Post-sowing soil cultivation

Rolling

Rolling is performed simultaneously with sowing or after it, before emergence in dry weather, especially on loose soils. Rolling compacts the soil of the seed layer and improves contact of seeds with the solid phase of the soil. Excessive looseness of the seed layer prevents water uptake by seeds; the top layer dries out quickly, which reduces field germination of seeds and delays emergence. Lack of moisture during tillering node formation negatively affects the formation of the secondary root system in cereal plants.

Post-sowing rolling also reduces air content in the soil; improves its warming, which ensures earlier emergence. It is especially effective on crops of grain legumes, as well as cereals and grasses when sown in dry soil. Post-sowing rolling of row crops increases field germination and accelerates emergence.

Rolling has negative aspects: continuous rolling of soil also stimulates the germination of seeds of weeds; soil compaction reduces its water permeability and absorption of atmospheric precipitation, and upon drying a soil crust forms. Therefore, with sufficient soil moisture and good pre-sowing cultivation, rolling is not advisable. When sowing small-seeded crops, rolling is combined with sowing.

To avoid continuous rolling, grain stubble seeders SZS-2.1, SZP-3.6A are used, equipped with special packer wheels that compact the soil only in the sowing rows and close the rows well. As a result, a dense seedbed is created and field germination of seeds increases.

Post-sowing rolling is carried out with smooth rollers of the ZKVG-1.4, SKG-2 type with additional loosening of the surface by light seeding harrows or drags. This creates a loose layer on the surface and prevents the formation of a soil crust. In leguminous crops, which carry cotyledons to the surface, soil crust hinders emergence. For this reason, rolling is carried out during pre-sowing treatment or combined with sowing.

In the steppe arid zone, post-sowing rolling of the soil is carried out, whereas in regions with sufficient moisture, pre-sowing rolling is used.

Harrowing

Pre-emergence harrowing is used to destroy soil crust, which impairs gas exchange between soil and atmosphere and hinders emergence. A hard surface crust increases moisture evaporation, reduces water and air permeability, and worsens conditions for seed germination and subsequent plant growth. It forms after heavy precipitation on poorly structured heavy and solonetzic soils as they dry.

The soil crust is loosened with light tine, wire, or mesh harrows before emergence. On cereal crops, harrowing is carried out before the crop reaches the awl stage; in beet fields, when the beet seedling is 1 cm long. It is important that the harrow tines do not reach the germinating seeds and do not damage the seedlings. For these purposes, light rotary hoes are used.

During post-sowing harrowing, up to 70–80% of seedlings of annual weeds in the “white thread” stage are destroyed.

Harrowing is especially effective in row crops with a long period from sowing (planting) to crop emergence, for example, in potato plantings.

Post-emergence harrowing is used to loosen the soil between plants, destroy crust, and kill weed seedlings. Harrowing improves the air regime of the topsoil and accelerates microbiological processes. Timely harrowing of ripe soil creates a mulching layer that prevents moisture evaporation and protects the soil from overheating.

The timing of harrowing depends on the condition of the soil and crops, as well as weather conditions. Spring cereal and winter crop sowings are harrowed in the tillering phase at physical ripeness, when the plants have rooted well. In beet fields, harrowing is carried out in the phase of the first pair of true leaves; on maize crops — in the 3–4 leaf phase. To reduce plant damage, treatment is carried out at low speeds of no more than 4–5 km/h, and on the harrows the passive side of the tine should be installed in the direction of movement of the unit. On solid-seeded crops, harrowing is performed across the rows or diagonally across the field.

Seedlings of grain legumes, potatoes, beets, and other crops are harrowed in the afternoon, when plant turgor weakens and they are less damaged.

Inter-row treatments

Inter-row cultivation in row crops is intended to loosen compacted soil, destroy soil crust, and cut weed seedlings. Periodic loosening and leveling of the soil in the inter-row spaces promotes aeration and water permeability of the soil, water supply to plants, activates microorganism activity, and increases nutrient availability.

The timing of inter-row loosening is determined depending on soil compaction in the rows, formation of soil crust, or the time of weed seedling emergence.

In wet years with frequent precipitation, the soil becomes more compacted, so inter-row loosening is carried out more often than in dry years.

The depth of inter-row loosening is determined by the plant growth phase, soil moisture, and degree of compaction. The first loosening in crops of sugar beet, fodder beet, maize, and other row crops is carried out when seedlings appear and plant rows become visible. It is called sharovka and is performed to a depth of 4–5 cm. Sharovka is carried out to destroy weed seedlings, loosen soil crust, conserve moisture, and accelerate plant growth. It is performed with row cultivators, for example, USMK-5.4A, KRD-5.4, KRN-4.2, KRN-5.6, equipped with single- and double-sided flat-cutting razor shares. To prevent damage to the root system of plants in row crops, a protective zone 10–15 cm wide is left in the rows. To prevent plant damage and covering them with soil during cultivation, the cultivators are equipped with protective disks on both sides of the row.

To destroy weeds and loosen soil in the protective zone of the rows, additional working parts are installed on row cultivators: weeding harrows, paired needle rotary disks, or rotary harrows of the BRU-0.7 type; for hilling soil to plants — moldboard shares or disk coverers-hillers.

The depth of the second cultivation is increased to 8–10 cm; all subsequent ones are reduced to 6–8 cm and 4–5 cm to prevent damage to the plant root system and soil drying. The protective zone near the row is increased to 15–20 cm.

For deeper loosening in the inter-row spaces, row cultivators are equipped with loosening chisel-shaped tines, fertilizer knives, sweep shares, and moldboard shares. For better soil leveling, they are supplemented with needle rotary disks or weeding harrows.

In band sowings, the soil is loosened in the wide inter-row spaces between the bands.

The use of herbicides, including narrow-spectrum ones, allows reducing the number of inter-row cultivations in row crops to 1–2.

Bunch thinning

When growing sugar beet, fodder beet, and some vegetable crops, inter-row soil cultivation is combined with cutting bunches consisting of several plants at equal distances from each other in the rows. Such thinning is called bunch thinning and is usually carried out with row cultivators, for example, USMK-5.4A, equipped with razor shares, and is performed across the sowing rows.

Bunch thinning of beet is carried out in the phase of one or two pairs of true leaves. The most common cutting patterns are 27 and 30 cm with bunch lengths of 18 and 15 cm. Mechanical cross-thinning of crops allows destroying germinating weeds while ensuring a stand density of 5–6 plants per 1 m.

Hilling

When growing potatoes, maize, tomatoes, cabbage, and some other crops, hilling is used.

Hilling is the covering of the base of plant stems with loose moist soil while simultaneously cutting the underground reproductive organs of perennial weeds in the inter-row spaces.

Under conditions of excessive moisture and irrigation, hilling helps prevent excessive waterlogging of the soil, promotes aeration, warming of the soil, and accumulation of available nutrients. During hilling, the lower part of the stems is covered with loose soil, which enhances the formation of adventitious roots in tomatoes and maize, and stolons in potatoes, increasing yield by 10–15%.

Hilling helps protect plants from spring frosts.

In drought or insufficient moisture conditions, hilling is not carried out to avoid additional soil drying.

The number of hillings and their timing are determined depending on biological characteristics, plant height, and weather conditions. Most often it is performed 1–2 times after rain or irrigation when plants are 15–20 cm high, with simultaneous soil loosening. The last hilling is carried out before the foliage closes in the rows. It is carried out with row cultivators of the KON-2.8PM, KON-2.8P, USMK-5.4 type and others, equipped with loosening tines or hillers.

Slotting

In some cases, as a post-sowing treatment, soil slotting is carried out when caring for winter crop and perennial grass sowings located on sloping lands. Slotting prevents water runoff, soil erosion, and nutrient removal with water, and promotes moisture accumulation in the soil profile.

On winter crop sowings, it is carried out in late autumn when the topsoil is slightly frozen; on perennial grasses, after the second cutting when the soil is dry. It is especially effective in winter crop sowings under which minimal surface tillage was carried out.

For slotting, slotting implements of the ShchN-2-140, ShchN-3-70 type are used, which cut the soil to a depth of 40–50 cm with a distance between slots of 70–140 cm.

References

1. Bazdyrev G. I., Loshakov V. G., Puponin A. I., et al. (2000). Agriculture. Textbook for universities. Moscow: Kolos Publishing House.
2. Evtefeev Yu. V., Kazantsev G. M. (2013). Fundamentals of Agronomy: A Textbook. Moscow: FORUM.