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System of tillage for spring crops

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The system of tillage for spring crops includes the following tillage:

  • summer-autumn;
  • spring (pre-sowing);
  • post-sowing.

Tillage

 

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Tillage

 

Summer-autumn tillage

Summer-autumn (also autumn) tillage – tillage in summer-autumn period for sowing spring crops in the following year. It may include one or more techniques performed in a certain sequence. Methods of autumn tillage depend on soil and climatic conditions: moisture of zone, soil type, granulometric composition, thickness of arable layer, probability of erosion, reaction of crops to tillage depth, preceding crops, weed infestation and other conditions.

Advantages of autumn tillage

Autumn tillage makes it possible to regulate factors limiting crop yields in relation to specific agro-landscape conditions. It affects the structure and regimes of the soil, allows the incorporation of organic and mineral fertilizers, ameliorants, crop residues. Pre-tillage provokes seed germination and weed root cuttings to sprout, subsequent plowing allows to incorporate to a sufficient depth, where they die.

Crop residues and weeds serve as a place of over-wintering pests and pathogens of disease, embedding which at plowing with a plow with a skimmer serves as an effective farming technique control.

Timely autumn tillage reduces soil drying after harvesting early harvested cereal crops and prevents excessive compaction. In absence of vegetative cover soil loses daily in dry weather up to 40 t of water from 1 ha, therefore one of the main tasks of autumn tillage is to prevent soil desiccation. In areas of moderate moisture this hold immediately after harvesting discing of stubble or plowing, in arid steppe areas – surface loosening of needle harrows or shallow flat-cutting tillage with the abandonment of the stubble on the surface. Plowing, as well as other tillage, dried soil leads to the formation of large numbers of clumps, reducing the quality of work and large energy costs.

In arid areas, autumn tillage is aimed at saving water, in the northwestern and western areas – at eliminating excessive moisture.

Autumn tillage has organizational and economic importance by distributing part of the field work from the spring to the fall and provides a better pre-sowing tillage and sowing in optimal agrotechnical terms. A special role in improving soil fertility is played by deepening of the arable layer, which is carried out in the system of autumn tillage.

Depending on previous crops, the degree of weeding of the field and technological properties of the soil, the following types of autumn tillage are distinguished:

  • after continuous-sowing annual crops,
  • after row crops,
  • after perennial grasses,
  • half-fallow tillage.

Technological features

The depth and number of tillage are determined depending on zonal features, crop requirements, soil type and weediness, thickness of the arable layer. On sod-podzolic soils with sufficient moisture as a rule, discing is carried out to a depth of 5-6 cm, plowing – to 20-22 cm on black and chestnut soils – 6-8 cm, and plowing, for example, for row crops – to 28-32 cm. If deep plowing was carried out for the previous crops in the rotation and the weediness of the field is small, deep tillage is carried out again in 2-3 years.

The best period of autumn tillage soils of medium and heavy granulometric composition are summer and autumn of the year preceding the sowing, as it allows a fuller use of water from precipitation. First of all treatment is carried out on weedy fields and soils with heavy granulometric composition.Late terms of treatment and overwatering of the soil leads to poor crumbling and excessive compaction. Soils of light granulometric composition can be cultivated in later autumn terms, as their good aeration accelerates decomposition of organic matter and washout of nutrients.

In areas with sufficient moisture, autumn plowing can be replaced by shallow disc cultivation or loosening by fallow cultivators such as КПЭ-3,8. In areas of wind erosion, it is acceptable not to conduct it or postpone it to the spring. On sloping lands to prevent water erosion, it is combined with slitting, construction of water-retaining barriers, such as ridges, wells, cells, cofferdams, etc.

Zonal peculiarities of autumn tillage

Non-Black Soil Zone

  • Post-harvest stubble tilling (discing) and autumn plowing.
  • Autumn plowing without pre-tillage discing followed by surface tillage.
  • Post-harvest discing of stubble and non-moldboard, chiseled loosening.
  • Small loosening of soil without plowing by disc, polydisk and other tools.

Central Black Earth zone, forest-steppe zone of the Volga region, Western Siberia, Northern Caucasus

  • Early autumn plowing followed by surface tillage.
  • Disc or polydisc and late autumn plowing.
  • Postharvest non-moldboard deep loosening with subsurface (flat-cut) deep tillers, paraplau ploughs, with SibIME tines and subsequent shallow flat-cutting.
  • Moldboard or non-moldboard tillage with water-retaining microrelief.

Forest-steppe and steppe areas prone to wind erosion

  • Post-harvest shallow flat-cutting and deep autumn loosening with subsurface (flat-cut) deep tillers.
  • Post-harvest surface loosening with needle harrows and autumn deep loosening with subsurface (flat-cut) deep tillers.
  • Post-harvest shallow flat-cutting 2-3-times loosening.

Tillage after annual crops of continuous sowing

Features and tasks

Annual crops of continuous sowing, such as winter rye, barley, winter wheat, peas, etc., have early harvesting dates and are removed from the field early. In the absence of vegetation cover, the soil dries out greatly, leading to significant losses of moisture to evaporation. Soil compaction occurs as the soil dries out and the harvesting equipment’s undercarriage systems act. Autumn precipitation is poorly absorbed by compacted soil, which leads to surface runoff and its loss.

The long post-harvest period promotes the growth and reproduction of weeds. Stubble and vegetating weeds left in the field serve as reservoirs for the overwintering of pests and pathogens of disease, creating foci of infection.

Under these conditions, the main task of the system of tillage for spring crops is to prevent soil drying, destruction of vegetating weeds and incorporation of their crumbling seeds into the moist layer.

Discing

The discing allows to cut vegetating weeds, to put fallen seeds into the soil, as well as pests and pathogens of diseases. It allows to reduce soil resistance during plowing by 25-34%, and the resulting mulch layer saves soil moisture from evaporation.

Turfing is most effective in areas with a warm, long post-harvest period.

Zonal features

On soils not at risk of erosion and in areas with a long warm post-harvest period, winter tillage begins with discing of stubble, which is carried out immediately after or simultaneously with the harvesting of crops.

In areas with insufficient moisture the positive effect of discing is manifested in years with sufficient precipitation in late summer, so in these areas more often carry out early plowing with plows with skimmers without discing.

In the steppe regions, where there is a risk of wind erosion, discing is replaced by loosening needle harrows such as БИГ-3А or flat-cut cultivators КПШ-5, КПШ-9 to a depth of 10-12 cm, which cut perennial weeds, while leaving the stubble on the surface of the field. When weeds grow back, the flat-cutting treatment is repeated. Such tillage reduces desiccation and allows for quite effective weed control.

In areas with a short growing season, such as the north-west, north and north-east of the European part of Russia, Western and Eastern Siberia, some areas of Kazakhstan and Trans-Ural, discing is not carried out, as seeds of weeds, crumbled in late summer or autumn, do not have time to germinate before plowing or do not give seedlings before the onset of warm weather the next spring. After harvesting cereal crops in these areas, the field is immediately plowed.

In the southern regions of the forest-steppe and steppe zones with a long warm postharvest period discing is carried out 2-3 times: the first at a depth of 6-7 cm, the second – to a depth of 9 cm and the third – 12 cm with an interval of 2-3 weeks, moving the plowing to a later date. This allows the accumulation of more moisture, better incorporation of crop residues, weed control, and facilitation of subsequent tillage.

Technological features

The depth of discing depends on the degree of weed infestation, species composition of weeds, soil density and moisture. In humid areas with a predominance of annual weeds the depth of discing is 5-6 cm, in arid areas – up to 6-8 cm. When the height of stubble is more than 15 cm because of lodging of cereals, the depth is increased to 10-12 cm.

When weed infestation by rhizomatous weeds, discing is carried out with disk tiller to the depth of occurrence of rhizomes along and across the field: the first trip to the 6-8 cm, the second – 8-10 cm. The second discing is carried out at mass regrowth of weeds. Shredding of rhizomes of perennial weeds stimulates their germination and depletion of nutrients. When young shoots appear, plowing with ploughs with skimmers is carried out.

For discing disc-tiller (topsoil) are used, such as ЛДГ-5А, ЛДГ-10А, ЛДГ-15А, on heavy soils – heavy disc-tiller such as БДТ-3, БДТ-7, БДТ-10. For better loosening and burial of the working tools, the angle of attack of disk disc-tiller increased to 30-35°. The best quality of processing is achieved with the coincidence of discing and plowing directions.

On heavy and compacted soils disc-tiller do not go deep and do not completely cut deep roots of weeds, such as sedge (Sonchus) and pigweed (Cynodon). Therefore the first shallow stubble discing by polydisc-tiller carry out type ППЛ-5-25, ППЛ-10-25 to a depth of 12-16 cm to extract the rhizomes on the surface or replace it with shallow plowing. Secondary discing is carried out by disk tools, which are quite good at shredding rhizomes. Heavy disc-tiller can be used for this purpose. After the regrowth of weeds, plowing is carried out.

To reduce soil drying and better contact with the seeds of weeds, discing is carried out in aggregate with harrows and rollers. According to the data of NGO “Podmoskovje” the field thistle (Cirsium arvense) is eliminated by 77% when discing at the depth of 10 cm with subsequent plowing at the depth of 20-22 cm, while discing at the depth of 14 cm and plowing at 20-22 cm – by 85%.

Autumn plowing

In case of mass germination of weeds, cultural plowing with ploughs with skimmers is carried out. It allows to embed into the soil weeds and their seeds, fertilizers, ameliorants and prepare the soil for early sowing of spring crops. Plowing gives the soil of the arable layer loose lumpy structure, which provides optimal conditions for accumulation and storage of water of fall and winter precipitation.

The advantage of autumn plowing compared with spring plowing is proven in most regions of Russia. Only in conditions of a short post-harvest period, snowy and windy winters it is advisable to postpone plowing as the main method of treatment to the spring. The field not ploughed in autumn in these areas with stubble left behind is less likely to dry out and accumulate more moisture.

Technological features

The timing of autumn plowing depends on the time of harvesting crops, the duration of the warm post-harvest period, soil moisture and the emergence of mass weed growth. For most regions of Russia, early autumn plowing is effective, which provides the most favorable conditions for decomposition of crop residues, organic fertilizers and accumulation of nutrients. According to generalized experimental data, the early period of autumn plowing is September 5 for the north and east of the country, the Central Black Earth zone, Central Black Earth zone and the Mid-Volga region – until September 20, in the south it is carried out even later.

The post-harvest period with temperatures above 10 °C in most of these regions lasts more than one month, which is enough to control weeds.Thus, annual and biennial weeds germinate in 15 to 20 days if there is enough heat and water, while perennial weeds take 23 to 30 days, which often determines the time of autumn plowing. In the North, North-West, East Siberia and other regions with a short growing season, plowing is carried out immediately after harvesting cereals, without prior discing.

Early plowing in the south of Russia in the conditions of the long post-harvest period allows to perform 1-2 additional cultivations or discing before the onset of winter. In dry weather, plowing is carried out with a plow in a unit with a ring-spiked roller, which contributes to moisture conservation and provocation of weed germination.

The depth of autumn plowing is determined depending on the thickness of humus layer, soil type, crop requirements, weed infestation and species composition of weeds.

Early plowing in the south of Russia in the conditions of the long post-harvest period allows to perform 1-2 additional cultivations or husking before the onset of winter. In dry weather, plowing is carried out with a plow in a unit with a ring-spiked roller, which contributes to moisture conservation and provocation of weed germination.

The depth of fall plowing is determined depending on the thickness of humus layer, soil type, crop requirements, weed infestation and species composition of weeds.

For sod-podzolic and gray forest soils with annual weeds for spring crops plowing is carried out to a depth of 16-17 cm for long-term weeds – to 20-22 cm. Plowing for row crops on black and gray forest soils is carried out at 28-32 cm. Deep plowing is effective in areas of excessive moisture, which provides an opportunity to remove moisture from the subsoil layer.

Deep autumn tillage creates excessive looseness of the soil and causes its overwatering, resulting in a delay with the sowing of early spring cereals and reduces yields. Therefore, on soils with excessive moisture plowing is replaced by shallow tillage to a depth of 10-12 cm with heavy disc-tillers or polydisc-tillers. Such tillage is effective for crops of late sowing period, as well as row crops, for which plowing is carried out in spring.

In areas with sufficient moisture, autumn plowing is carried out without harrowing. Ridge plowing reduces compaction of the top layer, contributes to snow retention, protects the soil from deep freezing, in the spring the ridges are better heated. On the contrary, in the steppe arid regions and Eastern Siberia with little snowy winters, plowing is carried out with simultaneous leveling of the surface by harrows and rollers to avoid soil drying. In areas at risk of wind erosion, autumn tillage is carried out with subsurface (flat-cut) deep tillers at 16-18 cm with stubble remaining on the surface.

For row crops and bare fallows the working depth is up to 25-27 cm. It is carried out by non-moldboard ploughs of paraplau type or equipped with SibIME tines.

Non-moldboard tillage protects the soil from wind erosion, reduces water losses for evaporation, reduces the rate of mineralization of organic matter by 25-30%. However, non-moldboard tillage leads to an increase weed infestation of crops. Therefore, deep non-moldboard loosening is effective to alternate with plowing, for example, in the form of strip tillage. In this case, one strip of the field is ploughed with the mouldboard plough, and the next one is deeply loosened with stubble left on the surface. In the next year, the strips are treated accordingly vice versa.

On non-weeded and poorly compacted soils, for example, after cereals, followed by bare fallow or row crops, autumn plowing is carried out to a shallow depth with flat-cut; compacted soils are tillered to a depth of 25-27 cm flat-cut and deep looseners.

Peculiarities of tillage after row crops

Row crops have late harvesting terms, the soil for them is usually deeply tilled, and the vacated fields are relatively clean from weeds with sufficiently loose and favorable nutrient regime of the soil. Autumn plowing, for example, after potatoes and root crops is replaced by discing with polydisc-tiller to a depth of 10-14 cm or non-moldboard loosening. Or carry out plowing without preliminary discing. With poor care of row crops, discing before autumn tillage is more important as an agronomic method of weed control. In this case, after potatoes and sugar beets is recommended to carry out tillage with discing with polydisc-tiller at a depth of 10-12 cm. Plowing is also necessary in case of significant soil compaction.

In the Non-Black Soil Zone row crops are harvested quite late, so after their harvesting discing is usually not carried out. The compacted ruts (roads) formed in the field during harvesting are discing twice or ploughed in.

On heavy soils and with a strong infestation of the field perennial weeds plowing is carried out with ploughs with skimmers. After highly vegetative row crops, such as corn, sunflower, sorghum, the field remains on the coarse plant residues stems for their grinding discing with heavy disc-tillers in 1-2 trails or use a root and stem shredder, milling cultivators. Then plowing with ploughs with skimmers is carried out.

During repeated corn cultivation on gray forest soils and black earth the depth of plowing is 23-25 cm, which ensures good embedding of plant residues and elimination of typical pests like corn moth, sunflower scabworm, etc.

On medium- and well-cultivated medium-loamy soils and fields weakly weeded with perennial weeds, plowing for spring cereal crops is replaced by shallow tillage at 10-12 cm, using disc-tillers or heavy disc-tillers such as БДТ-3, БДТ-7, БДТ-10, fallow heavy cultivators КПЭ-3,8, КТС-10-01, chisel cultivators КЧП-5,1.

The surface or shallow tillage after row crops with wide-spread tools allows reducing the number of machine passes, decrease soil compaction and carry out spring field works 3-5 days earlier for early sowing crops.

The choice of tillage methods should take into account the degree of weeding of fields, soil type and the risk of erosion. For example, on light soils at risk of wind erosion, the soil is cultivated with flat-cutting tools to a depth of 12-14 cm or leave the field without tillage. The depth of tillage of heavy soils is increased to 20-22 cm. For shallow tillage is used the flat-cut cultivators КПШ-5, КПШ-9, КПШ-11, ОПТ-3-5.

In arid conditions on soils free of weeds, after harvesting of row crops, it is better to replace the plowing by non-moldboard tillage.

Deep flat-cutting or chisel loosening at the depth of 25-27 cm or plough-riders with inclined tines of paraplau or SibIME type tines are used on saline compacted soils and lands of slopes. Fields littered with wild oat (Avena fatua), to provoke its sprouting, pre-processed needle tools such as БИГ-3А, БМШ-15, БМШ-20.

Tillage after seeded perennial grasses

The soil after cultivation of perennial grasses for 3-4 and more years, especially in grass-field soil-protecting crop rotations and non-rotation fields, remains more cohesive, strongly desiccated, and the top layer is densely interwoven with living and dead plant roots.

The top layer of soil penetrated by roots is well structured and has increased cohesion. Often fields after perennial grasses are weeded with perennial weeds, and turf is capable of regrowth. For these reasons, the main tasks of tillage of fields after perennial grasses are to deprive the viability of turf, improve the air regime and aeration of the soil, and create favorable conditions for decomposition of plant residues.

Depending on the composition of vegetation and the duration of use of perennial grasses, the following types of turf are distinguished:

  • The grass layer after the cutting of seeded perennial grasses;
    perennial fallow, or perelog, that is, an area previously cultivated under a
  • crop, but then left untreated and overgrown with wild vegetation;
  • virgin, or natural turf, which is an area that has not been cultivated before or that has been cultivated a very long time ago.

The quality of these types of turf varies, requiring a differentiated approach to their treatment.

In areas with a short growing season, fields after seeded perennial grasses are plowed with plows with skimmers. For good embedding of turf loose soil, the skimmer is set to a depth of 12-14 cm. Qualitative embedding of turf is achieved by plowing sod-podzolic soils to a depth of not less than 20-22 cm, chernozems – to a depth of 25-27 cm. To avoid drying of soil, accelerate decomposition of plant residues and in case of strong turf, after plowing discing, leveling and packing of soil is done. Early plowing of turf accelerates its decomposition.

Heavy soils infested with perennial weeds before plowing the soil is discing in two directions to a depth of 8-10 cm using heavy disc-tillers. This stimulates the growth of weeds, which use up the reserves of plastic substances. With their mass regrowth, plowing with ploughs with skimmers is carried out, which allows to clean the field from perennial weeds by 80% and prevents the regrowth of turf.

To prevent turf regrowth of alfalfa after plowing, the field 12-15 days before plowing, cultivate with polydisk-tillers or immediately plow to 25-27 cm. Ploughs with elongated skimmers ensure quality of layer embedding.

Early terms of plowing contribute to the decomposition of turf and increase the yield of spring cereals by 12-15%. Therefore, in the north and east, plowing is carried out immediately after mowing perennial grasses. If grass vegetation is good, tillage is carried out after the second cutting, which increases the productivity of the crop rotation by 15-20%. In irrigated agriculture, several haymaking operations are carried out, and after the last one, plowing is carried out.

Perennial grasses are ploughed before sowing winter wheat after the first cut, and for spring, millet, flax, and other spring crops, as a rule, after the second cut. Heavy soils are plowed earlier than light soils. Fields with strong turf, especially after cereal grasses such as Agropyron, are better tilled earlier.

In dry climates, early tillage is advantageous; otherwise, procrastination leads to severe soil drying and reduced yields of spring cereals.In the Non-Chernozem zone there are no big differences in yields with early and late plowing.On peaty and non-stony soils, dense grass turf is cultivated with milling implements to 8-10 cm before plowing. Deeper milling is possible, but it is associated with high energy costs.

When sowing spring cereals after perennial grasses the soil is plowed at 20-22 cm for row crops simultaneously with plowing deepen the topsoil by 8-10 cm.

On light soils due to strong aeration, leading to accelerated decomposition of plant residues and loss of nutrients, plowing is carried out at a later date.

In the steppe zone, the main tillage is carried out as early as possible after the first mowing. In the Altai region, on the recommendation of the Altai Research Institute of Farming, the soil-water conservation variant of the perennial grass layer treatment system is introduced, which consists in replacing the plowing by deep flat-cutting with thorough cutting of turf with heavy disc-tillers.

Half-fallow tillage

Half-fallow tillage is a set of methods of continuous tillage, carried out after early harvested non-fallow predecessors in the summer and autumn period. Non-fallow predecessors include winter rye, winter wheat, barley, corn, buckwheat, etc.

Half-fallow tillage is widespread in southern Russia, for example, in the North Caucasus, Middle and Lower Volga region, where 2.5-3.5 months of warm period with significant amount of precipitation remain after harvesting early preceding crops. For example, in Rostov region the amount of autumn precipitation is 80-100 mm, in Krasnodar region – 110-130 mm.

Half-fallow tillage allows to accumulate additional water reserve in the soil. Its main objectives are: preventing soil drying, improving tillage quality, weed control, accumulation of water and available forms of nutrients.

After non-fallow predecessors in the summer and autumn period the soil is cultivated on the type of bare fallow. 

When determining the methods of half-fallow tillage take into account the predecessor, moisture content and compaction of the soil, the species composition of weeds.

The most common variants of half-fallow tillage are:

plowing with plows with skimmers followed by periodic surface or shallow tillage throughout the postharvest period;
several discing by disc- or polydisc-tillers and followed by late autumn ploughing;
flat-cutting 2-4 times shallow tillage to the depth of 10-12 cm followed by deep subsurface non-moldboard loosening in late autumn.

In conditions of sufficient soil moisture and weak weeds after harvesting crops immediately plowing to a depth of the arable layer with simultaneous harrowing and rolling is carried out. For this purpose, a combined ploughing machine of the ПКА-2 type is used, including a plough, a rail leveling beam, a section of ring-spiked rollers, which loosens and levels the soil surface well and creates a compacted layer at a certain depth, preventing water evaporation. Such method of cultivation allows to provoke germination of weeds, which are eliminated during the following cultivations.

The number of subsequent cultivations is determined by the degree of soil compaction and weed germination. If the soil is dry or not damp enough, after harvesting the crop, the stubble discing is carried out to the depth of 6-8 cm with simultaneous rolling with ring-spiked rollers to provoke weeds germination. With the appearance of sprouts (2-3 weeks later), plowing with simultaneous harrowing is carried out. During the following period, several surface tillage operations are carried out with cultivators equipped with tooth or bar harrows, and in dry weather – with rollers.

In dry years, when the soil dries out during the plowing a large number of clumps are formed, which contributes to even greater evaporation of soil moisture. Therefore, plowing in such conditions is replaced by shallow tillage of 10-12 cm with the use of heavy disc-tillers or polydisc-tillers with simultaneous harrowing and rolling.

For a more complete destruction of root-shoot weeds in layers, double discing with simultaneous rolling is performed. The first one is carried out by disc-tillers at 8-10 cm, the second – by polydisc-tillers at 10-12 cm. When weeds grow, the field is ploughed with plows with skimmers and rolling. As soil compaction and weeds sprouting during summer and autumn period, several cultivations with surface leveling are carried out. If herbicides are used, the number of cultivations can be reduced.

For layer-by-layer clearing of fields from perennial weeds the depth is increased up to 12-14 cm, using wide-cut flat-cut cultivators such as КПШ-5, КПШ-9, КПШ-11. The last deep tillage is done in late fall for cereals to a depth of 16-18 cm for row crops – to a depth of 25-27 cm. The cultivation is carried out by subsurface (flat-cut) deep tillers, for example, КПГ-250, КПГ-2-150.

Half-fallow tillage has soil-protecting advantages, especially on heavy soils prone to flooding and in the zone of arid agriculture on saline black and chestnut soils.

In steppe regions at risk of wind erosion and in areas with insufficient moisture instead of plowing, non-moldboard cultivation with flat-cutting cultivators, deep looseners or a chisel tool is carried out. In case of spreading of annual weeds, instead of stubble discing after harvesting cereals, cultivation with flat-cut cultivators to the depth of 6-8 cm is carried out at once. Such tillage allows effective weed control with saving up to 70% of stubble on the surface of the field. As weeds emerge and the soil becomes compacted, the treatment is repeated for the whole post-harvest period.

Fallow tillage for spring wheat sowing

In the steppe zones of western and eastern Siberia, the south of the Urals and other regions with a short growing season and deep soil freezing the main crop is spring wheat. It is placed in cereal-fallow crop rotations after the strip fallows that remain after barley, oats, or spring wheat. The highest yields of spring wheat are obtained when it is sown after bare fallow, which retain the effect on subsequent crops.

The main tasks of tillage in these conditions are accumulation and preservation of the maximum amount of water, effective weed control and soil protection from wind erosion.

The methods of tillage of bare and strip fallows in the steppe zone depend on the amount of precipitation, granulometric composition of soil, weediness of fields and the severity of wind erosion.

In the arid steppe with light granulometric soils the autumn tillage is carried out by flat-cut cultivators КПШ-5, КПШ-11 to a depth of 10-12 cm to cut weeds. At late harvesting of cereals and on light soils prone to erosion autumn tillage is not carried out. When the fields are weeded with wild oat (Avena fatua) in the autumn treat needle tools such as БИГ-3А, БМШ-15, БМШ-20 at a depth of 4-6 cm for embedding the seeds of Avena fatua and create conditions for their germination.

On heavy and saline soils which are prone to strong compaction, autumn tillage is carried out to a depth of 20-22 cm or deeper using subsurface (flat-cut) deep tillers such as КПГ-250А, ПГ-3-100.

In the northern forest-steppe with sufficient rainfall and weak wind erosion the fallow fields are cultivated with plows with mouldboards in autumn. In winter snow retention is carried out.

The first treatment of bare fallow is carried out in early spring on stubble backgrounds using harrowing needle harrows, on the fields with moldboard tillage – with teeth.

In the fields where stubble is preserved, in spring it is impossible to keep moisture with tooth harrows because of the risk of depriving the soil of protection from the wind. Therefore, needle harrows-hoes are used for spring harrowing, such as БИГ-3А, БМШ-15, БМШ-20 with a rotary hoe, which can operate with any amount of stubble and straw in the field, keeps stubble, loosens and levels the soil well. For pre-sowing cultivation, the flat-cut cultivators or cultivators with boom attachments are used.

On weedy fields in spring with mass growth of weeds the cultivation is carried out by flat-cut cultivators to 8-12 cm for cutting weeds and preserving moisture. For fallow tillage, for example, in the Volga region, fallow cultivators with knife-shaped working tools are used.

In spring and summer period as weeds appear, shallow tillage is carried out by flat-cut cultivators, rod or in the absence of perennial weeds by needle harrows in the mode of active loosening. Shallow tillage allows to protect the soil from drying out. For more stable work of flat-cutters the depth of each subsequent cultivation is increased by 1-2 cm. Effective tillage with flat-cutter alternate with tillage with a rod cultivator, the effectiveness of the latter increases with a significant amount of summer precipitation, when they accelerate weeds regrowth.

On the fields infested with couch grass (Elytrigia), several cultivations are carried out in summer, with increasing the tillage depth to 12-14 cm to cut and comb out rhizomes. For this purpose, ОПТ-3-5 tools equipped with special combers for treatment of fields littered with couch grass (Elytrigia) are used.

Fields infested by Leymus with deep rhizomes are plowed in spring by extracting rhizomes to the surface. As the roots grow in summer, they are trimmed with heavy anti-erosion cultivators КПЭ-3,8 or flat-cutters. Dry and hot weather contributes to drying of the cut rhizomes.

To increase the moisture accumulation of fallow in the first half of July, sow three-line strips of mustard and rapeseed, which is combined with tillage of fallow. When weeds sprout, the interstrip spaces are tilled to cut the weeds.

Repeated tillage of bare fallow, which can be up to 4-5 during the summer, leads to almost complete destruction of stubble, which reduces the erosion resistance of the soil. Therefore, herbicides are used to control weeds in summer, reducing the number of mechanical treatments of the fallow to 1-2.

The last tillage of bare fallow is carried out in August-September depending on soil conditions. Soils with light granulometric composition and high permeability are processed by cultivators, flat-cut cultivators to a depth of 12-14 cm. On the contrary, the heavy soils are cultivated to the depth of 20-22 or 25-27 cm using subsurface (flat-cut) deep tillers КПГ-250А, ПГ-3-100, ОПТ-3-5 and others.

Pre-sowing tillage

Pre-sowing tillage can be:

Tooth, disk, knife, needle and other harrows, fallow cultivators, rollers, milling machines, flat-cut cultivators, as well as combined units that perform several technological operations during one pass are used for pre-sowing tillage.

To optimize soil conditions, accelerate seed germination and emergence of uniform sprouts, one should not allow a long break between pre-sowing tillage and sowing, especially for crops of early sowing period.

Tasks and requirements of pre-sowing tillage

Pre-sowing tillage should ensure the creation of favorable conditions for germination of seeds and, subsequently, for their growth and development. Despite the quality of autumn tillage, by spring the soil under the influence of precipitation, its own gravity and snow is compacted, crust is formed on the surface, with the onset of warm weather weeds appear.

Depending on the condition of the soil, pre-sowing tillage can be performed in one step or combine it with sowing.

Main tasks of pre-sowing tillage:

  • creation of a fine lumpy sowing layer with favorable for the germination of seeds structure and an even surface, reducing moisture evaporation and rapid warming;
  • clearing the field from the sprouting of weeds;
  • embedding of mineral fertilizers, chemicals into the soil, providing a complete or localized application of them into the soil;
  • creation of a compacted seed bed for uniform seeding to an optimal depth.

Clumpiness should not exceed 15-20% for humid areas and 10% for arid ones. Presence of clumps with area more than 10 cm2 in the sowing layer above the specified values is not allowed because of significant moisture evaporation.

The soil surface must be leveled, the presence of large lumps and clumps, piled ridges and collapsed furrows on the surface is not allowed. Non-compliance with these requirements leads to uneven seeding during sowing, uneven emergence of seedlings and maturation of grain, which affects the yield. Therefore, pre-sowing tillage should ensure the quality of crumbling up to 80% of lumps with diameter of 1-20 mm.

Harrowing

The first method of pre-sowing tillage in spring is to level the soil surface and give the top layer a loose, fine lumpy condition. A loose soil layer destroys capillaries through which water from the lower layers flows, preventing the loss of moisture. Quality loosening is possible when the soil is physically ripe, i.e. when moisture content is 60-80% of full moisture capacity. Delayed loosening of the soil sharply reduces the quality of cultivation.

For the majority of regions after autumn plowing the first method of pre-sowing tillage is harrowing, which helps to level the soil surface, destroy soil crust and damage young shoots of weeds.

The physical ripeness of the soil in different fields and plots can occur at different times. For example, fields and plots located on southern slopes and away from forest belts reach physical ripeness earlier because of better warming. Therefore, the first harrowing is carried out selectively, as the physical ripeness of the top layer of individual plots or fields is reached. Light soils reach physical ripeness faster than light and medium loamy soils.

On fields ploughed since autumn and black fallow lands, harrowing is carried out as soon as possible – in 1-2 days. For better leveling of the surface and good crumbling it is carried out across the direction of the autumn plowing or along the diagonal of the field.

The greatest effect of harrowing gives in the steppe arid areas, where the intensity of moisture evaporation is significant. For example, according to the data of the Research Institute of Agriculture of South-East, in the dry spring the black earth soil in the south in the absence of harrowing loses from 40 to 120 tons of water from 1 hectare per day to evaporation, which leads to the loss of 100 kg of grain.

In zones of sufficient and excessive moisture, harrowing in early spring is ineffective, so it is carried out when warm and dry weather is established.

On light well-structured soils the first harrowing is carried out by tooth light, medium harrows or plumes. Heavy БЗТС-1 harrows are used on heavy, clayey, prone to swamping. In the areas of wind erosion, needle harrows of the БИГ-3 type in the active loosening mode or harrow-hoes БМШ-20 are used for harrowing.

The best loosening is achieved by harrowing in two tracks, except for very loose soils. To reduce compaction of wet soil, it is desirable to use caterpillar tractors. When using wheeled tractors, special extenders are installed on the wheels, and additional chisel-like rippers are installed to loosen compacted ruts.

On well-cultivated sandy loam and medium loam soils with weak weed infestation by perennial weeds, double harrowing with heavy tooth harrows with immediate sowing of early spring crops is effective.

Cultivation

The number and depth of tillage for spring crops depends on soil compaction, weediness of the field and the depth of autumn tillage.

In areas with sufficient moisture on light soils for early spring crops after harrowing one pre-sowing cultivation is carried out to the seed embedment depth (5-6 cm) with harrowing and surface leveling. For this purpose fallow cultivators such as КПС-4А, КШУ-6, КШП-8 and others with spring, lancet and other ripper working tools in aggregate with tooth, bar and other harrows are used.

On heavy loam and clay soils to improve the air regime and heating loosening to a depth of 10-12 cm using heavy disc-tillers, heavy cultivators such as КПЭ-3,8, chiseled cultivators, heavy tooth harrows in two trails and more is used. The use of knife rotary harrows is also effective. When the fields are weeded with root-shoot weeds, discing with polydisc-tillers or shallow plowing to a depth of 16-17 cm with harrowing and leveling the soil surface, in dry years – with rolling.

Pre-sowing tillage of fields after perennial grasses cultivated in autumn consists of discing with heavy disc-tillers БДТ-3, БДТ-7, БДТ-10, which loosen the soil without extracting the turf on the surface. The tillage is carried out in aggregate with tooth harrows. In the case of ridged soil surface for pre-sowing cultivation special levellers such as ВПН-5,6, ВИП-5,6 and others are used.

The best quality of pre-sowing tillage and mixing of soil with fertilizers is achieved by using combined tillage aggregates, for example РВК-3,6; РВК-5,4, as well as milling machines and milling cultivators КФГ-3,6. These units loosen the soil in one pass, crumble clods, level and compact the surface. Their use allows to increase the grain yield by 0.15-0.25 t/ha. Combined aggregates with passive working tools are effective on condition of previously ploughed soil, on the contrary, milling tools can work on the fields without pre-tillage.

In wet years and on overwatered soils, the use of milling implements is inexpedient because of excessive floating and formation of soil crust in dry weather. In these conditions, fallow cultivators with loosening tools are used.

For small-seeded crops, such as clover, flax, alfalfa and other grasses, as well as vegetable crops two cultivations with harrowing and rolling are done more often or combined aggregates are used, as these crops have higher demands on the looseness and leveling of the top layer of soil.

For late-season crops, the soil needs to warm up to 10-12 ° C and be clean of weeds. Therefore, after the early spring harrowing two or three cultivations are carried out. The first of them is carried out at a depth of 8-10 cm with the use of loosening tools for better warming. When fertilizers are applied, the working depth is increased to 10-12 cm.

Subsequent cultivations are carried out at a shallower depth depending on soil compaction and emergence of weeds. On sandy loam and light loamy soils it is carried out two cultivations by fallow cultivators, for example, КШП-8, КШУ-12, КШУ-18. The last pre-sowing cultivation is carried out to the depth of seed embedding. All cultivations are combined with simultaneous harrowing by tooth ( БЗСС-1) or sowing harrows (ЗБП-0,6А) or with plume harrows ШБ-2,5. In dry weather, also rolling is applied.

Organic fertilizers for potatoes and vegetable crops are applied in spring, especially on light soils with a granulometric composition. For this make shallow plowing the fallow lands to a depth of 16-17 cm with plows without skimmers with simultaneous harrowing. Re-plowing at 16-17 cm is also effective on heavy soils for row crops. Good pre-sowing loosening and mixing of the soil with fertilizers provide milling machines, milling cultivators and rotary plows. If organic fertilizers were made in autumn, the plowing is replaced by deep non-moldboard loosening of 28-30 cm for potatoes with the use of the chisel implements such as ПЧ-2,5, ПЧ-4,5, equipped with lancet or chisel-like working tools. After tillage with a harrow on the surface of the field are ridges, for smoothing them aggregate with special devices ПСТ-2,5 and ПСТ-4,5. Pre-planting chiseling allows to increase the yield of potatoes by 3.8 t/ha.

Table. Yields of row crops depending on chiseling of sod-podzolic soil (according to the data of the Agricultural Department of the Moscow Agricultural Academy), t/ha

Crop
Ploughing at 16-17 cm
Chiseling at 28-30 cm
Yield increase, t/ha
Potatoes
26.1
29.9
+3.8
Fodder beets
71.4
80.3
+8.7
Corn for silage
44.2
50.4
+6.2

Non-moldboard loosening before planting potatoes is also carried out with the use of non-moldboard implements, ploughs with the mouldboards removed, deep rippers. For the embedding of organic fertilizers with simultaneous deep loosening, ploughs with cut-out mouldboards are effective. Such tillage, for example, gray forest soil contributes to an increase in potato yields by 3-4 t/ha.

Pre-sowing tillage in areas with insufficient moisture

The main task of pre-sowing cultivation in areas with insufficient moisture is to level the soil surface, creating a mulch layer to retain moisture. Therefore, in these conditions, flat-cut or needle tools are used that do not overturn the soil. Organic fertilizers are better to make in autumn, while at their introduction in spring for tilled crops embedding is carried out with a heavy disc-tiller at 14-16 cm. In the zone of insufficient moisture is carried out selective early spring harrowing in 2-3 trails on the background of the moldboard tillage, on the background of non-moldboard – loosening needle harrows or discing with flat discs. After harrowing, when the top layer reaches physical ripeness, the soil is cultivated with simultaneous harrowing. In areas of insufficient moisture in Siberia after harrowing one or two-times cultivation is carried out: the first – 5-6 days after harrowing, the second – before sowing.

Pre-sowing tillage of soils prone to wind erosion for early spring cereal crops in the steppe zone includes one harrowing with needle harrows БИГ-3А in the mode of active loosening. Immediately after it, sowing with the introduction of mineral fertilizers using СЗС-2,1 stubble seeder and rolling is carried out. Before sowing, one pre-sowing cultivation with simultaneous harrowing at seeding depth is carried out. For cultivation undercutting tines are used. Additional tillage in these conditions delays the sowing period, which leads to a decrease in yield.

In the steppe regions of Siberia, where autumn deep non-moldboard loosening was carried out, they close the moisture with needle harrows for 2-3 days after the ripening of the soil. With the onset of warm days, the field is tilled with flat-cut cultivators, if necessary, in conjunction with ring-spiked rollers. This treatment keeps some of the crop residues on the surface of the field.

Technological features of pre-sowing tillage

Fields weeded with wild oat (Aveba fatua) and wintering weeds are first cultivated with needle harrows, then when wild oat grows – by 6-8 cm with flat-cut cultivators such as КПШ-5, КПШ-9, КПШ-11. When weed infestation by annual weeds the number of cultivations is increased to two and depth – to 12-14 cm. To reduce losses of moisture from evaporation, the soil is concurrently rolled. 

For sugar beet and vegetable crops, as a rule, qualitative autumn tillage is carried out. On well-structured, poorly compacted black earth the moisture is closed in spring with wide-cut aggregates consisting of tooth and plume-harrow units. The best quality of loosening and leveling is achieved in two passes of the unit: the first pass includes a combination of plume-harrow + medium tooth or sowing harrows such as ЗБП-0,6; the second – plume-harrow + sowing harrows or ЗОР-0,7. On highly compacted soils, heavy harrows are used in the aggregate instead of medium-sized tooth harrows.

In dry sunny weather the interval between tillage should not be more than 3-4 hours. For better crumbling of the soil, each successive tillage is carried out across the direction of the previous one, or at an angle of 45°. When closing the moisture it is better to use tracked tractors for less soil compaction. Pre-sowing cultivation is carried out simultaneously with the sowing of sugar beets at a sowing depth of 4-5 cm.

The highly compacted or weedy perennial weeds on the fields, and on the fields from perennial grasses, a deeper tillage with disk or mouldboard tillers is used; on soils with strong turf – 2-3-tillage. When making spring organic fertilizers, the soil is cultivated with plows or polydisc-tillers at 14-16 cm, at the autumn introduction in the spring it is advisable to carry out deep loosening with plows or polydisc-tillers with removed moldboards or chisel-cultivators.

Deep spring plowing is undesirable, as plowed autumn stubble residues, weed seeds and disease-causing organisms may turn out on the surface. In years with spring drought the fields weeded with root-shoot weeds are subjected to deep loosening by polydisc-tiller without mouldboards, non-moldboard ploughs, and ripper-cultivators.

On strongly compacted, heavy sod-podzolic soils instead of the first cultivation the soil is plowed over, especially under the root and tuber crops, which require a deeper loose layer, with simultaneous harrowing. If there is no need in plowing with overturning the layer, especially in conditions of dry spring, non-moldboard deep loosening is used.

In cases where spring crops are sown by spring plowing, i.e. in the absence of autumn tillage, the first spring loosening should not be delayed. In this case the soil should be tilled as early as possible, otherwise it should be discing before plowing. The tillage depth should be less than the autumn tillage.

The use of fallow cultivators does not provide good and uniform loosening in depth. For pre-sowing cultivation it is better to use beet cultivators, such as УСМК-5,4А, equipped with one-sided blades and flat-cut lancets, as well as devices for applying herbicides. In dry weather, pre-sowing rolling is additionally carried out.

For late-sown spring crops, pre-sowing tillage includes covering harrowing and two to three cultivations with simultaneous harrowing, and in dry weather is supplemented by rolling. At ridged surface of the field after harrowing the soil is levelled with levellers or heavy levellers. The depth of the first cultivation is increased to 10-12 cm.

Simultaneous rolling with ring-spiked rollers helps to accelerate weeds germination and create a compacted layer in the soil profile preventing moisture evaporation. The second cultivation is carried out when weeds sprout.

On well-structured soils with a leveled surface and clean fields from weeds it is enough to harrow the seedbed and one pre-sowing cultivation with harrowing. Excessive loosening of soil does not contribute to germination of weed seeds.

Cultivation for corn and sunflower is carried out at the depth of 6-8 cm for millet and other small-seeded crops – at the depth of 4-6 cm. When sowing hybrids, such as sunflower, which have seeds smaller than sort, the cultivation is carried out to a depth of 5-6 cm. The best implements for pre-sowing tillage are cultivators with lancet tines. Pre-sowing aggregates are additionally equipped with smooth rollers, and the previous cultivation is carried out in the aggregate with ring-spiked rollers.

The depth of cultivation should not exceed the sowing depth. It is optimal to plant seeds on the compacted soil, covered with loose soil from above. In this case, good aeration and water inflow from the lower moist soil layers is provided. Sowing into deeply loosened soil is undesirable because the plant roots may be damaged when it sinks, and the tillering node of cereals will be on the soil surface.

Combination of pre-sowing cultivation with seeding in one aggregate allows to reduce the number of machinery passes over the field, reduce soil compaction and increase productivity. Modern powerful tractors allow you to combine a cultivator and a seeder or use combined tillage-sowing units, for example, КА-7.2, which includes a milling machine and a seeder, АКПП-3,6 cultivator-sower; ППК-7,2; ППК-8 or stubble seeders with mounted tines СЗС-2,1 and others.

The best quality of loosening, mixing the soil with fertilizers and weed control is provided by combined tillage aggregates of РВК-3,6, КФГ-3,6, ПАВ-6 etc.

It is possible to reduce the number of pre-sowing tillage by strip loosening the soil in the area of the row, where seeds of row crops are placed, and to treat the rest of the field with herbicides. This allows to reduce the time of work performance and energy costs for its performance.

Preparing the soil for intermediate crops

A limited period of time is left for tillage of intermediate crops, so the main tasks of tillage are to prevent the soil from drying out, to loosen it well and to level it.

Soil preparation for winter and wintering intermediate crops sown in autumn, such as winter rye, winter vetch, percoco hybrid, does not differ from cultivation of these crops for grain, taking into account the predecessor, soil type and moisture, weediness. When sowing winter crops after row crops, plowing is substituted by shallow tillage: 1-2 times discing on 8-10 cm with subsequent cultivation and harrowing. Pre-sowing cultivation for winter rape, winter rape melons and other small-seeded crops must also include the alignment and rolling of the soil, which is used for РВК-3,6, РВК-5,4, ВИП-5,6 and others.

When placing the intermediate crops after the winter and spring cereals discing with polydisc-tiller at 14-16 cm with simultaneous harrowing, in dry weather – with rolling. On heavy soils and weedy fields shallow plowing at a depth of 16-17 cm by plows equipped with devices for leveling the soil type ПВР-2,3, ПВР-3,5 or tillage aggregates ПКА-2А, combining a plow, dragline, sections of ring-spherical rollers.

On fields weakened by perennial weeds, milling tillage at 8-10 cm is effective, for which milling cutters and milling cultivators of КФГ-3,6 type are used. Milling allows to loosen the soil, mix it with fertilizers and prepare it for sowing in one pass of the unit without prior plowing. In wet years, milling is not effective because of the strong swamping of the upper layer of soil.

Due to the limited vegetation period, which is especially important for post-mowing and stubble crops, there is no gap between the harvesting of the forecrop, soil preparation and sowing. To reduce the time of soil preparation and sowing, combined pre-sowing cultivation and seeding, for example, winter crops using tillage and seeding aggregates КА-3,6, КА-7,2 (milling-sowing machine), АКПП-3,6 (cultivator-sowing machine). Combined tillage and seeding allows to reduce the number of machine passes over the field, time of soil preparation and seeding, improve the quality of work.

In arid conditions mouldboard techniques in the system of tillage for spring crops are ineffective due to large losses of moisture to evaporation, so the flat-tillage with leaving crop residues on the surface of the field is carried out. After stubble forecrop effective use of a combined unit type АКП-2,5, which combines surface loosening of the soil, tillage and rolling.

One of the main conditions for obtaining high yields of intermediate crops is thorough preliminary preparation of the soil. For uniform embedding of seeds and creation of a seed bed, the soil is loosened and leveled before sowing. For this purpose, КПЗ-9,7 fallow cultivators, ВПН-5,6, ВП-8 levelers, and КЗК-10 ring-toothed rollers may be used.

Tillage and sowing of corn, annual grasses after winter crops can be combined in one aggregate equipped with СПП-4, СЗС-2,1 and other direct sowing seeders without pre-tillage.

Under irrigated agriculture the soil is compacted more, so the loosening depth is increased to 18-20 cm, using both mouldboard and non-moldboard methods of cultivation, combining them with shallow loosening to the depth of seeding and rolling.

The preceding crops largely determine the methods of soil preparation. After harvesting row crops, e.g. fodder cabbage, turnip, it is enough to cultivate and harrow the field. Heavily compacted soil is disked and harrowed by the time of sowing of repeated crops. Heavy clay soils are plowed, which gives better results than discing. After ploughing the field is also disked, harrowed and rolled.

Tilling of newly-developed land

The task of tillage of fallow and virgin lands is to create a loose arable layer and conditions for decomposition of turf, accumulation of sufficient available nutrients, moisture and destruction of weed vegetation.

In the forest-steppe and steppe zones, fallow or virgin lands are plowed with a plough with skimmers in spring or in early summer for sowing next year.

Late plowing in the colder period reduces the amount of nutrients due to weak microbiological activity and deteriorates the water regime of the soil. Plowing is carried out to a depth of not less than 25 cm. With shallow plowing turf is poorly crumbled and poorly embedded, which requires additional surface treatments.

With a small humus layer, plowing is carried out to its full depth with the use of soil deepener. With a strong layer of turf before plowing discing in two directions by 6-8 cm, fallow lands infested with Elytrigia and Leymus – to a depth of 10-12 cm. After plowing the soil is rolled with heavy rollers with light harrowing. To level the surface, discing along or diagonally to the direction of plowing. Over the summer there are carried out cultivation or discing, harrowing to destroy the soil crust. This treatment achieves intensive decomposition of organic matter, accumulation of mineral nutrients, moisture retention and weed control.

When processing marsh and floodplain soils, powerful plows, milling machines, and heavy disc-tillers are used. Plowing is carried out by special bush-marsh or conventional plows without skimmers, with a screw mouldboard, well overturning the soil.

In case of high standing groundwater before plowing deep loosening is carried out, which also contributes to faster decomposition of turf because of better aeration. Soils with weak turf are cultivated with heavy disc-tillers. The optimal time for plowing for sowing in the spring of the next year – summer, in the south – early autumn. After 2-3 weeks perform discing. A very loose layer is rolled.

Plots covered with mounds, pre-till with a milling machine, then plow with a plow with skimmers. Floodplain land plow with skimmers. With thin humus horizon perform discing followed by deep non-moldboard loosening. The timing of plowing is determined depending on the granulometric composition and moisture of the soil. With excessive moisture the soil is pre-tilled with mole plows or deep loosened.

Land from under the forest, with small turf and weak forest litter is disked in combination with deep non-moldboard loosening. With strong turf and forest litter, deep plowing is carried out. After removal of bushes and stumps, the areas are treated with a rooting harrow, and then the soil is disked and plowed with a bush plow.

When developing low-productive dry lands, depending on the thickness of the humus layer and the degree of podzolization the soil is plowed with a plow with or without skimmers, or discing with simultaneous deep non-moldboard loosening is carried out.

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.