ISSUE 2 May 20, 2010
SULFUR DEFICIENCY, VIGILANCE AND REMEDIATION
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.
DRY BEAN FERTILIZER RECOMMENDATIONS
For a full explanation of dry bean fertilizer recommendations, see my web page - (http://www.soilsci.ndsu.nodak.edu/Franzen/Franzen.html, 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.
APPLICATION OF SLOW-RELEASE N PRODUCTS WITH HERBICIDES/FUNGICIDES IN SMALL GRAINS
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 (http://www.soilsci.ndsu.nodak.edu/Franzen/Franzen.html, 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.
NDSU Extension Specialist