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1

Effects of agricultural land use change on fungal community composition

100%
Wu M., Zhong G., Meng D., Wei W.
Polish Journal of Ecology
|
2015
|
tom 63
|
nr 3
Anthropogenic disturbances, such as tillage, management practices, and fertilization, can influence soil microbial communities, but little is known about the effects of land use type on soil fungal communities. In this study, fungal abundance, diversity and community composition in soils were analyzed, to determine the impacts of different agricultural land use types, including old rice paddies (ORP), the long-term and (LTV), short-term (STV) cultivation of vegetables and Magnolia nursery plantations (MNP). Compared to the soils in ORP, the fungal abundance, determined by real-time quantitative polymerase chain reaction, was significantly higher in soils from LTV fields and lower in those from MNP; the copy numbers of the fungal ITS genes in the LTV soils were 30 times greater than in the MNP soils. The terminal restriction fragment length polymorphism (T-RFLP) results showed that the fungal community composition was obviously different in the different soils, based on land use type. Only three T-RFs were found in the soils from the LTV fields, followed by seven in the STV soils and nine in the MNP soils; the most (11) T-RFs were found in the ORP soils. Of the measured soil chemical properties, SOC, available P and NO₃⁻-N were the dominant factors that influenced the fungal communities based on the canonical correspondence analysis (CCA). The present study showed that conversion from paddy soil to vegetable cultivation changed soil properties, decreased soil fungal diversity, increased fungal abundance, and shifted fungal community composition.
2
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Soil organic matter properties in Stagnic Luvisols under different land use types

84%
Jonczak J.
Acta Agrophysica
|
2013
|
tom 20
|
nr 4
The aim of the study was an assessment of the influence of land use type on some properties of soil organic matter (SOM) and susceptibility to oxidation of organic carbon in Stagnic Luvisols in the area of the Sławno Plain. Soil samples from humic horizon were taken in five replications from six stands under different land uses – more than 100-year old beech-oak forest (BOF), meadow (M), arable field (AF), fallow (F), post-arable afforestation with 15 year-old birch (SAB) and 30-year-old alder (SAA). Soil samples were analysed for chemical properties with standard methods used in soil science, fractional composition of humus with Shnitzer method, absorbance ratios of 0.01% alkaline solutions of humic acids and suscetibility to oxidation of organic carbon with 0.033, 0.167 and 0.333 mol dm-3 KMn O4 solutions. The data obtained confirm a strong influence of land use type on SOM properties. Especially high differences were observed between forest soils, soils never used for agriculture, and arable or post-arable soils. Contribution of fulvic acids after dacalcification in total organic carbon (TOC) was the highest in the soils of fallow, slightly lower in secondary afforestation with birch and arable field, and much lower in the remaining stands. Some differences were also observed between the stands in the contribution of fulvic and humic acids in TOC. Humic acids predominated over fulvic acids in BOF, AF, F and SAB stands. Absorbance ratios of alkaline solutions of humic acids proves higher maturity of humus in stands under grass vegetation in relation to other stands. The content of KMnO4-oxidisable fractions of organic carbon varied among the stands, especially between forest and arable/post-arable soils. Statistically significant, positive correlation coefficients between the contribution in TOC of the most susceptible to oxidation carbon fraction and light absorbance ratios of alkaline solutions of HA indicate higher susceptibility to oxidation of young humic acids over more mature ones.
3

Ground vegetation carbon and its relation to climate and species richness

67%
Solon J., Roo-Zielinska E.
Polish Journal of Ecology
|
2003
|
tom 51
|
nr 4
Ten pine forest sites located along the transect between 50°28′ and 70°09′ N were studied. The purposes of the present paper are: 1) to determine the volume of the organic carbon pool in selected layers of the analysed forest ecosystems (shrubs, herb layer, mosses and lichens, litter, and the humus horizon of the soil); and 2) to elaborate the correlation-based prediction models relating the organic carbon pools in these layers with the selected variables characterising the climate and the species richness of the pine forests. The results indicate a clear horizontal heterogeneity of the ground layer in the pine forests considered. This is reflected, in particular, through the differentiation of the carbon pool in particular places within the ecosystem. There is a distinct geographical variability in the carbon pool among the sites in particular layers, with the average annual and January temperatures having the largest influence on this variability. However, in different cases there are different combinations of the factors describing these relations in the best way. The relations between the carbon pool and the species richness of the sites along the transect show that either the minimal carbon pool occurs at sites of an average species richness, or there is no relation between these variables. The analysis implies that there are two points of the transect at which various characteristics of the system undergo an abrupt shift. The first of them is equivalent to the passage of the annual +1°C isotherm, while the second at approximately 5-6°C. There is the possibility that these regularities occur within the entire range of the pine forests.
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