ISSUE 1   May 5, 2005

SURFACE-APPLIED UREA

In the heat of the spring planting season, many growers have urea applied to the soil surface and leave it there unincorporated for a period of time. If the soil is dry and the pellet remains intact, losses due to breakdown of the urea molecule to free ammonia by the soil enzyme urease are negligible. However, if light rain falls, or dew or frost result in dissipation of the pellet, urease activity can be expected. A worst-case scenario on tilled land is a light rain, maybe 1/10 inch (enough to dissipate the pellet, but not enough to move the urea safely into the soil- that takes about ˝ inch of rain), then windy days. This would result in perhaps 10% of the urea lost in a week under cool conditions as we experienced April 20_May2, and 20% under warmer conditions. The ultimate worst-case scenario is the same conditions under no-till or stubble. Residue contains hundreds of times the concentration of urease enzyme as bare soil. The result of this case would be perhaps 25% losses under cool conditions, and up to 50% under warm conditions.

Addition of Agrotain® would prevent losses for about 10 days. This material is added before application through a urea impregnation process at the fertilizer retailer.

Another alternative is 28% applied through stream-bars. Liquid 28% is about one-half ammonium nitrate, which is not subject to volatilization. Concentration of a surface band also slows the volatilization process of urea.

An additional help for liquid 28% would be the addition of a small amount of ammonium thiosulfate (ATS). Research at NDSU in the mid-1980’s by Dr. Goos showed that addition of ATS to 28% slowed the rate of urease activity considerably, although it did not stop it completely like Agrotain.

The ultimate answer to the volatility issue is finding a suitable way for each grower to apply their N under the soil surface. They rainfall is not an issue anymore.

 

PHOSPHATE INOCULANTS

There have been many questions this winter regarding the use of phosphate inoculants. These materials are a soil fungus which acidifies its’ immediate environment. The fungus doesn’t know phosphate from Adam. All it does is excrete an acid. In the soil, there are many forms of phosphate- iron phosphate, aluminum phosphate, calcium phosphates of different types organic phosphates and very small amounts of ortho phosphate. If there are free carbonates in the soil, phosphate can become coated, or "occluded" with carbonates. If acid is applied to occluded phosphate, some of the carbonate coating dissolves, releasing some phosphate. In soils with occluded phosphate, as much as 10 lb P2O5 can be released in medium or higher testing P soils. In soils without occluded phosphate, no phosphate is released.

Soils where the product can work are soils with pH higher than 7, with carbonates. These would include soils like Bearden or Hegne in the Valley, or Buse and Hamerly in the till plain. Soils where this product has little chance of success would include Barnes, Fargo, or many soils west-river that are neutral or lower in pH.

This product would also perform less effectively in low testing P soils. There has to be P in the soil to release, after all.

Most fields contain some neutral or lower pH areas within fields. A precision ag field studied near Valley City contained pH ranges from 4.9 to 7.8. A composite test of the field showed a pH higher than 7. A composite soil test is not a good guide to whether the whole field would respond to a phosphate inoculant.

Dave Franzen
Extension Soil Specialist
david.franzen@ndsu.edu

 

SOIL TEMPERATURE REQUIRED FOR SUGARBEET SEED GERMINATION

Sugarbeet seeds will germinate over a wide temp. range in the presence of adequate soil moisture. Soil temperature in the seed placement zone must be 37.4EF or greater to initiate germination. The actual duration of optimum or sub-optimum temperatures will impact emergence rate and uniformity. The table below shows approximate days to emergence at different soil temperature ranges.

Soil Temperature (EF)

Days to Emergence

38-45

21 days or more

45-52

10-21 days

52-60

7-12 days

60-70

5-7 days

The average bare soil temperature at 4 inch depth at different weather stations in areas where sugarbeet is grown is provided in the table below. The average bare soil temperature ranged from 46 to 49EF in the eastern Red River Valley for the period April 11 through May 3. Consequently, early planted fields would already have had seedlings in the latter part of April. Hopefully, early emerged seedlings survived the recent frost conditions.

Weather Station

Average bare soil temperature at 4" depth for April 11 - May 3 (Low-High)

St. Thomas

47EF (38-59EF)

Grand Forks

49EF (40-60EF)

Hillsboro

49EF (40-60EF)

Fargo

46EF (39-54EF)

Wahpeton

46EF (39-56EF)

Sidney, MT

50EF (45-54EF)

 

2005 SUGARBEET ACREAGE

Total sugarbeet acreage in the US for 2005 is projected at about 1.32 million acres. Compared to 2004, sugarbeet acreage will be reduced by about 16% in Idaho and 9% in Michigan. Growers in North Dakota and Minnesota are fortunate - sugarbeet acreage in 2005 will be similar to 2004. American Crystal Sugar Company (ACSC) will plant about 500,000 acres, Minn-Dak Farmers Cooperative (Minn-Dak) will plant about 105,000 acres, Southern Minnesota Beet Sugar Cooperative (SMBSC) will plant 118,000 acres, and growers in western North Dakota will plant about 15,000 acres of Sidney Sugars 41,000 acres. This means that North Dakota and Minnesota will plant about 738,000 acres of sugarbeet which is about 55% of the total US sugarbeet acreage.

 

SUGARBEET CROP UPDATE

April was unseasonably warm and with little rainfall. As such, except for fields that were very wet since last fall, most growers managed to complete land preparation planting. As of May 3, SMBSC had completed over 98% planting, Minn-Dak and ACSC about 85% planting, and Sidney Sugars 100% planting. Fields now need a good ˝ -1 inch of rain to set the potential for a high yielding sugarbeet crop.

Mohamed Khan
Extension Sugarbeet Specialist
701-231-8596
mkhan@ndsuext.nodak.edu


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