Biology and Fertility of Soils 

About: Biology and Fertility of Soils is an academic journal published by Springer Science+Business Media. The journal publishes majorly in the area(s): Soil water & Soil biology. It has an ISSN identifier of 0178-2762. Over the lifetime, 4073 publications have been published receiving 220682 citations.

Ameliorating physical and chemical properties of highly weathered soils in the tropics with charcoal – a review

Abstract: Rapid turnover of organic matter leads to a low efficiency of organic fertilizers applied to increase and sequester C in soils of the humid tropics. Charcoal was reported to be responsible for high soil organic matter contents and soil fertility of anthropogenic soils (Terra Preta) found in central Amazonia. Therefore, we reviewed the available information about the physical and chemical properties of charcoal as affected by different combustion procedures, and the effects of its application in agricultural fields on nutrient retention and crop production. Higher nutrient retention and nutrient availability were found after charcoal additions to soil, related to higher exchange capacity, surface area and direct nutrient additions. Higher charring temperatures generally improved exchange properties and surface area of the charcoal. Additionally, charcoal is relatively recalcitrant and can therefore be used as a long-term sink for atmospheric CO2. Several aspects of a charcoal management system remain unclear, such as the role of microorganisms in oxidizing charcoal surfaces and releasing nutrients and the possibilities to improve charcoal properties during production under field conditions. Several research needs were identified, such as field testing of charcoal production in tropical agroecosystems, the investigation of surface properties of the carbonized materials in the soil environment, and the evaluation of the agronomic and economic effectiveness of soil management with charcoal.

The use of phospholipid fatty acid analysis to estimate bacterial and fungal biomass in soil

Abstract: The cell content of 12 bacterial phospholipid fatty acids (PLFA) was determined in bacteria extracted from soil by homogenization/centrifugation. The bacteria were enumerated using acridine orange direct counts. An average of 1.40×10-17 mol bacterial PLFA cell-1 was found in bacteria extracted from 15 soils covering a wide range of pH and organic matter contents. With this factor, the bacterial biomass based on PLFA analyses of whole soil samples was calculated as 1.0–4.8 mg bacterial C g-1 soil C. The corresponding range based on microscopical counts was 0.3–3.0 mg bacterial C g-1 soil C. The recovery of bacteria from the soils using homogenization/centrifugation was 2.6–16% (mean 8.7%) measured by PLFA analysis, and 12–61% (mean 26%) measured as microscopical counts. The soil content of the PLFA 18:2ω6 was correlated with the ergosterol content (r=0.92), which supports the use of this PLFA as an indicator of fungal biomass. The ratio 18:2ω6 to bacterial PLFA is therefore suggested as an index of the fungal:bacterial biomass ratio in soil. An advantage with the method based on PLFA analyses is that the same technique and even the same sample is used to determine both fungi and bacteria. The fungal:bacterial biomass ratio calculated in this way was positively correlated with the organic matter content of the soils (r=0.94).

Fatty acid patterns of phospholipids and lipopolysaccharides in the characterisation of microbial communities in soil: a review

Abstract: This review discusses the analysis of whole-community phospholipid fatty acid (PLFA) profiles and the composition of lipopolysaccharides in order to assess the microbial biomass and the community structure in soils. For the determination of soil microbial biomass a good correlation was obtained between the total amount of PLFAs and the microbial biomass measured with methods commonly used for determinations such as total adenylate content and substrate-induced respiration. Generally, after the application of multivariate statistical analyses, whole-community fatty acid profiles indicate which communities are similar or different. However, in most cases, the organisms accounting for similarity or difference cannot be determined, and therefore artefacts could not be excluded. The fatty acids used to determine the biomass vary from those which determine the community structure. Specific attention has to be paid when choosing extraction methods in order to avoid the liberation of fatty acids from non-living organic material and deposits, and to exclude the non-target selection of lipids from living organisms, as well. By excluding the fatty acids which were presumed to be common and widespread prior to multivariate statistical analysis, estimates were improved considerably. Results from principal component analysis showed that determining the levels of fatty acids present in both low and high concentrations is essential in order to correctly identify microorganisms and accurately classify them into taxonomically defined groups. The PLFA technique has been used to elucidate different strategies employed by microorganisms to adapt to changed environmental conditions under wide ranges of soil types, management practices, climatic origins and different perturbations. It has been proposed that the classification of PLFAs into a number of chemically different subgroups should simplify the evaluating procedure and improve the assessment of soil microbial communities, since then only the subgroups assumed to be involved in key processes would be investigated.

Short-term assay of soil urease activity using colorimetric determination of ammonium

Abstract: A rapid assay for soil urease in the absence of bacteriostatic agents has been developed. The method comprises incubation of soil with an aqueous or buffered urea solution, extraction of ammonium with 1 N KCl and 0.01 NHCl and colorimetric NH4 + determination by a modified indophenol reaction. The method is characterized by high sensitivity and stability of the coloured complex formed. Measurements obtained by this method showed that no change in urease activity occurred when field-moist samples of soils were stored at −20°C for as long as 5 months. Air-drying of field-moist soil samples may lead to an increase in urease activity.

Mechanisms of real and apparent priming effects and their dependence on soil microbial biomass and community structure: critical review

Abstract: The number of studies on priming effects (PE) in soil has strongly increased during the last years. The information regarding real versus apparent PE as well as their mechanisms remains controversial. Based on a meta-analysis of studies published since 1980, we evaluated the intensity, direction, and the reality of PE in dependence on the amount and quality of added primers, the microbial biomass and community structure, enzyme activities, soil pH, and aggregate size. The meta-analysis allowed revealing quantitative relationships between the amounts of added substrates as related to microbial biomass C and induced PE. Additions of easily available organic C up to 15% of microbial biomass C induce a linear increase of extra CO2. When the added amount of easily available organic C is higher than 50% of the microbial biomass C, an exponential decrease of the PE or even a switch to negative values is often observed. A new approach based on the assessment of changes in the production of extracellular enzymes is suggested to distinguish real and apparent PE. To distinguish real and apparent PE, we discuss approaches based on the C budget. The importance of fungi for long-term changes of SOM decomposition is underlined. Priming effects can be linked with microbial community structure only considering changes in functional diversity. We conclude that the PE involves not only one mechanism but a succession of processes partly connected with succession of microbial community and functions. An overview of the dynamics and intensity of these processes as related to microbial biomass changes and C and N availability is presented.