The Diversity and Community Assembly Process of Wetland Plants from Lakeshores on the Qinghai-Tibetan Plateau

Unravelling the patterns, potential processes and mechanisms underlying biodiversity has always been a crucial issue in community ecology. It is also a necessary first step for any conservation and restoration to better adapt fragile ecosystems to a changing climate. However, little is known regarding the structure and maintenance of plant communities in typical high-altitude wetlands. Here, we made a comprehensive analysis of the diversity and composition of wetland plant communities based on the distribution of plants near the shorelines of 19 lakes across the Qinghai-Tibetan Plateau. The latitude, mean annual temperature (MAT) and mean annual precipitation (MAP), along with the edaphic properties, were the dominant predictors affecting the taxonomic and phylogenetic α-diversity. Besides diversification, ecological drift, mixing with weak dispersal and weak selection shaped the community composition of wetland plants in our study. The latitude and MAP predictors, although modest, showed an impact on the community structure.

Shifts in Bacterial Community Associated with Green Manure Soybean Intercropping and Edaphic Properties in a Tea Plantation

The continuous cultivation with excessive application of agrochemicals has led to the deterioration of soils. Incorporating leguminous green manure (GM) was found to improve the physicochemical and biological properties of soils. However, the influence of GM soybean intercropping on the temporal distribution of bacterial communities in strongly acidic soils is less explored. In this study, a nine-month field trial of soybean intercropping was conducted in a deteriorated tea plantation. This was used to test the hypothesis that GM treatment ameliorates tea-cultivated environments through changing bacterial communities as well as edaphic properties. GM treatment was demonstrated to increase both functional and population diversity during all the months that were considered. An alteration of life strategies exhibited by bacterial communities in GM treatment was observed, which shifted from oligotrophy (Acidobacteria, Chloroflexi, and the candidate phylum WPS-2) to copiotrophy (Bacteroidetes and Proteobacteria). This also contributed to the remarkable increase in metabolic potential of bacterial communities toward all six carbon source categories. The potentially versatile organic matter decomposers and/or plant growth-promoting bacteria, such as Burkholderiaceae, Chitinophagaceae, Sphingobacteriaceae, and Sphingomonadaceae bacteria, were identified as the most effective biomarkers in GM treatment. These bacterial groups showed strong correlation with soil pH; organic matter; and available K, Ca, and Mg. The increased diversity, metabolic potential, and copiotrophic taxa provided insight into the benefits brought by soybean intercropping, with enhanced community stability, facilitated nutrient cycling, and microbe–plant interactions in the strongly acidic tea plantation.

Effect of Experimental Blocking on the Suppression of Spatial Dependence Potentially Attributable to Physicochemical Properties of Soils

One of the basic principles of experimental design is blocking, which is an important factor in the treatment of the systematic spatial variability that can be found in the edaphic properties where agricultural experiments are conducted. Blocking has a mitigating or suppressing effect on the spatial dependence in the residuals of a model, something desirable in standard linear modeling, specifically in design models. Some computer programs yield a p value associated with the blocking effect in the analysis of variance table that in many cases has been incorrectly used to discard it, and although it may improve some properties of the analysis, it may affect the independence assumption required in several models. Therefore, the present research recommends the use of the H statistic associated with the corrected blocking efficiency to show the role of blocking in modeling with the incorporation of an additional advantage rarely considered related to the suppression or mitigation of spatial dependence. With the use of the Moran index, the spatial dependence of the residuals was studied in a simple factorial design in a completely randomized and blocking field layout, which evidenced the advantages of blocking in the mitigation or suppression of the spatial dependence despite the apparently little or no importance it seems to show in the analysis of variance table.

Dependence of the Biological Activity of Brown Coal Humic Acids on the Concentrations of Macro and Trace Elements

The samples of humic preparations (HPs) containing macro and trace elements for plant nutrition were obtained based on humic acids isolated from brown coal of the Tisul deposit in the Kansk-Achinsk Coal Basin. The biological activity of the humic preparations was tested under laboratory and field conditions with the use of Iren and Novosibirskaya 89 varietal wheat seeds. A comparative assessment of the effects of the concentrations of various elements in the HPs on the growth parameters and productivity of cereals was carried out. The edaphic properties of soil substrates should be taken into account for a more effective use of humic preparations.

Forest biomass accumulation is an important source of acidity to forest soils: Data from Swedish inventories of forests and soils 1955 to 2010

The input of acidity to Swedish forest soils through forestry between 1955 and 2010 is compared with the acid input from atmospheric deposition. Depending on region, input of acidity from forestry was the minor part (25–45%) of the study period’s accumulated acid input but is now the dominating source (140–270 molc ha−1 year−1). The net uptake of cations due to the increase in standing forest biomass, ranged between 35 and 45% of the forestry related input of acidity while whole-tree harvesting, introduced in the late 1990s, contributed only marginally (< 2%). The geographical gradient in acid input is reflected in the proportion of acidified soils in Sweden but edaphic properties contribute to variations in acidification sensitivity. It is important to consider the acid input due to increases in standing forest biomass in acidification assessments since it is long-term and quantitatively important.