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Main tillage

Main tillage is deep and continuous tillage performed for a particular crop in a crop rotation, which changes the density of the arable layer and mixes the layers or horizons of the soil.

The basic tillage may consist of general methods, such as plowing or deep loosening, and special – two- or three-level tillage, slitting soil, moling, etc.

Depending on the method of basic processing is subdivided into:

  • mouldboard with full or partial turnover of the layer;
  • non-moldboard loosening without turning the layer;
  • tillage with full or partial mixing of the arable layer.

Plowing

Plowing is a method of main tillage, which ensures turning of the tilled layer layer by at least 135°, loosening and partial mixing of the soil, undercutting the underground part of plants, fertilizers and plant residues. Plowing changes the composition of the arable layer, giving it a loose lumpy structure.

Increased aeration of the soil during plowing increases the activity of soil microflora, part of the seeds, seedlings and vegetative organs of weeds moves to the deeper layers, losing germination or dying off.

Cultural plowing – plowing with ploughs equipped with skimmers, in which the upper and lower parts of the arable layer are simultaneously processed.

The main body of the plough lifts the underlying soil layer, crumbles and overturns it, while covering the reset layer. Turning over the layer allows to cover turf, fertilizers, seeds, vegetative organs of weeds, prevents washout of colloidal particles and nutrients in conditions of excessive moisture.

Plow designs

Ploughs with different bodies are used for plowing: cultural, screw, half-screw, cylindrical, cut-out, with a soil-deepener, with a retractable chisel, disc, etc. Degree of crumbling and turnover of layer depends on plough design, shape of moldboard and speed of movement.

Ploughs with half-screw and screw mouldboards turn the layer more strongly, but crumble it poorly. For this reason they are used on heavy and sodded soils, perennial grasses and virgin lands.

Cylindrical mouldboard crumbles the soil well, but the layer turnover is much less than that of half-screw and cultural mouldboards.

Combined moldboards are a combination of cultural and half-screw moldboards. The most perfect recognized plowing with plows with cultural and combined shape of the moldboard with skimmers.

Cultural mouldboards ploughs provide a good crumbling, layer turnover and embedding of crop residues of old arable land.For better crumbling and turnover, skimmers are installed, which additionally levels the surface, reduces the formation of clumps and reduces weed infestation of fields.

In conditions of irrigated agriculture, mountainous terrain and for better quality of plowing very heavy, sodded soils, special front turnover plows of PF-2A (ПФ-2А) type are used. This type of ploughing is called smooth ploughing.This plough is equipped with two bodies: right- and left-turning, which turn layer by 180 degrees and tilting it in one direction. In mountain conditions ridges and furrows are not created under slope. Additional housing, installed after the main – skimmer, undercuts the bottom ribs of layers and along with the main bodies stacks layers in the furrow. This creates a leveled surface of the field without ridges and furrows.

Disc ploughs are used to till stony soils. These ploughs consist of a number of spherical discs with cutting edges mounted on a common axis.

Ploughs are subdivided into:

  • mounted ploughs (ПЛН-3-35, ПЛН-4-35, ПЛН-5-35, ПОН-5, ПОН-4-35);
  • half-mounted (ПТК-9-35, ШШ-6-35, ПНИ-6-40, ПЛН-6-35);
  • front (ПФ-2А);
  • trailed (ПП-5-35).

Skimmer

Skimmer is installed in the front part of the plough body, which provides undercutting the upper part of the arable layer to a depth of 8-12 cm and a width of 2/3 of the width of the body, dumping it to the bottom of the furrow.

Ploughs with skimmers use when the depth of the arable layer is not less than 20 cm.This is due to the need to embed the top 10-12 cm layer, which is dropped into the furrow, by the underlying layer. It is especially important when incorporating turf. For this reason, soils with a thickness of the arable layer of less than 20 centimeters and homogeneous peatlands plow without skimmers.

The skimmers are not used when incorporating organic and green manure, or when it is necessary to mix them with the soil during the doubling of fallow, i.e. summer ploughing. 

Technological features of plowing

The depth of plowing is determined by zonal features, the thickness of the arable layer and soil type, the features of the crop, as well as the depth of the main tillage for the previous crops, weed infestation.

Plowing depending on the depth is subdivided into:

  • shallow – less than 20 cm,
  • normal – 20-23 cm,
  • deep – 24-40 cm,
  • plantation – more than 40 cm.

Sod-podzolic soils are cultivated to a depth of 20-22 cm, well-cultivated and gray forest – to a depth of 26-28 cm, chernozem soils for row crops is plowed to a depth of 28-32 cm.

The timing of plowing depends on soil and climatic conditions, soil moisture and cultivated crops. Autumn tillage for spring crops is carried out after harvesting of predecessors, spring tillage is carried out at physical ripeness. Winter crops are tilled 2-3 weeks before sowing.

On stony soils, plough bodies are fitted with a trashboard that cuts the corner of the layer during its movement on the mouldboard.

Non-moldboard tillage

Non-moldboard tillage is a method of main tillage, which consists in loosening the soil without turning it around. It is widely used in conditions of insufficient moisture and in the treatment of soils prone to wind erosion. Non-moldboard tillage allows to cut the weeds and loosen the soil by leaving up to 50% of the stubble on the field surface, which retains the snow and decreases the wind speed in the surface layer by 1,5-2 times.

Frost penetration depth of soils cultivated with non-moldboard implements is less, which contributes to its earlier thawing in spring. Melt water is better absorbed by the soil, its runoff decreases, and water reserves in the soil increase by 1.5-2 times in comparison with the mouldboard tillage.

Deep non-moldboard loosening at 25-27 cm is carried out during autumn tillage in bare fallows, for preplanting loosening for potatoes, row crops and other crops. It is carried out by non-moldboard ploughs of T.S. Maltsev design, non-moldboard tools paraplau, ploughs with removed mouldboards, ploughs with SibIME tines, ploughs-deep loosening ploughs.

In Trans-Urals, the system of non-moldboard tillage developed by T.S. Maltsev (Shadrinsk Agricultural Experimental Station, Kurgan Region) has been widely used. It excludes plowing with overturning the layer. Deep non-moldboard loosening is carried out to a depth of 35-40 cm once every 3-5 years, combining it with annual shallow tillage: husking or discing to a depth of 10-12 cm. The top layer of soil in such a system does not move, enriched with organic matter of plant residues of annual crops.

Non-moldboard tillage worsens the phytosanitary state of the soil: seeds and vegetative organs of weed reproduction, pathogens of diseases are accumulated.

Chiseling

Chiseling is a method of main tillage with chisel tools, which provides loosening and partial mixing. Chiseling is used for continuous deep loosening without overturning the layer in the care of fallows, for crops of continuous sowing and tilled crops, for deepening and cultivation of the arable layer, for example, podzolic and saline soils. Loosening depth is 20 to 40 cm.

Chiseling allows loosening the plough pan and compacted layers, which facilitates penetration into deeper layers of water, air and plant roots. Therefore, it is used on heavy and saline soils during leaching and moisture-accumulating irrigation. This method is effective for deep loosening before planting in root crops, potatoes, and forage crops, especially on heavy and easily swamped soils.

For chiseling plows are used ПЧ-2,5, ПЧ-4,5, which are equipped with devices for ridge levelling ПСТ-2,5 and ПСТ-4,5.

Chiseling allows you to increase the yield of crops by 15-20%.

Flat-cutting (subsurface tillers)

Flat-cutting (subsurface tillers) tillage is a method of non-moldboard tillage with the flat-cutting tools saving up to 80-90% of the crop residue on the field surface, providing loosening of the soil to a depth of 8 to 30 cm with cropping of weeds. It is mostly used in the areas of wind erosion and in dry conditions, in the system of winter and spring crops pre-sowing tillage, during the care of bare and strip fallows.

The stubble left after ploughing reduces by 2 times the wind speed in the surface layer, decreases the intensity of summer moisture evaporation, contributes to snow retention, especially in years with insufficient autumn and winter precipitation. Yield increase of grain crops with flat-cutting in such conditions is from 0.2 to 0.4 t/ha.

The depth and number of flat-cutting tillage depends on soil and weather conditions, and field weediness. For deep (16-30 cm) flat-cutting tillage use subsurface (flat-cut) deep tillers, such as КПГ-250А, КПТ-2-150, ПГ-3-5, ПГ-3-100. For shallow (7-16 cm) – flat-cut cultivators КПШ-5, КПШ-9, КПШ-11.

For application of granulated mineral fertilizers during flat-cutting, flat-cut deep tillers of КПГ-2,2 type with special fertilizer devices are used. Mulching layer on the surface of the soil and a good crumbling are created by rod cultivators type КШ-3,6. Mulching layer helps to reduce the risk of wind erosion. These cultivators are used in preparation of the field for sowing winter and spring crops, as well as for continuous loosening of the soil during the care of fallow lands.

Flat-cutting tillage, despite its high soil-protecting function and lower energy consumption as compared with mouldboard tillage, worsens the phytosanitary condition of the soil. Therefore, in crop rotations it is combined with mouldboard tillage, introduction of bare fallows in crop rotations and herbicides application.

Rotary tillage

Rotary tillage (milling) is a method of basic soil cultivation with the use of milling cutters, providing intensive loosening and thorough mixing. One pass of the rotary tillage machine allows to prepare the soil qualitatively for sowing, so milling can replace plowing, cultivation and other methods of loosening.

As a rule, it is used on deeply sodded and peaty soils to accelerate mineralization processes.

The milling unit is a drum with spring tines and knives of different shapes. The drum rotates in the opposite direction to the machine’s movement, with the tines cutting into the peat or turf and throwing them back in small pieces, where they hit the protective grid and strongly crumble without forming clumps. Conventional plowing does not allow for such rapid soil breaking.

However, rotary tillage strongly disperses the soil, so after one or two tillage milling peaty and sodded soils switch to plowing with a plow with skimmers. Milling is also used in the radical improvement of meadows and pastures.

Rotary tillage depth for root crops, potatoes and vegetable crops is 15-20 cm for cereals – 8-12 cm. Milling is an effective method for inter-row cultivation of orchards, berries and row crops.With the help of special devices for milling, ridges can be cut.


Rotary tillage is combined with other methods: the application of fertilizers, herbicides, seeding, leveling and rolling the soil surface. To do this, use a combined seeding units, such as for grain crops КА-3,6, КА-7,2, which is a combination of a milling machine and a grain seeder, КФС-3,6 and others. Milling machines can be garden (ФПШ-200, ФСН-0,9A), field (КФГ-3,6, КФ-5,4), swamp (ФБН-2, ФБН-1,5), etc.

Rotary tillage increases the field germination of seeds, for example, cereals by 15-25%. Milling the over-watered soil before sowing leads to its swamping, which reduces the field germination and yield. Therefore, it is desirable to use this method in dry years.

Long-term application of milling in field crop rotations increases the weed infestation, especially root-shoot and rhizomatous weeds.

Organization of tillage in the field

The organization of work during basic tillage in the field includes:

  • field preparation,
  • determining the direction of plowing,
  • choice of method of movement and work of the unit when plowing the paddock.

Preparation consists of:

  • clearing the field of stones, straw, plant residues;
  • leveling the surface;
  • dividing the field into paddocks (sections);
  • beating off of turn lanes;
  • plowing control furrows and piled ridges.

Determining the direction of plowing

The direction and method of machine movement depends on the size, configuration of the field, length of movement, slope and other conditions. On simple slopes, plowing is carried out in a perpendicular direction to the slope runoff. On difficult slopes – along the contours, the so-called contour plowing. On leveled fields it is carried out in the direction perpendicular to the previous plowing. In conditions of risk of wind erosion – in perpendicular to the direction of prevailing winds. Under conditions of excessive moisture at a slope up to 1-2° of the field, plowing is carried out along the slope, at a higher slope for more uniform drainage of excessive water – along the field diagonal.

Paddocks

Before tillage, the field is divided into paddocks (sections) with parallel sides, ensuring straight motion of the machine. The strip of the first pass is marked with milestones (stakes).

The width of the paddock depends on the length of travel, the method of machine travel and the number of bodies on the plow. For this purpose, reference data or a chart is used.

Dimensions of turn lanes for turning aggregates:

  • for МТЗ-80, МТЗ-82 tractors with three-hull plow (small tractors) – 0-12 m;
  • for ДТ-75, Т-74 with four-hulled plough (for medium-sized tractors) – 12-15 m;
  • for Т-150К, К-701 (for large, heavy tractors) – 24-30 m.

The piled ridge is plowed on all odd paddocks. As a rule, it is performed by plowing in three passes. During the first pass, the plough is adjusted so that the first body goes on the surface of the soil, and the last one plows to a predetermined depth. At the second pass all the plough bodies are set to the set depth and lead it in such a way that the first body walked on the penultimate one’s trail, partially filling in the open furrow at the first pass. During the third pass a low piled ridge is formed in accordance with the requirements.

The way of movement of machines

When plowing the field, the following methods of machine movement are most commonly used:

  • looping with alternation of paddocks in the pile and in the slump;
  • combined loopless;
  • circular without paddocks.

When starting plowing from the middle of the paddock, a piled ridge is formed in the middle of the paddock and furrows are formed along the edges. On the contrary, when starting plowing from the edges, a rutting furrow is formed in the middle of the paddock. When paddocks alternate between piled and slumped, the number of piled ridges and slump furrows in the field decreases.

For short driving lengths, a combined no-loop method is used whereby the first paddock is plowed into a slumped area as long as a no-loop turn is possible, the remainder of the paddock is plowed together with the adjacent paddock.

Loop plowing scheme
Scheme of paddock loop plowing with alternation of paddocks in the piled and in slumped:
I-IV - numbers of paddocks, 1-8 - race numbers, C - width of the paddocks

On levelled fields of rectangular or square shape with an area of at least 50 hectares the circular method is used without corrals. Plowing in this method is carried out in a circle, starting from the middle of the field to the periphery and vice versa. In the center of the field form a corral in the piled. Then at a width of corral 30-40 m it is ploughed in a circle with a left turn in the corners.

Circular method without paddocks allows to provide a smoothed surface of the field without piled ridges and slump furrows, increase productivity of the unit and reduce fuel consumption.Limitation of this method is complexity of field marking and uneven wear of machinery with constant left turn.

Sources

Farming. Textbook for universities / G.I. Bazdyrev, V.G. Loshakov, A.I. Puponin et al. – Moscow: Publishing House “Kolos”, 2000. – 551 с.

Fundamentals of agricultural production technology. Farming and crop production. Edited by V.S. Niklyaev. – Moscow: Bylina, 2000. – 555 с.

Fundamentals of Agronomy: Tutorial/Y.V. Evtefeev, G.M. Kazantsev. – M.: FORUM, 2013. – 368 p.: ill.