Soil functions

About: Soil functions is a research topic. Over the lifetime, 3706 publications have been published within this topic receiving 134250 citations.

The Nature and Properties of Soils

Abstract: 1 The Soils Around Us 2 Formation of Soils from Parent Materials 3 Soil Classification 4 Soil Architecture and Physical Properties 5 Soil Water: Characteristics and Behavior 6 Soil and the Hydrologic Cycle 7 Soil Aeration and Temperature 8 Soil Colloids: Seat of Soil Chemical and Physical Activity 9 Soil Acidity 10 Soils of Dry Regions: Alkalinity, Salinity, and Sodicity 11 Organisms and Ecology of the Soil 12 Soil Organic Matter 13 Nitrogen and Sulfur Economy of Soils 14 Soil Phosphorus and Potassium 15 Micronutrients and Other Trace Elements 16 Practical Nutrient Management 17 Soil Erosion and Its Control 18 Soils and Chemical Pollution 19 Geographic Soils Information 20 Prospects for Global Soil Quality Appendix A Soil Classification: World Resource Base Autralian and Canadian Systems Appendix B SI Units, Conversion Factors, Periodic Table of the Elements and Scentific Names of Plants Mentioned Glossary Index

Microbial diversity and soil functions

Abstract: Summary Soil is a complex and dynamic biological system, and still in 2003 it is difficult to determine the composition of microbial communities in soil. We are also limited in the determination of microbially mediated reactions because present assays for determining the overall rate of entire metabolic processes (such as respiration) or specific enzyme activities (such as urease, protease and phosphomonoesterase activity) do not allow any identification of the microbial species directly involved in the measured processes. The central problem posed by the link between microbial diversity and soil function is to understand the relations between genetic diversity and community structure and between community structure and function. A better understanding of the relations between microbial diversity and soil functions requires not only the use of more accurate assays for taxonomically and functionally characterizing DNA and RNA extracted from soil, but also high-resolution techniques with which to detect inactive and active microbial cells in the soil matrix. Soil seems to be characterized by a redundancy of functions; for example, no relationship has been shown to exist between microbial diversity and decomposition of organic matter. Generally, a reduction in any group of species has little effect on overall processes in soil because other microorganisms can take on its function. The determination of the composition of microbial communities in soil is not necessary for a better quantification of nutrient transformations. The holistic approach, based on the division of the systems in pools and the measurement of fluxes linking these pools, is the most efficient. The determination of microbial C, N, P and S contents by fumigation techniques has allowed a better quantification of nutrient dynamics in soil. However, further advances require determining new pools, such as active microbial biomass, also with molecular techniques. Recently investigators have separated 13C- and 12C-DNA, both extracted from soil treated with a 13C source, by density-gradient centrifugation. This technique should allow us to calculate the active microbial C pool by multiplying the ratio between labelled and total DNA by the microbial biomass C content of soil. In addition, the taxonomic and functional characterization of 13C-DNA allows us to understand more precisely the changes in the composition of microbial communities affected by the C-substrate added to soil.

Soil biodiversity and soil community composition determine ecosystem multifunctionality

Abstract: Biodiversity loss has become a global concern as evidence accumulates that it will negatively affect ecosystem services on which society depends. So far, most studies have focused on the ecological consequences of above-ground biodiversity loss; yet a large part of Earth’s biodiversity is literally hidden below ground. Whether reductions of biodiversity in soil communities below ground have consequences for the overall performance of an ecosystem remains unresolved. It is important to investigate this in view of recent observations that soil biodiversity is declining and that soil communities are changing upon land use intensification. We established soil communities differing in composition and diversity and tested their impact on eight ecosystem functions in model grassland communities. We show that soil biodiversity loss and simplification of soil community composition impair multiple ecosystem functions, including plant diversity, decomposition, nutrient retention, and nutrient cycling. The average response of all measured ecosystem functions (ecosystem multifunctionality) exhibited a strong positive linear relationship to indicators of soil biodiversity, suggesting that soil community composition is a key factor in regulating ecosystem functioning. Our results indicate that changes in soil communities and the loss of soil biodiversity threaten ecosystem multifunctionality and sustainability.

Microbial diversity in soil: Selection of microbial populations by plant and soil type and implications for disease suppressiveness

Abstract: An increasing interest has emerged with respect to the importance of microbial diversity in soil habitats The extent of the diversity of microorganisms in soil is seen to be critical to the maintenance of soil health and quality, as a wide range of microorganisms is involved in important soil functions This review focuses on recent data relating how plant type, soil type, and soil management regime affect the microbial diversity of soil and the implication for the soil's disease suppressiveness The two main drivers of soil microbial community structure, ie, plant type and soil type, are thought to exert their function in a complex manner We propose that the fact that in some situations the soil and in others the plant type is the key factor determining soil microbial diversity is related to the complexity of the microbial interactions in soil, including interactions between microorganisms and soil and microorganisms and plants A conceptual framework, based on the relative strengths of the shaping forces exerted by plant and soil versus the ecological behavior of microorganisms, is proposed