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In semiarid terrestrial ecosystems, optimized eco-rehabilitation strategies, such as land preparations and planting vegetation, are keys to achieve a successful ecological restoration. Land preparations and vegetation are supposed to have the coupled and respective impacts on soil ecosystem services, which are still unclear now. In this study, eighteen experimental plots with six different combinations and repetitions of land preparations and vegetation were built in the Chinese Loess Plateau in 2014 and soil moisture storages (SMS), soil carbon stocks (SCS) and other soil nutrient stocks were calculated at 0–100 cm, also the effects of land preparations and planting vegetation on soil eco-hydrological services are analyzed by mathematical methods. The results show that leveled ditches-M. sativa had the highest SMS (125 mm) while zig terraces-P. tabulaeformis had the lowest values (88 mm). Fish-scale pits-P. tabulaeformis had the most SCS (9804 g/m2) and leveled ditches-M. sativa had the lowest values (8163 g/m2). For soil nutrient stocks, leveled benches-C. microphylla and fish-scale pits-P. tabulaeformis had the highest levels while leveled ditches-M. sativa had the lowest values. The partial redundancy analysis (pRDA) and variation partitioning (VP) analysis indicated that soil nutrient stocks were most affected by the coupling effects of land preparation and vegetation. SMS at surface (0–10 cm) were mainly affected by precipitation (58.8%). Furthermore, SMS at subsurface (10–60 cm) and deep soil layer (60–100 cm) were affected by the shared effects of vegetation and land preparation (61.3%), and vegetation (72.2%), respectively. The findings quantified the coupling and respective contributions of vegetation restoration and land preparation to soil eco-hydrological services and demonstrate that the optimal combination of eco-rehabilitation strategies can achieve a sustainable land restoration.

The combination of land preparation techniques and vegetation could be an effective way to combat soil degradation on vulnerable, steep slopes. Because of the scale of re-vegetation and man-made micro-topographies in regions of hillies and gullies, quantifying the effects of land preparation techniques, precipitation, and vegetation on runoff and soil erosion remains challenging, particularly in semi-arid areas. This study investigated the runoff and erosion characteristics associated with different land preparation techniques (level bench, level ditch, fish-scale pits and adverse-grade tableland) in combination with different tree species (i.e., Caragana microphylla, Pinus tabulaeformis, Armeniaca sibirica, Platycladus orientalis) using network and redundancy analyses (RDA). Network analysis was used to identify the factors (rainfall features, vegetation types, and land preparation techniques) influential in surface runoff and erosion, while RDA was used to focus on the relations between surface runoff, soil erosion, and all of the influencing factors. Our results suggested that land preparation technique could reduce runoff generation on steep slopes, a key process that affects soil loss, although the extent was affected largely by the influence of the combination of the design of the engineering structure and the shape of the vegetation canopy. Our study indicated that Network analysis and RDA are practical methods to quantify the interactions and co-dependencies between rainfall features and other critical factors (vegetation type and ecological engineering) on runoff and soil loss that were difficult to assess previously using classical regression.

In water-restricted erosive mountains environments, large-scale vegetation plantation and diverse terracing measures have been widely used as the most powerful ecological-restoration tools to control water erosion and improve local degraded ecosystems, further enhancing the complexity of terracing, vegetation, and soil water relationships. In this study, 70 sampling sites across different hillslopes were selected and used for biweekly soil water measurement in a typical loess hilly catchment of China. The most typical terracing measures (broad bench terraces-BBT, narrow bench terraces-NBT, level ditch terraces-LDT, counter-slope terraces-CST, and half-moon terraces-HMT) and introduced vegetation types (wild peach, apricot, arborvitae, poplar, and Chinese pine) were included in the study. Based on multi-site measurements, the effects of terracing and vegetation on the profile of soil moisture dynamics at a depth of 2 m were analyzed. Results show that terracing generally has a very positive role in soil water enhancement. Compared with slope risers, terracing can increase soil moisture by 0.87% (±0.82%) to 37.71% (±9.01%), which benefits ecological restoration. However, the effects of various terracing measures on soil water differed. BBT measures were the most powerful in soil water recharge, with an incremental ratio of 21.88%, which is 4.94, 5.95 and 4.21 times that of CST (5.19%), LDT (4.43%) and NBT (3.68%), respectively. The existence of different plant communities can increase the uncertainties and complexities of soil water status. Introduced trees and shrubs generally induce a greater reduction in soil water than do natural plants in similar environmental conditions. The few remaining original hillslopes covered by natural grasses can better preserve soil water, because of large differences in water use strategies between planted and natural species. Such findings are expected to provide important references for the proper selection of terracing and artificial vegetation toward enhancing the efficiency of water conservation and ecological restoration in dry and degraded regions.

Dew, as an important contribution of non-rainfall water (NRW), plays a vital role in ecosystem processes in arid and semi-arid regions and is expected to be affected by climate warming. Infrared heater warming systems have been widely used to simulate climate warming effects on ecosystems. However, how this warming system affects dew formation has been long ignored and rarely addressed. In a typical alpine grassland ecosystem on the northeast of the Tibetan Plateau, we measured dew amount and duration using three independent methods: artificial condensing surfaces, leaf wetness sensors and in situ dew formation on plants from 2012 to 2017. We also measured plant traits related to dew conditions. The results showed that (1) warming reduced the dew amount by 41.6%-91.1% depending on the measurement method, and reduced dew duration by 32.1 days compared to the ambient condition. (2) Different plant functional groups differed in dew formation. (3) Under the infrared warming treatment, the dew amount decreased with plant height, while under the ambient conditions, the dew amount showed the opposite trend. We concluded that warming with an infrared heater system greatly reduces dew formation, and if ignored, it may lead to overestimation of the effects of climate warming on ecosystem processes in climate change simulation studies.

For thousands of years, humans have created different types of terraces in different sloping conditions, meant to mitigate flood risks, reduce soil erosion and conserve water. These anthropogenic landscapes can be found in tropical and subtropical rainforests, deserts, and arid and semiarid mountains across the globe. Despite the long history, the roles of and the mechanisms by which terracing improves ecosystem services (ESs) remain poorly understood. Using literature synthesis and quantitative analysis, the worldwide types, distributions, major benefits and issues of terracing are presented in this review. A key terracing indicator, defined as the ratio of different ESs under terraced and non-terraced slopes (δ), was used to quantify the role of terracing in providing ESs. Our results indicated that ESs provided by terracing was generally positive because the mean values of δ were mostly greater than one. The most prominent role of terracing was found in erosion control (11.46 ± 2.34), followed by runoff reduction (2.60 ± 1.79), biomass accumulation (1.94 ± 0.59), soil water recharge (1.20 ± 0.23), and nutrient enhancement (1.20 ± 0.48). Terracing, to a lesser extent, could also enhance the survival rates of plant seedlings, promote ecosystem restoration, and increase crop yields. While slopes experiencing severe human disturbance (e.g., overgrazing and deforestation) can generally become more stable after terracing, negative effects of terracing may occur in poorly-designed or poorly-managed terraces. Among the reasons are the lack of environmental legislation, changes in traditional concepts and lifestyles of local people, as well as price decreases for agricultural products. All of these can accelerate terrace abandonment and degradation. In light of these findings, possible solutions regarding socio-economic changes and techniques to improve already degraded terraces are discussed.