Quick Facts...
- Nitrogen is the most limiting nutrient for winter wheat production.
- Apply nitrogen fertilizers at rates based on expected crop yields minus credits for residual soil nitrates and nitrogen mineralized from organic matter, manure, and previous legume crops.
- Apply phosphate fertilizers at rates based on soil test results. Band applications are more effective than broadcast applications.
- Most Colorado soils contain sufficient available potassium for dryland winter wheat production.
Soil Sampling
The value of a soil test in predicting nutrient availability during the growing season depends on how well the sample collected represents the area sampled. Take surface samples from the tillage layer (4 to 8 inches) or the 1-foot soil depth. Take subsoil samples to a depth of 2 feet for determination of available NO3-N. If the field has been in no-till, reduce the sampling depth to the tillage layer.A good sample is a composite of 15 to 20 soil cores taken from an area uniform in soil type. This number of soil cores is especially important in sampling fields where P fertilizers were band applied in previous years. Sample areas with major differences in soil properties or management practices separately.
Thoroughly air dry all soil samples within 12 hours after sampling by spreading the soil on any clean surface where the soil will not be contaminated. Do not oven dry the soil because this can change the soil test results. Place the air-dried soil in a clean sample container for shipment to the soil test laboratory.
Submit a carefully completed information form with the soil sample. This form provides information so fertilizer suggestions can be tailored to your specific situation. Take soil samples for NO3-N analysis every year for optimum N fertilization of Crops. Soil analyses for availability of the other nutrients, pH, and organic matter content may be sufficient every three to four years.
Fore more detailed explanations of the importance of taking proper soil samples contact the Colorado State University Soil, Water, and Plant Testing Laboratory is located at Room A319, Natural and Environmental Sciences Building, Colorado State University, Fort Collins, CO 80523; (970) 491-5061; http://www.extsoilcrop.colostate.edu/SoilLab//soillab.html..
Base nitrogen rates for winter wheat on the expected yields for each field. Nearly all wheat requires some N fertilizer, unless there is a substantial release of available N in the soil prior to planting.
Other credits for N include the amounts expected to become available during the season from mineralization of soil organic matter, manure and previous legume crops. Subtract these credits from the total crop needs to determine the suggested N fertilizer rate for the expected yield.
Soil Nitrate-N Credit
Residual NO3-N in soil is immediately available to plants, so decrease the fertilizer rate to give credit for the amount of NO3 in the root zone. Sample soil to a depth of 2 feet in 1-foot increments and test for NO3-N. The sum of the ppm values for the two samples is used to estimate the NO3-N content in the soil. For example, if the NO3-N contents of the 0-1 and 1-2 foot soil samples are 10 and 4 ppm, use the N rates in the 13 to 15 ppm row in the second column of Table 1. When soil is sampled to a 1-foot depth, use the first column in Table 1.| Table 1: Suggested N rates for dryland winter wheat, as related to NO3-N in the soil and soil organic matter content (expected yield, 50 bu/A). | ||||
| ppm NO3-N in soil* | Soil organic matter, % | |||
|---|---|---|---|---|
| 0 - 1 ft | 0 - 2 ft | 0 - 1.0 | 1.1 - 2.0 | >2.0 |
| ---Fertilizer rate, lb N/A---- | ||||
| 0 - 3 | 0 - 5 | 75 | 75 | 75 |
| 4 - 6 | 6 - 9 | 75 | 70 | 50 |
| 7 - 9 | 10 - 12 | 75 | 45 | 25 |
| 10 - 12 | 13 - 15 | 50 | 20 | 0 |
| 13 - 15 | 15 - 18 | 25 | 0 | 0 |
| > 15 | > 18 | 0 | 0 | 0 |
| * Concentration of NO3-N in the top foot of soil or the sum of NO3-N concentrations in 1-foot sample depths to 2 feet. - To adjust N rate for expected yields different from 50 bu/A, add or subtract 25 lb N/A for each 10 bu/A difference (maximum N rate is 75 lb/A for dryland winter wheat). |
||||
Soil Organic Matter Credit
Nitrogen in soil organic matter becomes available to plants through the mineralization process. About 30 pounds of nitrogen per acre will be available to the crop during each growing season for each 1.0 percent organic matter in the surface soil layer. When a soil test result for organic matter is not available, assume a level of 1.5 percent organic matter for eastern Colorado soils.Dry-land Wheat
Suggested N rates for dryland wheat are given in Table 1 at an expected yield of 50 bushels per acre. Fertilizer N rates decrease with increasing levels of NO3-N in the top 1 or 2 feet of soil or increasing soil organic matter content. Suggested N rates in this table do not account for manure and legume N credits. Subtract these credits from the N rates in Table 1 to determine the N rate for the field.To increase grain protein content to above average levels (i.e., >12 percent protein), increase the N rate. It takes 20 to 30 pounds of nitrogen per acre to increase grain protein by one percentage point above 12 percent protein.
Irrigated Wheat
Table 2 gives suggested N rates for irrigated wheat at an expected yield of 100 bushels per acre. Fertilizer N rates decrease with increasing levels of NO3-N in the top 2 feet of soil or increasing soil organic matter content. Suggested N rates in this table do not account for manure and legume N credits. Subtract these credits from the N rates in Table 2 to determine the N rate for the field. Late season N applications are not suggested for soft wheat because a lower protein content is desired.| Table 2: Suggested nitrogen rates for irrigated winter wheat, as related to NO3-N in the soil and soil organic matter content (expected yield, 100 bu/A). | |||
| ppm NO3-N in soil* | Soil organic matter, % | ||
|---|---|---|---|
| 0 - 1.0 | 1.1 - 2.0 | >2.0 | |
| 0 - 6 | 125 | 95 | 75 |
| 7 - 12 | 105 | 75 | 55 |
| 13 - 18 | 85 | 55 | 35 |
| 19 - 24 | 65 | 35 | 15 |
| 25 - 30 | 45 | 15 | 0 |
| 31 - 36 | 25 | 0 | 0 |
| > 36 | 0 | 0 | 0 |
| * Sum of ppm NO3-N in 1-foot sample depths to 2 feet (for sample depths of 1 foot only, multiply the ppm value by 1.67
before using the table).
-To adjust N rate for expected yields different from 100 bu/A, add or subtract 20 lb N/A for each 10 bu/A difference. NOTE: Increase the above rates by 40 lb N/A for irrigated wheat in Alamosa, Conejos, Costilla, Rio Grande and Saguache counties. | |||
Methods and Timing of N Applications
Nitrogen fertilizer may be applied by various methods. Most efficient use of fertilizer N can be obtained by applying some of the N prior to or at planting and the remainder in the early spring. Some growers prefer to apply anhydrous ammonia in combination with P fertilizers in a tillage operation during the fallow period for dryland wheat. Some N may be applied with or near the seed in combination with P in starter fertilizers, but the rate should be less than 20 pounds of N per acre because seedling emergence may be decreased in dry soil at higher rates. All sources of N fertilizers are equally effective for wheat per unit of N if properly applied. Base your choice of N on availability, equipment needs and cost per unit of N.Topdressing N fertilizers in the spring is an efficient way to supply a portion of the total N needs of wheat. Producers can evaluate spring-stored moisture and plant populations to better predict yield potential in the spring than at planting, so N needs by the crop can be better determined. Granular fertilizer can be broadcast on the wheat just after greenup. Fluid N solutions also may be dribble-applied to the wheat crop, although there is some potential for leaf burn.
Apply nitrogen fertilizers through sprinkler irrigation systems for irrigated wheat. All closed-irrigation systems must be equipped with backflow prevention valves if N fertilizers are applied through the system.
There is a strong relationship between protein content of wheat and the N fertility status of a given field. Fields that produce grain with protein content less than 11 percent are likely to have N deficiencies. Those fields that produce grain with protein between 11 and 12 percent may respond to additional N fertilizer, while those that produce grain above 12 percent protein probably have adequate N for the present grain yield levels. Therefore, protein analysis of wheat will give the producer a good indication if the N fertilizer program was adequate for that season.
This information can be used to help plan N fertilizer management in future years. The above relationships do not hold well under extreme drought conditions. Field conditions also should be considered. For more information, see Fact Sheet 0.555, Grain Protein Content and N Needs.
Crop responses to P fertilizer are most likely on soils with low or medium levels of extractable P. Suggested P fertilizer rates (Table 3) are for band (or row) application and are similar for dryland and irrigated wheat. The main soil tests for extractable P in Colorado soils are the AB-DTPA and sodium bicarbonate (NaHCO3 also known as Olsen) tests. Values for both tests are given in Table 3.
| Table 3: Suggested phosphorus rates for band application to dryland and irrigated winter wheat. | |||
| ppm P in soil | Relative level | Fertilizer rate, lb P2O5/A | |
|---|---|---|---|
| AB-DTPA | NaHCO3 | ||
| 0 - 3 | 0 - 6 | low | 40 |
| 4 - 7 | 7 - 14 | medium | 20 |
| > 7 | > 14 | high | 0 |
Dual application of N and P together in a band improves efficiency of P uptake by Crops. Subsurface placement of P may be especially important for reduced tillage cropping systems. Monoammonium phosphate (MAP, 11-52-0), diammonium phosphate (DAP, 18-46-0), and ammonium polyphosphate (10-34-0) are equally effective per unit of P if properly applied. Base choice of fertilizer product on availability, equipment needs, and cost per unit of P.
An effective method of band application of P with hoe drills allows the P fertilizer to be banded on the soil surface directly above the seed row after row closure.
Potassium Suggestions
Most Colorado soils are relatively high in extractable K, and few crop responses to K fertilizers have been reported. Suggested K rates related to soil test values (AB-DTPA or NH4OAc) are similar for dryland and irrigated wheat (Table 4). The main K fertilizer is KCl (muriate of potash). Broadcast application incorporated into the soil prior to planting is the usual method.| Table 4: Suggested potassium rates for dryland and irrigated winter wheat. | ||
| ppm K in soil AB-DTPA or NH4OAc |
Relative level | Fertilizer rate, lb K2O/A |
|---|---|---|
| 0 - 60 | low | 30 |
| > 60 | high | 0 |
Other Nutrients
Most Colorado soils contain adequate levels of available S, and soil tests for available S are not routinely performed. Under rare situations some sandy soils may require S applications; the chances of getting a yield response to S fertilization increase when the soil pH is 7.5 or higher and the soil organic matter content is 1.5 percent or lower. Irrigation water from most surface waters and some wells often contains appreciable SO4-S, so irrigated soils usually are adequately supplied with S.There have been no confirmed deficiencies of boron (B), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), zinc (Zn), or chloride (Cl) in wheat in Colorado.
1J.G. Davis, Colorado State University Extension soils specialist and professor, and D.G. Westfall, professor soil and crop sciences. Original authors included J.J. Mortvedt, soils specialist and J.F. Shanahan, Extension crop specialist and professor. 3/96. Revised 5/09.
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Fertilizing wheat in Nepal
Keywords:
- Biological nitrogen fixation;
- denitrification;
- Mucuna;
- Oryza sativa;
- Triticum aestivum;
- Vigna radiata
Abstract
The
rice-wheat annual double cropping system occupies some 0.5 million ha
in the Himalayan foothills of Nepal. Alternating soil drying and wetting
cycles characterize the 6–10 weeks long dry-to-wet season transition
period (DWT) after wheat harvesting and before wetland rice
transplanting. Mineral fertilizer use in the predominant smallholder
agriculture is low and crops rely largely on native soil N for their
nutrition. Changes in soil aeration status during DWT are likely to
stimulate soil N losses. The effect of management options that avoid the
nitrate build-up in soils during DWT by N immobilization in plant or
microbial biomass was studied under controlled conditions in a
greenhouse (2001/2002) and validated under field conditions in Nepal in
2002. In potted soil in the greenhouse, the gradual increase in soil
moisture resulted in a nitrate N peak of 20 mg (kg soil)–1
that rapidly declined as soil moisture levels exceeded 40 % water-filled
pore space (equiv. 75 % field capacity). Similarly, the maximum soil
nitrate build-up of 40 kg N ha–1 under field conditions was
followed by its near complete disappearance with soil moisture levels
exceeding 46 % water-filled pore space at the onset of the monsoon
rains. Incorporation of wheat straw and/or N uptake by green manure
crops reduced nitrate accumulation in the soil to < 5 mg N kg–1 in pots and < 30 kg N ha–1
in the field (temporary N immobilization), thus reducing the risk for N
losses to occur. This “saved” N benefited the subsequent crop of
lowland rice with increases in N accumulation from 130 mg pot–1 (bare soil) to 185 mg pot–1 (green manure plus wheat straw) and corresponding grain yield increases from 1.7 Mg ha–1 to 3.6 Mg ha–1
in the field. While benefits from improved soil N management on lowland
rice are obvious, possible carry-over effects on wheat and the
feasibility of proposed options at the farm level require further
studies.
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| seeds of wheat |
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| National Wheat Research Program |
 |
Introduction
National Wheat Research Program (NWRP) was established
in 1972 at Khumaltar, Lalitpur under the name of National
Wheat Development Program. In 1975, it was transferred
to Bhairahawa Agricultural Farm, which was established
in 1960. Geographically, the station is located at 105
meters above sea level and 27°32’ north latitude
and 83°25’ east longitude. It is 300 km west
of capital city Kathamandu and 21 km east of Lumbini
the birthplace of Lord Buddha.The climate at NWRP is subtropical. The recorded maximum temperature in summer is 44.6°C and minimum temperature in winter is 4.8°C. The average annual rain fall is 1700 mm, with maximum and minimum mean temperature of June and January is 30.8 0C and 14.7 0C respectively. NWRP station has a total of 35 hectares of land area out of which 25 hectares are utilized for wheat research and production activities and rest 10 hectares are occupied by farm roads drainage, office and residence facilities.
Wheat is the third largest cereal crop in Nepal after rice and maize. Before the introduction of Mexican semi-dwarf wheat varieties, wheat cultivation in Nepal was limited to mid and far-western hills only and it was considered as a minor cereal in the country. After the introduction of semi-dwarf varieties from Mexico, the area and production of wheat in Nepal has been increased dramatically and now it has significant contribution to the national food supply. In 1965/66, wheat area in the country was 100,000 ha and the production was 112,000 metric tons. In 2006/07, its area and production have increased to 702664 ha and 1515139 metric tons respectively. The present national average wheat productivity is 2156 kg/ha. Wheat is cultivated in 20 percent of the total cultivated land area and contributes 18.8 percent to the total national cereal production. Per capita wheat consumption has increased from 17.4 kg in 1972 at the time of NWRP establishment to 60 kg in 2007. In Terai, as irrigation facility is steadily increasing there is still ample opportunity to expand the wheat area where the lands remain fallow after rice harvesting.
Goal and objectives
NWRP’s major goal is to contribute in enhanced livelihood and the main objective is to make the nation self-sustained in food supply through increased wheat production and productivity by conducting applied research in collaboration with related national and international organizations, developing improved wheat varieties, wheat production technologies, multiplying wheat breeder seed and disseminating wheat related information.
Mandate
Following are the major national mandates of NWRP: 1) Develop, implement, coordinate and monitor multilocational and multi-disciplinary adaptive research for developing superior varieties resistant/tolerant to biotic and abiotic stresses for different agro-climatic conditions 2) collect evaluate, identify, maintain and use of suitable donors for different biotic and abiotic stresses 3) develop appropriate wheat crop production technologies for optimal use of resources in a sustainable manner 4) produce nucleus and breeder seeds of popular varieties in required quantity 5) carryout off-season breeding work for rapid generation advancement at suitable hill site and 6) establish national and international linkages for strengthening wheat improvement research in the country.
Activities
The major activities include conducting wheat research on:
i) Varietal improvement
- Development of wheat varieties suitable for different agro-ecological domains (Terai under irrigated normal planting, irrigated late planting, rainfed conditions and mid and high hill environments).
- Development of high-yielding and disease-resistant wheat varieties suitable for existing cropping pattern
- Development of product specific wheat varieties required by various wheat based industrties.
- Development of improved wheat production technologies (Irrigation and fertilizer management, time and method of crop establishment, weed management etc.) suitable for different agro-climatic conditions
- Identification of farmers' problems through on-site inspection of farmers' fields and solving them through adaptive research
- Scaling up of resource conservation technologies (RCTs) to farming communities through pluralistic approach.
- Detection of major diseases and insects on wheat, estimation of their damage, identification and development of insects and disease resistant wheat varieties and disease management techniques.
- On-farm verification of station developed technologies through farmers' field testing and mini-kit distribution of recently released and pre-release wheat varieties and other technologies under farmers' situations.
- Provide farmers with technical knowledge through different media.
- Produce wheat nucleus and breeder seeds as per need
- Provide breeder seed to different farms /stations,
seed companies for foundation seed production and
supervise them - Assist farmers in seed multiplication program through technical advice
- Assist in wheat production in coordination with different stakeholders
with different (CIMMYT, ICARDA, DWR- India, WRC-Bangladesh etc.) national and international agencies
Economic achievements
Research Achievements
NWRP has made remarkable achievements in its almost 50 years of wheat research and development.
- Since 1960/61, wheat area has increased six folds and reached 702664 hectares from 100000 hectares. In the same period, wheat production has increased 14 folds and reached 1515139 metric tons from 112000 metric tons. In 1972, when the wheat development program was started, wheat productivity was 933 kg/ha, which has now more than doubled to 2156 kg/ha.
- NWRP has released 29 improved wheat varieties in last 40 years and assisted in their dissemination through different ways.
- Recommended wheat varieties are very popular among farmers.
- More than 95% of the total wheat area has been covered by improved wheat varieties.
- Cropping intensity has increased due to early maturing wheat varieties.
- Per capita wheat consumption has been increased.
- Quantitative growth has been observed in wheat based industries in the country.
- Wheat has provided direct employment to the farmers for about five months.
- Wheat based products like noodle, biscuits and Cookies are exported to India and China.
- Wheat crop has played a great role in internal food supply in the country, equivalent to more than 26 billion rupees annually.
- Economic analysis of the past three decades (1960-1992) wheat research showed that the nation has gained 75 to 84% internal rate of return to the total investment in wheat research.
- In comparison with the old varieties, new wheat
varieties have contributed increased annual wheat
yield by 1.5%.
- Mr. Madan Raj Bhatta, Senior Scientist, Coordinator of the Program
- Mr. Janmjay Prasad Tripathi, Senior Scientist
Contact Address
Nepal Agricultural Research Council
National Wheat Research Program
Bhairahawa, Rupandehi
Phone: 071-522196,520226,520431
Fax: 071-521905
E-mail: nwrp@nec.com.np
Website: www.narc.org.np
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How to Plant Wheat for Higher Yields
By Erick Larson, Extension Grain Specialist
Early-planted wheat is prone
to disappointment, due to many issues which you may not be able to
control, including freeze injury. All it needs is to successfully
emerge and begin tillering in the fall.
Planting wheat early is very tempting, but can limit wheat grain productivity more than any other factor. In fact, our record wheat yields this year were likely promoted by dry conditions which delayed planting till early November last fall. Records from the Kentucky Wheat Production Contest (where winners typically produce more than 100 bushels per acre) justify the significance of timely planting, as top yielding plots rarely result from plantings prior to the recommended dates. Planting wheat early needlessly exposes it to developmental, fertility, weed and numerous pest problems which ultimately limit yield potential. Our mild southern winters further intensify this issue, because the onset and degree of wheat dormancy may vary considerably from year to year. Thus, the developmental advantages gained from planting summer crops early, such as corn and soybeans, do not apply to winter wheat. The adverse effects from excessive fall growth include spring freeze injury, development of Barley yellow dwarf virus, Hessian fly and armyworm infestation, more disease infection, more weed competition, poor nutrient use, and increased lodging. Growers in both north and south Mississippi have experienced severe freeze injury during recent seasons and ensuing yield loss generally increases drastically with early-maturing wheat. Thus, we need to carefully manage variety maturity and planting date, as both these factors affect wheat maturity. Early-maturing varieties should be planted later than normal, to avoid excessive development, which could expose them to substantial freeze damage in the spring. Conversely, late-maturing wheat varieties should be planted before early varieties. We should also plant multiple varieties differing in maturity, to spread risk, since seasonal temperatures also influence maturity.
Our suggested wheat planting dates (within 10-14 days of the average first fall freeze date) should provide warm enough temperatures and long enough days for seedling emergence and tillering to begin before dormancy occurs. This can vary considerably depending upon seasonal temperatures, but normally corresponds to
