Interactions among Soil Physical, Chemical and Biological Properties under Different Farming Systems

抄録

The definition of soil quality has always been changing over time within the soil science community. At first, the study focused more on chemical and physical properties and less importance on a sustainable environment. Therefore, the definition of soil quality has changed in the last decade. The importance of biodiversity that exists both on the surface and within the soil began to be understood. These organisms have essential functions such as nutrient cycling, provision of plant nutrients, and modification of physical soil structure, water regimes, and suppression of undesirable organisms on cropland. It has defined soil quality as the function it has within the environment, sustaining productivity, maintaining environmental quality, and promoting health in plants and animals. However, the interaction between some microorganisms is still unknown, or how it could affect the different parameters in the biodiversity of an agro ecosystem. Furthermore, it is unknown what parameters are important in determining soil quality. Therefore, this study analyzed the biological, physical, and chemical properties of the soil of two farms whose practices is different. Water retention capacity, aggregate distribution, organic matter, total nitrogen, NO₃, NH₄, and biomass of microorganisms were measured. Soils were air dried and sieved to 2mm. They were analyzed after drying in an oven at 105° C for 24 h. The biomass of microorganisms was measured by the direct extraction method. The results indicated that there was a significant difference between the microorganisms but could not be found with physical and chemical properties. This result could indicate the importance of biological properties over other parameters to discuss soil quality. In addition, the differences observed could be explained by the different practices carried out on each farm.