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[学术文献 ] Multivariate Assimilation of Satellite-based Leaf Area Index and Ground-based River Streamflow for Hydrological Modelling of Irrigated Watersheds using SWAT+ 进入全文
ScienceDirect
Vegetation dynamics have different effects on the terrestrial water cycle and therefore play an important role in catchment-scale biophysical and hydrological modeling. Meanwhile, validation of hydrological models of irrigated watersheds concerning vegetation dynamics has rarely been studied. In this study, we propose a combinatorial approach for modelling irrigated watersheds; at first, based on Sentinel-2 (S2), we provide crop/land-use mapping; then we retrieve S2-based leaf area index (LAI) through the neural network algorithm and the PROSAIL model; finally, we employ sequential particle filter (PF) technique to explore the benefits of jointly assimilating high-resolution S2-LAI as well as in-situ river discharge observations for improving the predictive accuracy of SWAT+ model. Moreover, we explain how SWAT+ source code must be modified to implement the assimilation procedure. The developed methodology is applied to an irrigated watershed in Iran; we provide 66 raster LAI maps with a spatial resolution of 20 meters for the study area related to January to December of 2019 as well as crop/land-use mapping of 2019 with a spatial resolution of 10 meters. Results show that improvements in the hydrological simulation of LAI, evapotranspiration, and river discharge are achieved when we apply multivariate assimilation of S2-LAI and streamflow observations, compared to univariate assimilation scenarios. Results also reveal that LAI assimilation has a significant influence on the estimation of irrigation volume and timing.
[学术文献 ] Land use impacts on weathering, soil properties, and carbon storage in wet Andosols, Indonesia 进入全文
ScienceDirect
We investigated changes in geochemical soil properties in response to deposition age and land use management over 30 – 50 years on tropical volcanic soils. Our purpose was to find out how weathering stage and land use interactively affect soil properties and organic carbon, and to check if phenoforms (management-related soil subtypes) exist within the genoforms (genetic soil types). Soil samples were taken at land uses that have been converted (pine forest and agricultural land) and a natural forest as the original land use. The results showed that pine forest soil displayed more intense weathering as indicated by higher values of three weathering indices. Intensive agricultural practices also improved soil chemical properties such as pH, exchangeable base cations, base saturation, and organic carbon stock leading to WRB-qualifier of “eutric” in cultivated soils, whereas the average of bulk density was relatively similar between forests and cultivated soils. Positive correlations were found between amorphous materials and Alo, specific surface area, and micropore volume. Correlations between the content of short-range order Al (hydr-) oxides (indicated by Alo) and organic carbon were found in pine forest and agricultural soils, particularly in subsoils. Our results clearly indicate the increase of base cations retention due to less acidification and an increase of organic carbon stock under agricultural land use, likely due to stabilization with non-crystalline materials.
[学术文献 ] 覆砂和灌水量对退耕压砂地生态枣林土壤水热及枣果产量的影响 进入全文
农业资源与环境学报
为探明覆砂和灌水量对退耕压砂地生态枣林土壤水热及产量的影响，在宁夏中部干旱带开展大田试验，通过设置2种覆盖方式 [覆砂（M）、裸土（N）]和3个灌水量 [低水：180 mm（W1）、中水：210 mm（W2）、高水：240 mm（W3）]，研究覆砂和灌水量对土壤温度、土壤贮水量以及枣果产量和水分利用效率的影响。结果表明：与裸土相比，覆砂使0～10 cm土壤温度提高0.8～3.1 ℃。覆砂后土壤升温时段（10:00—14:00）明显滞后于裸土（8:00—14:00），升温速度比裸土处理快0.4 ℃·h-1。覆盖方式及灌水量对枣树全生育期0～80 cm土壤贮水量影响显著（P<0.05），覆砂处理较裸土处理平均提高10.97%，且在土壤含水率较低的萌芽展叶期增幅最高，达14.54%。覆砂条件下枣树生长指标、产量和水分利用效率均高于裸土，不同灌水量的产量从高到低依次为W3>W2>W1，分别较裸土处理增加5.98%、10.54%、26.80%，其中MW2处理水分利用效率最高，为1.55 kg·m-3。综上，MW2处理（覆砂、中水210 mm）可作为宁夏中部干旱带退耕压砂地生态枣林适宜的种植模式。
[学术文献 ] 基于土地利用变化的山东省生境质量时空演变特征 进入全文
土壤通报
厘清近20年山东省生境质量演变特征，明确土地利用变化对生境质量的影响。运用InVEST模型、GIS空间分析方法分析了2000～2018年山东省生境质量的时空演变特征。研究表明：（1）2000～2018年山东省生境质量整体处于中级水平且空间差异显著，总体呈现中东部高、西部低的空间格局；较低及以下等级生境质量区趋于沿湖、沿海地区及城市市区集中分布，较高及以上等级生境质量区呈现山地、丘陵集聚特征。（2）生境质量指数从0.558下降到0.538，生境质量级差化特征明显，生境质量提升区趋于济南、淄博、潍坊、青岛、临沂等城市边缘区集中分布，生境质量退化区集聚于滨州、东营、潍坊市沿海地区。山东省生境质量时空变化受土地利用变化影响显著，生境质量提升区主要发生在耕地向林地、草地转化以及未利用地向林地、水域、草地转化地区。
[学术文献 ] Analysis of the regional differences in agricultural water poverty in China: Based on a new agricultural water poverty index 进入全文
ScienceDirect
China's agricultural water resource utilization contradiction is prominent, and there are obvious differences in the distribution and utilization of water resources among regions. The theory of agricultural water poverty is of great significance to promote the efficient utilization of agricultural water resources and alleviate the contradiction of agricultural water use. However, the definition of the existing agricultural water poverty theory is quite controversial, and the mainstream agricultural water poverty index (AWPI) for measuring agricultural water poverty has disadvantages such as complex index selection and lack of unified weights. In this regard, this research takes the lead in providing a more complete definition of agricultural water poverty with reference to the definition of water poverty. In terms of method, the research refers to the Social Water Stress/Scarcity Index (SWSI) framework and proposes a new agricultural water poverty index from the two aspects of agricultural water scarcity and agricultural development capability. Based on this index, the regional differences in agricultural water poverty in China are analyzed. The main findings of the study: The agricultural water poverty index proposed in this study has rich connotations, is easy to compare objectively between regions and is applicable in the field of agriculture. The regional differences in agricultural water poverty in China are large, the number of areas with serious agricultural water poverty problems is large, and such problems last for a long time. The distribution of agricultural water poverty in China has spatial autocorrelation rather than a random distribution. China's relative agricultural water poverty index fluctuates around high values, the gap in agricultural water poverty between regions has not narrowed, and the contradiction in relative agricultural water poverty is prominent. The occurrence paths of agricultural water poverty in different regions are different, and the situation in different regions should be identified based on the scarcity of agricultural water resources and the development capability of agricultural production. Finally, this study expects to improve agricultural water poverty theory to effectively alleviate the problem of agricultural water poverty in different regions and promote balanced regional development.
[学术文献 ] Global meta-analysis shows progress towards recovery of soil microbiota following revegetation 进入全文
ScienceDirect
The global declines in biodiversity and ecosystem integrity demand effective restoration. Soil microbiota are fundamentally linked to biodiversity and ecosystem restoration, as they are central to important ecological functions (e.g., nutrient cycling) and are extremely species rich. Their importance, plus the growing affordability of high-throughput sequencing, has resulted in rapid growth of studies that associate soil microbiota recovery and ecosystem restoration via native plant revegetation. Here we provide a systematic literature search and meta-analysis of the association between native plant revegetation and recovery of soil microbiota, identifying 26 datasets. We show that the soil microbial composition in revegetated sites was more similar to reference sites than degraded sites, indicating the recovery of soil microbiota with revegetation. However, a significant difference in composition between revegetated and reference sites indicates that a restoration gap remains. Bacteria showed greater recovery than fungi, which is consistent with bacteria having shorter generation times and being less dispersal-limited than fungi. We observed no general effect of revegetation on soil microbial richness. Showing that soil biodiversity is generally being returned via native plant revegetation should help conservation policymakers and practitioners that utilise this approach be more confident that their efforts are helping to combat global ecological and biodiversity declines. However, more research is required into the drivers of – and solutions to – the restoration gap, such as long-term monitoring of soil microbiota recovery, as this gap may present a long-term legacy that cannot be overcome with current-day revegetation practices.
