Tillage

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In agriculture and horticulture, soil cultivation is the term used to describe operations involving mechanical intervention in the soil , which are intended to produce or maintain a soil condition that is favorable for plant growth but also avoids damage (e.g. erosion ). In addition, the procedural requirements for plant production (e.g. drivability, pitting, ridge formation) should be created.

It is characteristic of all tillage methods that they bring the solid soil particles and the air and water content in the soil into the correct ratio or that this ratio is maintained. This is achieved, for example, by increasing the proportion and volume of the macropores or by interfering with the living conditions of the soil fauna, the biogenic pores in the soil and the living structures of the soil aggregates being promoted.

Suitable soil cultivation methods can also influence the water balance of the soil (e.g. reducing evaporation by breaking the soil capillaries), regulate competitive and harmful plant growth ( weeds ), control plant and animal pests, improve the availability of nutrients or their leaching reduce as well as deepen the arable top.

The various tillage methods are divided into primary tillage and secondary tillage. Mechanical intervention in the soil down to the depth of the soil is characteristic of primary tillage, and U. even beyond this ( subsoil , deep plowing ). Secondary tillage, on the other hand, includes machining operations up to a depth of approx. 10 cm to create a seedbed . Further cultivation work, which is also only superficial, is care work for root crops , for example to regulate weeds, break capillaries to reduce evaporation or ventilate the top crumb.

Primary tillage

In agriculture and horticulture, primary soil cultivation or primary soil cultivation is a not only superficial loosening, mixing and, under certain circumstances, turning (falling) cultivation of the upper soil layers . Common tools for basic soil cultivation are the manually operated spade (see also spade culture ), the spading machine , the cultivator or heavy cultivator , the tiller or the plow . The processing takes place in the crumb depth, i.e. in the area of ​​the so-called processing horizon, processing depths between 15 cm and 35 cm are therefore common.

Basic tillage precedes secondary tillage and sowing . Sometimes, however, primary and secondary tillage are done either by using an agricultural machine at the same time (example: top-deep milling) or by combining several tillage devices in one operation to save time and money.

Conventional tillage

The result of plowing should, among other things, be a clean field surface free of plant residues

Typical of the conventional tillage , and tillage operations or break called, is the regular use of the plow . Plowing causes turning, loosening, crumbling and ventilation of the topsoil at the depth of the soil. The cultivation process results in a clean field surface free of residues, as fertilizer, crop residues and vegetation (e.g. weeds ) are worked under by the turning process. The plowing of the fields thus also makes an important contribution to weed regulation, pest and disease control. However, the strong interference in the soil fauna through plowing also has negative effects, for example by damaging the earthworm population. The plowing of arable land can also be a major cause of soil erosion . In intensive arable farming it is the predominant method used to prepare the seeds of the main crop.

When draft animals were used, the plowing depth was often only around 10–15 cm before the one or two-horse carriage plow at the beginning of the 20th century. Larger working depths, such as those required when growing sugar beet , required the use of three or five powerful draft animals. With the advent of combine harvesters and the stay of straw in the field, the furrow depth had to be increased to ensure proper secondary tillage. However, nowadays the optimal depth of usually approx. 25 cm is exceeded many times. The plow bed compaction caused by plowing is difficult to remove by loosening the soil or growing deep-rooted plants (see green manure ).

Plowless tillage

A characteristic of tillage without a plow , also called non-turning or conservative tillage , is the renouncement of tillage (see also no-till ). Plant residues from the preculture, fertilizers or any weeds are not worked under to cover, but rather mixed into the top crumb depending on the intensity of the working method used. The practical importance of ploughless tillage only increased with increasing tractor performance , because on the one hand the working width of the machines should be at least the tractor width and on the other hand the devices used have a very high traction requirement. Typical devices for tillage without a plow are the cultivator and the heavy cultivator , which is sometimes also called a chisel cultivator or chisel plow.

Because of the extensive preservation of the soil horizons and the soil fauna, the plow-free cultivation increases the soil fertility and also helps to stabilize the soil structure. Not turning the soil can help reduce the occurrence of erosion and silting.

However, plowless arable farming requires consistent strategies for controlling diseases, pests and weeds. The lack of accommodation for stubble and straw can lead to the spread of fungal infections and pest invasions in the subsequent crop. Weed seeds accumulate in the upper soil layer, so that the effort required to control unwanted weeds increases. Often, no-till tillage is combined with the use of pre-emergence herbicides .

Ploughless primary tillage is currently the usual method for the cultivation of catch crops . In view of the problematic soil erosion in maize cultivation, non-reversing methods are also increasingly being used. Because of the disadvantages outlined above, it is often found in agricultural practice alternating with the plow furrow. It is not advisable to refrain from plowing on silty or sandy soils that tend to become dense, on waterlogged areas or when seeds are propagated.

Secondary tillage

Seedbed preparation with a rotary harrow after previous basic tillage by plowing

The secondary tillage is usually limited to the topmost 10 cm thick soil layer. It is used to prepare for sowing or planting and is therefore also called seedbed preparation . During secondary tillage, the top soil layer is often more finely crumbled than is the case with basic soil tillage, so that a level and non-encrusted top soil layer is created that the seedlings can easily break through. On the other hand, secondary processing is also widely aimed at securing the crop plants connection to the capillary system of the subsoil and thus the soil water stored there by means of reconsolidation measures under a thin, uppermost loose soil layer.

No-till method

In the no-till method , there is no need for any tillage before sowing. No-till is used on a large scale under arid conditions in pure grain crop rotations, for example in the USA or Australia. It is still a matter of dispute whether doing without soil cultivation makes economic and ecological sense even under the humid conditions in Central Europe.

literature

Web links

Commons : tillage  - collection of pictures, videos and audio files
Wiktionary: Soil cultivation  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. ^ Gustav Fischer: Agricultural engineering . Ulmer, Stuttgart 1928, reprinted by Weltbild, Augsburg 2005, ISBN 3-8289-5400-6 , p. 223.
  2. ^ Website of the Society for Conserving Soil Processing eV on methods of conservation soil cultivation (accessed on February 3, 2011).