Sowing directly into the stubble
Direct seeding or no-till system is also known as no-till, zero-till, zero-tillage, slot seeding, mulch system, stubble system, organic system. Direct sowing involves sowing the seed directly into the stubble of the pre-seeded crop without any prior tillage, except for opening a very narrow strip (slot) of only a few centimetres at the same time as sowing, to allow the seed to enter the soil.
For direct seeding, special seeding machines are needed to ensure that the slot is opened and the seeds are placed in the soil at the same time. Ploughing, discing, harrowing, mechanical harrowing are no longer carried out, as the soil surface after sowing is almost completely covered with plant residues. Weed control, including weeds, is carried out only by chemical methods, using herbicides, and/or biological methods if possible.
Direct seeding into stubble is considered the most conservative tillage system, as it most closely approximates the natural soil establishment underneath perennials.
The main advantages of the direct seeding system are:
- it significantly reduces erosion risk and increases soil water reserve, due to its more compact laydown and the large amount of plant debris on the surface, which it practically covers almost entirely, being most useful on sloping soils;
- reducing erosional processes contributes to reducing the risk of pollution of downstream surface waters;
- improvement of the water and air movement regime in the soil, by increasing soil permeability to water and air as a direct consequence of the change in macropore configuration;
- increasing the amount of organic matter on the surface improves the structural characteristics of the soil;
- stimulating biological activity, especially that of macrofauna and thereby increasing soil macroporosity and improving aeration processes;
- reduction in soil temperature, and especially large temperature variations in the top 10 cm during hot periods of the year;
- reduced risk of anthropogenic compaction due to fewer inputs on the land, as well as the presence of plant debris on the soil surface acting as a buffer layer;
- improving the workability and trafficability characteristics of the sowing and harvesting period, so that they can be carried out within a wider range of humidity (compared to the conventional system) and also facilitating harvesting in wetter periods or climates;
- long-term increase in soil fertility as a result of improved physical, chemical and biological condition and reduced risk of degradation through destructuring, erosion and compaction;
- The yield obtained is frequently almost equal to, or at most 5-10% less than that obtained by the conventional system, and in dry years it can be even higher.
Among the limitations of the direct seeding system are the following:
- requires a fairly large investment in a new agricultural machinery system, or the modification and adaptation of the existing one, so that sowing is carried out as close to optimal conditions as possible, i.e. the seed is introduced into the soil at an appropriate depth and as evenly as possible, and contact with the soil is as good as possible;
- for effective control of all weeds there is a strong dependence on herbicides as there is no possibility of mechanical control;
- Disease and pest control is difficult as chemicals cannot be incorporated into the soil and the retention of large amounts of plant debris on the soil surface creates a favourable environment for disease and pest proliferation;
- Regular pest and disease control is necessary and seed treatment is absolutely mandatory at sowing;
- In general, the quantities of pesticides used are higher compared to the conventional system;
- Mineral fertilisers that have a low solubility, such as organic fertilisers and soil improvers, are difficult to use because they cannot be incorporated into the soil;
- Long-term sowing with contrasting plants is regarded as a decisive factor in the success of direct sowing;
- Seed germination, like seed sprouting, can be slow and uneven, so this system is not recommended in cold springs;
- late spring frosts can affect autumn crops to a greater extent than the conventional system due to the mulch layer and lower soil radiation;
- the direct seeding system is suitable for coarse and medium textured soils, which are loose and well drained, and unsuitable on fine textured soils with poor drainage, on soils that are already heavily degraded by erosion or compaction.
Source: cotidianulagricol.ro
Last Updated on 17 November 2023