Planning a tillage system within the crop rotation of an agricultural enterprise

How to plan a soil tillage system in crop rotation

An effective Tillage system soil" system of soil tillage cannot be built without a rational crop rotation established on the farm. All technological operations in a specific field must be coordinated with the agricultural practices of preceding crops and alternated annually. The main guide for an agronomist should be the recommendations of local scientific institutions, cultivar testing stations, and the results of their own field trials.

Example of a soil tillage system in crop rotation

Below is a scheme of soil tillage for field crop rotation in the northern zone. The rotation includes the following crops:

• Corn for silage
• Corn for grain

• Stubble disking — from 6–8 cm
• Ploughing for sugar beet — 30–32 cm
• Pre-sowing cultivation — no deeper than seed placement

Field 1. Spring peas after winter wheat

After harvesting the predecessor, perform disking to a depth of 8–10 cm to undercut, shred, and better incorporate stubble during ploughing. Perform primary tillage with a plough with a jointer at 20–22 cm or with a stubble plough (sweep plough) to the same depth. Include a heavy drag, disk battery, or roller in the ploughing unit — this will improve the crumbling of dry and cloddy soil. If soil moisture is optimal and the soil crumbles well, harrowing may be sufficient.

Field 2. Winter wheat after spring peas

Use soil-protecting mulch tillage. Start by shredding crop residues with disk implements in several passes. As weeds emerge, treat the field with a sweep cultivator to the depth of best crumbling or perform surface disking in several passes. Before sowing, treat the soil with disk implements and cultivators.

Field 3. Sugar beet after winter wheat

Immediately after harvesting the predecessor, start the technological cycle of soil preparation:

1. Perform disk stubble tillage to a depth of at least 6–8 cm. In case of mass weed emergence, perform a second stubble tillage. If the field is infested with perennial species, work with a stubble plough or sweep plough at 12–14 cm, or perform shallow ploughing at 16–20 cm with harrows or rollers.
2. Perform autumn ploughing with ploughs with jointers to a depth of 30–32 cm after weed regrowth following the second stubble tillage (no later than the end of September – October). If the field is free of perennials, deep autumn ploughing can be done earlier — in August or early September after the first stubble tillage.
3. Treat early autumn-ploughed soil with cultivators as weeds emerge. In case of heavy infestation or compaction, reploughing to 12–16 cm is allowed, but preference should be given to regular cultivation.

Field 4. Spring cereals after sugar beet

After completing the beet harvest, perform autumn ploughing to a depth of 20–22 cm. Surface tillage of the soil with sweep or disk implements is also possible.

Field 5. Winter wheat after cereal crops

Immediately after harvesting the predecessor, plough the field with a combined unit consisting of a plough, disk battery (or needle disks), roller, and drag to the depth of best crumbling. If it is impossible to plough the field immediately or the soil forms large clods, perform stubble tillage to 6–8 cm first. Maintain the field-in-fallow using harrow-cultivators or sweep cultivators as weeds and volunteer crops emerge. The depth of pre-sowing tillage should not exceed the Seeding depth seeds">seeding depth.

Field 6. Corn for silage after winter wheat

Soil-protecting tillage is required for this field:

Soil-protecting mulch tillage in crop rotation

To protect the soil from erosion and preserve productive moisture after cereal predecessors, a system of non-inversion loosening is applied. It allows for creating a dense mulch layer of plant residues on the field surface. When preparing soil for winter and row crops in this system, a strict sequence of operations is observed.

1. Immediately after cereal harvest — treatment with a needle harrow to provoke weed emergence and break the crust.
2. As weeds grow — cultivation with a sweep plough to a depth of 8–12 cm.
3. During mass appearance of root-sucker weed rosettes — chemical weeding with herbicides.
4. At the end of autumn — deep non-inversion loosening to 27 cm with a deep-ripping sweep plough.

For the remaining fields of the crop rotation, technological solutions depend on the biological characteristics of the crops and the preceding crops:

• Depth of autumn non-moldboard loosening — 27 cm
• Depth of sweep tillage for sunflower — 22–25 cm
• Depth of the first sweep cultivation — 8–12 cm

Primary tillage in the central zone

In the central zone of the region, a combined system is used for crop rotations involving grain and silage maize, sugar beet, and a specialized field for perennial grasses. It combines moldboard ploughing using a plough with a jointer and shallow disk tillage. The scheme takes into account the degree of weed infestation and the specific relief features of the terrain.

For the specialized perennial grass field and subsequent crops in the rotation, the following rotation scheme has been adopted:

• Field 1. First-year alfalfa
• Field 2. Second-year alfalfa
• Field 3. Winter wheat after perennial grasses
• Grain maize

Tillage schemes by crop rotation fields

Each field in the crop rotation requires an individual approach to tillage. The depth of ploughing and the choice of implements depend on the preceding crop, soil type, and the level of weed infestation in a specific area. Proper selection of equipment helps to conserve soil moisture and effectively break down the furrow slice.

• Ploughing after alfalfa cut — 22–25 cm
• Ploughing for wheat after wheat — 20–25 cm
• Autumn ploughing for soybean — 25–27 cm
• Pre-ploughing stubble cultivation for wheat — 8–10 cm
• Number of weed count quadrats — more than 20 units

Field 4. Winter wheat after winter wheat. Immediately after harvesting the preceding crop, the stubble is ploughed to 20–25 cm with a combined ploughing unit. Depending on the quality of soil crumbling, the plough is equipped with disks, rotary harrows, or tines. Until autumn sowing, the ploughed field is managed using a green fallow system.

Fields 5 and 8. Soybean after winter wheat. Soil preparation for soybean includes a multi-stage system of stubble cultivation and deep autumn ploughing. On grey forest and other soils with a thin humus layer, the tillage depth is adjusted according to the depth of the arable horizon. If the subsoil is highly compacted (as in self-mulching chernozems), subsoilers must be used.

1. Stubble cultivation with a disk implement to a depth of 6–8 cm immediately after wheat harvesting.
2. Second disk cultivation after mass emergence of weeds.
3. Full-body cultivation to a depth of 12–16 cm or shallow ploughing with harrowing and packing (if root-sprouting weeds predominate in the field).
4. Primary autumn ploughing in October to a depth of 25–27 cm.

Field 6. Corn after soybean. After soybean harvest, the field is treated with a disk cultivator to incorporate crop residues. This is followed by autumn ploughing with a plough equipped with a jointer to a depth of 22–25 cm. On soils with an over-compacted subsoil (self-mulching chernozems, grey forest soils), ploughing is combined with the use of subsoilers.

Fields 7 and 9. Winter wheat after corn and soybean. Immediately after harvesting the preceding crop, pre-ploughing disk cultivation is carried out to a depth of 8–10 cm. Ploughing is performed to the depth that ensures the best soil crumbling (20–25 cm) using a unit equipped with disks, a roller, or a tine harrow. If necessary, additional field cultivation is performed.

Weed control and field mapping

A pre-developed soil tillage plan should not be applied blindly. Weed infestation on each field changes dynamically, so it is important for an agronomist to adjust the technology in a timely manner according to the species composition of weeds. A timely reaction to the appearance of weeds helps save the herbicide budget and prevent harvest losses.

Weed infestation in crops can be assessed using two methods: visual and quantitative. The visual assessment uses a point scale that divides weed infestation into four degrees:

• 1 point — weeds are found sporadically (light infestation);
• 2 points — weeds account for no more than a quarter of the total plant stand (moderate infestation);
• 3 points — the number of weeds is close to the density of the crop plants (heavy infestation);
• 4 points — weeds predominate in the crop (very heavy infestation).

For precise planning, a quantitative method is used on one-square-meter sampling quadrats. The number of such quadrats depends on the field size and visual infestation. In case of heavy or very heavy infestation, more than 20 frames are placed in the field. Data for each square meter is recorded in a logbook separately by species, and weed clusters are marked on a draft map.

At the end of the survey, the average indicator for each species is calculated, and the type of field infestation is determined. The type of infestation refers to a specific combination of weeds that requires a unified set of measures for control. The following types of infestation are distinguished:

• root-sprouting;
• rhizomatous;
• annual/biennial;
• mixed (root-sprouting-rhizomatous, root-sprouting-annual, root-sprouting-rhizomatous-annual).

Based on the obtained data, a final weed map of the crop rotation fields is compiled. Types of weed associations are indicated on it by color or hatching, and the degree of infestation of each field is shown using pie charts with sectors proportional to the quantity of weeds of a specific species. This allows for targeted selection of tillage methods according to the problem in each specific area.

Before choosing a tillage method, conduct a reconnaissance survey of the field. A weed map provides a general picture, but in practice, it is important to assess the real situation at the current moment. Walk through the plot, determine the species composition of the weeds, their quantity, and their growth stage. Pay special attention to clusters of weed spread in order to differentiate protection measures.

1. Perform a visual inspection of the field to assess the weed species composition and growth stage.
2. Map weed infestation hotspots for differentiated tillage.
3. Determine potential soil weediness by washing soil samples for the presence of weed seed.

• Lower limit of chernozem ripeness — 21–22% humidity
• Upper limit of chernozem ripeness — 24–27% humidity
• Start of soil adhesion to metal — 28–29% humidity
• Critical soil bulk density — 1.3–1.35 g/cm³

Assessment of soil moisture and bulk density in the field

Qualitative indicators of the tilled layer directly determine the choice of implements, tillage depth, composition of machinery units, and equipment speed. In field conditions, chernozem humidity can be quickly determined by the organoleptic method. To do this, dig a pit to the depth of the intended tillage. Take soil samples from different layers and evaluate their physical state.

The bulk density of the tilled layer is determined on the vertical wall of the test pit. If the density exceeds optimal values at low humidity, a smooth, shiny surface forms on the cut. Operating under such conditions will inevitably lead to negative consequences for the field structure.