Illinois Fertilizer
Conference Proceedings
January 25-27, 1999
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K.A. Ames*, S.A. Ebelhar, K.L. Barber and W.L. Pederson1
Soil-borne diseases are responsible for significant yield losses each year. Plant pathogens can reduce stand, reduce root development, and ultimately reduce yield. These pathogens can be controlled with the use of fungicide seed protectants. However, most fungicides are effective for only a few weeks, and most soybeans grown in Illinois are not treated with seed protectants.
Previous research has proven that the severity of several soil-borne diseases
is reduced by the application of chloride fertilizers. For example, take-all
of wheat was suppressed by a spring application of Cl in Oregon (Christensen
et al., 1981; Scheyer et al., 1987). This project was designed to evaluate the
possible effect of chloride on soil-borne diseases of wheat and soybeans.
Field studies were conducted at University of Illinois research stations located at Urbana and Dixon Springs in 1997 and 1998. The studies evaluated four KCl levels (0, 32, 64, and 128 lb per acre) in 1997 and three KCl levels (0, 32, and 64 lbs per acre) in 1998 with two application methods (pre-emergence and V2 post applied). Three soybean varieties (Pioneer 9363, Pioneer 9395, and Pioneer 9451) were grown in 1997 and four varieties (Pioneer 9363, Pioneer 9395, Pioneer 9451, and Essex) were grown in 1998. The KCl applications provided 0, 15, 30, and 60 lbs of Cl per acre, respectively. The experimental design was a split plot, with the main plot treatments being the KCl level by method of application combinations and the subplot treatments being cultivars. Plots were arranged in a randomized complete block design with five replications in 1997 and four in 1998.
Field studies were conducted at University of Illinois research stations located in Urbana and Dixon Springs in 1997 and 1998. This study consisted of three varieties (Pioneer 9363, Pioneer 9395 and Pioneer 9451), three sources of salts (KCl, K2SO4 and CaSO4), two methods of application (pre-emergence and V2 post applied), five replications in 1997, and four replications in 1998. Plots receiving K-containing material were applied at 64 lbs of K per acre, whereas S-containing materials were applied at 26 Ibs of S per acre. The experimental design was a split plot; the main plot treatment was the type of salt by method of application combinations and the subplot treatments were soybean varieties. Plots were arranged in a randomized complete block design. For both studies, individual plots in Urbana were 4 feet by 12 feet in 1997 and 4 feet by 15 feet in 1998, and the Dixon Springs plots were 5 feet by 16 feet in 1997 and 1998.
Studies were conducted at Urbana, Brownstown, and Dixon Springs in 1998 using three wheat varieties: Ernie, Patterson, and Madison. Treatments included 0, 32, 64, and 128 lbs. of K per acre, and the fertilizer was applied to the wheat either pre-plant in the fall of 1997 or in the spring of 1998. Plots were 4 feet by 15 feet, and treatments were arranged in an RCB design with four replications. Root ratings for Rhizoctonia root rot and Fusarium root rot were made at milk-stage. Grain yields and grain moisture were obtained and analyzed.
Field studies were done at Urbana, Brownstown, and Dixon Springs to evaluate different sources of K. The sources included CaCl2, KCl, and KNO3. Plots were arranged as described for the level of K study, with one rate of each fertilizer applied at either planting or spring top-dressing. As with the previous studies, roots were examined and rated for disease severity and yields were determined.
The application of all rates of chloride at both Urbana and Dixon Springs (Table 1, Table 2, and Table 3) reduced yield of the sensitive variety Essex. Essex was added in 1998 because of its sensitivity to chloride. Despite the uptake of chloride, Essex had the highest level of root disease. There was little difference among the application time or rate, but the varieties had different yield potential.
The different forms of chloride had no effect on yield or disease level at either location (Table 4, Table 5, and Table 6). However, there was a significant difference among the three varieties, with P9491 having the highest level of Rhizoctonia root rot.
There was a significant effect of the rate of chloride on wheat yield at Urbana (Table 7, and Table 8). The 32 lbs/a rate applied at planting had the highest yield, while the 64 lbs/a applied at planting had the lowest yields. Similarly, the 64 lbs/a rate applied at planting had the highest level of disease, and the 32 lbs/a had one of the lowest disease levels. At Brownstown, there was a significant variety effect on yield, while disease was significant for variety and rate (Table 9 and Table 10). At this location, the 32 lbs/a rate had the highest level of disease, while the 64 lbs/a had the lowest disease.
The source of chloride study on wheat showed a significant effect on both yield and disease control at Urbana and Brownstown. The highest yield at Urbana was obtained from plots treated with KCl applied at planting, while the lowest yield was obtained from plots treated with KNO3 at planting (Table 12, Table 13, Table 14, Table 15, and Table 16). At Browstown, the highest yield was obtained from plots treated with KNO3, either top-dressed or at planting; however, the highest disease was found with the KNO3 application at planting. There was no significant effect of source of chloride on yield at Dixon Springs.
1 K.A. Ames is a graduate student, Dept. of Crop Sciences; S.A. Ebelhar is Agronomist, Dixon Springs Agricultural Center; K.L. Barber was Senior Research Specialist, Brownstown Agronomy Research Center, and is now Research Agronomist, Golden Harvest-Thorp Seed Co., Clinton, IL; W.L. Pedersen is Associate Professor, Dept. of Crop Sciences; all Univ. of Illinois.
