CIRCULAR 870, U. S. DEPARTMENT OF AGRICULTURE 



F-460560 



Figure 3. — Cage made of 2-inch mesh poult^ netting used to protect vegetation 



from grazing by cattle. 



herbage was measured on another set of quadrats each fall during a 7-year 

 period, 1936-42. This J^-acre area was located within pasture 1. 



To facilitate comparison of yields between experimental range units 

 with different amounts of waste area, yields were measured only on 

 productive, grazable land. Rocks, brush, and other waste areas were 

 excluded from the samples. Then the amount of waste area was measured 

 in 1942 on 16 transects across each of the six grazing-intensity pastures 

 and subtracted from the total area to determine the grazable acreage. 

 In evaluating the productivity and grazing capacity of different kinds of 

 land, a range site classification was employed. The development of this 

 classification entailed the making, in 1945, of a site-class map of the six 

 grazing-intensity pastures. 



Measurements were also made to determine the seasonal pattern of 

 plant growth. During the 1937-45 period, plant density and height 

 were measured at one fixed station in each of the six pastures at intervals 

 of 1 to 4 weeks. The average growth and development of vegetation 

 by sites were determined in each year by observations of plant growth 

 over all of the experimental pastures and by color photographs at selected 

 stations. Detailed observations were made on critical features of plant 

 growth, such as the amount of precipitation required to germinate the 

 seed and start growth of the several species, growth on south slopes 

 contrasted with growth on north slopes, growth at different air tempera- 

 tures, and the relative dates of flowering, fruiting, and drying of the 

 different species on different sites. Many comparisons of plant heights 

 were made across fence lines between experimental pastures grazed at 

 different degrees and between spots grazed to different degrees within 

 pastures. 



