Sixteen reasons why grain growers should never sell crop residues

Read this article and you’ll never sell baled straw again

Could it be the last straw or the straw that broke the camel’s back?

If you grow lentils, peas, canola, dry beans, fava beans, soybeans or grain corn, it’s normal practice to harvest the grain and leave the combined residue on the cropland. There are exceptions when some of the aforementioned crops may be baled. On the other hand, wheat, barley, oat, rye and triticale straw is frequently baled, particularly oat and barley straw. Now, if you run a cattle, beef or dairy operation this would be good practice since the straw and manure can be returned to your cropland.

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If, on the other hand, you are strictly a grain farmer, I can give you 16 good reasons why you should never sell a bale of grain straw ever again. This article is prompted by the fact that I live in an area west of Edmonton where much of the soil is either sandy or a sandy loam, the very worst type of cropland to bale or remove straw. Straw removal, particularly on this kind of sandy land, is a short-term gain for a long-term pain.

Cattle farmers though, particularly when they purchase hay and straw, classically run into problems when they have insufficient cropland on which to spread the manure that results. Such land often gets to be overfertilized and high in nitrogen (N), phosphate (P) and potash (K). Such excess fertility leads to contamination of ground and surface waters and drainage areas. Crop lodging of canola and cereals is frequent on such overfertilized cropland due to excess or unbalanced fertility.

An acre of wheat may produce 1 1/2 to 2 1/2 tons of straw depending on variety or weather conditions in a given season. Wheat bales are generally around 1,000 pounds (450 kilograms) providing an average of four bales per acre. At a rough estimate, two tons of wheat straw would contain at least $72 of nutrients based on current prices, that’s $18 per 1,000-pound bale. Baling itself, if properly wrapped, would be around $6 per bale and traction power and per bale removal from the field about $2 per bale.

Returning cereal straw to cropland

That comes to $26 per bale of wheat straw. If you sell these bales for $25 per bale you are losing money. Selling them because of a glut of straw or a mild winter may only get you $15 per bale — a real fertilizer and financial loss.

Returning cereal straw to cropland, preferably using a straw chopper, provides the following 16 benefits:

  • Cereal straw and other crop residues are very good holders of water in the soil, particularly sandy soil.
  • Soils high in organic matter modify and mute soil residual herbicides — you have seen herbicide residue damage on eroded hilltops but not on the main part of the field.
  • The crop residual organic matter holds onto fertilizers, particularly leachable nitrogen and sulphur.
  • Crop residues allow for easier crop root penetration when they are lightly disked into the soil or during seeding.
  • Crop residues help water penetration into the soil and significantly prevent water runoff and soil erosion.
  • Crop residue is food for increased earthworm activity. Earthworms tunnel down into the soil from the surface greatly aiding soil aeration and water penetration.
  • Soil with many years of 100 per cent crop residue returns become more mellow and reduces tractor draw pull, allowing for less horsepower or fuel consumption.
  • Organic matter will blacken light-coloured soils and speed up soil warming.
  • Crop residues combat soil diseases by providing lots of food for harmless saprophytic fungi and bacteria which, in turn, kill off or reduce plant disease-causing microbes.
  • Crop residue provides a food source when it breaks down to free-living nodulating bacteria, such as rhizobia, in the soil so they survive better between legume crops (soybeans, peas, etc.).
  • Crop residues greatly reduce soil compaction, particularly in clay-based soils.
  • Returns nutrients to the soil, which are released over a few years. As calculated earlier, each acre of wheat straw releases around $72 of nutrients.
  • High bacterial and fungal populations in soil high in crop residues will help release more nutrients such as potash (K) and phosphate (P) from soil minerals.
  • Your fertilizer input will be reduced by an estimated $72 per acre by leaving the cereal straw on your cropland.
  • A straw chopper attachment to your combine is much cheaper to operate than a straw baler, resulting in improved cropland and financial returns.
  • Compacted clay soils — especially when wet — are most subject to loss of nitrate via denitrification. When they are wet and compacted bacteria use the nitrate for energy breaking it down to nitrogen gas and oxygen. Organic matter increased aeration and reduces nitrate loss significantly.

When you have finished reading this article, remember to bring this topic up the next time you visit the coffee shop with your fellow producers. You will note the smug smiles on those growers who never sell baled straw.

About the author

Contributor

Dr. Ieuan Evans is a forensic plant pathologist based in Edmonton, Alta. He can be reached at [email protected]

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