ably altered by nitrogen fertilization (Eheart 
and Pratt 1942; Poulton et al. 1957). Several 
other workers have reported decreases in ‘‘sol- 
uble carbohydrates” in forage with nitrogen 
fertilization (Jones et al. 1961; Reid et al. 1966; 
Waite, 1958). Reductions in soluble carbohy- 
drates with nitrogen fertilization were attrib- 
uted to the increased respiration and to the util- 
ization of soluble carbohydrates for synthesis of 
protein and structural materials. 
CHANGES IN THE BOTANICAL 
COMPOSITION OF RANGELANDS 
The effects of fertilization upon the botani- 
cal composition and upon the condition of 
rangeland plants vary with the climate, the 
soil, and the plants. Huffine and Elder (1960) 
reported greater cattle gains on fertilized than 
on unfertilized native grass pastures in Okla- 
homa. They attributed this difference to an in- 
crease in weedy plants due to fertilization. In 
Wyoming, Cosper et al. (1967) found that ni- 
trogen fertilization on a deteriorated range site 
changed the botanical composition from forbs 
and shortgrass to western wheatgrass and 
shortgrass. Nitrogen increased the yield of for- 
age and the percent of crude protein in the for- 
age. Changes in forage yield were the result of 
changes in the botanical composition as well as 
increases in plant growth. 
In the northern Great Plains, Rogler and 
Lorenz (1957) reported that a higher forage 
yield after nitrogen fertilization was due pri- 
marily to an increase in the percentage of 
western wheatgrass in the species composition. 
They also reported that the crude protein level 
was higher on fertilized than on unfertilized 
plots. 
Lodge (1959) noted that fertilization may 
enable range managers to manipulate the bo- 
tanical composition of native ranges. But he in- 
dicated that such manipulation, to best serve 
the nutritional requirements of the grazing an- 
imal, would first require more knowledge of 
the effects of fertilization on the nutrient sta- 
tus of individual plant species and on the total 
vegetation complex. 
Climatic and soil conditions in some areas of 
California have made fertilization economi- 
cally feasible because of increased forage 
yields, favorable changes in botanical composi- 
tion, and increased livestock gains per acre. 
However, most reports in the literature deal 
with increases in forage yields and in beef 
production. And effects of fertilization on the 
quality of forage are often a sidelight or are 
not mentioned at all. 
Jones and Evans (1960) described 3 years of 
results of fertilization and grazing on botanical 
composition changes in annual grassland in 
California. Nitrogen fertilization increased the 
percent of soft chess on grazed plots on native 
ranges for 2 of the 3 study years, but for only 
the first year on ungrazed plots. It increased 
for 2 years the percentage of soft chess on re- 
seeded ranges that were grazed, but decreased 
it when not grazed. Slender wild oats and 
broadleaf filaree also responded favorably to 
nitrogen fertilization, but both decreased when 
grazed. Little fertilization effect could be mea- 
sured in the filaree on grazed plots. Nitrogen 
fertilization generally decreased the abundance 
of clovers, while phosphorus fertilization gen- 
erally increased the amount of clovers. The 
percentage of clovers on the resident-range, 
and the crimson clover on the reseeded range, 
decreased under grazing, while rose clover and 
subclover increased under grazing. Phosphorus 
also increased the percentage of ripgut brome 
on resident-range, but this increase was less on 
grazed than on ungrazed plots. On the reseeded 
range, where phosphorus was adequate, ripgut 
was increased by nitrogen fertilization. Graz- 
ing reduced the percentage of ripgut on both 
resident and reseeded ranges. 
Examples of changes in forage quality re- 
sulting from changes in botanical composition 
by fertilization are reported in a series of arti- 
cles from a long-term study of sulfur fertiliza- 
tion in the California foothills (Bentley et al. 
1958; Green et al. 1958; Wagnon et al. 1958). 
In most years, the percent of legumes in- 
creased significantly more than that of grasses 
on ranges fertilized with 60 pounds of sulfur 
per acre every 3 years. Total herbage produc- 
tion was increased by more than 50 percent 
over an 8-year period. This increase resulted in 
substantial increases in stocking rates and in 
steer gains. On ranges fertilized with sulfur 
the abundant clovers were grazed first, and 
then grasses made up most of the steer diet. 
Walker and Williams (1963) concluded that 
sulfur can be an important fertilizer element 
on annual-type range and can directly enhance 
the growth of resident grasses much more than 
the growth of resident forbs. However, the ni- 
trogen needs of the grasses must first be met. 
This study did not include a treatment of sul- 
fur alone. 
In a preliminary report on a current study, 
Conrad et al. (1966) noted that clover respon- 
ses to sulfur fertilization were negligible in 
dry years. But in favorable rainfall years, sul- 
fur-fertilized ranges had a higher percentage 
of clover than nitrogen-fertilized or nonfertil- 
ized areas. In general, sulfur has increased the 
number and the size of legumes on annual-type 
ranges; nitrogen has resulted in fewer and 
smaller legumes but more and larger grasses 
than no fertilization. 
From a small plot study at the San Joaquin 
Experimental Range in central California (re- 
sults unpublished), we found that the applica- 
tion of sulfur encouraged legume growth, 
while nitrogen reduced legume growth but in- 
59 
