Einführung in die Bodenphysik PDF

In agriculture, soil compaction is a complex problem in which soil, crops, weather and machinery interact. External pressure due to the use of heavy machinery and inappropriate soil management can lead to the compaction of subsoil, creating impermeable layers einführung in die Bodenphysik PDF the soil that restrict water and nutrient cycles. Unlike salinization or erosion, soil compaction is principally a sub-surface problem and therefore an invisible phenomenon. Special identification methods are necessary to locate, monitor and manage the problem appropriately.


Författare: Karl Heinrich Hartge.

Böden bestehen aus festen, flüssigen und gasförmigen Phasen. Sie stehen in intensivem Kontakt sowohl mit Niederschlags- und Grundwasser als auch mit der Atmosphäre und sind das Substrat für Pflanzen. Komplexe chemische und physikalische – meist quasi dynamische – Gleichgewichte bilden die Grundlage für die Eignungsbewertung eines Bodens zur ackerbaulichen Nutzung, die angesichts steigender Bevölkerungszahlen intensiviert werden muss. Die nun vorliegende, vollständig überarbeitete 4. Auflage führt in die grundlegenden physikalischen Prozesse in Böden ein und zeigt, wie die Veränderungen physikalischer Eigenschaften und Parameter (z.B. Körnung, Dichte, Durchlässigkeit, Belastung) die Stabilität und Ertragskraft von Böden beeinflusst. Die maßgeblichen Prozesse der Bewegung von Wasser, Gas und Wärme sowie die Interaktionen mit der festen Phase werden auf verschiedenen Skalenebenen detailliert behandelt und Möglichkeiten der Bodenverbesserung und des Bodenschutzes diskutiert. Englische (2014) und spanischsprachige (2014-2015) Ausgaben dieses Titels sind in Vorbereitung.

Top soil compaction is considered partly reversible and its occurrence controllable. Subsoil compaction, however, is regarded as the major problem because it can be permanent, meaning the pore functions can potentially not be restored after deterioration. Soil compaction is not a recent issue. Before the beginning of mechanized agriculture, the usage of plough-pans was associated with soil compaction. However, multiple studies have shown that modern farming techniques increase the risk of harmful soil compaction. In healthy, well-structured soils, particles interact with each other forming soil aggregates.

The resulting soil structure increases in stability with the number of interactions between soil particles. Water and air fills the voids between soil particles, where water interacts with soil particles forming a thin layer around them. This layer can shield particle-particle interaction thus reducing the stability of soil structure. Mechanic pressure applied to the soil is counterbalanced by an increase of soil particle interactions.

This implies a reduction in soil volume by reducing the voids in between soil particles. As a consequence water and air is displaced and soil bulk density increases, resulting in a reduced permeability for water and air. Soil structure, with angular, heterogeneous structures being more stable. Initial bulk density, dense soils are more resistant to compaction as the number of particle interactions is higher. Soil compaction can occur naturally by the drying and wetting process called soil consolidation, or when external pressure is applied to the soil. Use of large and heavy machineries for agriculture often causes not only topsoil but subsoil compaction. Subsoil compaction is more difficult to be regenerated than topsoil compaction.

It should be noted that not only may the weight of machineries i. Whether heavy machinery is in use or not, tillage practice itself can cause soil compaction. While the major cause of soil compaction in a tillage activity nowadays is due to machineries, the influence of compaction resulting from lighter equipments and animals to the topsoil should not be neglected. Moreover, inappropriate choices of tillage systems may cause unnecessary soil compaction. Significant livestock trampling resulting from livstock farming on meadows and agricultural land is also viewed major cause of soil compaction. This is not affected whether the grazing is continuous or short term, however it is affected by the intensity of grazing. Major effects on soil properties due to soil compaction are reduced air permeability and reduced water infiltration.