48 CIRCULAR 870, TJ. S. DEPARTMENT OF AGRICULTURE 



rapidly from February or March until the rains cease in April or May. 

 Then they mature rapidly and are dry during the hot, dry summers. 

 Thus, annual-plant range has three rather distinct forage periods: 



(1) inadequate green forage during part of the fall and most of the winter; 



(2) ample green forage during the spring; and (3) dry forage during the 

 summer and early fall. 



Fitting ranch operation to forage growth. — The range is grazed in other 

 periods than during the four spring months when there ordinarily is an 

 adequate, well-balanced forage supply. The foothills are the chief source 

 of grazing for cattle in California during most of the fall and winter, and 

 in many operations cattle are kept yearlong on foothill range. Efficiency 

 in use of the range can be increased by feeding of supplements during 

 the periods when the forage is deficient in quantity or quality and by 

 adopting management practices aimed at increasing the length of the 

 green-forage period. 



The length of the critical forage period of fall and winter and the needs 

 for supplemental feeds usually cannot be predicted far in advance. 

 The average termination date for supplemental feeding, according to the 

 study, was near February 1; however, in years when rains sufficient to 

 start forage growth were delayed until mid-November, feeding was 

 needed until late February or early March. 



The length of the adequate green-forage period is variable. For 

 example, this period at the experimental range varied in length from 72 

 to 176 days, with an average of 127 days for 14 years. 



Most of the herbage is usually dry in June; occasionally in May. The 

 dry roughage consumed, mainly annual grasses, provides sufficient energy 

 but a supplemental feed is needed to provide protein. Bur-clover, 

 perennial bunchgrasses, or other plants, may serve as a partial supple- 

 ment during the summer on some ranges. 



A management objective is to lengthen the period during which foot- 

 hill ranges provide well-balanced forage. Cultural practices for this 

 purpose are being developed for some soil and climatic conditions. Such 

 practices include reseeding or fertilization, to provide earlier green 

 forage in the winter and improved forage during the summer. Forage 

 will be adequate over a longer period if sufficient dry vegetation is left 

 each year to promote early plant growth and if each kind of range is 

 grazed at a time when it produces especially needed green forage. De- 

 ferring grazing of some range units, or portions of a single unit, until the 

 end of the spring growth period will allow cattle to select an improved 

 diet at that time and should delay the date when supplements are needed. 

 Deferring areas with considerable acreage of swales should be most 

 effective. 



Adjusting ranch stocking to herbage production. — As an aid in stocking, 

 herbage production and grazing capacity can be estimated by a simple 

 classification of the different range sites. For example, in six experi- 

 mental pastures the grazing capacities estimated from classification of 

 the sites agreed closely with actual grazing results. The site classes were 

 recognized by characteristics of soil, topography, and waste area. This 

 method of land classification can be used in appraisal of California foothill 

 range. 



Swales are the most productive of the site classes. In acres required 

 per animal-unit month, the grazing capacity of each site class in the 

 experimental pastures is as follows: swales, 0.5 to 0.7; gentle slopes 



