No-till farming

Under no-till refers to a farming method without tillage prior to sowing, which is already used on more than 100 million hectares worldwide. The seed is without tillage directly after harvest or in the unprocessed Barrens. The residues of the plant material of the pre-culture to remain as mulch on the field. Special devices on the drill as chisel, cutting discs or Phillips coulters open only narrow slits in the soil surface. These slots are covered by seed tray with soil. The soil is well known from the actual seed rows mechanical intervention, but there is no processing of the total arable land among other things, the emergence of weeds to prevent. Weed control is carried mainly by crop rotation measures, targeted use of green manure and the use of herbicides.

Of modified tillage is called when the connection with the direct sowing additional work is carried out. This can be either the use of shredders, disc harrows and the cultivation of row milling in front of the coulter. Objectives of this no-till seedbed preparation are: interference-free seed, uniform seeding depth and soil cover of the seed as well as faster soil warming, with more uniform crop emergence especially in maize and sugar beet.

The exact delineation of no-tillage and minimum tillage Saatverfahrenbegriffe is controversial and is handled regionally very different. While on the one hand, proposed to use the extent of tillage at sowing process as a concept definition (Direct <50 % ground motion - mulch > 50 % ground motion ), on the other hand, refers in some regions of the German-speaking world itself a seed without soil tillage as mulch.

Method

When direct seeding is omitted any, in the modified no-tillage largely on a tillage before sowing. Only the sowing process itself is in the tillage intervention in the ground dar. can be sown direct seeding in the main not only fruits but also various cover crops that have positive effects on the subsequent main crop. The catch crops or the Remains of the main fruits after harvest are killed either chemically or mechanically or collapsed by freeze off in winter ( cf. green manure ) to obtain the typical method for this mulch layer. Depending on the combination of main crop and intercrop it is in some cases considered to sow the main crop directly into the cover crop into it.

Criticism

Per

Since it is largely or completely apart at the different tillage practices on soil tillage, fall machine and labor costs for the field order. Also causes the abandonment of tillage to improve the structural stability and promotes especially the population epigäischer earthworms. Characteristic of the no-till system is the mulch layer covering the ground at best, all year round. This layer of mulch slows impacting raindrops, thus reducing soil erosion. They also suppressed, together with the fruit between the growth of field weeds. Due to the permanent coverage of the water loss is reduced by evaporation also.

Because only the main crop is removed by harvesting and crop residues and cover crops remain in the field, builds up over time, a large amount of organic carbon in the form of humus on which affects soil stability and fertility positive.

Contraindications

A major disadvantage of no-till farming as a system is that the system pays off only after a certain time. The proportion of organic carbon will for example shortly after the transition from first to rise at a later point in time. During this time, the yield drops significantly in comparison to conventional panels with the soil. Further, in the no-till a high susceptibility to pest infestation is observed. Especially snails have a large negative impact on the farming system and can force the farmer to a complete upheaval of the surface, whereby the hitherto accumulated carbon is mineralized and escapes the system. Due to the increased proportion of catch crops in the crop rotation management, agriculture, professional point of view is more complex. Since the managed areas must continue to be driven to sowing or mechanical mulching with machines, but no tillage is done, will adjust with time increased soil compaction. Since the no-till system is dependent on chemical interventions, it can not be reconciled with the standards of organic farming in harmony.

Controversy

It is controversial how the tillage effect as cropping system on the environmental impact of herbicide use. For a higher load would say that by killing the cover crops increases the application rate. Likewise, caused by the lack of tillage preferred flow paths in which herbicides can quickly get into the groundwater than in conventional tillage. Herbicides are also able to slow down the mineralization process, which is the key advantage of the system. For a lower environmental impact would talk that through the mulch cover takes place a lower surface runoff and so herbicides are flushed in a lesser amount. In addition, a larger amount is retained in the ground by the large number of micropores. The climate also influences the degree of environmental impact. Thus, a high proportion of heavy rain causes the rapid release and leaching of the herbicides. A light rain before a heavy rain event triggers the herbicides only, so they can then be bound by physical means into the much more stable aggregates.

Particularity in the tropics

Through the mulch cover creates a higher albedo, the soil temperature compared to conventional tillage to 8 - 16 ° C lowers. The result is a much better moisture conservation, which has a positive effect on earnings. But if for any reason the mulch layer to be thinner than usual or not at all be present, so the moisture loss by evaporation in hot tropical climate increases considerably.