Moderne Reifen bieten groses Potenzial im Hinblick auf Boden schonenden Maschineneinsatz was selten konsequent genutzt wird. Der Einsatz im Grenzbereich mit minimalem Reifeninnendruck fur maximale Bodenschonung birgt das Risiko eines Reifenschadens durch Uberbelastung und ist in der Praxis schwer beherrschbar. Die vom Hersteller in den Reifentabellen vorgegebenen Grenzen konnen nur ausgeschopft werden, wenn die im Betrieb auftretenden dynamischen Belastungen des Reifens bekannt sind. Es wird gezeigt: die online gemessene Einfederung des Reifens ist ein verlasslicher Indikator und liefert ein praziseres Bild der tatsachlichen Lastsituation als die alleinige Berucksichtigung statischer Radlasten.

Part IV: A practice oriented solution-approach to prevent detrimental soil compaction The use of modern machines and equipment in farming carries with it the potential danger for soil compaction, and as a consequence, a reduction of soil functions. Knowledge drawn from long term soil observation areas, regional status surveys and systematic stress studies are essential to assess the level and acuteness of soil compaction damages and to derive recommendations for preventative soil protection. The solution-approach introduced in this paper is based on stress tests over a period of 15 years with practice oriented agricultural technology on para-brown soils. For farm management, at first a decision matrix is presented that offers assistance at both the investment and planning level for farm machinery. The available field working days and days of trafficability in a given region are considered. The second building block in the recommended solution approach is the monitoring during the deployment of machinery. The current compaction hazard is monitored with a specially developed hydrostatic settlement measuring tool. The online measurement coupled to the track depth is, for the driver, a sign of a critical or uncritical passage. In critical situations vehicle parameters are changed in a direction to reduce soil pressure, for instance with the help of an ultrasonic sensor in the tire rims to observe the tire deflection when reducing the inflation pressure. With the presented solution-approach it is possible to draw treatment recommendations based on the actual compaction hazard to the soil and to implement them. Thus they provide the farm with a maximum of preventive soil protection.

Soil compaction has a long-term negative impact oil the physical, chemical and biological processes in soil and therefore affects different functions of soil. The literature pertaining to this plant production problem is extensive and covers all facets. lit contrast, only few studies exist on file spatial distribution of harmful soil compaction in Germany.The purpose of this Study is to make a statement concerning soil compaction for southern Lower Saxony. Field and laboratory studies were to be linked to results from Ruhm (1983) after more than 50, and after 20, years. To assess the level of soil compaction, a system of indicators according to LEBERT et al. (27) was used, which is based on the evaluation of soil functions and soil structure. Here neither the soil bulk density (nor the porosity) determine the harmful compaction but rather the damage thresholds for the criteria air capacity, saturated water conductivity and the packing density, since all three must be fulfilled. Oil 47 arable fields in southern Lower Saxony, a total of 4440 soil core samples (100 cm(3)) were taken in each of two soil profiles and at each of four depths with 15 (2002) and 10 (in 2003) repetitions. The soils studied were mainly haplic luvisols (WRB) with loess as parent material. The sites considered were in sugar beet-cereal crop rotations, because the total weight of sugar beet- and cereal harvesting machines are often criticized today from the perspective of soil conservation.In the laboratory the dry bulk density or rather the porosity, the field soil moisture, the saturated water conductivity, the air conductivity, the pore size distribution, and thus the air capacity, field capacity, total available water content and permanent wilting point were determined.On the basis of the results from the laboratory studies, eight fields were selected which had critical air capacity and saturated water conductivity values according to the indicator system and thus Supported the assumption that harmful compaction might exist. Soil structure evaluations were conducted in the respective soil profiles in the year 2006 by assessing the packing density.According to the results presented, no large area compaction damage is found at present in the subsoil of the studied arable fields. While 10 of the 47 fields fulfil the criteria of air capacity and saturated water conductivity for compaction damage, the structure evaluations show a packing density for all fields of under "4". However, for prevention purposes, all possibilities for soil-protecting wheeling should be used.Some areas of the topsoil basis show slight partial harmful compaction; in tramlines and headlands harmful compactions were detected.Based on the results, the proposal was made to include the intensively tested fields in the program for permanent observation of soil areas in the state of Lower Saxony. Thus further changes in the soil structure, differentiated according to subsoil and topsoil basis in the agricultural production areas as well as for headlands would be documented. Already at the mid-term, an early warning system against soil compaction damage would thus be established.

To safeguard the ecological soil functions and the functions linked to human activities, measures against harmful changes to the soil are required, in line with the precautionary principle. The German Federal Soil Protection Act sets obligations for precaution in agricultural land use and, if harmful changes to the soil are foreseeable, measures for averting a danger.The results of a research project of the Federal Environmental Agency show that it is possible to describe an impairment of the soil structure, using methods of soil analysis. But this as a sole information would not quality for the identification of harmful changes to the soil in the context of the Soil Protection Act, which requires an assessment of the severity of disruption of soil functions and the respective subject of protection. This would make additional soil investigations on site mandatory.Approaches in agricultural engineering and soil physics have introduced procedures to preserve the soil structure, in accordance with the precautionary principle. But these procedures have different goals and different ranges of application and hence offer partial solutions to safeguard against soil compaction. The assessment model of "trafficability by measuring the rut depth" provides information about the compaction status of the soil under applied conditions for farming gear, without providing detailed information about affected soil layers. The soil-physical model of classifying soils into "risk classes for harmful soil compaction" focuses on the relationship between topsoil compaction and crop yields.The soil-physical models "precompression stress" and "loading ratio" provide information for the assessment of subsoil compaction and a prognosis of a possible impairment of the soil structure at the water content of field capacity.It is necessary to validate the individual models with additional regional data about soil structure before a final assessment of the prognoses is made.

At the Institute for Production Engineering and Building Research of the German Federal Agricultural Research Centre in Braunschweig, a measurement system has been developed which enables in situ vertical soil displacement measurements in the subsoil, caused by travelling with heavy wheel loads. In contrast to others, this method [1, 2] makes it possible to drastically reduce the input required for field measurements by using further-developed technology. The simple handling permits simultaneous measurements at different soil depths with multiple parallel measurements each time. In field trials, promising and reproducible results were obtained for different soils, under different soil conditions and loads.

Protecting soil structure against compaction—proposed solutions to safeguard agricultural soils To safeguard the ecological soil functions and the functions linked to human activities, measures against harmful changes to the soil are required, in line with the precautionary principle. The German Federal Soil Protection Act sets obligations for precaution in agricultural land use and, if harmful changes to the soil are foreseeable, measures for averting a danger. The results of a research project of the Federal Environmental Agency show that it is possible to describe an impairment of the soil structure, using methods of soil analysis. But this as a sole information would not qualify for the identification of harmful changes to the soil in the context of the Soil Protection Act, which requires an assessment of the severity of disruption of soil functions and the respective subject of protection. This would make additional soil investigations on site mandatory. Approaches in agricultural engineering and soil physics have introduced procedures to preserve the soil structure, in accordance with the precautionary principle. But these procedures have different goals and different ranges of application and hence offer partial solutions to safeguard against soil compaction. The assessment model of “trafficability by measuring the rut depth” provides information about the compaction status of the soil under applied conditions for farming gear, without providing detailed information about affected soil layers. The soil-physical model of classifying soils into “risk classes for harmful soil compaction” focuses on the relationship between topsoil compaction and crop yields. The soil-physical models “precompression stress” and “loading ratio” provide information for the assessment of subsoil compaction and a prognosis of a possible impairment of the soil structure at the water content of field capacity. It is necessary to validate the individual models with additional regional data about soil structure before a final assessment of the prognoses is made.

In the interest of agriculture and to fulfil legal requirements, land cultivation in farming must be precautionary and protective. According to §17 of the Federal Soil Conservation Law, (BBodschG) maintaining the productive functions (crop yield; costs), the regulative functions (gas exchange, infiltration) and soil habitat functions (soil organisms) are the basis of the best practice management. Hence soil compaction, especially in the subsoil, must be prevented. Three differing concepts for quantitative action recommended are discussed.

Journal of Plant Nutrition and Soil ScienceVolume 167, Issue 6 p. 761-761 Brief an die Redaktion Kommentar zu „Ist der Konzentrationsfaktor k eines aggregierten Bodens als steuernde Größe der mechanischen Druckverteilung in Böden eine Konstante?”︁ von H. H. Becher; J. Plant Nutr. Soil Sci. 167, 525–531 (2004). Claus Sommer, Claus Sommer claus.sommer@fal.de Search for more papers by this author Claus Sommer, Claus Sommer claus.sommer@fal.de Search for more papers by this author First published: 19 November 2004 https://doi.org/10.1002/jpln.200490036AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume167, Issue6December, 2004Pages 761-761 RelatedInformation

Field trials were conducted in Malice near Zamosc (South-east Poland) in the years 1996-2000 to assess the effect of different soil tillage methods and weed control measures on soil physical properties under a potato cultivation. The experiment maintained as a split-plot was carried out on leached brown soil, formed from light loamy silty soil (clay 13%, pH 5.6, org.-C 10.4 g kg(-1)). The soil tillage methods considered were: conventional tillage (CST), ridge tillage (ART) and spring reduced tillage (RST). The weed control measures considered were: mechanical (MWC), mechanical-chemical (MCC) and chemical (CWC). The results showed that the advantageous physical conditions of the soil for potato cultivation were ART and CST with CWC and MCC and RST with MCC. Also in these cases the yield of potato tubers was highest. The lowest yield of potato tubers was observed by using RST with MWC. In this case the yield of potato tubers was determined under low content of available water and higher penetrometer resistance conditions.

The loads imposed by modern farm machinery have considerable potential to increase subsoil stress. Within the context of economically viable and environmentally sustainable systems, the practices associated with subsoil damage and methods for avoidance are identified. The greatest potential for damage is on fragile, wet or loosened subsoils combined with high wheel or track loads and contact pressures that create noticeable ruts in the topsoil. In-furrow ploughing increases this potential considerably by placing loads on the subsoil. Measures to avoid this potential involve a whole farm approach and an understanding of the many interactions between cropping systems and machinery. Alternatives to in-furrow ploughing that involve working from the surface and building a protective topsoil are discussed. Key measures to reduce the risk to subsoils involve a clear understanding of tyre load and inflation data and simple on-farm methods of achieving this are suggested. Although avoidance has the potential to reduce the risk, confinement of damage to specific strips in the field is seen as a realistic alternative. Controlled traffic operations, together with precision guidance, offer an economic means by which compaction on the cropped area can be avoided. The most effective route to improvement in soil care across the European Union (EU) is an appropriate management structure coupled with a best practice framework.

Subsoil compaction is a severe problem mainly because its effects have been found to be long-lasting and difficult to correct. It is better to avoid subsoil compaction than to rely on alleviating the compacted structure afterwards. Before recommendations to avoid subsoil compaction can be given, the key variables and processes involved in the machinery–subsoil system must be known and understood. Field traffic-induced subsoil compaction is discussed to determine the variables important to the prevention of the compaction capability of running gear. Likewise, technical choices to minimise the risk of subsoil compaction are reviewed. According to analytical solutions and experimental results the stress in the soil under a loaded wheel decreases with depth. The risk of subsoil compaction is high when the exerted stresses are higher than the bearing capacity of the subsoil. Soil wetness decreases the bearing capacity of soil. The most serious sources of subsoil compaction are ploughing in the furrow and heavy wheel loads applied at high pressure in soft conditions. To prevent (sub)soil compaction, the machines and equipment used on the field in critical conditions should be adjusted to actual strength of the subsoil by controlling wheel/track loads and using low tyre inflation pressures. Recommendations based on quantitative guidelines for machine/soil interactions should be available for different wheel load/ground pressure combinations and soil conditions.

Le tassement du sol en culture est un probleme tres complexe. On donne les precautions a prendre contre les degats au sol par compression et specialement au sous-sol. L'adoption de techniques de recolte efficientes, et souvent aussi plus lourdes, mais menageant toutefois le sol, est possible sur base des recommandations et des aides de la pratique professionnelle. Celles-ci sont par consequent a developper pour donner des conseils et pour la pratique. Quant aux possibilites de diminuer les degats au sol par compression, il faut prendre en compte l'adaptation de la pression interieure des pneus du vehicule ainsi que l'indication de la profondeur des ornieres lors du passage.

Journal of Plant Nutrition and Soil ScienceVolume 165, Issue 6 p. 746-747 Book Review Buchbesprechung: Subsoil Compaction — Distribution, Processes and Consequences. Von R. Horn, J. J. van den Akker und J. Arvidsson Claus Sommer, Claus Sommer BraunschweigSearch for more papers by this author Claus Sommer, Claus Sommer BraunschweigSearch for more papers by this author First published: 18 December 2002 https://doi.org/10.1002/jpln.200290021AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume165, Issue6December 2002Pages 746-747 RelatedInformation