50 CIRCULAR 870, U. S. DEPARTMENT OF AGRICULTURE 



tion was satisfactory in all four of the experimental pastures grazed from 

 moderate to light from February to August. 



Close grazing was clearly inefficient from the standpoint of forage 

 production also. Plant growth was always short during the winter on 

 range closely grazed during the preceding year, and in late winter forage 

 became adequate about 3 weeks later than on range grazed moderately 

 or lightly. Total herbage yield was also lower at plant maturity, par- 

 ticularly on the very heavily grazed bottom lands, the most productive 

 part of the range. Yield of each major species on slopes was lower, but 

 each composed about the same proportion of the total yield as under 

 moderate or light grazing. There was some increase in weedy species of 

 low value under close grazing. Most important in the long run, close 

 grazing did not maintain sufficient litter on the soil surface to promote 

 full forage production year after year, and it produced other indications 

 of soil deterioration. 



Light grazing resulted in the best soil-surface conditions and winter 

 growth of forage. It also maintained highest production of soft chess, 

 filaree, clovers, and other valuable forage species. But it left on the 

 ground a considerable bulk of herbage that could have been grazed to 

 increase cattle production. 



An intermediate degree of grazing, between close and light, was the 

 most efficient. It maintained a satisfactory litter cover without apparent 

 soil deterioration. Winter growth of forage was also satisfactory, and 

 there was no significant decrease in amount of desirable forage species. 

 Keeping to a moderate degree of grazing on the average, with all practic- 

 able flexibility in numbers of livestock, appears feasible as a means of 

 obtaining efficient production from the fluctuating quantity of forage on 

 foothill ranges. 



Condition of the soil surface on annual-plant range is best judged during 

 the winter. Where the layer of old herbaceous material is nearly absent 

 or of spotty occurrence over most of the range at this time of year, the 

 mineral soil will be readily apparent through a thin cover of new plants. 

 Conversely, under satisfactory conditions a fairly continuous thin layer 

 of litter and a thick carpet of vigorous new plants will leave almost no 

 bare soil apparent on most of the range. Accordingly, the extent of 

 herbaceous litter on the soil surface and the vigor of plant growth during 

 the winter are dependable guides to maintenance of satisfactory produc- 

 tion from the present cover of annual plants. 



Photographic standards for judging degree of grazing of annual-plant 

 vegetation, developed and tested during the experiments, have been 

 used successfully in rating utilization on almost all kinds of California 

 foothill range. 



COMMON AND BOTANICAL NAMES OF SPECIES 

 MENTIONED 



Common name Botanical name 



Alfileria, redstem filaree Erodium cicutarium (L.) L'Her. 



Barley, Mediterranean Hordeum gussonianum Pari. 



Bluegrass, pine Poa scabrella (Thurb.) Benth. 



Brome, ripgut Bromus rigidus Roth. 



Bur-clover, California Medicago hispida Gaertn. 



Cats-ear, smooth Hypochoeris glabra L. 



Chess, soft Bromus mollis L. 



