pasture in 1936; and 80 to 160 quadrats per 

 pasture in 1938, 1939, 1940, and 1943. Continuity of density records 

 was maintained in 1941, 1942, and 1944 by estimates from 100 quadrats 

 in lightly grazed pasture 2, and closely grazed pasture 3. Density 

 measurements were made as nearly as possible at the time of maximum 

 plant density in April, when the early-maturing species first started to 

 dry. 



The yield of herbage on slopes was measured in May 1942 on 100 

 square-foot quadrats in each of pastures 2 and 3. The vegetation on 

 each quadrat was protected from grazing by small wire "cages" (fig. 3) 

 and was clipped at 3^-inch stubble height in May, after almost all the 

 herbage had made full growth and started to dry. Herbage from each 

 quadrat was placed in a paper bag, dried in a greenhouse, and weighed 

 when relative humidity of air was below approximately 30 percent. In 

 1943, 1944, and 1945 the yield on slopes was measured on 100 quadrats 

 in each of pastures 1, 2, and 3 and on swales, or bottom land, on 60 to 100 

 quadrats in each pasture. The vegetation was protected from grazing, 

 clipped, sorted, and weighed as in 1942. The wire cages were moved to 

 new locations each January. 



The total yield of herbage within a 34-acre area from which cattle and 

 rodents were excluded was measured on 100 quadrats at plant maturity 

 each spring during an 8-year period, 1940-47. In addition, the dry 



