North Dakota State University Extension Service

May 2, 2005

Topdressing Winter Wheat: There=s Still Time

Winter wheat fields look good across the region. April has been dry and most growers have been waiting for a good chance of precipitation before broadcasting nitrogen on their winter wheat...... most are still waiting. As of late April, winter wheat is in the 2 to 4 leaf stage with many fields just starting to tiller.

If it stays dry, the decision to apply will come down to the fertilizer source. Urea can be applied, and if it is really dry, volatility would not immediately be a problem. Having the fertilizer dealer impregnate the urea with a urease inhibitor, Agrotain, would help and prevent significant volatility for about 10 days. Another option would be to apply N through streamer bars using UAN (28-0-0). UAN is about 2 ammonium nitrate and is not volatile like urea. The other half of UAN is urea, so regardless of how much urea portion was lost, at least 2 of the total N applied would stay on the field and not be lost. If dry conditions continue using UAN would be advisable to reduce to potential losses due to volatilization.

A winter wheat fertilizer timing trial was conducted at Mohall, ND in 2004. Nitrogen source and timing were evaluated. Urea and UAN were applied to winter wheat at the 2 leaf stage (April 21), 4 leaf stage (May 4) and jointing (May 26). Precipitation was recorded within 7 days of each application date. Yield was similar across timings and nitrogen sources. So there is time in May to get the nitrogen on before yield losses occur.

Winter Wheat Growers Need to be monitoring for Wheat Streak

Wheat streak mosiac was found in northern Bottineau County last fall. This disease is caused by a virus and all growers need to be looking for any symptoms this spring. Serious infections will occur in the fall, but the disease symptoms may not appear until spring. Infected plants have a general appearance of yellowing and stunting. If infection occurred early last fall, plants will become stunted fairly quick this spring. Symptoms on individual leaves appears as yellow stripes or streaks parrallel to the veins. As the disease progresses, the leaves may become mottled, and eventually the yellowed leaves turn brown and die. Yield loss is correlated with the percent of plants infected and the time of infection. The earlier the infection, the greater the loss. If the plants are infected early, almost no growth occurs and no heads are produced. If plants are infected at late tillering (late May), heads could form but most likely will be streile with no grain produced.

Growers should be looking for any winter wheat that appears to be yellowing or is stunted. If suspicious plants are found in which a confirmation is needed please contact your county agent and/or send plants to the NDSU Plant Diagnostic lab in Fargo, ND, 231-7854.

Seeding Date:
Flax should be seeded early to maximize yields. However, keep in mind flax needs warmer soil temperatures for germination than canola, peas or small grains. The minimum soil temperature for flax germination is 48 F. So seeding early into cold soils like one can with wheat and peas should be avoided with flax.

Seeding Rate:
The recommended seeding rate fro flax is 3/4 to 1 bushel per acre. The optimum stand for flax is approximately 80 plants per square foot. Seeding flax at 1 bushel per acre is recommended if the flax will be straight combined.

Nitrogen:
Nitrogen inputs for flax are less than wheat. Excessive nitrogen rates may actually hold down yield potential through greater susceptibility to lodging. Nitrogen yield goals of 30 to 40 bushel per acre requires 80 pounds of total nitrogen. When determining nitrogen needs for flax start with a base of 80 pounds per acre and subtract soil residual N and any other N credit .

NEW NDSU PHOSPHATE RECOMMENDATIONS
Flax is not very responsive to phosphate fertilizer. Mycorrhizae are soil fungi that live in a symbiotic relationship between most plants. The mycorrhizae receive carbohydrates from the plants, and in return the plant receives mineral nutrients from the mycorrhizae, particularly phosphate. Mycorrhizae hyphae explore the soil within a couple feet of the host plant and are very good at mobilizing phosphate from the soil and transferring it to the host. Research in Manitoba has shown that when flax is not fertilized with P, yield is maintained regardless of soil test and mycorrhizae infection is high. When flax receives fertilizer P, banded or broadcast, mycorrhizae infection is reduced and the net result is no yield increase. Since yield increase is seldom achieved through the application of phosphate, no phosphate fertilizer is recommended directly to flax. However, maintaining soil P levels for other crops is important. Phosphate can be applied to flax to serve as a carrier for zinc, but do not expect a yield increase due to the phosphate portion of the application.

SEED PLACED FERTILIZER
The maximum amount of nitrogen that can be placed with flax will vary on the distance of seed spread and soil type. A maximum/@safe@ rate of 10 lb of actual N is recommended across all drill spacings and soil types. Do not apply urea as a seed placed fertilizer with flax.

ZINC
Zinc deficiency in flax is not common; however, it=s documented every year in North Dakota. If soil zinc levels (DTPA extract) are less than 1 ppm, application of zinc would be recommended. Zinc deficiency is expressed as a condition known as "chlorotic dieback". Zinc deficient plants are pale yellow at the growing point. In most cases the growing point dies and the plant regrows from lower nodes. Application of zinc sulfate at seeding is an option. Side‑banded treatments of zinc EDTA or small amounts of ammoniated zinc liquid fertilizers may also be effective. Rescue foliar treatments can effective, but some yield loss may have already taken place.

Dan Folske
Extension Agent/Burke County
Soil Conservation Technology Specialist
PO Box 280
Bowbells, North Dakota 58721
dfolske@ndsuext.nodak.edu
701-377-2927


North Dakota State University Extension Service - Burke County
	Burke County AgAlert
	May 2, 2005 Topdressing Winter Wheat: There=s Still Time Winter wheat fields look good across the region. April has been dry and most growers have been waiting for a good chance of precipitation before broadcasting nitrogen on their winter wheat...... most are still waiting. As of late April, winter wheat is in the 2 to 4 leaf stage with many fields just starting to tiller. If it stays dry, the decision to apply will come down to the fertilizer source. Urea can be applied, and if it is really dry, volatility would not immediately be a problem. Having the fertilizer dealer impregnate the urea with a urease inhibitor, Agrotain, would help and prevent significant volatility for about 10 days. Another option would be to apply N through streamer bars using UAN (28-0-0). UAN is about 2 ammonium nitrate and is not volatile like urea. The other half of UAN is urea, so regardless of how much urea portion was lost, at least 2 of the total N applied would stay on the field and not be lost. If dry conditions continue using UAN would be advisable to reduce to potential losses due to volatilization. A winter wheat fertilizer timing trial was conducted at Mohall, ND in 2004. Nitrogen source and timing were evaluated. Urea and UAN were applied to winter wheat at the 2 leaf stage (April 21), 4 leaf stage (May 4) and jointing (May 26). Precipitation was recorded within 7 days of each application date. Yield was similar across timings and nitrogen sources. So there is time in May to get the nitrogen on before yield losses occur. Winter Wheat Growers Need to be monitoring for Wheat Streak Wheat streak mosiac was found in northern Bottineau County last fall. This disease is caused by a virus and all growers need to be looking for any symptoms this spring. Serious infections will occur in the fall, but the disease symptoms may not appear until spring. Infected plants have a general appearance of yellowing and stunting. If infection occurred early last fall, plants will become stunted fairly quick this spring. Symptoms on individual leaves appears as yellow stripes or streaks parrallel to the veins. As the disease progresses, the leaves may become mottled, and eventually the yellowed leaves turn brown and die. Yield loss is correlated with the percent of plants infected and the time of infection. The earlier the infection, the greater the loss. If the plants are infected early, almost no growth occurs and no heads are produced. If plants are infected at late tillering (late May), heads could form but most likely will be streile with no grain produced. Growers should be looking for any winter wheat that appears to be yellowing or is stunted. If suspicious plants are found in which a confirmation is needed please contact your county agent and/or send plants to the NDSU Plant Diagnostic lab in Fargo, ND, 231-7854. FLAX PRODUCTION GUIDELINES: Seeding Date: Flax should be seeded early to maximize yields. However, keep in mind flax needs warmer soil temperatures for germination than canola, peas or small grains. The minimum soil temperature for flax germination is 48 F. So seeding early into cold soils like one can with wheat and peas should be avoided with flax. Seeding Rate: The recommended seeding rate fro flax is 3/4 to 1 bushel per acre. The optimum stand for flax is approximately 80 plants per square foot. Seeding flax at 1 bushel per acre is recommended if the flax will be straight combined. Nitrogen: Nitrogen inputs for flax are less than wheat. Excessive nitrogen rates may actually hold down yield potential through greater susceptibility to lodging. Nitrogen yield goals of 30 to 40 bushel per acre requires 80 pounds of total nitrogen. When determining nitrogen needs for flax start with a base of 80 pounds per acre and subtract soil residual N and any other N credit . NEW NDSU PHOSPHATE RECOMMENDATIONS Flax is not very responsive to phosphate fertilizer. Mycorrhizae are soil fungi that live in a symbiotic relationship between most plants. The mycorrhizae receive carbohydrates from the plants, and in return the plant receives mineral nutrients from the mycorrhizae, particularly phosphate. Mycorrhizae hyphae explore the soil within a couple feet of the host plant and are very good at mobilizing phosphate from the soil and transferring it to the host. Research in Manitoba has shown that when flax is not fertilized with P, yield is maintained regardless of soil test and mycorrhizae infection is high. When flax receives fertilizer P, banded or broadcast, mycorrhizae infection is reduced and the net result is no yield increase. Since yield increase is seldom achieved through the application of phosphate, no phosphate fertilizer is recommended directly to flax. However, maintaining soil P levels for other crops is important. Phosphate can be applied to flax to serve as a carrier for zinc, but do not expect a yield increase due to the phosphate portion of the application. SEED PLACED FERTILIZER The maximum amount of nitrogen that can be placed with flax will vary on the distance of seed spread and soil type. A maximum/@safe@ rate of 10 lb of actual N is recommended across all drill spacings and soil types. Do not apply urea as a seed placed fertilizer with flax. ZINC Zinc deficiency in flax is not common; however, it=s documented every year in North Dakota. If soil zinc levels (DTPA extract) are less than 1 ppm, application of zinc would be recommended. Zinc deficiency is expressed as a condition known as "chlorotic dieback". Zinc deficient plants are pale yellow at the growing point. In most cases the growing point dies and the plant regrows from lower nodes. Application of zinc sulfate at seeding is an option. Side‑banded treatments of zinc EDTA or small amounts of ammoniated zinc liquid fertilizers may also be effective. Rescue foliar treatments can effective, but some yield loss may have already taken place. Dan Folske Extension Agent/Burke County Soil Conservation Technology Specialist PO Box 280 Bowbells, North Dakota 58721 dfolske@ndsuext.nodak.edu 701-377-2927
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