As a main restoration measure to address degraded grasslands, the installation of fences is often accompanied by accumulation of organic litter. This accumulated litter is a layer of physical moisture which intercepts rainfall and may inhibit plant growth and development. One of the important means to judge a reasonable length of time of fencing (the time a fence is present) is through assessing the water-holding mechanism and capacity of the litter. In this study, four meadows in the Chinese Hulunbuir grassland with different years of fencing duration were investigated in order to obtain data on organic community and litter accumulation. A soaking method was used to study water-holding characteristics of the litter and was divided into three parts of stem, leaves and decomposed parts as a means to summarize the water-holding mechanism within the litter. The results showed that: (1) Compared with the light grazing meadows, the diversity and uniformity of communities in meadows of fencing displayed a downward trend, while the accumulation of litter increased. (2) The stems, leaves, and decomposed components of litter in different communities showed a highly positive linear correlation with their maximum water-holding capacity (WHC). This indicates that the stem/leaf mass ratio and decomposition degree of litter are key factors in regulating WHC. (3) Based on this understanding, we established a model based on stem and leaf mass to predict the water-holding potential of litter in real world situations.

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Rising temperature causes a process of phosphorus release, which can be characterized well using phosphorus release rates (VP). The objective of the present study was to investigate the major factors affecting sediment phosphorus release rates through a wetland habitat simulation experiment. The results showed that the VP of different wetland sediments were different and changed with the order of W–R (river wetland) > W–L (lake wetland) > W–M (grassy marsh wetland) > W–A (reservoir wetland). The main driving factors which influenced sediment phosphorus flux velocity in the sediment–water interface were sediment B-SO42−, B-MBN and A-MBP content. Path analysis and determination coefficient analysis indicated the standard multiple regression equation for sediment phosphorus release rates in the sediment–water interface, and each main factor was Y = −0.105 + 0.096X1 + 0.275X2 − 0.010X3 (r = 0.416, p < 0.01, n = 144), where Y is sediment phosphorus release rates; X1 is sediment B-SO42− content; X2 is sediment B-MBN; and X3 is sediment A-MBP content. Sediment B-SO42−, B-MBN and A-MBP content and the interaction between them were the main factors affecting sediment phosphorus release rates in the sediment–water interface. Therefore, these results suggest that soil chemical properties and microbial activities likely play an important role in phosphorus release rates in the sediment–water interface. We hope to provide effective scientific management and control methods for relevant environmental protection departments.

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A plant's foliar uptake of dew can mitigate the adverse effects caused by drought stress. However, in grassland ecosystems, it is inconclusive whether the dew condensation characteristics of plants at different heights are consistent. In this study, we wanted to know whether plant height had a significant effect on the formation of dew. In addition, we wanted to understand the difference of dew formation between C3 plant Leymus chinensis (LC) and C4 plant Cleistogenes squarrosa (CS) which have different heights and can succeed each other in the community. In nine dew nights, we measured the amount of dew formed on simulated condensation surface (different heights) and two plants at the same time. The results showed that in the height range of 5–80 cm, the dew amount increases with the canopy height, but its increase rate gradually slows down and approaches zero. The shorter CS (5–15 cm) has a similar dew amount (0.095 mm) as LC (40–70 cm) due to its compact structure of the leaves with pubescence and the more stable micro-meteorological conditions. The CS can obtain more potential dew per unit organic matter, and this may be one of the potential mechanisms for the succession from LC communities to CS communities under drought stress.