Cereal straw left after harvesting consists of various types of organic substances, and its decomposition products affect the physical, chemical and biological properties of the soil, and thus the growth and yield of plants. In times of growing popularity of carbon and regenerative agriculture, the importance of good management and proper direction of the straw decomposition process in the soil is growing.
Straw – leave it if possible
After harvesting cereals, we have to manage a certain amount of post-harvest residues: on farms engaged in animal production, only the lower parts of the stalks together with the roots and some chaff remain in the field, but on farms without livestock, the mass of post-harvest residues is much greater thanks to the large amount of straw – on average approx. .4-6 t/ha. Together with these amounts, we introduce into the soil several dozen kilograms of nutrients worth several hundred zlotys (calculated to the price of pure ingredients in mineral fertilizers), of which 25-30% will be used by the successor plants in the first year after plowing. nitrogen, 20-25 percent phosphorus and 50 percent potassium. The rest of the ingredients are released over the next few years. Harvest residues are also a source of significant amounts of organic matter (reproduction coefficient of soil organic matter for 1 t of straw: +0.18-0.21), which improves the physical, chemical and biological properties of the soil. In conservation tillage, where part of the crop residue remains on the field surface, straw provides additional benefits – protection against erosion and limiting water losses from the soil. In the new CAP, leaving straw in the field is also a chance to obtain larger subsidies – the practice "mixing straw with soil" in the eco-scheme "carbon farming and nutrient management" is paid approximately PLN 200/ha.
