Fertilizing hard red spring wheat, durum, winter wheat and rye
SF-712, March 1997
D.W. Franzen, Extension Soils Specialist
R.J. Goos, Associate Professor, Department of Soil Science
Nutrients required for wheat production
Soil testing and N recommendations
Use of fallow
Use of manures
Use of green manures
Commercial N fertilizers and use in hard red spring wheat, durum and rye
Topdressing for yield or protein increase
Phosphorus
Potassium
Chloride
Sulfur
Copper
Other nutrient and fertility problems
Spring wheat and durum are particularly adapted to the relatively cool and dry North Dakota climate. The short growing season of spring wheat and durum allows the crops to mature with little chance of frost damage which may sometimes occur as early as August.
More acres are seeded to wheat in North Dakota than any other crop. The primary wheat grown in the state is hard red spring wheat. Durum wheat makes up a higher proportion of acres in the northern half of North Dakota, with a smaller portion in the rest of the state. Winter wheat is grown on a relatively small acreage primarily in the southwest. Rye is a relatively minor crop in North Dakota (Table 1). In 1995, North Dakota was ranked as the number one state in wheat production (Table 2). Spring wheat and durum are particularly adapted to the relatively cool and dry North Dakota climate. The short growing season of spring wheat and durum allows the crops to mature with little chance of frost damage which may sometimes occur as early as August. Producers often grow wheat in a rotation with other crops such as barley, field peas, sunflower, sugarbeet, canola and dry bean. Growing other rotational crops reduces disease in either crop and lengthens the planting and harvest seasons.
Table 1. Harvested acreage of major crops in North Dakota, 1995. ----------------------------- Crop Acreage ----------------------------- Wheat, all 11,114,000 Hard red spring 8,200,000 Durum 2,880,000 Winter 34,000 Barley 2,250,000 Corn 510,000 Oat 450,000 Sunflower 1,210,000 Canola 211,000 Dry bean 540,000 Sugarbeet 204,200 Potato 121,000 Soybean 640,000 Flax 115,000 Alfalfa 1,400,000 Grass hay 1,300,000 -----------------------------Table 2. Wheat production, United States, top 5 states, 1995. -------------------------- State Ranking -------------------------- North Dakota 1 Kansas 2 Montana 3 Washington 4 Oklahoma 5 --------------------------
Nutrients required for wheat production
Nitrogen
Nitrogen is the nutrient most often limiting to wheat production. Adequate nitrogen fertility is necessary to produce high yields and to increase quality (protein content) of grain. High levels of protein are important for superior wheat flour milling and baking characteristics. Nitrogen (N) availability plays a key role in determining tiller number, kernel number and kernel size in the wheat plant. Properly fertilized hard red spring wheat will normally have a protein content greater than 14 percent. Pasta processors prefer that durum wheat should have less than 20 percent starch, or "yellow bean" kernels. Winter wheat should have at least 12 percent protein content. Protein content consistently lower, or starch content higher than these values is an indication that a wheat producer needs to use more N fertilizer or better manage the N being applied (Figure 1).
Figure 1. Relative yield of Len hard red spring wheat as related to grain protein content. Goos, 1981-1982.
Soil testing and N recommendations
Studies have shown that fertilizing to the point of maximum economic yield and a good grain protein content takes about 2.5 lb N (soil nitrate-N + fertilizer N)/bushel. This value is not an absolute, but is an average taken from years of research (Table 3).
Table 3. Soil plus fertilizer N needs for spring wheat, 1981-1982. Goos, North Dakota Farm Res., 41(1):27-33, 1983. ----------------------------------------------- Minimum soil + Maximum fertilizer N yield, needed for Site bu/acre maximum yield lb N/bu ----------------------------------------------- 1981 Battleview 35 106 3.0 Dickinson 13 93 3.5 Fortuna 18 51 2.8 Minot 37 23 0.6 Minot 35 42 1.2 New Town 26 93 3.5 Stanley 43 104 2.4 Williston 33 75 2.2 Williston 32 75 2.4 1982 Bowbells 17 43 2.5 Fortuna 35 69 2.0 Minot 34 98 2.9 Rawson 35 48 1.4 Stanley 31 95 3.1 Williston 18 54 3.0 ----------------------------------------------- Average and 95% confidence interval 2.5 � 0.5
Soil samples are taken to a depth of 0-2 ft. for wheat. Following analysis, recommendations are based on soil test results and yield goal according to the following formula:
N recommendation = (2.5 X YG) - STN - PCC - SDA
Where YG = yield in bu/A
STN = soil test nitrate-N in lb/A 2 ft.
PCC = Previous crop credits (Table 4)
SDA = Sampling date adjustment used if samples
are collected in the fall before
September 15. N needs are decreased
by 0.5 lb/A per day the samples were
taken prior to September 15.
Recommendations at selected yield goals are listed in Table 5. N recommendations at other yield goals can be calculated using the formula above. Predicting a yield goal for a given year is nearly impossible because of the many factors which influence yield, particularly rainfall patterns. However, yield goals should be cautiously optimistic, with the producer using the long-term average yield for the land as a starting point and highest yields achieved on the farm as a possible goal. Modifying factors include soil moisture levels at the beginning of the season and perhaps long-range weather forecasts.
Table 4. Previous crop credits for small grains. ------------------------------------------------- First Year N Credits Previous crop Soybean 0.5 lb N/bu Edible bean 10 lb N/acre Pea and lentil 1.25 lb N/bu Sweet clover that was harvested 10 lb N/acre Alfalfa that was harvested and unharvested sweet clover >5 plants/sq ft 75 lb N/acre 3-4 plants/sq ft 50 lb N/acre 1-2 plants/sq ft 25 lb N/acre <1 plants/sq ft 0 lb N/acre Red clover that was harvested 35 lb N/acre Sugarbeet Yellow leaves 0 lb N/acre Yellow-green 15-20 lb N/acre Dark green leaves 60-70 lb N/acre ------------------------------------------------- Second Year N Credits half of credit given for the first year for red clover, sweet clover and alfalfa, but none for other categories. Soil test nitrate-N levels from the second year usually would be expected to reflect second year contributions from annual legumes. -------------------------------------------------Table 5. Nutrient recommendations for wheat and rye. -------------------------------------------------------------- Soil Test Phosphorus, ppm ------------------------------ Soil N plus VL L M H VH Yield fertilizer Bray-1 0-5 6-10 11-15 16-20 21+ goal N required Olsen 0-3 4-7 8-11 12-15 16+ -------------------------------------------------------------- bu/A lb/A 2 ft. -------- lb P2O5/acre -------- 20 50 20 15 10 0 0 40 100 40 30 15 10 0 60 150 60 40 25 10 0 80 200 80 55 35 10 0 -------------------------------------------------------------- Soil Test Potassium, ppm ----------------------------------- Soil N plus VL L M H VH Yield fertilizer Bray-1 0-40 41-80 81-120 121-160 160+ goal N required Olsen -------------------------------------------------------------- bu/A lb/A 2 ft. ----------- lb K2O/acre ---------- 20 50 50 35 20 0 0 40 100 95 70 40 15 0 60 150 140 100 60 20 0 80 200 190 135 80 25 0 -------------------------------------------------------------- Nitrogen recommendations = 2.5 YG - STN - SDA - PCC Bray-1 P recommendations = (1.071-0.54 STP)YG Olsen P recommendations = (1.071-0.067 STP)YG Potassium recommendations = (2.710-0.017 STK)YG The abbreviations used in the equations are as follows: YG = yield goal STN = soil test nitrate-N STP = soil test phosphorus STK = soil test potassium SDA = sampling date adjustment PCC = previous crop credit
Use of fallow
Historically, N fertility has been the sum of release from the degradation of organic matter following the break up of prairie soils and the addition of supplemental N. Fallow was once a very common production practice throughout North Dakota which allowed a portion of land to idle for a season and recharge with water, ideally producing more yield the second year. Fallow land was typically tilled several times during the idle period to kill weeds. Tillage introduced oxygen into the soil, allowing aerobic microorganisms to break down organic matter into carbon dioxide and mineral components. Producers were able to increase N levels through organic matter breakdown during fallow, since for every 10 pounds of carbon released into the atmosphere, about 1 pound of nitrogen was made available in the soil.
In recent years, the practice of fallow has diminished. Research has shown that continuous cropping often returns more income than leaving land idle. In addition, organic matter levels have plummeted to less than half original prairie levels. Organic matter levels have been depleted to the point that soil tests show that over one-third of fallowed fields require supplemental N fertilizer. Losing organic matter also has a detrimental effect on soil physical properties, such as increased crusting, poor aggregation, limited water holding capacity and higher bulk density. By continuous cropping, producers are more likely to hold organic matter levels steady. Adding N fertilizers into the cropping program and reducing tillage has been observed to slowly increase organic matter levels.
Use of manures
Supplemental N can be added as manures, green manures and commercial fertilizers. To use manures properly, the application should be directed by soil testing. Applications should be made as evenly to the soil as possible and incorporated within 24 to 48 hours. Composting manure creates high temperatures within the manure pile to kill weed seeds. Composting, however, reduces the nitrogen content of the manure through ammonia volatilization. Manure N content should be estimated through the use of an appropriate chart (Table 6) and a sample of the manure taken on the day of application and sent to a laboratory for confirmation of analysis. Additional N can then be added before seeding.
Manure application is limited by the practical distance manure can be hauled by livestock producers. Consideration should be given to both the fertilizer value of the manure and its long-term value to improved soil health.
Table 6. Average nutrient analysis of liquid and solid manure. From Livestock Waste Facilities handbook, Midwest Plan Service, March, 1985.* ------------------------------------------------- Dry Total Form Condition Matter N P2O5 K2O ------------------------------------------------- (%) -- lb/1000 gal. -- Liquid - Beef anaerobic pit 11 40 27 34 Dairy anaerobic pit 8 24 18 29 Swine anaerobic pit 4 36 27 22 ----- lb/ton ----- Solid - Beef no bedding - dirt 15 11 7 10 concrete 52 21 14 23 with bedding 50 21 18 26 Dairy no bedding 18 9 4 10 with bedding 21 9 4 10 Swine no bedding 18 10 9 8 with bedding 18 8 7 7 Turkey no bedding 22 27 20 17 with bedding 29 20 16 13 ------------------------------------------------- * Nutrient values may vary due to animal diet, time of manure sampling, method of manure sampling and age of the manure.
Use of green manures
Green manures are crops grown to be plowed under. After the residues are incorporated into the soil, microbes decompose the tissues and release a portion of the nitrogen they contained. Green manure crops should have a low carbon/nitrogen (C/N) ratio for greatest benefit. C/N ratios less than 17/1 allow nitrogen release into the soil. C/N ratios greater than 30/1 result in N tie-up following decomposition. C/N ratios between the two values generally have no effect on net nitrogen content of the soil. Legumes generally have low C/N ratios and produce their own N if properly inoculated with N-fixing bacteria at seeding. The leafy part of the legume needs to be incorporated into the soil to attain the maximum benefit of legume N fixation. Harvesting the legume and leaving stubble greatly reduces the nitrogen benefits of the green manure.
Green manure use in North Dakota is limited by reluctance to leave land idle, by fear that excessive water will be taken from the soil during green manure growth and decomposition, and because the timing of N release by the green manure is less predictable than N availability from an application of commercial N fertilizer.
Commercial N fertilizers and use in hard red spring wheat,
durum and rye
Anhydrous ammonia
Anhydrous ammonia is a gas at atmospheric pressure but is stored as a liquid under pressure. Anhydrous ammonia is a potentially hazardous material, and there are specific safety precautions related to its use (see Extension Circular SF-962). One major problem associated with anhydrous ammonia use is the escape of the vapor from the soil during and after application. An occasional "puff" of ammonia vapor may be expected during application, but in general, ammonia should be applied so that vapor losses are minimized. Vapor loss is reduced by applying ammonia in soil conditions which allow sealing behind the band, and by fitting the ammonia application equipment with covering tools that help to cover the application slits. Applying ammonia deeper in the soil is often effective in sealing an ammonia band.
Fall application
Fall application of anhydrous ammonia is very popular for a number of practical reasons. The spring workload is decreased, soils are usually drier than they are in the spring, and the cost of ammonia is often lower in the fall. Fall application of ammonia is recommended in very late September or early October when early morning soil temperatures at 4 inch soil depth fall to 50� F or less.
Use of this guideline includes a degree of risk. The bacteria that convert ammonium-N to nitrate-N do not stop their activity when soil temperatures fall below 50� F, but the process greatly slows. In most years, colder temperatures follow soon after application, so conversion to nitrate is very low. However, there may be years when soil temperatures remain warm for several weeks following application. In these unusual years, significant levels of nitrate may be produced.
If only a small amount of water, 2 inches or less, is contributed to the soil between late fall and spring, the nitrate formed in the fall will largely be held in the top foot of soil and crop response to fall applied fertilizer will be as good as a spring application. This is usually the case in drier years statewide, and in most years in central and western North Dakota. However, if spring soil moisture levels are high, then significant leaching is possible in coarse textured soils. Leaching of nitrate out of the soil before a crop has a chance to take up the N is very uncommon in medium and heavier textured soils. In these soils, nitrate may move downward enough that early wheat growth is poorer than had the N been spring applied. Visually, wheat will usually outgrow this condition, but yields may be somewhat reduced.
In general, wheat responds profitably to fall applied anhydrous ammonia in North Dakota when it is applied on the proper soils with the proper timing.
Spring application
Spring application of anhydrous ammonia is an effective practice if two problems are avoided. The first problem is direct ammonia loss during and after application. The second is reduced germination and seedling damage. Ammonia is toxic to seedlings. Using traditional tillage and seeding equipment, little seedling damage occurs if the ammonia is placed at a depth of 5-6 inches and the seed placed at 1-1.5 inches deep. Application of ammonia at a slightly different angle to seeding may also reduce damage.
Simultaneous seed and fertilizer placement is being used as a result of air-seeder technology. Minimum separation between wheat seed and the ammonia band should be 2 inches in medium or heavier soils and 3 inches in coarse textured soils. However, at higher N rates or with unfavorable seedbed conditions such as cloddiness, some seedling damage may occur. As this practice is still relatively new, producers are advised to go slow in adopting it until they have adequate first hand experience to know that seedling damage will not occur with their equipment, soils and N rates. Another potential problem with applying ammonia using air seeders is that sometimes the ammonia is applied too shallow for soil conditions, leading to ammonia loss as vapor.
More details regarding anhydrous ammonia application may be found in the North Dakota Fertilizer Handbook (EB-65).
Urea
Applying N in urea form is increasing in popularity despite a higher price per pound of N than anhydrous ammonia. Part of the popularity may be due to convenience and flexibility of use and safety concerns with ammonia application. Urea is broken down into carbon dioxide and ammonia by a soil enzyme called urease. Urease is more active when temperatures are warm, but somewhat active at temperatures as low as near freezing. Urea needs to be covered with soil to keep ammonia formed during urea breakdown from volatilizing off the soil surface. Coverage may be achieved through tillage or by at least 1/4-1/2 inch of precipitation depending on residue and soil surface conditions and initial moisture content.
The time interval between urea application and soil coverage necessary to minimize ammonia volatilization depends on soil temperature, wind speed, air dryness and the evaporation of water from the soil surface. Cool temperatures, dry soils and low wind speed allows more time for urea to lay on the surface. High temperatures, moist soils and windy conditions may require urea incorporation much sooner. In the spring, urea may generally lay on the soil surface for up to a week. If weather conditions are more favorable for ammonia volatilization, incorporation within two days prevents ammonia loss from occurring, as loss generally does not begin until three to four days after application. Recent research in a number of states shows that impregnation of urea fertilizer with NBPT urease inhibitor may hold off urea volatilization for another week.
Applying urea with the seed is restricted because of some salt effect, but mostly because of the ammonia toxicity from urea breakdown around the seed zone. With air-seeder seed spread devices, urea rates can be increased due to a dilution effect. However, seed and fertilizer spread must be measured and confirmed to minimize seed injury and stand loss. Table 7 shows the amounts of urea-N allowed with different seed spreading and row widths. Rates are also modified by surface soil texture.
Table 7. Maximum urea-N fertilizer rates recommended with wheat seed at planting based on planter spacing, type and seed spread. Assumes a coarse soil texture for the lower end or each range and heavier texture for the upper end of each range of urea-N values. For more detail, see NDSU Ext. Cir. EB-62. ------------------------------------------------------ Planter Seed Planter Spacing, inches Type Spread 6 7.5 10 12 ------------------------------------------------------ (inches) ------ lb urea-N/acre ------- Double disc 1 20-30 19-28 17-23 15-20 Hoe opener 2 32-44 27-38 23-31 20-27 3 44-58 37-48 30-40 26-34 Air seeder 4 56-72 46-58 37-48 32-42 5 68-86 56-68 44-57 38-49 6 80-100 66-79 51-55 44-56 7 76-90 58-74 50-64 8 66-83 56-71 9 73-92 62-78 10 80-100 68-86 11 74-93 12 80-100 ------------------------------------------------------
Urea-ammonium nitrate liquid fertilizers (UAN)
UAN is a liquid formulation of urea and ammonium nitrate. The analysis usually used is 28-0-0, but this may vary depending on the source. Broadcast applications of UAN should be treated similarly to urea, although the ammonium nitrate fraction is not subject to the same ammonia volatilization risk as urea. UAN is sometimes applied in a surface band to reduce urea volatilization risks. UAN is also frequently used as a foliar application for yield or protein enhancement under certain conditions.
Winter wheat N fertility considerations
Although equivalent total rates of N are recommended for winter wheat as spring wheat, a minimum amount of N is desirable before planting in the fall. Excessive N before planting may reduce winter hardiness. Most of the N needs are topdressed in early spring immediately before or after dormancy is broken. Nitrogen application is usually made with dry or liquid N fertilizer sources.
Topdressing for yield or protein increase
Although most nitrogen should be applied before or at planting, sometimes circumstances do not permit N application until after seeding. Application after planting is called topdressing. Usually the fertilizer source is urea, especially if greater than 20 lb N/acre is needed. UAN solutions are sometimes used, but liquid fertilizers may cause serious leaf burning if used at high rates or applied at midday. Topdressing for yield enhancement should be made as soon as possible after planting. Data in Table 8 show that wheat yield response to topdressing is greatest through tillering.
Recent research has shown that although yield is not increased with a post-anthesis application of N, protein may be increased (Table 9). Application of 30 lb N/acre (about 10 gal of 28-0-0 liquid, diluted 50-50 with water) was effective in increasing protein about 1 percent. This research also demonstrated that application at flowering is not as desirable, and that application is best made in the early morning or evening to avoid burning. Improper application may result in leaf burning and plant injury resulting in grain shriveling and lower test weights.
Table 8. Influence of rate and time of foliar application of nitrogen on grain yield, 1986, Swenson, Dahnke and Johnson. -------------------------------------------- Application Rate Growth stage of wheat ---- lb N/acre ---- at time of application 0 20 40 60 -------------------------------------------- 2 leaf (Feekes 2) 26 28 38 33 Tillering (Feekes 2-3) 28 36 37 34 Boot (Feekes 10) 24 28 28 31 Flowering (Feekes 10.2) 25 26 30 25 --------------------------------------------Table 9. Percent protein with different foliar N rates applied post-anthesis to `Butte 86' hard red spring wheat, Carrington, ND, 1988-1991. ------------------------------------- lb N/acre -------------------------- Year 0 15 30 45 ------------------------------------- ---- percent protein ---- 1988 16.0 16.5 16.9 16.8 1989 11.6 12.1 12.8 13.0 1990 13.6 13.2 13.6 13.6 1991 13.4 13.6 15.3 14.1 Average 13.6 13.8 14.7 14.4 -------------------------------------
Phosphorus
It is important for wheat to have adequate P near the young root system early in its growth, as well as adequate P available in the entire rooting zone in order to feed the plant through kernel fill. P nutrition should be approached using both short-term and long-term fertility.
Banding at planting with or near the seed is important since wheat roots initially are in cool soils relative to air temperature. Leaves make demands on the young plants that young roots may be unable to accomplish without some phosphate placed so that roots are able to intercept high concentrations early in the season. Wheat plants make "decisions" concerning the number of tillers early in growth. Inadequate P will reduce tiller number and therefore reduce potential yield. Providing early, banded P is very important and is the "short-term" P strategy. Wheat will respond to starter phosphate regardless of soil test P levels.
Banding P provides early P needed for adequate tiller initiation and development. Where soil test levels are medium or higher, the soil provides the late season demands of P for wheat kernel fill. When soil test levels are low or very low, P levels are not adequate to meet late season demands. The percentage of the root system in contact with high levels of P is very small when P is banded alone. To allow P uptake within the entire root system, P levels should be adequate in the whole soil surface. Therefore, the long-term P fertilization strategy should be to apply enough P to build soil levels to at least medium levels during a reasonable period and to maintain these levels by applying starter P with or near the seed. The P recommendations shown in Table 5 provide enough extra P to build P levels from low and very low levels within a 10 year period or less. It takes about 40 lb/acre of P2O5 to build Olsen P soil test levels 1 ppm.
Phosphate fertilizers may include 10-50-0/11-52-0 (MAP, monoammonium phosphate) or 18-46-0 (DAP, diammonium phosphate) dry fertilizers. Liquid phosphate fertilizers include 10-34-0 (ammonium polyphosphate) or other liquid P grades. Phosphate fertilizer rates which can be applied with the seed are restricted due to the nitrogen content of the application as shown in Table 7. Manure is also an excellent supplier of P to wheat (Table 6).
Potassium
Potassium (K) is required for wheat growth, but, most North Dakota soils contain adequate levels of K for maximum wheat growth. Need for supplemental K is usually restricted to leachable sandy or gravelly soils. K recommendations are shown in Table 5.
Chloride
Wheat is sensitive to low chloride levels. Adequate chloride reduces disease incidence and severity. It is also necessary for photosynthesis and helps the plants maintain turgor. Chloride is an anion and can move with soil water. It is not a nutrient whose level can effectively be built up in the soil. The decision to fertilize with chloride should be made with soil testing and an understanding of the probability of response based on test results. The probability of response using South Dakota information is listed in Table 10. Based on the table, a soil test level of 60 lb/acre or higher in the top 2 feet is not responsive to chloride. Levels between 30 and 60 lb/acre responded about 31 percent of the time. The average response was only 2.6 bu/acre. Levels below 30 lb/acre were responsive 69 percent of the time with an average response of over 4 bu/acre. Therefore, chloride application is most justified when levels are under 30 lb/acre. If soils are very low in chloride, even a modest application of 10 lb chloride/acre (20-25 lb 0-0-60/acre) can be very helpful.
Table 10. Probability of response of small grains to chloride based on soil test chloride levels. From S. Dakota data. ----------------------------------------------------- Yield Average response at: Soil Test Soil Cl Response Responsive Across Category Content Frequency Sites Only All Sites ----------------------------------------------------- lb/acre 2-ft. % bu/acre Low 0-30 69 5.0 4.0 Medium 31-60 31 6.3 2.6 High 60+ 0 -- 0.3 -----------------------------------------------------
Sulfur
Wheat does not accumulate high levels of sulfur (S). However, S deficiencies are identified occasionally in North Dakota. Deficiencies are almost always associated with low organic matter soils or areas with higher topography which are sandy or gravelly and leachable. Sulfur deficiency is also more common when rainfall is plentiful and yield levels are high. Wheat absorbs S as the sulfate anion. Fertilizer S needs to be applied so that adequate sulfate is available early enough in the season to provide adequate full season nutrition. Elemental S needs to be broken down to sulfate by soil bacteria. In seasons of dry, cool weather, breakdown is delayed. Ammonium sulfate (21-0-0-24S) is a fertilizer with immediately available sulfate-S. Ammonium thiosulfate (12-0-0-27S) is a rapidly available liquid S source.
Nitrogen and S deficiency symptoms can easily be confused.
Sulfur needs are most often identified through soil testing. Levels below 16 lb/acre in the top 2 feet are generally low in S and are likely to respond to S fertilizer. Plant tissue testing is also very helpful in diagnosing S deficiency. Addition of 10 lb/acre S at planting is usually adequate to correct S deficiency in wheat.
Copper
Responses to copper are common in Canada in high organic matter soils. Copper is excessively chelated (bound by organic compounds) in high organic soils, reducing its availability. Copper deficiency can be observed as browning of wheat leaf tips, higher incidence of ergot and false black chaff symptoms. Response to copper has been observed in the Red River Valley. However, not enough is known in North Dakota to determine whether or not copper would be useful in increasing yields or plant health or under what conditions to expect a response.
Copper deficiency is treated with a preplant application of 3 lb/acre copper sulfate applied to the soil and incorporated. Copper sprays are not effective after the symptoms are seen. Canadian recommendations call for supplemental copper when copper soil test levels fall below 0.6 ppm using the DTPA soil extractant.
Other nutrient and fertility problems
Zinc, boron and iron deficiencies in wheat are rare. Wheat is not very sensitive to low soil levels of these nutrients in North Dakota soils.
Excessive salinity may lower wheat yields. Salts are not lowered by addition of soil amendments. Sometimes manure is applied to salty areas, but the effect is one of temporary dilution and is not a long time benefit. Manure itself contains salts and may contribute to the problem long-term. Salt levels are related directly to water table depth. The water table should be lowered through management of soil water through tillage, cropping and residue management to lower salt levels. Saline soil management and development is discussed in two extension bulletins, EB-57, Salinity and Sodicity in North Dakota Soils, and SF-1087, Managing Saline Soils in North Dakota.
SF-712, March 1997
