The harvest is just around the corner. Therefore, it is necessary to carefully consider how to manage crop residues. Cereal or rapeseed straw is a fertilizer rich in nutrients and organic matter. How to cultivate stubble? Should cover crops be sown? We invite you to read our article.
The fertilizing value of straw
Cereal straw is very rich in nutrients. Well-managed crop residues allow you to reduce fertilization for the next crop. What is the fertilizer value of cereal straw? It is assumed that one ton of winter wheat grain produces 0.8 to 1.2 tons of straw. This value may vary depending on the variety, growing conditions, and soil type. On average, one ton of wheat straw contains about 5 kg of nitrogen, 2.4 kg of phosphorus, 12.4 kg of potassium, 1.4 kg of magnesium, 3.4 kg of calcium, and a significant amount of micronutrients.
The situation is slightly different with rapeseed straw, as it is much richer in nutrients than cereal straw. On average, one ton of rapeseed straw contains about 7 kg of nitrogen, 3 kg of phosphorus, 20 kg of potassium, 13 kg of magnesium, and 15.6 kg of calcium + a significant amount of micronutrients. Considering the amount of nutrients left in the soil by rapeseed, it can be safely said that this plant creates a very good growing environment, e.g. for winter wheat.
It is worth noting that cereal and rapeseed straw also contain a very large amount of organic matter, which helps build humus in the soil.
Cover crops as an additional source of organic matter
To further enrich the soil with organic matter, it is a very good idea to sow a cover crop, a stubble intercrop. Cover crops should be sown as soon as possible after harvest to ensure the longest possible vegetation period.
Plants that produce a large amount of green mass in a short time, such as oil radish, mustard, buckwheat, and phacelia, are best suited for this purpose. Legumes, such as lupine, peas, vetch, and field beans, are also a very good choice. In addition to producing a large amount of green mass, these plants have the ability to fix atmospheric nitrogen, which means that they “collect” nitrogen from the air and introduce it into the soil. The nitrogen accumulated in this way can be successfully used by the plant sown in the main crop.
Shallow stubble cultivation – machinery
Shallow stubble cultivation is best carried out in two stages. The first stage involves cultivating the soil as shallowly as possible and breaking up the stubble. The aim is to stimulate self-seeding and weed seedlings to germinate. This treatment is best carried out immediately after harvesting.
The second stage of shallow cultivation involves shallow mixing of the stubble again, together with sowing a cover crop. We recommend a break of about a week between the first and second cultivation. The ideal machine for this purpose is the TITANUM STANDARD or TITANUM HEAVY short disc harrow and the VIBROCUT spring-mounted disc harrow. Shallow stubble cultivation with a disc harrow should be carried out at a depth of about 10 cm at a working speed of 10-12 km/h. Another machine that is ideal for shallow post-harvest cultivation is the RAPTOR PLUS stubble cultivator. This machine is equipped with two rows of tines on spring protection with side cutters, a row of raking discs, and a finishing roller. The working depth of the stubble cultivator should be between 12 and 15 cm, maintaining a working speed of approximately 10 kg/h. These operating parameters will allow the stubble to be cut thoroughly and the residues to be mixed with the soil.
In the case of rapeseed stubble, the MULCZER PWN, i.e. a double knife roller, may be a good choice. Thanks to the use of two rollers equipped with spirally mounted cutting knives, this machine will perfectly cope with high rapeseed stubble, breaking and effectively destroying hard stems. This treatment significantly accelerates the decomposition of crop residues and the release of nutrients. The working speed of the mulcher should be around 18 km/h.
