Difference between Pre-sowing compaction and after sowing compaction

Pre-sowing compaction

• It is mainly to treat the soil before the sowing operation. It can compact the tillage layer soil, eliminate large clods and pores, and make the soil surface smoother. For example, on the land after autumn plowing, after the alternation of freezing and thawing in winter, the soil may become loose. Pre-sowing compaction can restore the soil to a compact state suitable for sowing and create a stable basic environment for seed placement.

Post-sowing compaction

• It is an operation performed after the seeds are sown in the soil. It is to compact the soil around the seeds when the seeds are already in the soil, so that the seeds are in close contact with the soil, ensuring that the seeds have a good soil environment during the germination process. For example, after wheat is sown, compaction can enable wheat seeds to better absorb moisture in the soil, which is conducive to seed germination.

Pre-sowing compaction

• One is to conserve moisture. By compacting the soil, the pores in the soil are reduced and the evaporation rate of soil moisture is reduced. This measure is particularly important in arid and semi-arid areas, as it can effectively maintain moisture in the soil and reserve enough moisture for seed germination. Second, it facilitates sowing operations. A flat and compacted soil surface allows the seeder to work better and ensure consistency in sowing depth. For example, when finely sowing vegetable seeds, the soil compacted before sowing allows the seeder’s furrow opener to accurately control the sowing depth and make the seeds more evenly distributed.

Post-sowing compaction

• Its core purpose is to promote seed germination. When the seeds fit tightly to the soil, they can absorb moisture from the soil more quickly and accelerate the germination process of the seeds. At the same time, it can also fix the position of the seeds to prevent them from shifting when watering or being slightly disturbed by the outside world. Taking corn sowing as an example, post-sowing compaction can keep the corn seeds in the right position in the soil, preventing the seeds from being exposed to the soil surface or shifting to a position that is not conducive to germination due to factors such as wind or irrigation.

Pre-sowing compaction

• It will reduce the aeration of the soil to a certain extent. Because it makes the soil compact and reduces the number of soil pores, especially large pores. However, this effect is usually temporary, and under reasonable suppression, it will not cause serious ventilation obstacles to seed germination and subsequent crop growth. Moreover, after sowing, as the seeds germinate and the roots grow, the soil structure will gradually improve.

Post-sowing compaction

• The effect on soil aeration is relatively small. Because it mainly compacts the soil locally around the seeds, and the root activity after seed germination can also regulate the soil aeration around the seeds to a certain extent. After suppression after sowing, the soil can still maintain a certain air permeability to meet the oxygen demand of the initial seed germination.

Pre-sowing compaction

• Achieved using implements like rollers, cultipackers, or other compaction tools.

Post-sowing compaction

• Implements like seed rollers or light harrows are used for this purpose.

Pre-sowing compaction

• Overcompaction may limit root penetration and water infiltration.

Post-sowing compaction

• Excessive compaction after sowing may cause crusting on the soil surface, which can hinder seedling emergence.