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Tillage of soils prone to wind erosion

The causes of wind erosion are high wind speed at the soil surface, a high degree of spraying with weak topsoil structure, its low moisture content and lack of protective plant cover. Soil erosion often occurs on cultivated lands whose tillage technology does not match the landscape conditions.

The tasks of erosion control tillage include:

  • loosening the soil while keeping the maximum amount of stubble and other plant residue on its surface;
  • creation of optimal conditions for moisture accumulation and retention in the soil;
  • preventing soil dispersion and enhancing its aeration by minimizing tillage.

The stubble left on the surface of the field reduces the wind speed in the near-surface layer of the ground to 3-4 m/s, thereby preventing the soil from blowing out. In winter it allows to retain snow, contributes to moisture accumulation, and in the hot summer period it reduces its evaporation.

Scientists of the former All-Russian Research Institute of Grain Farming together with the institutes of Kazakhstan, Siberia, Trans-Ural and other regions under the leadership of Academician A.I. Barayev have developed soil-protective system of agriculture for steppe regions, for the development and implementation of which the Lenin Prize was awarded. Academician A.I. Barayev laid down the theoretical foundations of anti-erosion tillage of soils subjected to wind erosion, which are as follows:

  • soils resistant to wind erosion should be classified as soils, the content in the upper layer of which is more than 50% of structural aggregates with a size of more than 1 mm.
  • Covering more than 40% of soil surface with plant residues and stubble allows reducing wind speed in the near-surface layer to 3-4 m/sec, which reduces moisture evaporation, increases soil moisture content and, as a result, increases wind resistance.

Based on these principles, the anti-erosion tillage is based on flat-cutting without overturning with retention of most of the stubble on the field surface.

Soil-protection system of tillage, developed in the All-Russian Research Institute of Grain Farming, is used in the steppe regions of the North Caucasus, Western Siberia, the Lower and Middle Volga region, the Southern Urals and other arid regions of Russia.

According to the data of A.I. Barayev and E.F. Gossen, the yield of spring wheat on average for ten years at autumn flat-cutting in comparison with autumn plowing is higher by 0.48 t/ha. At Turgay regional agricultural experimental station on average for eight years – by 0.35 t/ha.

According to Kustanay regional agricultural experimental station, snow accumulation due to stubble preservation on the surface increases by 2 times, and the increase in yield of spring wheat on average for ten years is 0.38 t/ha.

On light loamy and sandy loam soils stubble does not provide complete protection of soil from wind erosion. For this reason on such soils Kustanai station recommended in addition to non-moldboard tillage apply strip planting crops width of 30-50 m. They are sown with spring wheat, and buffer strips 30 m wide – with agropyron and melilot.

The proposed tillage system consists of:

  • rejection of the plow and other tillage implements that embed crop residues;
  • tillage with flat-cutting implements that retain stubble and plant residues on the surface.

In addition to the basic techniques are used:

  • introduction and development of soil-protective crop rotations with strip
  • placement of annual crops and perennial grasses;
  • strip planting of fallows and cereals;
  • use of strip fallows;
  • use of herbicides;
  • use of hoe harrows instead of tooth and needle harrows for spring moisture closure and fallow tillage for better stubble retention;
  • use of stubble seeders, such as СЗС-2.1, СЗС-8, СЗС-12, which combine mineral fertilizer application, soil loosening, sowing of cereals and soil rolling.

The use of implements with loosening flat-cutting working tools in the autumn tillage system allows to increase anti-erosion resistance due to less soil spraying and preservation of up to 75% of plant residues on the field surface.

Table. Methods and implements of anti-erosion tillage of soils subject to wind erosion

Tillage method
Purpose and conditions of the method
Types and makes of implements
Harrowing of autumn ploughed soil and fallowsSurface loosening of the soil by 4-6 cm. Elimination of weed sprouts, moisture retentionNeedle harrows БИГ-3А, hoe harrows БМШ-15, БМШ-20
Pre-sowing cultivationSurface loosening of the soil by 6-8 cm, leveling the surface and trimming weedsRod cultivators КШ-3,6А, КЛШ-10, falt-cut cultivators КПГ-2,2, ОП-8, ОП-12, etc.
Cultivation of fallows in the system of autumn and spring tillageShallow flat-cutting loosening the soil at 8-16 cm with leaving stubble, trimming weedsFlat-cut cultivators КПШ-5, КПШ-9, КПШ-11, heavy cultivators КПЭ-3,8, КТС-10-1, КТС-10-2 with rod devices
Non-moldboard loosening in the system of autumn tillageDeep flat-cutting soil loosening at 25-27 cm with saving stubble and straw mulch, trimming weedsSubsurface (flat-cut) deep tillers КПГ-250А, ПГ-3-100, ПГ-3-5, КПГ-2-150
Non-moldboard loosening of perennial grassesLoosening the layer of perennial grasses at 14-16 cm, trimming weedsTool for non-moldboard tillage ОПТ-3-5

For this purpose they use subsurface (flat-cut) deep tillers such as КПГ-250А, ПГ-3-100, ПГ-3-5, ploughs with inclined tines of paraplau type or with SibIME tines.

Strip fallows in steppe and forest-steppe areas prone to wind erosion are important in increasing the yield of cereal crops. Therefore, the system of tillage of strip fallow should be based on soil-protective methods of tillage. The autumn tillage is shifted to the spring period on the light soils with light granulometric composition, which are the most exposed to erosion. Stubble left after harvesting cereals and mulching with straw promote accumulation of snow, absorption of meltwater by soil, and protect the soil from blowing out.

In the conditions of black earth and chestnut soils to protect against spraying and water erosion, plowing is carried out to a depth of 27-30 cm or more. This allows to lift and mix from the subsoil layer to the top structural water-resistant soil aggregates, thereby increasing the resistance to wind erosion. This method is carried out periodically, alternating it with ordinary plowing.

In the arid southern regions, where winter wheat is sown after the stubble forecrop, non-moldboard flat-cutting is used. Up to 80% of stubble is retained on carbonate and chestnut soils, which reduces wind speed in the surface layer by 1,5-2 times, and the accumulation of moisture increases by 150-200 m3/ha.

For shallow surface spring tillage instead of polydisc-tillers and disc tools they use flat-cut cultivators type КПШ-5, КПШ-9, КПШ-11, КПЭ-3,8А in aggregate with a needle harrow. The use of such units allows to save up to 70-90% of stubble and plant residues and creates a mulching layer, and needle harrows level the soil surface.

For seeding cereals on fallow not weeded field, use press seeder СЗП-3,6 type, for seeding of the following crops after the fallow – seeders-cultivators СЗС-2,1, СЗС-6, СЗС-12, which together perform pre-sowing tillage, sowing, fertilizing and rolling of the sown rows. In conditions of overwatering, a hoe-sowing machine is more effective.

In the summer period to control weeds and prevent drying of the soil, as well as when taking care of fallow land use rod cultivators КШ-3,6А, КЛШ-10 or anti-erosion cultivators such as КПЭ-3,8, КТС-10-2 with a rod attachment. Rotating from the drive wheels at a depth of 5-7 cm square or circular rod breaks the root system of weeds and brings them to the surface, loosening and leveling the top layer of soil, creating a mulching layer.

Needle harrows with rotary hoe-type tools are used for postharvest autumn and spring loosening of stubble, moisture closure and seeding of weeds. This type of harrow can operate with any amount of stubble or straw on the surface of the field, saving up to 85% of plant residues, well loosening and leveling the soil.

In the fields of crop rotation deep loosening by deep rippers alternate shallow tillage by flat-cut cultivators. Thus, in five-field crop rotations deep loosening by deep rippers at 25-27 cm is carried out on a fallow field, and for the third crop after the fallow – to a depth of 20-22 cm. For the second and fourth crops tillage is carried out by flat-cut cultivator to 10-12 cm.

Important in terms of risk of wind erosion are methods of minimum tillage, contributing to increased soil moisture. It consists in reducing the number of passes of machinery in the care of bare and strip fallows and the use of herbicides.

Soil-protecting tillage methods ensure sustainable crop yields while protecting the soil from wind erosion, provided that crops are banded, the soil is mulched and other moisture-accumulating measures are taken.

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.