An insight to calculate soil conservation service

Quantifying soil conservation service is critical for sustainable land management. However, the traditional algo-rithm includes a gap between barren land and real soil erosion (BSERef), and its paradox is that a mass of barrenland rarely exists in ecologically adaptable areas with fertile soils, which might overestimate soil conservationservice. This study suggests a practical algorithm to effectively evaluate soil conservation service of differentecosystems. We propose a new algorithm based on the difference between cropland without control practicesand real soil erosion (CSERef), which is compared with the BSERef algorithm. Our results show that: (1) a nearlyfive times smaller mean soil conservation amount of cropland occurred in the CSERef algorithm (3.76×106 t·yr–1)than in the BSERef algorithm (20.04×106 t·yr–1);(2) land use has higher explanatory power for the spatial dif-ferentiation of soil conservation rate in the CSERef algorithm (15.93% – 46.34%) than in the BSERef algorithm(5.95% – 44.49%). Our results demonstrate that the BSERef algorithm overestimates the soil conservation serviceof cropland in ecologically adaptable areas, whereas the CSERef algorithm can effectively assess the influence ofland use change induced by anthropogenic activities on soil conservation service. Furthermore, we develop anassessment framework in terms of land use classification system following the Chinese Academy of Sciences. Theframework considers that for water bodies, there is no soil conservation service;for non-ecologically adaptable ar-eas (unused land) with vast barren lands and vegetation cover below 5%, the BSERef algorithm is recommended;the CSERef algorithm is suggested to use in ecologically adaptable areas (including woodland, grassland, crop-land and construction land). This assessment framework can provide scientific assistance for decision-makers toformulate strategies for sustainable land management.

Rainfall erosivity estimation over the Tibetan plateau based on high spatial-temporal resolution rainfall records

The Tibetan Plateau(TP)in China has been experiencing severe water erosion because of climate warming.The rapid development of weather station network provides an opportunity to improve our understanding of rainfall erosivity in the TP.In this study,1-min precipitation data obtained from 1226 weather stations during 2018–2019 were used to estimate rainfall erosivity,and subsequently the spatial-temporal patterns of rainfall erosivity in the TP were identified.The mean annual erosive rainfall was 295 mm,which accounted for 53%of the annual rainfall.An average of 14 erosive events occurred yearly per weather station,with the erosive events in the wet season being more likely to extend beyond midnight.In these cases,the precipitation amounts of the erosive events were found to be higher than those of the daily precipitations,which may result in implicit bias as the daily precipitation data were used for estimating the rainfall erosivity.The mean annual rainfall erosivity in the TP was 528 MJ mm·ha^(-1)·h^(-1),with a broader range of 0–3402 MJ mm·ha^(-1)·h^(-1),indicating a significant spatial variability.Regions with the highest mean annual rainfall erosivity were located in the forest zones,followed by steppe and desert zones.Finally,the precipitation phase records obtained from 140 weather stations showed that snowfall events slightly impacted the accuracy of rainfall erosivity calculation,but attention should be paid to the erosion process of snowmelt in the inner part of the TP.These results can be used as the reference data for soil erosion prediction in normal precipitation years.

Manipulating hot carrier cooling in silicon phononic crystals opens new application opportunities

Phononic crystals(PnCs)have had a multiple of important and promising applications such as sonic diodes,acoustic cloaking,optomechanic,and thermoelectrics[1–5].Undoubtably,it is of significance to explore new findings for PnCs,which can open new application opportunities.