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Problems of energy conservation and soil compaction

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Tillage is the most energy-intensive and expensive technological method of farming. Currently, it accounts for up to 40% of energy and 25% of labor costs of the total amount of field work. To estimate, if we recalculate all tillage techniques for plowing, 6,000 tons of soil is moved on each hectare annually.

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Tillage

 

For example, when growing potatoes and sugar beets the fuel consumption for tillage operations is 18% of the total consumption, when growing winter wheat, corn and sunflowers – 41 and 43%.

The most energy-consuming tillage is plowing, which accounts for more than 50% of total fuel consumption. At the same time, fuel consumption and energy intensity of the technological process increase with the use of wheeled tractors. According to the data of zonal research stations, the use of wheel tractors for plowing such as К-700 increases fuel consumption by 22% compared with tractors such as ДТ-75, and the total energy consumption by 35%, respectively 604 and 812 MJ/ha.

Table. Consumption of diesel fuel for growing field crops, kg/ha (M.M. Severnev, 1992)[1]Farming. Textbook for universities / G.I. Bazdyrev, V.G. Loshakov, A.I. Puponin et al. - M.: Publishing house "Kolos", 2000. - 551 p.

Crop
Total consumption
For plowing
For other tillage operations
Total for tillage
Winter wheat
64
15
11.4
26.5 (41)
Corn
92
19
18.8
37.8 (41)
Sunflower
88
19
18.9
37.9 (43)
Sugar beet
210
23
14.8
37.8 (18)
Potatoes
260
32.1
16.6
48.7 (18)

Measures to reduce energy costs

In the system of agro-technical measures to reduce energy costs are important:

  • increasing soil fertility,
  • increasing the content of humus,
  • creation of deep arable layer with a good state of cultivation,
  • improvement of all soil properties,
  • saturation of crop rotations with deep penetrating root systems,
  • applying increased doses of organic and mineral fertilizers,
  • application of grasses and sideration,
  • application of chemical reclamation,
  • integrated plant protection system,
  • conducting all field work in optimal agrotechnical terms.

That is the creation of a arable layer with a good state of cultivation, helps to reduce energy costs for its tillage and reduces the negative impact of soil compaction. For example, fuel consumption when plowing compacted soil in optimal conditions is 12-14 kg/ha, whereas when plowing compacted soil heavily littered with couch grass (Elytrigia repens) – about 20-25 kg/ha. On soils with a good state of cultivation it is possible to use technologies of minimum tillage.

The solution of problems in the direction of energy saving and ecologization are the following organizational and technological measures:

  • development and application of economical and environmentally friendly techniques and technologies of tillage with maximum effective material, energy and labor performance with minimum negative impact on soil fertility. The methods should take into account the soil and climatic conditions, biological and technological features of crops, the availability of accompanying technical resources in the farm and the features of the agricultural landscape;
  • application of highly productive large-capacity and combined machines and units with the maximum combination of technological operations;
  • wide implementation of minimum tillage methods;
  • use of tractors with a lower specific pressure of the undercarriage systems;
  • correct selection of working tools of tillage machines and implements;
  • use of a special symmetric frame with a set of quick-changing working tools as a carrier machine to make up units that perform several technological operations in one pass;
  • elimination of residual deformations in subsoil layers by deep chiseling, slitting and other methods;
  • use of tires in the running systems of machinery of larger size, arched and wide profile tires, twin wheels, half-track and pneumatic tracks;
  • rational combination of tractors and tillage machines and implements;
  • regulation and optimization of technological parameters and speed modes of operation of tillage implements;
  • performance of tillage methods on the scientific-based movement routing basis. Reducing the number of passes of machinery on the field, especially heavy wheeled, filling machines with fuel, fertilizers, herbicides, seeds at the margin of fields.

Research and practice show that in crop rotations it is rational to apply different methods combining surface, shallow and deep; mouldboard and non-moldboard tillage taking into account soil-climatic conditions, phytosanitary state of soil, crops of crop rotation and agrolandscape features.

Perspective tasks of farming development in the field of energy saving and reduction of negative impact of heavy machinery on the soil are:

  • development of soil-protective running systems of agricultural machinery, for example, new types of caterpillar and pneumatic-tracked mover, flexible – ultra-low pressure tires, working tools of tillage machines and implements, non-tractor machine systems (bridge or cable farming), combined machines and implements, large-capacity units with less metal intensity and acceptable pressure on the soil;
  • creation of a new generation of soil-protecting complex of machines in accordance with modern requirements and directions of development of agro-landscape farming.

Excessive soil compaction

Harm caused by excessive soil compaction

The use of heavy tillage machines and transport vehicles under the existing multi-operational technology of soil and crop care leads to excessive soil compaction under the influence of running systems.

Soil compaction leads to:

  • reduction of water permeability and overwatering of the upper layer, which increases water erosion;
  • formation of surface crust when compacted soil dries out;
  • deterioration of gas exchange;
  • poor quality of seed embedding and reduced field germination, for example, barley germination is reduced by 27-30%, and winter wheat germination – by 23.4%;
  • a decrease in the number of beneficial microorganisms;
  • slowing down microbiological and redox processes, thus reducing the availability of nutrients to plants;
  • 24-30% reduction in fertilizer efficiency.

Losses of grain yield per hectare due to compaction amount to 0.82-1.24 t, and overuse of diesel fuel – 2.5-3.5 kg. The most tangible losses are noted in wet areas.

One passage of tractor consolidates the soil to the depth of 45 cm, at multiple passes, especially in tractor К-700 – to 50-60 cm. The consequence of compaction is steadily manifested for several years, especially in the subsoil layers.

When growing crops machine-tractor units make 5-15 passes on the field, compacting tillage and subsoil layers. During the period of pre-sowing tillage and sowing only machine-tractor systems cover up to 80% of the field area, and potato, sugar beet and other row crops planting during spring period are subjected to 3-5 times influence of aggregates only. The total area of their traces during the whole complex of field works reaches 100-200% of the field area.

According to the data of the Department of Agriculture of the Moscow Agricultural Academy, at seeding with tractors ДТ-75 direct and indirect deformation is exposed 21.6% of the field area, tractors Т-150К – 29,4%, tractors К-700 in aggregation with three seeders – 39%. Density of sod-podzolic soil on the trail of wheeled tractors increases by 0,1-0,3 g/cm3, thus reaching 1,35-1,55 g/cm3 that is significantly higher than optimal density of soil for field crops. Crop yields in the grain-row crop rotation of vetch-oat mixture – winter wheat – barley – potatoes decreased for 10 years by an average of 6-22% due to the compaction effect of tractors. The greatest decrease was observed from wheeled tractors Т-150К, К-700.

Table. Weight of tractors and specific pressure of running systems on the soil[2]Farming. Textbook for universities / G.I. Bazdyrev, V.G. Loshakov, A.I. Puponin et al. - M.: Publishing house "Kolos", 2000. - 551 p.

Tractor make
Tractor weight, kg
Specific pressure on the soil, kg/cm2
medium
maximal
МТЗ-52
2700
1.71
5.0
ДТ-75
6100
0.48
2.4
Т-150К
8020
1.64
4.4
К-700
12000
1.70
4.8

According to the data of the Moscow Agricultural Academy named after K.A. Timiryazev, under autumn plowing at the depth of 20-22 cm sod-podzol medium-loamy soil of the Non-Black Earth zone at the depth of 20-80 cm the density for 10 years of using tractors Т-150К and К-700 increased by 0.1-0.15 g/cm3, reaching the value 1.38-1.62 g/cm3.

According to long-term experiments of the North-Caucasus branch of the All-Russian Research Institute of Agricultural Mechanization, on black earths the resistivity of the soil at plowing on 20-22 cm on the tracks of light wheeled and tracked tractors is 12-15% higher than beyond the tracks, and on the tracks of tractors Т-150К and К-701 – by 44%. Quality of soil crumbling worsened: out of tracks degree of crumbling of layer was 87%, and on tracks of tractors Т-150К – 83%, К-701 – 56%. Compaction effect of these tractors extends to a depth of 40-60 cm, maximum – to 1 m.

Permissible specific pressure for the majority of soils is 0,4-0,5 kg/cm2, maximum – 1,0-1,5 kg/cm2. However, power-packed wheeled tractors have an indicator up to 3-4 kg/cm2 and more. According to the level of compaction impact on the soil Russian tractors can be placed in the following order: ДT-75 < МТЗ-52, МTЗ-100 < МTЗ-82 < Т-150К, К-700 < К-701.

Excessive soil compaction leads to deterioration of agrophysical, biological and agrochemical properties. At a constant depth of cultivated layer a plow pan is formed – excessively compacted layer, negatively influencing water, air and heat regimes of soil.

The strongest reconsolidation takes place at increased soil moisture. For this reason the optimum condition for tillage is the state of physical ripeness, which is in the range of moisture for sod-podzolic soils – 12-21%, gray forest – 15-23%, black earth – 15-24%. For all types of soils, the recommended moisture content for processing is not higher than 65-70% of the smallest moisture capacity. The permissible pressure on the wet soil at 60% of the smallest moisture capacity for the early spring harrowing is 0.3-0.4 kg/cm2, during the pre-sowing tillage – 0.5-0.6 kg/cm2, the main tillage – not more than 1-1.5 kg/cm2.

Loss of yield of field crops in the link of grain-row crop rotation vine-oat mixture – winter wheat – barley – potatoes on average for two rotations was 6-22% depending on the compaction action of tractors. The greatest decrease was noted when using Т-150К and К-700 tractors.

According to calculations of the Soil Institute named after V.V.Dokuchaev, the total losses of cereal crops from excessive compaction of soils in Russia reach 13-15 million tons, sugar beet – more than 2 million tons, corn grain – about 0.5 million tons.

Table. Effect of tractors' running systems on the yield of field crops in the conditions of Non-Black Earth zone, 100 kg/ha (N.S. Matyuk, average for 10 years, 1993)[3]Farming. Textbook for universities / G.I. Bazdyrev, V.G. Loshakov, A.I. Puponin et al. - M.: Publishing house "Kolos", 2000. - 551 p.

Tractor
Vicia-oat mixture for hay
Winter wheat
Barley
Potatoes
On average, %
No compaction, control
55.3
42.2
37.0
282
100
МТЗ-80
52.4
40.6
32.6
271
94
ДТ-75 (Т-150)
48.4
40.2
33.1
263
91
Т-150К
47.8
37.5
31.4
250
87
К-700
46.4
34.0
31.4
235
78

The tillage of compacted soils is associated with an increase in energy costs. According to calculations, fuel consumption in the tillage of compacted soils increases sharply, for example, when plowing more than 1 million tons per year.

The main reason for the decrease in crop yields with soil compaction is the deterioration of conditions for the formation of a powerful root system and its active functioning. According to the data of the Minnesota Agricultural Experiment Station (USA), increasing the density of loamy soil from 1.16 to 1.38 g/cm2 leads to a 6.2-fold decrease in pea root length and 1.9-fold decrease in mass. Soil compaction causes the formation of a surface root system, which affects the mineral nutrition of plants, which deteriorates by 36-42%, even with sufficient moisture supply.

Measures to reduce soil compaction

The basis of the system of measures to limit the level of impact of heavy machinery on the soil are preventive measures aimed at reducing the number of passes of machinery and decompaction of the soil in its processing, the introduction of increased doses of organic fertilizers and enrichment of organic matter, liming or application of gypsum, improving the structure.

To prevent excessive compaction, the soil is tilled when it reaches physical ripeness. On all types of soils, tillage is carried out at a moisture content of not more than 60-70% of full moisture capacity.

According to the recommendations of the Russian Academy of Agricultural Sciences the permissible load limits for wet (60% of the smallest moisture capacity) sod-podzolic loamy soil during early spring harrowing are 0,3-0,4 kgf/cm2, during pre-sowing tillage – 0,5-0,6, during the main tillage – 1,0-1,25 kgf/cm2. For typical heavy loamy black earth the pressure on the soil during the main tillage should not exceed 0.8-1.0 kgf/cm2, during sowing and pre-sowing tillage – 0.4-0.6 kgf/cm2.

To reduce excessive soil compaction during early spring works, such as harrowing, sowing and pre-sowing cultivation, it is necessary to use tracked tractors or tractors with twin tires, pneumatic-tracks and, if possible, avoid using wheeled tractors such as Т-150К, К-701.

Especially great damage to the undercarriage of tractors cause crops of winter cereals and grasses during the early spring fertilization with nitrogen fertilizer. Heavy fertilizer spreaders compact the soil, so it is advisable to use aircraft or tractors with pneumatic-tracks for fertilizing.

When using wheeled tractors, they are aggregated so that the tractor track coincides with the track of the trailed implement. Tractor and trailed implement tracks are additionally loosened during pre-sowing work, and the depth along the track is increased by 3-4 cm. Filling aggregates with seeds, fertilizers, herbicides or fuel is carried out outside the field or on specially designated roads.

Optimization of the routes of agricultural machinery on the field is an important preventive measure to prevent excessive compaction of the soil. For this purpose, permanent routes (tracks) for movement of aggregates during sowing and plant care are established. Movement of machinery by permanent routes using the same marks allows reducing the area of soil compaction by 1.7-2.7 times in comparison with uncontrolled movement.

When tilled crops are taken care of, repeated movement of machinery should be carried out on the same track on which the planting was carried out.Failure to comply with this rule leads to plant damage by the working elements of the cultivator, because the width of the docking rows is not always maintained during sowing.

Minimization of tillage involves reducing the number of passes of machinery on the field, which is achieved by combining several technological operations and techniques and performing them in one work process. This approach allows reducing the number of passes over the field by 2-3 times.

Reducing soil compaction is achieved by replacing or reducing the number of deep tillage by surface and shallow tillage at the expense of using large-capacity aggregates on weakly weeded fields. For example, in the conditions of the steppe zone the autumn plowing for early spring cereals is replaced by shallow tillage with the use of large-capacity units, for example, КПШ-9, КПШ-5, КПШ-11.

Reduction of soil compaction by mechanical tillage is achieved by different-depth tillage in the crop rotation; a combination of mouldboard and non-moldboard tillage, flat-cutting, disc tillage, chisel tillage, etc. Such systems allow reducing the load on the soil and the area of compaction by 30-40%.

An effective method of reducing compaction of subsoil horizons is periodic, carried out once every 3-4 years, chiseling to a depth of 30-40 cm. Deep loosening destroys the plow pan, loosens compacted subsoil layer, and improves water and air permeability. For this purpose they use chisel deep loosening tillers ПЧ-2,5, ПЧ-4,5, ploughs-loosening ПРПВ-5-50, subsurface (flat-cut) deep tillers, tools for non-moldboard tillage such as paraplau, ploughs with notched bodies.

The highest efficiency of deep loosening of subsoil layers is achieved when cultivating row crops: corn, potatoes, sugar beets and others, as well as winter crops. The yield of row crops thus increases by 15-20%.

Methods of deep loosening are also carried out in the system of contour meliorative farming. On soils at risk of water erosion, deep loosening across the slope contributes to the transfer of water flow across the surface into the intra-soil flow, increasing water reserves and reducing soil washout.

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.