USE OF ANNUAL PLANTS IN CALIFORNIA FOOTHILLS 



29 



Figure 14. — Estimated annual production of air-dry herbage from grasses and 

 grasslike plants per grazable acre, San Joaquin Experimental Range, 1936-48. 



winter. Grasses are the chief source of dry forage at that time of year. 

 During the 13 years, 1936-48, the production by grasses and grasslike 

 plants each year in pastures 1, 2, and 3 (fig. 14) was estimated from 

 clipped samples, density records, and other field observations. These 

 records show that the yield of grasses and grasslike plants varied less 

 than did total herbage production (fig. 13) up to and including 1946. 

 Livestock adjustments based on variations in total herbage were sufficient 

 in these first 11 years. 



After 1946, however, grass yields fluctuated more than total yields, 

 presenting a more critical stocking problem. The proportion of grasses in 

 the herbage was progressively lowered during the dry years after 1946. 

 Filaree dominated the plant cover in 1947 and 1948; consequently, grass 

 yields were lowered much more than total yields. By 1948 grass yields 

 were only about 42 percent of the 13-year average. Under these condi- 

 tions a greater amount of supplements was needed in the summer to 

 balance the lower quality of the dry roughage, and hay was needed during 

 the fall and winter, even though fewer livestock were grazed. 



Nevertheless, most fluctuations in individual species have relatively 

 minor effects on range stocking. Observations on several important 

 forage species bear out this conclusion. In years of high clover yields, 

 for example, the herbage was considered of better forage value than in 

 other years. However, in "good clover years" there is no shortage of 

 forage and the problem may be to increase stocking. Again, because soft 

 chess matures late, its growth and seed production depend on adequate 

 late spring rains. Value of the dry herbage was considered better in the 



