Rd. Tinline et al., EFFECT OF FERTILIZERS AND OF LIMING ACID SOIL ON COMMON ROOT-ROT IN WHEAT, AND OF CHLORIDE ON THE DISEASE IN WHEAT AND BARLEY, Canadian journal of plant pathology, 15(2), 1993, pp. 65-73
Field experiments were conducted in Saskatchewan to ascertain the effe
ct of fertilizers and of liming acid soil at Scott [pH 4.8 (CaCl2)] on
common root rot (CRR) and yield of wheat, and of potassium chloride (
KCl) fertilizer on these variables in wheat and barley at several loca
tions. Application of lime to raise soil pH to 6.5 or 7.0 in 1963 or 1
965 had no influence on CRR severity in spring wheat that was rated in
8 years between 1973 and 1982. However, grain yields were improved si
gnificantly by the lime treatments in 5 of 7 years with an overall mea
n increase of about 15% for the wheat on soil limed to pH 6.5. On soil
limed to pH 7.0, mean yields over 3 years were improved by 27%. Sever
ity of disease was not affected by phosphate (P) and nitrogen plus pho
sphate (NP) fertilizer. It was significantly reduced by KCl in 5 of th
e 8 years. A yield increase averaging about 12% was associated with P
fertilization. The response to P fertilizer was most pronounced in the
untreated soil and least in the limed soil. This differential respons
e likely was due to the lower availability of soil P in the unlimed th
an limed soil. In an experiment on fertilizer rates and K sources, bot
h added K and Cl significantly reduced CRR of wheat in 1 of 4 trials c
onducted from 1980 to 1982, and over the 4 trials. However, applied K
reduced the average yield compared to the control. Mean disease severi
ty and grain yield increased as rates of NP increased. Chloride, but n
ot K, reduced the severity of CRR significantly in 4 of 11 wheat trial
s and in 7 of 11 barley trials conducted in 1987 to 1989. The Cl effec
t was consistent in wheat at Swift Current, and in barley at Saskatoon
and Scott, suggesting a differential influence of the fertilizer on C
RR in these crops. Yields were obtained in 7 trials for each of wheat
and barley. Neither K nor Cl provided a yield benefit. The total N and
P content of wheat and barley foliage were not modified consistently
by K or Cl fertilizers. Cochliobolus sativus was the primary cause of
CRR. It was isolated from more than 80% of subcrown internodes from wh
eat and barley plants in the 1988 and 1989 trials.