Effects of Different Modes of Returning Farmland to Forest on Physicochemical Properties of Soil in Bashang Area of Northern Hebei Province

[Objective]The research aimed to understand the change rules of physicochemical properties of soil in the different modes of returning farmland to forest.[Method]The physicochemical properties of soil in three different types of returning farmland to forest(Hippophae rhamnoides Linn.forest,Caragana korshinskii forest and Ulmus pumila L.forest)were analyzed by taking the enclosed grassland as comparison in Bashang area of northern Hebei Province.[Result]The results showed that there were significant differences among different types.Order of the bulk density of soil:H.rhamnoides Linn.forest(1.17 g/cm^3)<U.pumila L.forest(1.24 g/cm^3)<C.korshinskii forest(1.26 g/cm^3)<enclosed grassland(1.61 g/cm^3);order of the total porosity of soil:H.rhamnoides Linn.forest(55.29%)>U.pumila L.forest(52.55%)>C.korshinskii forest(51.93%)<enclosed grassland(38.85%);order of the organic matter content of soil:H.rhamnoides Linn.forest(3.191%)>C.korshinskii forest(3.128%)>U.pumila L.forest(2.804%)>enclosed grassland(2.536%).[Conclusion]After returning farmland to forest,vegetation played a positive role in physicochemical properties of soil.There were significant differences in physicochemical properties of soil among different modes of returning farmland to forest,and the improvement effect of H.rhamnoides Linn.forest on physicochemical properties of soil was the best.

HUMAN IMPACT ON SOIL EROSION AND SEDIMENT YIELD IN NORTHERN SHAANXI, CHINA

Soil erosion in northern Shaanxi region has been greatly affected by human activities. On the one hand, newly occurred soil and water loss has been observed due to accelerated soil erosion caused by irrational human economic activities such as excessive reclamation, mining, etc.. On the other hand, great economic, social and ecological benefits have been brought into play due to vast amount of sediment trapping in watershed management as a result of adoption of engineering measures like silt arrester and horizontal terracing and of biological measures like afforestation and grass planting.

陕北煤矿区采动地裂缝对土壤抗蚀性的影响规律研究

采动地裂缝作为黄河流域中游陕北煤矿区最突出且典型的采动损害问题,引发的水土流失效应已经不容忽视。为了研究采动地裂缝发育对周边土壤抗蚀性的影响,以陕北煤矿区内宽度分别为0~10,10~20,20~30 cm的采动地裂缝为研究对象,采集周边水平距离80 cm以内,垂直深度40 cm以浅的土壤,测定了土壤水稳性团聚体、微团聚体、无机黏粒、有机黏粒、物理性质类等14个国内外学者普遍关注的用于量化表征土壤抗蚀性的指标,采用层次分析法、敏感性分析和因子分析相结合的方法甄选出陕北采动地裂缝发育区土壤抗蚀性的重要量化指标,构建了陕北采动地裂缝发育区土壤抗蚀性综合指数模型。结果表明:①综合层次分析法、敏感性分析和因子分析,甄选确定>0.25 mm水稳性团聚体含量、平均重量直径、<0.001 mm细黏粒含量、土壤团聚度、土壤有机质含量5个指标作为量化表征陕北采动地裂缝发育区土壤抗蚀性的重要指标;②采动地裂缝会降低周围土壤的5个土壤抗蚀性重要指标,其中>0.25 mm水稳性团聚体含量变化最为明显;③根据土壤抗蚀性重要指标,基于因子分析原理构建了陕北采动地裂缝发育区土壤抗蚀性综合指数模型;④采动地裂缝会降低周围土壤的抗侵蚀综合能力,且该效应随着裂缝宽度的增大和水平距离的减小而增强,当距采动地裂缝的水平距离超过170 cm时,采动地裂缝对周围土壤抗侵蚀综合能力的负效应基本消失,其可作为陕北采动地裂缝发育区土壤侵蚀防控的关键区域。研究结果可为黄河中游陕北矿区水土流失的精准防控提供科学依据。

Geodetection analysis of the driving forces and mechanisms of erosion in the hilly-gully region of northern Shaanxi Province

This paper analyzes the spatial variation in soil erosion in the loess hilly-gully region of northern Shaanxi Province, China. It sums up existing research, describes the factors that drive soil erosion, and uses geodetection to investigate the factors individually and in pairs.Our results show that soil erosion in the loess hilly-gully region of northern Shaanxi is mainly hydraulic erosion. There are significant spatial differences in the severity of soil erosion in the region. Generally, it is more severe in the north and west and less severe in the south and east. Individual factor detection results show that the major risk factors affecting soil erosion are human population distribution, precipitation, land-use type, elevation, and soil type. Interactive detection results show that interacting factors play much bigger roles in soil erosion than do individual factors. Based on forced detection results from different periods of time, we can see that forest and grass coverage, urbanization, and economic development in the study area all clearly inhibit soil erosion.

Spatio-temporal characteristics of soil protection efforts of the Grain for Green Project in northern Shaanxi Province

This paper looks at the Green for Grain Project in northern Shaanxi Province.Based on remote sensing monitoring data,this study analyzes the locations of arable land in northern Shaanxi in the years 2000,2010 and 2013 as well as spatio-temporal changes over that period,and then incorporates data on the distribution of terraced fields to improve the input parameters of a RUSLE model and simulate and generate raster data on soil erosion for northern Shaanxi at different stages with a accuracy verification.Finally,combined with the dataset of farmland change,compared and analyzed the characteristics of soil erosion change in the converted farmland to forest(grassland)and the unconverted farmland in northern Shaanxi,so as to determine the project’s impact on soil erosion over time across the region.The results show that between 2000 and 2010,the soil erosion modulus of repurposed farmland in northern Shaanxi decreased 22.7 t/ha,equivalent to 47.08%of the soil erosion modulus of repurposed farmland in 2000.In the same period,the soil erosion modulus of non-repurposed farmland fell 10.99 t/ha,equivalent to 28.6%of the soil erosion modulus of non-repurposed farmland in 2000.The soil erosion modulus for all types of land in northern Shaanxi decreased by an average of 14.51 t/ha between 2000 and 2010,equivalent to 41.87%of the soil erosion modulus for the entire region in 2000.This suggests that the Green for Grain Project effectively reduced the soil erosion modulus,thus helping to protect the soil.In particular,arable land that was turned into forest and grassland reduced erosion most noticeably and contributed most to soil conservation.Nevertheless,in the period 2010 to 2013,which was a period of consolidation of the Green for Grain Project,the soil erosion modulus and change in volume of soil erosion in northern Shaanxi were significantly lower than in the previous decade.

北方土石山区坡面水土流失特征研究

[目的]揭示北方土石山区坡面水土流失规律,为山区土壤侵蚀防治和生态建设提供科学依据。[方法]利用1988—1991年坡面径流小区观测数据,运用统计和相关分析等方法,对不同下垫面条件下坡面水土流失特征进行了分析,并探讨了坡面径流深度、土壤侵蚀模数、土壤入渗率与有效降雨量、平均降雨强度、降雨历时、降雨等级的关系。[结果](1)在5°08′~24°08′坡度范围内,坡面径流深度随坡度增加逐渐减小,土壤侵蚀模数和土壤入渗率随坡度增加逐渐增大;(2)在2.18~33.19 m坡长范围内,坡面径流深度随坡长增加逐渐减小,土壤侵蚀模数和土壤入渗率随坡长增加呈现先增后减的变化趋势,存在临界坡长;(3)随着植被覆盖度增加,坡面径流深度、土壤侵蚀模数迅速减小,土壤入渗率逐渐增加;裸地的坡面径流深度和土壤侵蚀模数显著高于30%植被覆盖度坡面,但植被覆盖度由30%增加到60%,90%时,坡面水土流失过程的影响差异并不明显,说明在水土流失治理中存在临界植被覆盖度;(4)坡面径流深度、土壤侵蚀模数主要受到有效降雨量和平均降雨强度影响,且均呈显著正相关;而土壤入渗率主要受到平均降雨强度和降雨历时影响,与平均降雨强度呈显著正相关,与降雨历时呈显著负相关;随降雨等级的增加,坡面径流深度和土壤侵蚀模数呈增加趋势而土壤入渗率呈先增加后减少的趋势。[结论]下垫面条件和降雨因素对北方土石山区坡面水土流失过程产生了重要影响。未来应结合室内试验和模型模拟,进一步加强该区域不同自然因素和人类活动对坡面水土流失过程和影响机制的研究。

陕西省葡萄主产区土壤养分状况分析初报

为探明陕西省葡萄主产区果园土壤养分状况,以主产区渭南、西安、咸阳和宝鸡的葡萄园土壤为研究对象,分别测定0~20、20~40、40~60 cm土层土壤理化性质和营养成分。结果表明:陕西省葡萄主产区内,总体上土壤pH值为强碱性,土壤容重大,土壤过于紧实,有机质含量偏低;氮含量偏低,而磷、钾含量较高,且含量在土壤垂直水平上分布不均匀,除速效氮含量随着土层深度的增加而增加外,全氮、全磷、全钾、速效磷、速效钾含量均随着土层深度的增加而降低;Cu含量丰富,Fe、Mn含量缺乏,Zn含量除在0~20 cm土层丰富外,在更深的两个土层含量急剧下降,处于一种缺乏的状态,Fe、Mn、Zn、Cu含量均随着土层深度的增加而降低。

陕北风沙草滩区覆膜对土壤理化性质和春玉米产量的影响

试验旨在探究覆膜方式对陕北风沙草滩区土壤理化性质和春玉米产量的影响。试验选取当地主推玉米品种中榆968,设置膜上栽培、膜际栽培和无膜栽培3个处理,分析覆膜对土壤含水量、pH值、有机质、玉米农艺性状、产量和籽粒营养品质的影响。结果显示,在0~20、21~40 cm土层,膜际栽培土壤含水量高于无膜栽培(P<0.05);在41~60 cm土层,膜上栽培和膜际栽培土壤含水量高于无膜栽培(P<0.05)。随着土壤深度的增加,各处理的土壤pH值均呈现下降趋势,不同土层的土壤pH值排序均为无膜栽培>膜际栽培>膜上栽培;其中0~20 cm土层膜上栽培土壤pH值低于无膜栽培(P<0.05)。在0~20 cm土层,膜际栽培与膜上栽培土壤有机质含量高于无膜栽培(P<0.05);41~60 cm土层膜际栽培土壤有机质含量高于膜上栽培和无膜栽培(P<0.05)。膜际栽培玉米的株高、鲜穗重、穗粒数和产量高于其他处理(P<0.05),茎粗和百粒重高于无膜栽培(P<0.05)。膜际栽培的玉米籽粒粗蛋白和粗脂肪含量为8.22%和4.58%,均高于无膜栽培(P<0.05)。研究表明,膜际栽培更适于陕北风沙草滩区的春玉米种植,可在该地进一步推广应用。

陕西省典型矿区土壤和食用林产品中重金属污染与风险评估

为探明陕西省典型矿区土壤和食用林产品中重金属污染特征与风险情况,通过对渭南华州、商洛柞水县、宝鸡凤县金属矿区土壤和食用林产品进行样品采集并分析测定其As、Hg、Pb、Cd、Cr、Cu含量,采用单因子污染指数法、内梅罗综合污染指数法、土壤和农产品综合质量指数法对土壤和食用林产品重金属污染状况进行评价。结果表明,研究区内土壤均出现不同程度的As、Hg、Pb、Cd、Cr、Cu含量积累;受检食用林产品均出现不同程度的Cr、Cu积累,华州区油松籽2个样品出现Pb含量超标;单因子污染指数表明Cd为凤县研究区土壤的主要污染物,Cr、Cu为柞水县研究区土壤的主要污染物;内梅罗综合污染指数表明凤县和柞水县研究区域土壤为轻度污染状态(质量等级Ⅲ),华州区研究区域土壤为尚清洁状态(质量等级Ⅱ);综合质量影响指数表明,凤县土壤呈现轻微污染(sub-Ⅱ),华州区呈现轻度污染(sub-Ⅲ),柞水县呈现重度污染(sub-Ⅴ)。凤县、华州区和柞水县研究区土壤均出现重金属污染问题,部分食用林产品存在重金属Cr、Cu积累以及Pb超标风险,应及时采取治理修复措施,以缓减土壤和食用林产品的重金属污染问题。

冀北山地桦木林土壤细菌群落特征对坡向的响应

为了揭示冀北山地桦木林土壤细菌群落特征对坡向的响应规律,以冀北山地阴坡、半阴坡和半阳坡桦木林土壤为研究对象,采用高通量测序技术,分析了土壤细菌群落结构和多样性。结果表明:细菌群落组成主要包含41门、107纲,其中优势细菌门为变形菌门和酸杆菌门;土壤细菌群落α多样性指数在坡向间存在显著差异,阴坡>半阴坡>半阳坡;土壤含水量、容重、硝态氮和氨态氮均影响细菌微生物群落的结构组成,其中,土壤含水量与多种细菌门存在显著相关性,且与细菌α多样性存在极显著的正相关性。综上所述,不同坡向桦木林土壤细菌群落结构和多样性呈现出一定的变化规律,坡向和土层深度变化引起的土壤含水量变化是该地区桦木林土壤细菌群落结构和多样性差异的主要因素。

陕北榆林滴灌春玉米不同生育期适宜土壤水分控制界限研究

【目的】确定陕北榆林滴灌春玉米各生育期适宜的土壤水分界限,得到该地区滴灌春玉米的灌溉制度。【方法】采用正交试验设计方法,在春玉米苗期、拔节期、抽雄期、灌浆期、成熟期5个生育期设置4种灌溉水平,探究不同灌水方案对滴灌春玉米的生长及水分利用效率的影响。【结果】(1)陕北榆林滴灌春玉米关键生育期为拔节期、抽雄期。苗期、灌浆期及成熟期为非关键期。在拔节期和抽雄期适当降低灌溉水平更有利于春玉米后续生长发育;(2)综合各灌水方案对春玉米株高、茎粗、叶面积指数和产量的影响,最优的田间土壤水分控制界限为:苗期适宜土壤水分界限为59%~79%FC(FC代表土壤田间持水率),拔节期为70%~90%FC,抽雄期为68%~88%FC,灌浆期为56%~76%FC,成熟期为49%~69%FC。【结论】最优的灌溉制度为全生育期灌水9次,即苗期2次(m=20 mm),拔节期3次(m_(1)=20 mm,m_(2)=m_(3)=30 mm),抽雄期3次(m_(1)=m_(2)=m_(3)=30 mm),灌浆期1次(m=25 mm),成熟期不灌水,综合灌溉定额为235 mm。该制度下春玉米产量为14664 kg/hm^(2),水分利用效率达3.01 kg/m^(3)。较对照组产量提高15.56%,WUE提高19.19%。该研究结果对陕北榆林滴灌春玉米田间水分管理具有重要指导意义。

鄂北浅覆盖金矿区土壤微细粒分离测量有效性试验研究

土壤微细粒分离测量方法在中国北方覆盖区的找矿勘查中应用效果良好,但南方覆盖区地理、地质条件与北方地区差异较大,需要开展有效性试验研究。在鄂北浅覆盖区的小玉皇顶金矿区及卸甲沟金矿区开展方法试验,探讨该方法在鄂北浅覆盖区的采样要求,并分析其探测隐伏矿的有效性。研究表明,鄂北浅覆盖区土壤微细粒分离测量方法较为适合的采样层位为BC层,采样粒度为-120目,能够在保证结果科学性的前提下兼顾采样的经济性。卸甲沟金矿区隐伏矿脉上方的土壤微细粒分离测量结果中存在Au-Pb-Bi-W综合异常,与该区原生晕异常组合相似,表明其极有可能是隐伏矿体的地表显示,说明土壤微细粒分离测量方法在鄂北浅覆盖区具有一定的有效性。

陕西省水土保持率远期目标值与分阶段目标值的确定与探讨

[目的]探讨和明确陕西省水土保持率远期目标值与分阶段目标值,为准确评价该区水土保持工作成效和科学推进水土流失综合防治工作提供科学支撑。[方法]综合考虑陕西省社会经济条件与自然条件,分析对应年度水土流失面积变化情况及水土保持率变化情况,结合各年度水利年鉴和全国水土保持规划实施情况考核评估结果,结合土壤侵蚀分类分级、土地利用、海拔地形、植被覆盖、地理空间数据,研判现状条件下陕西省水土流失治理形势,确定陕西省2050年水土保持率远期目标值,及2025,2030和2035年分阶段目标值,并结合目标责任考核,提出陕西省水土保持率的实现途径。[结果]①自2011年以来陕西省水土流失面积年均减少量不断降低,治理难度不断加大,陕西省水土流失面积由72686.00 km^(2)降低至2022年的62637.02 km^(2);②至2050年,水土流失治理措施全部实施后,预计削减水土流失面积21607.05 km^(2),水土保持率远期目标值为79.02%;③2025,2030和2035年分阶段目标值分别为71.42%,73.97%和75.62%。[结论]科学合理地确定陕西省水土保持率目标值,可以满足陕西省落实生态文明建设目标评价考核与水土保持目标责任考核等工作的需求。

晋陕蒙采煤区水土流失现状调查与分析研究

以晋陕蒙采煤区为研究对象,采用文献资料收集、野外调查与室内分析相结合的方法,重点对松散堆积物、排土(矸)场、塌陷区域等人为水土流失进行典型调查研究,查明在建、在产的煤矿和采石场的分布、数量及规模,阐明引起水土流失的原因,为晋陕蒙能源区水土流失治理和生态环境建设提供依据。

Vegetation and soil wind erosion dynamics of sandstorm control programs in the agro-pastoral transitional zone of northern China

To combat soil erosion and desertification,large-scale sandstorm control programs have been put in place since 2000 in the agro-pastoral transitional zone of northern China.Vegetation dynamics as well as soil wind erosion control effects are very important for assessing the ecological success of sandstorm control programs in China.However,no comprehensive evaluation of vegetation dynamics and soil wind erosion control effects in this region has been achieved.In this study,we illustrate the vegetation and soil wind erosion dynamics of sandstorm control programs in the northern Shanxi Province using remote sensing data and soil wind erosion models.There was a significant increase in vegetation cover for 63.59% of the study area from 2001 to 2014 and a significant decrease for 2.00% of the study area.The normalized difference vegetation index (NDVI) showed that the largest increase occurred in autumn.Soil wind erosion mass decreased from 20.90 million tons in 2001 to 7.65 million tons in 2014.Compared with 2001,the soil wind erosion moduli were reduced by 43.05%,36.16%,and 62.66% in 2005,2010,and 2014,respectively.Spatially,soil wind erosion in most of the study area was alleviated between 2001 and 2014.The relationship between NDVI and soil wind erosion mass showed that the increased vegetation coverage reduced the soil wind erosion mass.In addition,wind was the main driving force behind the soil wind erosion dynamics.The results indicate that the vegetation coverage has increased and soil wind erosion mass has been reduced following the implementation of the sandstorm control programs.However,the ecological effects of the sandstorm control programs may vary over different periods.While the programs appear to be beneficial in the short term,there may be unintended consequences in the long term.Research on the sustainability of the ecological benefits of sandstorm control programs needs to be conducted in the future.

陕北黄土沟壑区采煤沉陷对黄土坡面形态的影响及土壤侵蚀效应

如何破解煤炭开采与水土保持之间的矛盾是实现黄河中游生态环境保护与高质量发展的关键科学问题。以陕北黄土沟壑采煤沉陷区为研究对象,针对主采煤层典型地质赋存特征,以地下采厚(9、7、5 m)、地表黄土自然坡面坡形(直线坡、凹形坡、凸形坡、复合坡)及坡度(5°、15°、25°、35°、45°)为变量,共构建了60个数值模型,基于FLAC3D数值模拟软件,研究了黄土自然坡面形态及采厚耦合作用下坡面形态演变过程与规律,基于中国水土流失方程(CSLE模型)和经验模型,计算与分析了沉陷坡面土壤侵蚀效应。研究结果表明:(1)采煤沉陷会导致地表黄土坡面的坡度增大,且采厚越大,坡度增幅越大,大采厚对采煤沉陷导致地表黄土坡面坡度的增大会产生明显的放大效应。凹形坡普遍对沉陷坡面坡度的影响显著,特别是在“采厚5 m、自然坡度>5°”“采厚7 m、任意自然坡度”“采厚9 m、自然坡度≤35°”条件下。无论在何种采厚及自然坡形情况下,≤5°的自然坡度对沉陷坡面坡度增幅的影响均最大。(2)采煤沉陷会导致“年侵蚀降雨”尺度下地表黄土坡面的土壤侵蚀模数M_(1)增大,且采厚越大,M1增幅越大;当采厚从5 m增大到9 m时,M_(1)增幅增大了1倍左右;4种坡形中凹形坡对沉陷坡面M1的增幅影响最大;≤15°自然坡度对沉陷坡面的M1增幅影响较大,在“采厚9 m,凹形坡”条件下超过了20%。(3)采煤沉陷会导致“典型场次侵蚀降雨”尺度下地表黄土坡面的土壤侵蚀模数M_(2)增大,且采厚越大,M_(2)增幅越大;当采厚从5 m增大到9 m时,M2增幅增大了1倍左右;4种坡形中凹形坡对沉陷坡面M2的增幅影响最大;≤15°自然坡度对沉陷坡面的M2增幅影响较大,在“采厚9 m,凹形坡”条件下超过了17%。该结果可为陕北矿区乃至黄河流域中游的水土流失精准防控与高质量发展提供科学依据。

陕北采煤沉陷区黄土坡面形变与土壤侵蚀效应

为研究采煤沉陷区黄土坡面变形规律及水土流失情况,以陕北黄土采煤沉陷区地质条件为基础,地表黄土坡面4种典型自然坡形(直线坡、凹形坡、凸形坡、复合坡)和5种典型自然坡度(5°,15°,25°,35°,45°)为考察变量,采用有限差分数值模拟法,构建20个数值模型,模拟分析了在既定采矿条件下,采煤沉陷对地表黄土坡面形态的影响规律,基于数值模拟结果采用美国通用土壤流失方程计算坡面土壤侵蚀模数并分析其变化规律。结果表明:任意自然坡形和坡度下,采煤沉陷均会导致黄土坡面坡度增大,增幅为12.60%~3.57%,自然坡度为15°~35°时,凹形坡坡度增幅最明显;任意自然坡形和坡度下,采煤沉陷均会导致黄土自然坡面坡长减小,降幅为3.92%~12.11%,自然坡度为5°~35°时,凹形坡坡长降幅最明显;任意自然坡形和坡度下,采煤沉陷均会导致黄土坡面土壤侵蚀模数增大,增幅为2.70%~12.64%;自然坡度小于15°和等于35°的凸形坡、介于15°~25°的凹形坡土壤侵蚀模数对采煤沉陷最敏感。研究成果可为陕北采煤沉陷区水土流失防治提供科学指导。

陕北不同地貌类型区采煤沉陷对土壤微生物和酶活性的影响

深刻认识采煤沉陷的衍生生态损害效应已经成为当前修复西部煤矿区生态环境采动损害的关键基础科学问题和研究热点。掌握不同地貌类型单元采煤沉陷对土壤微生物和酶活性的影响规律有利于西部采煤沉陷区的生态环境保护与修复。以陕北煤矿区榆树湾井田(风沙地貌)、柠条塔井田北翼(黄土地貌)的典型沉陷坡面土壤为研究对象,分别采集不同坡面部位(垂直深度为0~60 cm)的土壤样品,分别采用绝对定量PCR方法和酶标仪法测定土壤细菌、放线菌、真菌的数量和蔗糖酶、过氧化氢酶、脲酶、磷酸酶的活性,细致分析土壤微生物数量和酶活性在沉陷坡面上的空间变化特征,综合土壤主要理化特性,揭示不同地貌类型下采煤沉陷对土壤微生物和酶活性的影响规律。结果表明:(1)风沙地貌类型单元和黄土地貌类型单元的采煤沉陷都会导致沉陷坡面土壤微生物数量和酶活性显著降低,土壤微生物数量的降幅分别达到8.27%~42.39%和11.53%~45.95%,土壤酶活性的降幅分别达到6.52%~39.83%和9.09%~42.42%;随坡面部位由坡顶到坡中再到坡脚的转换,该效应对于土壤3种微生物和4种酶呈现出不同的变化特征;(2)黄土地貌类型单元的采煤沉陷对“坡中部位的0~10 cm土层+各类土壤微生物数量和酶活性”的降低效应最为显著,风沙地貌单元的采煤沉陷对“坡中部位的0~10 cm土层+土壤放线菌数量及蔗糖酶、脲酶、磷酸酶活性”“坡中部位的10~20 cm土层+土壤细菌、真菌数量”“坡中部位的20~40 cm土层+土壤过氧化氢酶活性”的降低效应最为显著,其可作为陕北采煤沉陷区坡面土壤微生物修复的靶向区域;(3)无论在风沙地貌类型单元还是黄土地貌类型单元,土壤真菌数量和脲酶活性对采煤沉陷最为敏感,其降幅分别达到23.28%~45.95%和22.78%~42.42%,二者可作为分析陕北矿区采煤沉陷损害土壤微生物特性的标志物;(4)无论在风沙沉陷坡面和黄土沉陷坡面,土壤中速效磷、有机质含量与土壤微生物和酶活性的相关系数最高,分别超过0.8和0.7,可作为采煤沉陷影响土壤微生物特性的关键指示性因素。

陕北沙区长柄扁桃害虫种类及危害调查

【目的】长柄扁桃是陕北沙区重要生态树种和经济树种,在区域经济和生态建设中发挥着重要作用。近年来受到多种害虫侵扰,受害面积不断增加且日益严重。为此进行了该研究,以明确陕北沙区长柄扁桃害虫种类及害虫危害情况,为今后长柄扁桃害虫监测和科学防控提供基础资料。【方法】于2017年3月至2020年10月,采用人工采集法和黑光灯诱法对陕北沙区长柄扁桃害虫进行采集,对采集到的标本进行了鉴定、整理和区系分析;随后采用标准地调查法对害虫的危害程度做了系统的调查。【结果】共计调查到陕北沙区长柄扁桃害虫35种,隶属3个目19科,鞘翅目害虫种类为15种,占害虫种类的42.86%;半翅目害虫种类为11种,占害虫种类的31.43%;鳞翅目害虫种类为9种,占害虫总数的25.71%。区系分析表明,长柄扁桃的鞘翅目害虫古北种最多,占73.33%,鳞翅目害虫和半翅目害虫广布种最多,分别占88.89%和81.82%。危害程度研究表明,危害严重的害虫有5种,危害中度的害虫有8种,危害轻的害虫有22种。【结论】陕北沙区长柄扁桃害虫主要分布在鞘翅目和半翅目,鞘翅目害虫以古北种为主,半翅目和鳞翅目害虫以广布种为主。长柄扁桃害虫的优势种为华北大黑鳃金龟、苹毛丽金龟、阿拉善舌喙象、李小食心虫和桃蚜。

陕北煤矿区不同形态的采动地裂缝对土壤可蚀性的影响

黄河流域中游作为国家水土流失重点预防和治理区,解决其煤炭开采与水土保持间的矛盾对于矿区生态环境保护与高质量发展具有重要意义。以陕北柠条塔井田北翼采动地裂缝发育区内“平开式”、“台阶式”、“组合式”3种典型形态的采动地裂缝及其周边土壤(水平距离100 cm以内、垂直深度20 cm以浅)为研究对象,测定了土壤机械组成和有机质含量,基于EPIC模型计算了土壤可蚀性K值,分析了不同形态采动地裂缝影响下土壤机械组成和有机质质量分数的空间变化特征,解译了不同形态采动地裂缝在小空间尺度下的水土流失效应。结果表明:①“平开式”、“台阶式”、“组合式”3种形态的采动地裂缝均会导致其周围土壤黏粒质量分数、有机质质量分数明显下降和土壤可蚀性K值明显增大,土壤黏粒质量分数的平均降幅依次为21.50%、43.93%、58.70%(p<0.05),土壤有机质质量分数的平均降幅依次为45.72%、61.79%、78.66%(p<0.05),土壤可蚀性K值的平均增幅依次为12.49%、17.82%、32.35%(p<0.05),且均以水平负效应为主;②在相同水平距离及垂直深度下,“组合式”裂缝降低周围土壤黏粒质量分数、有机质质量分数和提升土壤可蚀性K值的能力显著高于“平开式”和“台阶式”,排序均为“组合式”>“台阶式”>“平开式”;③基于指数函数分别建立了3种形态采动地裂缝影响周围土壤可蚀性K值的作用范围预测模型,发现不同形态采动地裂缝提升周围土壤可蚀性的作用范围基本在155 cm以内,再结合差异显著性对比分析,明确了“平开式”、“台阶式”、“组合式”采动地裂缝提升周围土壤可蚀性的关键作用范围依次为40、60、100 cm以内,其可作为陕北矿区采动地裂缝小空间尺度下水土流失效应的精准防控靶区。