No-till

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Sugar beets sown by no-till
Universal seed drill with disc coulters suitable for direct sowing

Under direct seeding is defined as a farming method with no tillage prior to sowing , which is already used on about 124 million hectares worldwide. The sowing takes place without plowing and harrowing directly after the harvest or in the unprocessed fallow land . The biomass of the preculture remains as mulch on the surface of the field. Special devices on the seed drill such as chisel, cutting disc or cross-slot shares only open narrow slots in the soil surface. These slots are covered with soil after the seed has been deposited. The soil is experiencing a mechanical intervention only in the actual seed rows, but there is no processing of the total arable land, to which, among other things emergence to prevent weeds. Weed control takes place mainly through crop rotation measures , targeted use of green manure and the use of herbicides .

Of modified no-till is called when additional work is carried out in connection with the direct seeding. This can be the use of mulchers, disc harrows or the attachment of row cultivators in front of the coulter. The goals of this ploughless seedbed preparation are: trouble-free sowing, more uniform placement depth and soil cover of the seed as well as faster soil warming, with more even field emergence, especially with maize and sugar beet sowing .

The exact delimitation of the terms no-till and mulch sowing is controversial and is handled very differently from region to region. While it is proposed, on the one hand, to use the scope of tillage during the sowing process as a definition of terms (direct sowing <50% soil movement - mulch sowing> 50% soil movement), on the other hand, in some regions of the German-speaking area even sowing without tillage is referred to as mulch sowing.

Procedure

Sweet peas as green manure. The dense soil cover also suppresses weeds
Frozen and collapsed yellow mustard stock as a basis for mulch or direct sowing
Harvested sugar beet field in which winter wheat was sown using modified direct sowing
The same field as in the previous picture after the winter wheat emerged, almost a month later

With direct sowing, there is no need for tillage prior to sowing, with modified direct sowing. Only the sowing process itself represents an intervention in the soil with direct sowing. In the direct sowing process, not only main crops can be sown, but also various catch crops that have positive effects on the following main crops. The crops or the remains of the main crops after harvest are killed either chemically or mechanically, or by freeze off in the winter (see FIG. Are green manure ) collapsed to the typical procedure for this mulch layer to obtain. Depending on the combination of main crop and cover crop, it is even possible in some cases to sow the main crop directly into the cover crop.

criticism

Per

Since the different no-till methods largely or completely refrain from tillage, the machine and labor costs for cultivating the fields decrease. Dispensing with tillage also improves the structural stability and particularly promotes the population of epigeous earthworms. The mulch layer is characteristic of the no-till system and, in the best case scenario, covers the soil all year round. This layer of mulch slows down impacting raindrops and thus reduces soil erosion . In addition, together with the catch crops, it suppresses the growth of field weeds. The permanent covering also reduces water loss through evaporation .

Because only the main crop is removed by the harvest and the crop residues and catch crops remain on the field, a large amount of organic carbon in the form of humus accumulates over time, which has a positive effect on soil stability and fertility.

Cons

A major disadvantage of no-till as a cultivation system is that the system only pays off after a certain period of time. For example, the proportion of organic carbon initially decreases shortly after the changeover and only increases again at a later point in time. During this time, the yield drops significantly compared to fields with conventional tillage. In addition, direct sowing is highly susceptible to pest infestation. Snails in particular have a major negative impact on the cultivation system and can force the farmer to completely plow up the area, whereby the organic matter that has accumulated up to that point is mineralized and the carbon escapes from the system in the form of CO 2 . Therefore, it is necessary to pay close attention to the properties of the catch crop and their consequences. Ideally, a mix of catch crops should be preferred to a monoculture . Due to the increased proportion of catch crops in the crop rotation, management is more complex from an agricultural point of view. Since the cultivated areas still have to be driven on with machines for sowing or mechanical mulching, but no tillage takes place, increased soil compaction will set in over time if the machine weight and weather are no longer considered. In the meantime, mechanical methods of terminating catch crops represent an alternative to the still widespread use of herbicides. One example is the so-called “ roller crimper ”, which creates a dense mulch from the catch crop into which it is then planted.

controversy

There is a controversial discussion as to how direct sowing as a cultivation system affects the environmental pollution caused by herbicide use . A higher load would be indicated by the fact that killing the catch crops increases the amount of effort. The lack of tillage also creates preferred flow paths in which herbicides can get into the groundwater more quickly than with conventional tillage. Herbicides are also able to slow down the mineralization process, which is the key advantage of the system. A lower environmental impact would be indicated by the fact that the mulch cover results in less surface runoff and so herbicides are flushed out in smaller quantities. In addition, due to the large number of micropores, a larger amount is retained in the soil. The climate also influences the level of environmental pollution. A high proportion of heavy rain, for example, causes the herbicides to dissolve and wash out quickly. A light rain before a heavy rain event first dissolves the herbicides, so that they can then be physically bound in the much more stable aggregates.

Special feature in the tropics

The mulch cover creates a higher albedo , which lowers the soil temperature by 8–16 ° C compared to conventional tillage. This creates a much better moisture preservation, which has a positive effect on the yields in a hot, dry climate. However, if, for whatever reason, the mulch layer is thinner than usual or not present at all, the loss of moisture through evaporation increases significantly.

Experience and practice in North America

No-till is the increasingly common form of land management in North America. In 2001, soil conserving farming practices, including no-till, were practiced on 60 percent of Canada's arable land. In 2004 no-till was used on 23 percent of the arable land in the United States. The geomorphologist David R. Montgomery expects that by 2018 this will be the usual method of cultivation to more than 50 percent of North American farmland. Various studies in the USA show that the complete abandonment of plowing results in a sometimes drastic reduction in soil erosion. For example, soil erosion on corn fields in the US state of Indiana fell by 75 percent, and on tobacco-growing areas in Tennessee by as much as 90 percent. However, the amount of soil erosion reduction depends on the respective soil and the crops grown.

However, the switch to no-till in the United States was made less because of the farmers' understanding of the need for soil protection measures, and more because of economic considerations. Thus, the 1985 and 1990 adopted "Food Security Act" forced the farmers cultivated the most vulnerable to erosion soils to appropriate countermeasures, as they otherwise grants and subsidies from the US Department of Agriculture would have been (USDA) deleted.

In the meantime, no-till is also increasingly being practiced on areas less affected by erosion, because it has proven to be a very time and cost-efficient method. Not plowing immediately reduces a farmer's fuel consumption by up to 50%, which compensates for the initially reduced yield. In the beginning, the method often means an increased use of pesticides and herbicides, which, however, decreases again when the soil organisms have recovered.

literature

  • CJ Baker, KE Saxton, WR Ritchie, WCT Chamen, DC Reicosky, F. Ribeiro, SE Justice, PR Hobbs: No-Tillage Seeding in Conservation Agriculture. CABI Publishing, Wallingford / New York 2007, ISBN 978-92-5-105389-8 .
  • Andrea Beste: Agricultural soil protection in practice. Basics, analysis, management. Preservation of soil functions for production, water protection and flood prevention. (= Series of Agricultural Science. Volume 15). 2005, ISBN 3-89574-536-7 .
  • BMVEL: Position paper on the definition of “good professional practice” in the Federal Soil Protection Act. 2001.
  • W. Buchner, K. Köller: Integrated tillage. Ulmer, Stuttgart 1990, ISBN 3-8001-4071-3 .
  • David R. Huggins, P. Reganold: Soil protection by avoiding plowing. In: Spectrum of Science. May 2009, ISSN  0170-2971 , pp. 78-85.
  • Rolf Derpsch, Theodor Friedrich, Amir Kassam, Li Hongwen: Current status of adoption of no-till farming in the world and some of its main benefits. (PDF) In: International Journal of Agriculture & Biological Engineering. Vol. 3 (2010), No. 1, doi : 10.3965 / j.issn.1934-6344.2010.01.0-0 (currently unavailable) .
  • DLG: no-till. 1997, leaflet 301 of the German Agricultural Society.
  • Sjoerd W. Duiker, Joel C. Myers: Steps towards a successful transition to no-till. College of Agricultural Science, Agricultural Research and Cooperative Extension, PennState University, 2006, cas.psu.edu (PDF; 4.2 MB).
  • G. Kahnt: Agriculture without a plow, requirements, methods and limits of no-till in grain crops. Ulmer, Stuttgart 1976.
  • Karlheinz Köller, Christian Linke: Successful agriculture without a plow. 2nd Edition. DLG-Verlag, Frankfurt am Main 2001, ISBN 3-7690-0574-0 .
  • Holger Kreye: Effects of non-turning tillage on the occurrence of harmful organisms in a sugar beet-wheat-wheat crop rotation. (Dissertation) Cuvillier Verlag, Göttingen 2001, ISBN 3-89873-390-4 .
  • Nina Waldorf, Sabine Grimm: Crop production and economic effects of different methods of tillage. “System comparison tillage.” Test report 1995–2002. As part of the research project: "Ecological effects of different tillage methods" on behalf of the Ministry for Nutrition and Rural Areas Baden-Württemberg. (= Information for plant production. Special issue 1/2003). State Institute for Crop Production Forchheim, ltz-bw.de (PDF; 1.4 MB).
  • Christian Linke: No-till - an inventory with special consideration of technical, agronomic and economic aspects. (Dissertation) Institute for Agricultural Engineering in the Tropics and Subtropics, University of Hohenheim 1998.
  • Norbert Lütke-Entrup, Marco Schneider: Sustainability and environmental compatibility of agricultural systems of soil use through crop rotation and conservation tillage / no-till. In: Umweltbundesamt (Hrsg.): Soil protection and agricultural land use - environmental effects using the example of conservative tillage. Texts 35/04 Umweltbundesamt, Berlin 2004, pp. 7–35 ( complete volume (PDF; 2.2 MB)).
  • David R. Montgomery : Dirt - The Erosion of Civilizations. 2nd Edition. University of California Press, Berkeley (CA) 2012, ISBN 978-0-520-27290-3 .
  • Shirley H. Phillips, Harry M. Young: No-Tillage Farming. Reiman Associates, Milwaukee (WI) 1973, OCLC 855476 .
  • WG Sturny, A. Chervet, C. Maurer-Troxler, L. Ramseier, M. Müller, R. Schafflützel, W. Richner, B. Streit, P. Weisskopf, U. Zihlmann: No-till and plow in a system comparison - a synthesis. In: AGRICULTURAL RESEARCH. (now Agricultural Research Switzerland ). Vol. 14 (2007), No. 8, pp. 350–357 ( agrarforschungschweiz.ch ; alternative full text (PDF; 157 kB)).
  • Ronald E. Phillips, Shirley H. Phillips: No-tillage agriculture. Principles and Practices. Van Nostrand Reinhold, New York a. a. 1984, ISBN 1-4684-1469-0 .

Web links

Commons : No-till  - collection of images, videos and audio files

Individual evidence

  1. Rolf Derpsch: No- till (as of April 15, 2014). No-till sowing: sustainable agriculture in the new millennium.
  2. Horst Eichhorn (Ed.): Landtechnik. 7th edition. Ulmer, Stuttgart 1999, ISBN 3-8001-1086-5 , p. 311 and 316.
  3. Rolf Derpsch: Sustainability (as of April 14, 2014). No-till sowing: sustainable agriculture in the new millennium.
  4. ^ A b c d David R. Montgomery: Dirt - The Erosion of Civilizations. 2nd Edition. University of California Press, Berkeley (CA) 2012, ISBN 978-0-520-27290-3 , pp. 211 f.