What’s the nutrient value of wheat straw?
With wheat harvest right around the corner, the value of the straw is a very popular question. Over the past several years, baling and selling wheat straw has become a more common practice. While uses for wheat straw are varied, the increased demand is driven by livestock farms using straw as part of their feed rations. Sellers should consider the value of the nutrients as well as the organic material that will be leaving when the straw is sold.
From a pure nutrient standpoint, wheat straw contains very little in terms of phosphorus (P2O5), but moderate amounts of nitrogen (N) and potassium (K2O). The actual amounts of N, P2O5 and K2O contained in a ton of wheat straw are 13, 3.3 and 23 pounds respectively, according to Michigan State University Extension bulletin E-2904, “Nutrient Recommendations for Field Crops in Michigan”, Table 3, Nutrient removal in harvested portion of several field crops. Actual nutrient content can vary based upon environmental conditions during the growing season and after the grain is harvested as well as soil nutrient supply. So if you really want to know the actual value, straw analysis can be conducted by any lab that processes plant samples.
How much is that straw worth from a nutrient perspective? Well, it obviously depends upon the current market value of nutrients. Using today’s prices, a pound of N, P2O5, and K2O costs $0.42, $0.50, and $0.34, respectively. Thus a ton of straw will contain $14.93 worth of nutrients. Again, this number can be variable, but it gives you a starting point for your own economic analysis.
It’s always best if prices are determined on a “per ton” basis rather than “per acre” basis. This takes the guess work out of determining actual yield. Average wheat straw yields are about 1.5 ton per acre. However, exceptional wheat can yield over 2 tons per acre, or yields can be 1 ton if stubble is cut high or wheat yield was poor.
The value of the organic matter is more difficult to put a price on. Removing the organic material will diminish the carbon content and can result in negative impact on soil health and on the physical, chemical and biological properties of your soil. It is important to consider these factors when estimating the true value of straw.
The seller has to determine how much profit over the cost of fertilizer is reasonable and put a value on the organic material that is leaving the farm. Farmers should consider planting cover crops or applying manure to replace this organic material. The buyer must consider the harvest costs, which vary based on harvest method. Harvest costs are available in the “2016 Custom Machine and Work Rate Estimates.”