ISSUE 2   May 20, 2010


Winter wheat is beginning to show signs of sulfur (S) deficiency in several areas of the state. The presence of S deficiency should not be a surprise. Prediction of possible S deficiency is: a wet fall and/or a wet spring (we have had both) and/or a heavy snowfall (three for three). Winter wheat is our most mature crop right now, so it is showing deficiency first. Other crops will follow suit when they emerge and grow. S deficiency will be more common in rolling terrain on coarser textured, low organic matter soil (loams and coarser with less than 3% organic matter). S deficiency will be less common on heavier, higher organic matter soils; however crops on these soils may show early deficiency and grow out of it later on as roots grow into more sulfate-laden groundwater. Growers who have not applied any supplemental S this spring (note "this spring") or used any kind of elemental S product may be at risk for S deficiency and should be vigilant at the first sign of unusual yellowing. Yellowing will be most severe on new growth, not old growth. S deficiencies can be corrected by applications of 5-10 lb/acre of actual S as dry ammonium sulfate granules, gypsum granules, or stream-bar solutions of ammonium thiosulfate or ammonium sulfate liquids. Rainfall following application will be needed for the products to be most effective. S in these products is not volatile. If applying liquids with stream-bars or stream nozzles, be sure that wind does not break up the application into a broadcast application. A broadcast application particularly with ammonium thiosulfate will result in severe leaf burn. All crops are at risk for S deficiency.



For a full explanation of dry bean fertilizer recommendations, see my web page - (, look at left side for "Extension Publications," then look for SF-720 (revised).) Dry bean N recommendations were revised in 2006. Previously the recommendations were - N rate = (Yield potential) X 0.05 less credits. Due to results from revisiting modern data, there are just two numbers to remember for dryland dry beans- 40 lb N less credits if inoculation is used; 70 lb N less credits if not inoculating. The exception is for irrigated beans only. Irrigated dry bean recommendations are still Yield potential X 0.05 less credits.

Phosphorus (P) is important to apply in soils with P tests (Olsen/sodium bicarbonate) of 11 ppm or less. Broadcast the P or band it away from the seed. Do not apply any fertilizer outside of a water/zinc fertilizer mix in the seed furrow.

Potassium is of minor importance for dry bean. Some K is suggested if soil test K is below 120 ppm.

Apply zinc as a band or a broadcast if soil test Zn is 1 ppm or less.

For S recommendations see the companion article in this Crop and Pest Report edition.



Low protein of last years wheat crop is on most growers minds this spring. There has been some interest in adding 1-2 gal/acre of slow-release N products with herbicides/fungicides in small grain crops to boost potential protein at harvest. I conducted experiments with in-season low rates of slow-release N products in several experiments over a number of years. Others at NDSU and elsewhere have conducted similar experiments. The results of these studies are presented on my webpage (, look at left column, select "foliar slow-release N studies for wheat protein enhancement"). These studies show that the amount of N from application of 1-3 gal/acre of slow-release N products is not sufficient to increase wheat protein/yield significantly. The economic return from adding these materials is not positive. Water is a lot cheaper, and it appears to do the same thing with regards to wheat protein enhancement. A study at Carrington in 2009 showed that if a slow-release N product was applied at a 30 lb N/acre rate post-anthesis, it resulted in a similar protein gain as 30 lb N/acre as 28-0-0. However, the cost of applying that rate of slow-release N product would be prohibitively expensive compared with 28-0-0.

Dave Franzen
NDSU Extension Specialist

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