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The Fertilizer Value of Wheat and Barley Straw, 2021 (07/29/21)

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Wheat straw contains some of all essential plant nutrients, but nitrogen (N), phosphorus (P) and potassium (K) are the only nutrients in sufficient amounts to be considered. Calcium and magnesium are also present in similar amounts, but all regularly cropped and productive soils in North Dakota have very large amounts of each of these, so they are not considered a value that needs to be considered in the fertilizer value of the wheat straw.

Generally, there are about 10 pounds N, 5 pounds P2O5 (phosphate fertilizer equivalent) and 24 pounds K2O (potassium fertilizer equivalent) in a ton of wheat straw. At present day retail fertilizer estimates, the value of these is:

            N at 40 cents per pound = $4/ton

            P2O5 at 66 cents per pound = $3.30/ton

            K2O at 53 cents per pound = $12.72/ton

            Total fertilizer value of wheat straw = $20.02/ton

 

For barley straw, there are about 15 pounds of N, 5 pounds of P2O5 and 30 pounds of K2O per ton. The value of these nutrients is:

            N at 40 cents per pound = $6/ton

            P2O5 at 66 cents per pound = $3.30/ton

            K2O at 53 cents per pound = $15.90/ton

            Total fertilizer value of barley straw = $25.20/ton

 

Eastern growers (Stutsman county and east) have generally grown soybeans and also corn for more than 20 years and have depleted their native potassium supply. The new corn potassium recommendations result in a higher soil test critical level (200 ppm instead of the old 150 ppm recommendation in highly smectitic clay soils) to sustain corn production in drier summers. 

However, western growers have very high K tests as a rule. Many western fields have soil test K levels over 400 ppm, and these growers probably would not put a value on the K since they do not consider K in their fertilizer budget, except as a carrier for the nutrient chloride. Eastern growers have to consider the K value of the straw or experience decline of soil test K requiring fertilization. Failure to do so will result in yield losses in alfalfa, sugar beet and corn production, particularly.

For average values of nutrients contained in other straw/crop materials, the NDSU circular SF1978- ‘Effectiveness of using low rates of plant nutrients’ may serve as a helpful guide. https://www.ag.ndsu.edu/publications/crops/effectiveness-of-using-low-rates-of-plant-nutrients

Also, since yield of grain and straw is reduced compared to most years, the amount of nutrients in the straw is likely greater than those indicated in the SF1978 tables. It is also important that if these straws/green chop are intended to be used for livestock feed, a nitrate test is performed to help the end-user know how to best mix the ration.

 

 

Dave Franzen

Extension Soil Specialist

701-799-2565