Effect of farm management on topsoil organic carbon and aggregate stability in water: A case study from Southwest England,UK

There are few reliable data sets to inspire confidence in policymakers that soil organic carbon (SOC) can be measured on farms. We worked with farmers in the Tamar Valley region of southwest England to select sampling sites under similar conditions (soil type, aspect and slope) and management types. Topsoils (2–15 cm) were sampled in autumn 2015, and percentage soil organic matter (%SOM) was determined by loss on ignition and used to calculate %SOC. We also used the stability of macroaggregates in cold water (WSA) (‘soil slaking’) as a measure of ‘soil health’ and investigated its relationship with SOC in the clay‐rich soils. %SOM was significantly different between management types in the order woodland (11.1%) = permanent pasture (9.5%) > ley‐arable rotation (7.7%) = arable (7.3%). This related directly to SOC stocks that were larger in fields under permanent pasture and woodland compared with those under arable or ley‐arable rotation whether corrected for clay content (F = 8.500, p < .0001) or not (F = 8.516, p < .0001). WSA scores were strongly correlated with SOC content whether corrected for clay content (SOC_adj R² = .571, p < .0001) or not (SOC_unadj R² = 0.490, p = .002). Time since tillage controlled SOC stocks and WSA scores, accounting for 75.5% and 51.3% of the total variation, respectively. We conclude that (1) SOC can be reliably measured in farmed soils using accepted protocols and related to land management and (2) WSA scores can be rapidly measured in clay soils and related to SOC stocks and soil management.     

土壤调理粉剂处理下茶园土壤重金属污染特征及潜在风险评价

本文以贵州安顺不同土壤调理粉剂处理下“瀑布毛峰”茶园土壤为供试样品,通过样品测试与理化分析,对CK处理(0 kg/hm²)、A处理(600 kg/hm²)、B处理(750 kg/hm²)和C处理(900 kg/hm²)下茶园土壤重金属含量特征及污染水平进行探讨。结果表明：不同土壤调理粉剂处理下,研究区域土壤重金属Cr、Hg、Pb、Cu、Zn、Ni、As和Cd的变异程度各异,且土壤中这8种重金属含量也各不相同,其中pH、Cr、Pb和Ni含量在C处理中最高,As、Hg和Cd含量在A处理中最高,Cu和Zn含量在B处理中最高;对各重金属元素进行相关性分析可知,Ni与Pb之间存在极显著相关性,表明两者之间的同源性极高,其余元素之间相关性特征不明显;由综合污染指数（P_综）得出A处理为轻度污染,CK处理、B处理和C处理均为中度污染,不同处理土壤中Cr均在国家Ⅱ级标准(GB15618—2008)规定范围内,样点达标率为100%,在所选定的污染评价因子中,Cu的贡献率最高,为土壤主要影响因子,其次是Cd和Ni;研究区土壤重金属单项潜在生态风险指数($E_{r}^{i}$)中Hg属于强生态风险,其余7种重金属处于轻微潜在生态风险等级;综合潜在生态风险指数(RI)平均值为196.79,总体处于中等潜在生态风险水平,Hg对RI的贡献率最大,是最主要的生态风险元素。     

土壤生态环境损害鉴定评估中基线确定方法讨论

随着近年来我国经济的高速发展,各地生态环境污染和破坏形势日益严重,特别是涉及土壤环境的污染和破坏事件日益增加,需要对发生土壤污染的场地进行损害鉴定评估工作。根据生态环境部《生态环境损害鉴定评估技术指南总纲和关键环节第1部分:总纲》(GB/T39791.1-2020)等技术规范,规定了4种基线确定方法:即历史数据法、对照数据法、标准基准和专项研究等方法。通过相关案例,主要分析了土壤生态环境损害鉴定评估工作中对照数据法中基线值确定方法,为后续开展相关土壤环境损害鉴定评估工作提供一定的参考。     

洞庭湖烂泥湖水系洪涝灾害风险评估与应对措施

近年来,洪涝灾害是全球发生频繁、危害最严重的气象灾害之一,国内不少学者开始对洪涝灾害进行研究,目前对于洞庭湖区洪涝灾害风险的研究较少。采用综合评价法建立模型对洞庭湖区烂泥湖水系洪涝灾害风险进行评估并提出应对策略,结果表明:新泉寺闸内水位和滞涝水面率的不同导致暴雨对烂泥湖水系的影响程度也不同。同时采取提高滞涝水面率和降低内湖水位,基本可以消除一般年份处于高风险的范围,对于减少低风险范围、增加无风险范围效果更为显著;对于平均风险度为高风险的年份,能够消除大部分高风险区域。     

基于WOFOST模型的辽宁省春玉米干旱灾损风险评估

利用锦州农业气象试验站的作物生长发育和土壤实测数据对WOFOST模型水分胁迫模块进行了调参，适用性验证表明，WOFOST模型适用于辽宁省春玉米生长发育和产量的模拟，辽宁省春玉米受干旱的影响可以利用WOFOST模型较敏感地反映出来。利用调参后的WOFOST模型模拟了全生育期及出苗~拔节、拔节~抽雄、抽雄~乳熟和乳熟~成熟各阶段发生轻、中、重旱情景对辽宁省春玉米产量的影响，并根据模拟结果确定了不同干旱风险等级下辽宁省东、中、西部玉米生产的灾损范围。结果表明：不同生育期发生干旱对产量的影响不同，总体上，抽雄~乳熟期发生干旱的影响最大，其次是拔节~抽雄期，而出苗~拔节期和乳熟~成熟期发生干旱对产量的影响较小，全省春玉米在抽雄~乳熟期发生重旱的减产风险达30%~70%；在相同干旱水平下，不同区域受影响程度也不同，在全生育期及各生育阶段发生轻、中、重旱情景下，干旱导致的减产率总体上表现为由东部向西部地区逐渐加重的趋势，在全生育期重旱情景下，辽宁省东部的春玉米减产率为40%~75%，中部为60%~90%，西部达65%~95%。     

Assessing the effects of vegetation and precipitation on soil erosion in the Three-River Headwaters Region of the Qinghai-Tibet Plateau,China

Soil erosion in the Three-River Headwaters Region (TRHR) of the Qinghai-Tibet Plateau in China has a significant impact on local economic development and ecological environment. Vegetation and precipitation are considered to be the main factors for the variation in soil erosion. However, it is a big challenge to analyze the impacts of precipitation and vegetation respectively as well as their combined effects on soil erosion from the pixel scale. To assess the influences of vegetation and precipitation on the variation of soil erosion from 2005 to 2015, we employed the Revised Universal Soil Loss Equation (RUSLE) model to evaluate soil erosion in the TRHR, and then developed a method using the Logarithmic Mean Divisia Index model (LMDI) which can exponentially decompose the influencing factors, to calculate the contribution values of the vegetation cover factor (C factor) and the rainfall erosivity factor (R factor) to the variation of soil erosion from the pixel scale. In general, soil erosion in the TRHR was alleviated from 2005 to 2015, of which about 54.95% of the area where soil erosion decreased was caused by the combined effects of the C factor and the R factor, and 41.31% was caused by the change in the R factor. There were relatively few areas with increased soil erosion modulus, of which 64.10% of the area where soil erosion increased was caused by the change in the C factor, and 23.88% was caused by the combined effects of the C factor and the R factor. Therefore, the combined effects of the C factor and the R factor were regarded as the main driving force for the decrease of soil erosion, while the C factor was the dominant factor for the increase of soil erosion. The area with decreased soil erosion caused by the C factor (12.10×10³ km²) was larger than the area with increased soil erosion caused by the C factor (8.30×10³ km²), which indicated that vegetation had a positive effect on soil erosion. This study generally put forward a new method for quantitative assessment of the impacts of the influencing factors on soil erosion, and also provided a scientific basis for the regional control of soil erosion.     

基于主成分分析的吸鱼泵对鱼类损伤评价方法

采用主成分分析法建立吸鱼泵的损伤综合评价方法,为吸鱼泵的研究与改进提供装备技术参数。使用真空吸鱼泵对鲫鱼进行吸捕试验,获取鱼体损伤数据。通过测定体表损伤面积比率、24 h存活率、红细胞数量、白细胞数量、超氧化物歧化酶(SOD)活力、谷丙转氨酶(ALT)活力、肌酐(Cr)含量等多个关键指标值,采用主成分分析法进行相关性分析,建立损伤综合评价模型。结果显示：采用主成分分析法提取出3个主成分的累积贡献率达到78.232%,可反映出鱼体损伤的大部分情况;损伤评价综合评价模型：F=0.285X₁+0.111X₂+0.316X₃+0.366X₄-0.118X₅+0.234X₆,真空吸鱼泵对鱼的体表和内脏无显著损伤情况,综合得分-0.102,与对照组接近,表明真空吸鱼泵对鱼的损伤影响很小。研究表明,SOD活力、白细胞数和体表损伤面积比率是对损伤评价影响较大的数据指标,采用主成分分析法建立的综合损伤评价模型可以作为评价鱼损伤情况的一种可行方法,为吸鱼泵的改进研究提供了有力参考。     

Soil quality assessments in integrated crop–livestock–forest systems: A review

Integrated crop–livestock–forest is a promising strategy to improve soil quality. It comprises four different integrated farming systems: crop–livestock, crop–forest, forest–livestock and crop–livestock–forest. This work systematically reviewed studies about integrated crop–livestock–forest systems and soil quality. A total of 92 papers were retrieved from the Web of Science—Clarivate Analytics platform, and the following information was analysed: publication year, institution, region of the studied site, type of integrated system, soil type, tillage system, maximum soil depth and the soil quality indicators assessed. Most studies were published in the second half of the 2010s. Brazil is a prominent focus of research about soil quality and integrated crop–livestock–forest systems, with significant contribution from its central and southern regions. The Embrapa was the main publishing institution, present in over one‐third of the studies. Crop–livestock was the most common integrated system, Ferralsols was the most common soil group, and most of the studied soils were clayey. No tillage was the main tillage system. Most studies focused on the topsoil, assessing physical and/or chemical soil quality indicators. More emphasis on biological indicators of soil quality is required, as well as assessments integrating biological, physical and chemical indicators of soil quality. Future works should compare different integrated systems, including assessments deeper in the soil profile, especially in systems with the forest component, and also in sandy and silty soils. Soil quality indicators that have been rarely used should be further tested. Novel indicators should be added to better understand the promotion of soil quality by integrated crop–livestock–forest systems.     

广西某食蟹猴规模化养殖场饮用水和青饲料卫生质量监测

为了对广西某规模化食蟹猴养殖场饮用水和青饲料卫生质量情况进行监测,对饮用水和青饲料进行连续抽样监测,按照《生活饮用水卫生标准》《生活饮用水卫生标准检验方法》和《国家禁用和限用的农药名单》进行检测与评价。结果显示:抽取6份饮用水样检测26项理化指标,有3份不合格,超标率达50.0%,超标指标有浑浊度、肉眼可见物;抽取147份饮用水检测微生物指标,有22份超标,超标率达15.0%,超标微生物指标为细菌总数、总大肠菌群、耐热大肠菌群和大肠埃希氏菌;抽取13个品种青饲料48份检测10种禁用农药残留情况,甲胺磷、敌敌畏、乐果、氧化乐果、氰戊菊脂、多菌灵、啶虫脒、吡虫啉、三唑磷、毒死蜱检出率分别为2.1%、0、0、0、0、12.5%、2.1%、12.5%、2.1%、2.1%。说明该规模化食蟹猴养殖场饮用水存在不合格情况,青饲料检出农药残留。