Hydrolysis of organic phosphorus(P) by soil phosphatases is an important process of P cycling in terrestrial ecosystems, significantly affected by nitrogen(N) and/or P fertilization. However, how soil acid phosphatase(ACP) and alkaline phosphatase(ALP) activities respond to N and/or P fertilization and how these responses vary with climatic regions, ecosystem types, and fertilization management remain unclear. This knowledge gap hinders our ability to assess P cycling and availability from a glo... 相似文献
The productivity of the Vertisols in the Ethiopian highlands could be raised by facilitating the removal of excess water from the fields in the main rainy season. This could be accomplished by the introduction of an animal powered broadbed maker (BBM) which shapes the soil into broadbeds and furrows. Thus with proper drainage, early sowing of crops becomes feasible. This study compared the plant-available water in the soil layer and the water use efficiency of local wheat and eight other cropping options and also assessed the grain and fodder productivities. Replacing late-sown local wheat with an early-sown improved wheat variety (ET-13) improved the utilization of the plant-available water during the rainy season and significantly increased grain and straw yields with a high rate of water use efficiency. The variations of the available moisture in the soil layer between the different cropping options tested were small during the rainy months of July and August due to the continuing replenishment of the used water. Differences of plant-available water in both upper and lower soil layers for the various cropping options became distinct at the onset of the dry season. Even though results showed that growing of a sequential crop, such as grass pea, following wheat is possible with a starter irrigation in the dry season, yields were generally depressed. 相似文献
This study aimed to explore the potential feasibility of magnetite powder as an erosion tracer for national-scale soil erosion monitoring in China.
Materials and methods
This study evaluated the effectiveness of silt-sized magnetite powder, a magnetic erosion tracer, in four representative erodible soils in China with distinct textures (from sandy loam to silty clay). The χlf values of different magnetic tracer-tagged aggregate size ranges (>?0.05 mm) were similar based on dry aggregate analysis.
Results and discussion
Simulated long-term leaching tests showed that the tracer had low mobility in soil profiles. The simultaneous separation of the tracer and tested soils under surface flow scouring conditions indicates that the tracer exhibited good bonding ability with different soils.
Conclusions
These findings indicate that magnetite powder is suitable for erosion monitoring in China. This method may be extended to other regions over the world.
In a Quercetum petraeae–cerris forest in northeastern Hungary, we examined effects of litter input alterations on the quantity and quality soil carbon stocks and soil CO2 emissions. Treatments at the Síkfőkút DIRT (Detritus Input and Removal Treatments) experimental site include adding (by doubling) of either leaf litter (DL) or wood (DW) (including branches, twigs, bark), and removing all aboveground litter (NL), all root inputs by trenching (NR), or removing all litter inputs (NI). Within 4 years we saw a significant decrease in soil carbon (C) concentrations in the upper 15 cm for root exclusion plots. Decreases in C for the litter exclusion treatments appeared later, and were smaller than declines in root exclusion plots, highlighting the role of root detritus in the formation of soil organic matter in this forest. By year 8 of the experiment, surface soil C concentrations were lower than Control plots by 32% in NI, 23% in NR and 19% in NL. Increases in soil C in litter addition treatments were less than C losses from litter exclusion treatments, with surface C increasing by 12% in DL and 6% in DW. Detritus additions and removals had significant effects on soil microclimate, with decreases in seasonal variations in soil temperature (between summer and winter) in Double Litter plots but enhanced seasonal variation in detritus exclusion plots. Carbon dioxide (CO2) emissions were most influenced by detritus input quantity and soil organic matter concentration when soils were warm and moist. Clearly changes in detritus inputs from altered forest productivity, as well as altered litter impacts on soil microclimate, must be included in models of soil carbon fluxes and pools with expected future changes in climate. 相似文献
Nests of the yellow meadow ant (Lasius flavus) occur at high densities in grasslands worldwide. Although many studies have shown that L. flavus nests influence soil nutrient contents, little is known about their effect on soil nutrient cycling rates. The aim of this study was to examine the role of nest-mounds inhabited by L. flavus as potential ‘hot spots’ for soil nutrient cycling. Six pairs of nest-mounds and control soils were selected at a grassland site at the plateau of the Alter Gleisberg (Thuringia, Central Germany). L. flavus significantly modified the soil environment within the nest. In comparison to the control soils, nest-mounds were characterized by slightly higher soil temperatures during the summer months. In addition, we found that nests were related to decreased potential C mineralization rates and increased potential net N mineralization rates. Nest-mound soil exhibited lower amounts of SOC, hot-water extractable DOC and DN, and higher concentrations of leachable DOC and DN. Moreover, ants promoted the enrichment of base cations in the nest. Differences in the soil environment between nests and control soils were possibly a result of the burrowing activity of ants, soil mixing, accumulation of aphid honeydew, and decreased plant-derived nutrient inputs into the nest-mound soil. In conclusion, L. flavus nest-mounds had a significant but element dependent effect on the soil nutrient cycling and may represent cold spots for C cycling and hot spots for N cycling. Thus, L. flavus nests increase the spatial heterogeneity of soil properties and create unique micro-sites within grassland ecosystems. 相似文献