Illinois
Fertilizer Conference Proceedings
January 25-27, 1993
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John E. Sawyer and Stephen A. Ebelhar1
Winter wheat has historically been an important crop in the rotations of southern Illinois. In recent years the acreage of winter wheat has increased substantially. According to the January 24, 1990 Illinois Farm Report published by the Illinois Agricultural Statistics Service (USDA, 1990), a total of 1.78 million acres of winter wheat were harvested for grain in 1989, an increase of 42 percent from 1988 and an increase of 87% from 1987. In addition, yield production was at record levels in 1987 and 1989.
With the current large acreage of winter wheat, especially in southern Illinois, and with the potential for record levels of production, increased demand on the soil to supply nutrients required for adequate growth and production of wheat may be creating deficiencies of nutrients not currently being applied for crop production, such as sulfur.
In the past, S deficiencies have been recognized in the midwest United States, but have not been widespread (Alway, 1940; Hoeft and Walsh, 1970; Thorup and Leitch, 1975; Rehm, 1976; Hoeft, 1980). However, as a result of several factors, increased likelihood of S deficiencies may occur. These factors include increased crop production level, less application of S as impurities in fertilizers (such as phosphatic fertilizers) and pesticides, less contribution of S from the atmosphere (either from precipitation, dry deposition, or direct absorption of atmospheric compounds), use of minimum tillage systems which may reduce S mineralization from crop residues and soil organic matter, and fewer crop-livestock operations resulting in increased crop acreage that receives no manure applications.
As crop demands for S increase, deficiencies are more likely to occur on soils that inherently supply less available S or can retain less available S within the rooting zone; those that have low organic matter content, have a coarse texture, and have low or physically unavailable sources of S in the subsoil. Many of the soils in southern Illinois could fit into this category. However, soils with acidic and high clay content subsoils (free iron and aluminum oxides) accumulate more profile sulfate-S (Kamprath et al., 1956). Most reported wheat responses to applied S have occurred on coarse textured - low organic matter soils with low capacity to retain sulfate in the subsoil (Oates and Kamprath, 1985; Mahler and Maples, 1986; Wells et al., 1986; Mahler and Maples, 1987).
In a statewide survey of soils in Illinois, Hoeft et al. (1985) found little corn response to S application in the field, a total of only 5 of 82 sites responded, but in the greenhouse 60% of the soils (surface samples) responded to S application. This was an indication that many soils in Illinois have a limited ability to supply adequate available S for crop production and that contributions from sources other than the soil were major factors in supplying S for crop uptake in the field. They did measure an average growing season rainfall deposition of 9.7 lb S/acre in 1978 at sites in southern Illinois. Also, they found no relationship between extractable soil S level, Ca(H2PO4)2 o HOAc extractant, and corn yield response to S application.
It has been approximately 10 years since the survey by Hoeft et al. (1985) was conducted and it may be possible that atmospheric contributions have declined to the point that little S is applied to soils from that source. Recent measured annual average sulfate-S deposition from precipitation (1978-1987) in southern Illinois was 8.21b S/acre and winter plus spring deposition was 3.9 lb S/acre (NADP/NTN, 1990).
Today, possible S deficiencies will occur most readily on soils that have low S supplying power. In the survey by Hoeft et al. (1985), two of the five responding sites were in southern Illinois on low organic matter soils. Also, the only crop studied was corn. Little if any S research has been conducted on winter wheat in Illinois.
The overall goal of this project was to determine if sulfur nutrition is currently limiting winter wheat production in southern Illinois. Specific objectives were to: (i) measure plant nutrient composition and grain yield response of several adapted wheat varieties to the spring topdress application of S fertilizer and tillage system, (ii) determine plant nutrient composition and wheat grain yield response to rate of spring topdress S application.
Field studies were conducted in three crop years, 1989 - 1992, at two sites in southern Illinois, the Brownstown Agronomy Research Center located in south central Illinois and the Dixon Springs Agricultural Center located in extreme southern Illinois. For each experiment, winter wheat was grown after a preceding soybean crop.
A randomized complete block experimental design with three replicates was used at each location with a split-split plot arrangement of treatments: main plot-- tillage system, no-till (NT) and conventional-till (CT); sub plot--spring topdress S application, either no S or 25 lb S/acre as ammonium sulfate; and sub-sub plot-- winter wheat variety, Becker, Cardinal, Caldwell, and Pioneer variety 2555 (Pioneer variety 2548 at Dixon Springs). Plot dimensions were main plot, 48 by 165 ft; sub plot, 48 by 70 ft; and sub-sub plot, 12 by 70 ft at Brownstown and plot dimensions were main plot, 40 by 80 ft; sub plot, 40 by 40 ft; and sub-sub plot 10 by 40 ft at Dixon Springs. Chemical characteristics of the surface 8 in. of soil at each location (pH, BrayP,,and ammonium acetate extractable K) were within optimal ranges for field crop production. Organic matter contents ranged from approximately 2.2 to 2.8%.
Conventional-tillage was performed with one pass of a tandem disk and one pass with a field cultivator. Individual varieties were planted in 7 in. rows at a rate of 90 lb seed/acre. At Brownstown, both NT and CT was planted with a conventional double disk opener drill. It was not fitted with no-till coulters. At Dixon Springs, the drill was fitted with no-till coulters. Nitrogen rate was uniform on all plots (total of 110 lb N/acre) with 40 lb N/acre applied as diammonium phosphate in the fall before tillage and planting and the remainder (701b N/ acre) applied either as ammonium nitrate or a combination of ammonium sulfate and ammonium nitrate as a topdress application in early spring (early March) each year. Harmony Extra (thifensulfuron plus tribenuron) 0.5 fl. oz. /acre, plus surfactant, 0.25% v/v, was applied for weed control at Brownstown in late March, 1991 and at Dixon Springs in early April, 1992.
Soil samples, 5 cores/sample, 0-8 in. depth, were collected periodically during the growing season from the non-S treated sub-plots. Samples were also collected by 8 in. increments to 24 inches once during the growing period from the non-S treated sub-plots. Flag leaf samples, 100/plot, and whole above ground plant samples, 20/plot, were collected at Feekes' stage 10.1 (head emergence), early May, and grain samples were collected at harvest. The number of wheat heads/ft2 was counted in 2 ft sections of row at two places in each plot and the plant height to the top of the wheat head was measured at two places in each plot. At Brownstown each entire plot was harvested and at Dixon Springs a 5 ft wide pass was harvested from each plot.
Four rates of spring topdress (early March) S, 0, 5, 15, and 301b S/acre as ammonium sulfate, were arranged in a randomized complete block design with four replicates. Winter wheat variety Cardinal was conventionally planted (90 lb seed/acre) at each location. The N rate was a uniform 110 lb N/acre at each location, applied at 40 lb N/acre as diammonium phosphate in the fall before tillage and as a combination of ammonium sulfate and ammonium nitrate as a spring topdress. Harmony Extra (thifensulfuron plus tribenuron) 0.5 fl. oz./acre, plus surfactant, 0.25 % v/v, was applied in early April, 1992 at Dixon Springs for weed control. Plot size was 20 by 45 ft at Brownstown and 10 by 40 ft at Dixon Springs. A 5 ft wide pass was harvested for grain yield at Dixon Springs and a 12.5 ft wide pass was harvested from each plot at Brownstown.
Chemical characteristics of the surface 8 in. of soil at each location (pH, Bray-P1, and ammonium acetate extractable K) were within optimal ranges for field crop production. Organic matter content ranged from approximately 2.0 to 2.8%. Potassium (muriate of potash) was applied in the fall before tillage at 25 lb K/acre at Dixon Springs and diammonium phosphate at 45 lb P/acre at both locations.
Flag leaf samples, 100/plot, and whole plant samples, 20/plot, were collected at Feekes' stage 10.1, early May, at each location. Grain samples were collected at harvest. Soil samples, 5 cores/sample, 0-8 in. depth, were collected periodically during the growing season from the zero S rate plots. Samples were also collected by 8 in. increments to 24 inches from the zero S rate plots once during the growing period.
Grain weight and moisture content were determined from each plot and grain yield was adjusted to 13.5% moisture. Plant samples were dried at 140°F, ground in a Wiley mill to pass a 0.0394 in. screen, and analyzed for total N and S. Total N, including NO3, was determined using a Leco (St. Joseph, MI) model FP-428 N analyzer. Total S was determined by digestion with nitric-perchloric acid (Blanchar et al., 1965) and analysis of the digestate by inductively coupled plasma spectrometry (ICP). Soil samples were analyzed for S by extraction with Ca(H2PO4)2 o HOAc (Hoeft et al., 1973) and S in the extract determined by ICP. Analysis of variance for all measured parameters were carried out using the Statistical Analysis System (SAS Institute, 1988) using the General Linear Models (GLM) procedure. Orthogonal coefficients were utilized to determine significant S rate effects.
Precipitation was collected at each site and analyzed for SO4-S. Collection
started on 12 March 1990 at Brownstown, with SO4 determined by the turbidimetric
method (Standard Methods, 1980). Dixon Springs is a collection site of the ongoing
National Atmospheric Deposition Program, IR-7, National Trends Network (NADP/NTN),
Fort Collins Colorado. The concentrations were used to calculate S deposited
in precipitation at each site.
Yearly reports detailing all results and statistical analyses have been submitted to the Fertilizer Research and Education Council. Space does not permit an accounting of those details in this report, however, important summary results will be presented here. Because interactions between treatments were not consistent and few were statistically significant, only main effects of treatments are listed.
Plant Growth
Wheat plant heights and head counts were generally not influenced by a 25 lb S/acre application or tillage system at either location (Table 1). Sulfur application increased plant height by one inch in 1991 at Dixon Springs but had no effect at Brownstown. For an unexplained reason, the head count was significantly decreased by S application in 1990 at Brownstown. Plant heights and head counts were the same all years for CT and NT at Dixon Springs. At Brownstown, plant heights were significantly lower in 1990 for NT compared to CT but were the same in 1991 and 1992. Head counts were the same in 1990 and 1992 at Brownstown for NT and CT, but was significantly lower for NT in 1991.
Varietal differences in plant heights were measured each year and at each location (Table 1). This would be expected because of differing growth habits of the varieties. Varietal differences in head counts were also measured each year and at each location. The variety Cardinal consistently had the lowest head counts at both locations. These varietal differences were much larger than the differences due to S application or tillage system.
Flag Leaf and Whole Plant S Concentrations
At both locations, and for all years measured, flag leaf S concentrations from the non-S treated plots were above the level (0.20% S) considered sufficient (Reneau et al., 1986) (Table 2). Flag leaf S concentrations were significantly increased by application of S. However, because concentrations were above the critical level without application of fertilizer S, the increased levels could indicate accumulation of inorganic S above plant requirements in the leaf tissue (Stewart and Porter, 1969; Rasmussen et al., 1975; 1977).
Tillage system affected flag leaf S concentrations only in 1990 at Brownstown (Table 2). In that case, the S concentration was reduced by 0.02 % S with NT compared to CT. In all other years, S concentrations were the same for both CT and NT. In no instances were the S concentrations below the critical level for either NT or CT. Varietal difference in flag leaf S concentrations were measured each year and at each location. The variety Cardinal consistently had the lowest flag leaf S concentration at both locations. While the differences between varieties were not overly large, difficulties in interpretation of S deficiencies may be compounded by these types of varietal differences.
Except in 1992 at Brownstown, whole plant S concentrations were slightly below the 0.15 % S critical level (Ward et al., 1973) (Table 2). Whole plant samples were not collected in 1990. Application of 25 lb S/acre significantly increased the whole plant S concentration in 1992 at Brownstown and in 1991 at Dixon Springs. Tillage system had no effect on whole plant S concentrations. Varietal differences, as was measured for flag leaf S concentrations, were also measured for whole plant S concentrations at each location and each year. While the variety Cardinal consistently had the lowest flag leaf S concentration, it had the highest whole plant S concentration.
Grain
Grain S concentrations were not affected by application of S or by tillage system at either_ location or in any year (Table 3). Small significant varietal differences occurred in 1990 and 1991 at Brownstown and in 1991 at Dixon Springs. All grain S concentrations were above the 0.12 % S critical level (Randall et al., 1981; Mahler and Maples, 1987).
Wheat grain yields were not significantly increased by the spring topdress application of 25 lb S/acre at either location or in any year (Table 3). In 1992 at Brownstown, a significant 3 bu/acre decrease in yield occurred with application of S. Yields were not significantly different between tillage systems except in 1991 at Dixon Springs when a 3 bu/acre lower yield was measured with NT. However, the production level was quite low that year (29 bu/acre). In better production years at Dixon Springs and Brownstown, no significant differences were found between tillage systems.
Variety had the largest impact on production level. Differences in variety yields were much larger than any differences between tillage system or application of S fertilizer. The variety Cardinal produced the highest yields 2 out of 3 years at Brownstown while Pioneer 2548 produced the highest yields both years at Dixon Springs. Cardinal had high yields despite having the lowest head counts and flag leaf S concentrations.
No significant grain yield interactions were found between S application and tillage system or S application and variety. This indicates that tillage practices, as utilized in this study, are not differentially affecting S availability and that, although differences were noted in leaf and plant S concentrations, S nutritional requirements were adequate for the range of varieties studied.
Flag Leaf and Whole Plant S Concentrations
Wheat flag leaf and whole plant S concentrations generally increased with increasing rate of S application at both Brownstown and Dixon Springs (Table 4). Measured concentrations were at or within the ranges considered to be sufficient, even when no S was applied. Application of low rates of S had little effect on flag leaf or plant S concentrations.
Grain
Grain S concentrations were generally not increased by application of S fertilizer (Table 5). Concentrations were at or above the critical level.
Wheat grain yields were not consistently affected by spring topdress application of S fertilizer (Table 5). An increase in yield occurred in 1991 at Brownstown with the 5 lb S/acre rate, but the yield also then declined when 15 or 30 lb S was applied. In 1990 at Dixon Springs, a significant yield decrease was measured with application of S. However, because the production level was so low, the response has little real meaning. In two out of the three years at both locations, grain production did not significantly respond to S rate of application.
Extractable SO4-S in the surface soil remained fairly constant throughout the growing period in 1989-1990 and 1990-1991 (Table 6). In 1992 the levels decreased as the growing season progressed (Table 6). Although the S soil test has not been reliable for predicting past crop responses to S application in Illinois (Hoeft et al., 1985), at both locations the measured SO4-S levels would indicate that no response would be expected from S application, that is , test levels above the 10 ppm S critical level (Hoeft et al., 1973).
Increased levels of extractable SO4-S were measured in the subsoils at both locations (Table 6) and reflect accumulation of sulfate at the depth where each soil becomes quite acidic and the impedance of water flow occurs. The values were lower in 1992 than those measured in 1991. In conjunction with the high levels of extractable S in the surface layer, these high subsoil levels provide an explanation as to why plant S concentrations are adequate without application of fertilizer S and why no production response has been found from S application. That is, a more than adequate supply of SO4-S is available within the rooting zone on both soils and reflects the reason why most reported wheat responses to applied S have occurred on coarse textured-low organic matter soils with low capacity to retain sulfate in the subsoil (Oates and Kamprath, 1985; Mahler and Maples, 1986; Wells et al., 1986; Mahler and Maples, 1987).
Rainfall was collected at Brownstown to determine SO4-S deposition beginning March 1990. Total SO4-S deposition for the March 1990 through August 1990 period was 10.7 lb S/acre, for the September 1990 through June 1991 period 13.61b S/acre, and for the July 1991 through June 1992 period 13. 61b S/acre. This is a sizable amount of S, and would represent approximately the entire S requirement of a 55 bu/acre wheat crop.
At Dixon Springs, a NADP/NTN collection site, the yearly deposition in precipitation was 6.8 for 1989, 9.2 for 1990, and 8.5 lb S04-S/acre for 1991. Data for the 1992 year is not yet available. In all time periods, this represents a large portion of the S requirement for crop production.
Overall, response to treatments were quite similar each year of the study. Winter wheat grain yield was not increased by spring topdress application of S. The lack of yield response was consistent across all varieties tested and on both tillage systems, no-till and conventional-till. Application of S rates from 0 to 301b S/acre resulted in increases in plant S, but not increases in plant growth or grain yield. All parameters used to determine possible wheat response to application of S, including plant S concentration, flag leaf S concentration, grain S concentration, and soil test, indicated that sufficient levels were available without application of supplemental fertilizer S.
Most likely, combined input of available S from sources other than fertilizer S -- such as the levels of subsoil sulfate and precipitation deposition measured in this study, plus dry deposition, atmospheric SO2 absorption by plants, and mineralization of organic matter -- supply more than an adequate amount of available S for wheat production. For example, the total amount of S taken up by an 80 bu/acre wheat crop would be approximately 201b S/acre (Beaton and Wagner, 1985).
It is important to remember that most reported wheat responses to application of S have occurred where the soil supply of available S was low -- coarse textured sands with low organic matter content and low capacity to retain sulfate in the subsoil. The silt loam soils of southern Illinois have low organic matter, but clay subsoils and fragipans limit the leaching or movement of sulfate out of the profile. In fact, quite high levels of SO4-S were measured at that depth at both experimental locations. Also, it is important to note that most of southern Illinois is in the highest SO4-S precipitation deposition area of the Continental United States --1989 through 1991 annual average deposition pattern of 6 to 9 lb S/acre (NADP/NTN, 1990; 1991).
Some differences in plant growth and plant nutrient concentrations were found between varieties, tillage systems, and S rates, but, in general, those differences did not ultimately reflect or result in differences in overall grain production. This probably results from the fact that most plant parameters measured, such as number of heads/ft2, S concentrations, and N concentrations always tended to be in an optimum range for crop production, even when differences existed between treatment factors. The factor that consistently affected production level the most was wheat variety itself.
In conclusion, based on these three years of field research at two locations
in southern Illinois, routine application of topdress sulfur fertilizer for
winter wheat production is not warranted.
Table 6: Extractable soil sulfate-S concentration by soil depth -- Experiments 1 and 2
Alway, F.J. 1940. A nutrient element slighted in agricultural research. J. Amer. Soc. Agron. 32:913-921.
Blanchar, R.W., G. Rehm, and A. C. Caldwell. 1965. Sulfur in plant materials by digestion with nitric and perchloric acid. Soil Sci. Soc. Am. Proc. 29:71-72.
Beaton, J.D., and R.E. Wagner. 1985. Sulphur-a vital component of maximum economic yield systems. Sulphur in Agric. 9:1-7.
Hoeft, R.G., and L.M. Walsh. 1970. Alfalfa and corn respond to sulfur. Better Crops with Plant Food. 2:28-31.
Hoeft, R.G., L.M. Walsh, and D.R. Keeney. 1973. Evaluation of various extractants for available soil sulfur. Soil Sci. Soc. Am. Proc. 37:401-404.
Hoeft, R.G. 1980. Crop response to sulphur in the midwest and northeastern U.S. Sulphur in Agriculture. 4:12-15.
Hoeft, R.G., J.E. Sawyer, R.M. Vanden Heuvel, M.A. Schmitt, and G.S. Brinkman. 1985. Corn response to sulfur on Illinois soils. J. Fert. Issues. 2:95-104.
Kamprath, E. J. , W. L. Nelson, and J. W. Fitts. 1956. The effect of pH, sulfate and phosphate concentrations on the adsorption of sulfate by soils. Soil Sci. Soc. Proc. 20:463-466.
Mahler, R.J and R.L. Maples. 1986. Response of wheat to sulfur fertilization. Commun. Soil Sci. Plant Anal. 17:975-988.
Mahler, R.J. and R.L. Maples. 1987. Effect of sulfur additions on soil and the nutrition of wheat. Commun. Soil Sci. Plant Anal. 18:653-673.
National Atmospheric Deposition Program (IR-7)/National Trends Network. 1990. NADP/NTN Coordination Office, Natural Resource Ecology Laboratory, Colorado State Univ., Fort Collins, CO 80523.
National Atmospheric Deposition Program. 1990. NADP/NTN ANNUAL DATA SUMMARY. Precipitation Chemistry in the United States. 1989. Natural Resource Ecology Laboratory, Colorado State Univ., Fort. Collins, CO 80523. 482 pp.
National Atmospheric Deposition Program. 1991. NADP/NTN ANNUAL DATA SUMMARY. Precipitation Chemistry in the United States. 1990. Natural Resource Ecology Laboratory, Colorado State Univ., Fort. Collins, CO 80523. 475 pp.
Oates, K.M. and E.J. Kamprath. 1985. Sulfur fertilization of winter wheat grown on deep sandy soils. Soil Sci. Soc. Am. J. 49:925-927.
Randall, P.J., K. Spencer, and J.R. Freney. 1981. Sulfur and nitrogen fertilizer effects on wheat. I. Concentrations of sulfur and nitrogen and nitrogen to sulfur ratio in grain, in relation to the yield response. Aust. J. Agric. Res. 32:203-212.
Rasmussen, P.E. R.E. Ramig, R.R. Allmaras, and C.M. Smith. 1975. Nitrogen-sulfur relationships in soft white winter wheat. II. Initial and residual effects of sulfur application on nutrient concentration, uptake, and N/S ratio. Agron. J. 67:224-228.
Rasmussen, P.E., R.E. Ramig, L.G. Ekin, and C.R. Rohde. 1977. Tissue analyses guidelines for diagnosing sulfur deficiency in white wheat. Plant Soil. 46:153-163.
Rehm, G. W. 1976. Sulphur response on irrigated corn in Nebraska. Sulphur Inst. J. FallWinter, pp. 13-14.
Reneau, R.B., Jr., D.E. Brann, and S.J. Donohoe. 1986. Effect of sulfur on winter wheat grown in the coastal plain of Virginia. Commun. Soil Sci. Plant Anal. 17:149-148.
Roberts, S., and F.E. Koehler. 1965. Sulfur dioxide as a source of sulfur for wheat. Soil Sci. Soc. Proc. 29:696-698.
SAS Institute. 1988. SAS user's guide. SAS Institute, Inc., Cary, NC.
Spencer, K., and J.R. Freney. 1980. Assessing the sulfur status of field-grown wheat by plant analysis. Agron. J. 72:469-472.
Standard methods for the examination of waste and wastewater. 15th ed. 1980. p. 439-440. American Public Health Association, Washington, D.C.
Stewart, B.A., and L.K. Porter. 1969. Nitrogen-sulfur relationships in wheat riti um es ivum L.), Corn (Zea ma s ,and beans (Phaseolus v l axis . Agron. J. 61:267-271.
Thorup, R.M., and D.G. Leitch. 1975. Corn response to S in Iowa. Sulphur Inst. J. Spring, p. 5.
United States Department of Agriculture. 1990. Illinois Farm Report, Vol. 11, no. 2, released 24 January, 1990. Illinois Agricultural Statistics Service, Illinois Dept. of Agric., Springfield, IL.
Ward, R.C., D.A. Whitney, and D.G. Westfall. 1973. Plant analysis as an aid in fertilizing small grains. p.329-348. In L. M. Walsh and J.D. Beaton (ed.). Soil Testing and Plant Analysis. SSSA, Madison, WI.
Wells, B.R., R.K. Bacon, W.E. Sabbe, and R.L. Sutton. 1986. Response of sulfur deficient wheat to sulfur fertilizer. J. Fert. Issues. 3:72-74.
