USE OF ANNUAL PLANTS IN CALIFORNIA FOOTHILLS \) 



To help determine how different degrees of use affect the condition 

 of the site, in January 1943 the depth and weight of the litter on the soil 

 surface were measured and correlated with the height and yield of new 

 herbaceous growth on 100 quadrats in each of pastures 1, 2, and 3. 

 Many other observations on litter conditions, soil erosion, and plant 

 growth were made at the experimental range and other parts of the foot- 

 hill area. 



Cattle records taken included weights and forage preferences. Each 

 animal was weighed several times: When removed from one pasture 

 to another, at the start of the supplemental feeding period, just before 

 calving, at weaning time, at the end of the green-forage period, and at 

 other times when forage changed noticeably in quality or amount. In 

 the first years of the experiment the cattle were weighed soon after 

 watering in the corrals, but later they were shrunk overnight in a dry 

 lot before each weighing to minimize the differences in "fill" of water 

 and herbage at different times of year. 



The manner in which the cattle selected the various plant species 

 at different growth stages was determined by observation of grazing 

 habits and of grazed vegetation. In 1936, R. H. Klugh 5 recorded 

 detailed observations on the preference of cattle for the different plants 

 during the spring. During 1936-40, Kenneth A. Wagnon, resident 

 animal husbandman in charge of University of California cattle-manage- 

 ment studies, at daily or weekly intervals collected samples of the forage 

 that cows were grazing. These samples were analyzed for chemical 

 composition. Other observations on use of the vegetation by cattle 

 were made during the course of the studies by other technicians. 



FITTING RANCH OPERATIONS TO FORAGE GROWTH 



Foremost among the results of this study is a clear understanding of 

 the seasonal growth of foothill forage plants. The availability and 

 nutritive value of the plants, and the species selected by cattle, change 

 during the year as the plants progress through different stages of develop- 

 ment. At certain stages, the need for supplemental feeds is critical. 

 Knowledge of these changes is basic to skillful fitting of ranch operations 

 to forage plant growth — and hence to efficient use of the annual-plant 

 cover. 



Availability of Forage During the Year 



The characteristic California foothill climate results in three rather 

 distinct plant-growth periods (fig. 4). The first period usually starts in 

 October. Seeds of annual plants start to germinate after the first rains 

 of 0.5 to 1.0 inch. This amount is enough to start germination over most 

 of the range. After the first effective fall rains, however, plant growth is 

 often limited by insufficient soil moisture, unfavorable temperatures, or 

 both. In November mean air temperature for most days of the week 

 usually drops below 50° F. After this, growth is retarded regardless of 

 soil moisture. Plants grow intermittently, during short rainy periods 

 or other occasional periods of mild weather. Cold, dry weather with 

 frequent frosts that stop all growth or freeze back part of the plants can 



5 Formerly Junior Range Examiner, California Forest and Range Experiment Station. 



