'Soil Physical Quality'
2-4 Oct 2003
organizers: Prof. Anthony R. Dexter,
Assoc. Prof. Ewa A.Czyz
The international workshop on "Soil Physical Quality" was organised by the EC Centre of Excellence PROLAND in IUNG, Pulawy, Poland from 2 - 4 October 2003 with 39 registered participants including 12 from abroad. The workshop included three working groups: A - "Soil structure, stability and soil mechanics"; B - "Soil hydraulic properties"; C - "Soil management and organic matter"
Working group A identified a range of practical soil problems in the field that are associated with soil structure: wind and water erosion, loss of organic matter, loss of stability, sealing and crusting, compaction, insufficient aeration, stratification, pore continuity, rootability and workability. It was stressed out that research in the filed should be done as much possible in collaboration with pedologists , while the laboratory experiments should provide more good data on soil porosity and pore continuity, soil structural stability, the strength of soil aggregates, shear strength and soil compressibility. It was pointed out that a current barrier to progress is the lack of accepted standard methods for the measurement of many soil physical properties. Discussion led to the conclusion that undisturbed soil generally has a more favourable structure and physical properties than soil that has been disturbed To reduce the problem in the field soil should be disturbed as little as possible. However, some tillage is still needed to control weeds and plant pathogens.
Working group B reached four principal conclusions: - The principal problems in soil hydraulics are generally identical in all the countries represented; - Solution of these problems will be achieved through close cooperation in studies involving quantitative soil micromorphology and research on the hydrostatics and hydrodynamics of the soil pore system; - The pedotransfer functions developed have to include a well-defined value on the soil water retention curve; - For broader use and for applications of soil hydraulic properties, the working group recommended the building-up of a database involving as many countries as possible. The system should contain the directly measured values of soil hydraulic properties together with the associated soil-site information.
Working group C recognized that organic matter is beneficial for soil physical quality but noted that many countries are reporting declining levels of soil organic matter. Measurement of the total amount of soil organic matter is not easy because of stratification and mixing effects. Carbon sequestration was considered to be good for the soil, however, it is predicted not to have much impact on atmospheric levels of CO2 (a greenhouse gas). Some problems were identified with existing measurement facilities and techniques as well as factors limiting scientific progress in this field. New technologies were recognized which could be valuable in improving the soil organic matter status and hence the soil physical quality. Some factors limiting scientific progress were discussed.
Workshop materials are available on request at: email@example.com