全国水土保持规划主要成果及其应用

全国水土保持规划首次完成了全国水土保持区划,依法划分了水土流失重点预防区和重点治理区,明确了未来水土保持发展目标、布局及重点,形成了一批专题规划与研究成果,搭建了水土保持规划协作平台。应用全国水土保持规划成果要做好以下工作:充分认识落实好规划内容就是贯彻国家生态文明建设决策部署;从当地实际情况出发,优化水土流失防治格局,提升区域水土保持功能;抓紧制定专项规划,将现有国家水土保持重点工程进行整合和分类,突出防治重点;通过制定符合当地实际的配套法规和相关制度,促进水土保持工作的法制化、制度化、规范化建设;加强水土保持规划、监测网络、科教、技术标准、信息化、社会化服务等六大体系建设,夯实水土保持基础性工作。     

呼和浩特市水土流失重点防治区划分及分区研究

水土流失重点预防区和重点治理区划分是水土保持规划中水土保持措施合理布局的重要依据。在国家和自治区水土流失重点预防区和重点治理区划分的基础上,根据全市地形地貌特征、植被类型及分布、水土流失现状及分布特点、现有水土流失治理成效及水土流失防治工作实际需要,并充分考虑原水土流失重点防治区“三区”划分成果及划分区内相似性和区间差异性,按照以乡镇为基本划分单元、集中连片面积达到一定规模、定量指标与定性分析相结合的要求,进行了呼和浩特市水土流失重点预防区和重点治理区划分。合理划定水土流失重点预防区和治理区,为落实地方政府水土保持目标责任制和考核奖惩制度,为全市水土流失防治明确了重点工作区域,确定了分区防治方略,为规范生产建设项目水土保持管理工作提供了重要技术支撑。     

总结工作以利再战 精心部署再创佳绩——山西省2018年度水土保持工作回顾与2019年计划安排

2018年,山西省水土保持工作成绩斐然,完成水土流失治理面积35.47万hm2,超额目标任务1.34%。水土保持重点工程进展顺利,水土保持监督管理进一步强化,水土保持监测和信息化加快推进,水土保持淤地坝全年安全运用。其主要做法与经验:一是积极对接国家部委,掌握重大政策和改革发展方向,争取更大支持;二是召开重点工程现场会,现场推动、交流学习,以点带面抓落实;三是根据新的水土保持形势和工作要求,及时组织开展培训,提高人员业务水平;四是组织省内外重要新闻媒体开展形式多样的宣传报道,营造良好的社会氛围。2019年是实现脱贫攻坚和"十三五"规划的重要之年,我省计划在以下8个方面卓有成效地开展工作,再创新业绩:一是全面完成规划的水土流失治理任务;二是继续抓好水土保持重点工程建设;三是持续推进水土保持监测和信息化建设;四是加大水土保持监督执法力度,依法防治人为水土流失;五是切实加强水土保持扶贫攻坚;六是落实岗位责任,排查安全隐患,确保淤地坝安全度汛运用;七是推动落实《全国水土保持规划(2015-2030年)》,组织开展好规划实施和自查自评;八是多角度、多形式开展水土保持宣传,不断增强全民水土保持意识和法制观念,营造良好的水土保持舆论氛围。     

涪陵区石灰岩采石场水土流失原因及防治对策

涪陵区石灰岩出露面广,采石场多、小、乱,缺乏水土保持方案和水土保持措施,造成了严重的水土流失。针对造成采石场水土流失的原因,提出了制定科学规划,加大宣传力度,严格编制和审批水土保持方案,督促业主落实水土保持“三同时”制度,查处违法案件等水土流失防治对策。     

紧抓机遇 科学推进黄河流域甘肃段水土保持工作

甘肃省黄河流域是黄河流域重要的水源涵养补给区,水土流失严重。经过多年的治理,甘肃省黄河流域水土保持综合治理取得了明显成效,但还面临一些困难和挑战。下一步要紧抓机遇,继续推进规划编制完善,做好重点区域水土流失综合治理,深入落实最严格的水土保持管控制度,全力推进水土保持监测和信息化建设,持续深化水土保持改革发展,科学推进黄河流域甘肃段水土保持工作。     

北京市水土保持规划探讨

水土保持规划是区域水土保持工作的发展蓝图和重要依据,是水土流失防治工作的指导性文件,是实现水土流失依法治理和依法监管的重要科学依据。结合北京市水土保持规划的发展历程,探讨规划的地位和作用,提出北京市水土保持规划的总体思路,并将全市划分为地表水源涵养区、地下水源涵养区、城市径流控制区、土壤侵蚀控制区四大水土保持类型区。针对每个分区提出防治对策,并从水土保持生态建设、监督管理、监测、科技支撑和信息化等方面对规划的重点任务进行了探讨。     

改革开放以来吉林省水土保持生态文明建设纪实

改革开放以来,水土保持工作备受国家和领导重视,吉林省水土保持工作全面开展,水土保持组织机构不断加强,水土流失综合治理快速推进,水土保持监督管理不断强化,水土保持监测与信息化建设逐步完善。新时代赋予水土保持工作新的使命,面临新形势,吉林省水土保持工作依然任重而道远。     

乘势而上 担当作为 奋力推动新阶段水土保持高质量发展

2021年以来，各级水利水保部门深入贯彻习近平生态文明思想和习近平总书记关于治水重要讲话指示批示精神，全面贯彻新发展理念，认真落实党中央、国务院决策部署，狠抓工作落实，推动新阶段水土保持高质量发展迈出了坚实步伐，“十四五”取得良好开局：一是“十四五”水土保持规划体系基本形成；二是人为水土流失监管效能进一步提升；三是重点区域水土流失治理加快推进；四是水土保持监测评价不断深化；五是水土保持工作地位和科技支撑能力不断提升。2022年下半年，在高效统筹疫情防控和经济发展的同时，扎实做好深化水土保持“放管服”改革、深入推进体制机制法治创新、抓好水土流失综合治理工程组织实施、着力推进智慧水土保持建设、全面落实从严治党有关要求等工作。近期需要抓紧布置落实好淤地坝安全度汛工作和全国水土保持先进集体和先进个人评选表彰活动。各级水利水保部门要提高政治站位、深化改革创新、强化履职担当、提升能力水平，确保如期实现各项年度目标。     

延边地区水土流失现状及防治对策

延边地区位于吉林省东部,属长白山脉,地形以中低山和丘陵为主,在夏季暴雨、山洪的作用下,山坡地、坡耕地表土流失严重,导致耕地面积减少、土地肥力下降、土壤瘠薄化,加剧了农业生态环境恶化。根据延边地区水土流失现状和成因,制定了低山丘陵区水土流失防治对策,包括科学规划,综合治理;落实国家政策,加强监督管护;水土保持工程、植物措施相结合;科学配置,建立有效的水土流失防治体系等。     

湖州市水土保持工作实践与思考

浙江省湖州市作为"两山"理论诞生地,始终坚持生态优先的发展理念,科学编制水土保持规划,深入推进水土保持各项工作,取得了显著成绩。其主要实践经验是以小流域为治理单元,综合消减山区水土流失;严格落实水土保持"三同时"制度,防控建设项目水土流失;强化水土保持监督检查,严厉打击违法行为。进入新时代,对照高标准,湖州市积极推进水土保持改革试点,将在建设项目承诺报备制、水土保持宣传教育、专业人才培养等方面开展积极有益的探索。     

硫酸根自由基高级氧化技术对污染场地多环芳烃的修复效果研究

硫酸根自由基高级氧化技术(sulfate radical(SO_4~(·–))based advanced oxidation processes,SR-AOPs)是一种被广泛应用于降解土壤有机污染物的原位氧化修复技术。然而,关于SR-AOPs降解土壤多环芳烃(polycyclic aromatic hydrocarbons,PAHs)的报道相对较少。本研究以南京某炼钢厂附近土壤作为试验样本,通过设置不同比例混合体系的过硫酸钠(Na_2S_2O_8)和亚铁离子(Fe~(2+))以及反应不同时间,探究SR-AOPs对土壤中16种PAHs的修复效果以及最佳技术方案。结果表明:Na_2S_2O_8和Fe~(2+)的配比会显著影响土壤PAHs的降解效果,当两者比例达到10︰1时,即Na_2S_2O_8用量为5 mmol/g,Fe~(2+)用量为0.5 mmol/g,反应时间为24 h时,PAHs总降解率最高,可达到29.32%;不同环数的PAHs决定了SR-AOPs的降解效果,其中SR-AOPs对四环PAHs降解效率最高,总降解率达到37.32%;此外,降解效率随反应时间增加而增加,在24 h达到效果最佳。因此,本研究结果可为SR-AOPs修复土壤PAHs提供理论依据。     

A method for estimating coefficients of soil organic matter dynamics based on long-term experiments

The one-compartment C model C_t=C₀e^−k₂t+k₁A/k₂(1−e^−k₂t) is being long used to simulate soil organic C (SOC) stocks. C_t is the SOC stock at the time t; C₀, the initial SOC stock; k₂, the annual rate of SOC loss (mainly mineralization and erosion); k₁, the annual rate to which the added C is incorporated into SOC; and A, the annual C addition. The component C₀e^−k₂t expresses the decay of C₀ and, for a time t, corresponds to the remains of C₀ (C_0 remains). The component k₁A/k₂(1−e^−k₂t) refers, at time t, to the stock of SOC derived from C crops (C_crop). We herein propose a simple method to estimate k₁ and k₂ coefficients for tillage systems conducted in long-term experiments under several cropping systems with a wide range of annual C additions (A) and SOC stocks. We estimated k₁ and k₂ for conventional tillage (CT) and no-till (NT), which has been conducted under three cropping systems (oat/maize −O/M, vetch/maize −V/M and oat + vetch/maize + cowpea −OV/MC) and two N-urea rates (0 kg N ha⁻¹ −0 N and 180 kg N ha⁻¹ −180 N) in a long-term experiment established in a subtropical Acrisol with C₀ = 32.55 Mg C ha⁻¹ in the 0–17.5 cm layer. A linear equation (C_t = a + bA) between the SOC stocks measured at the 13th year (0–17.5 cm) and the mean annual C additions was fitted for CT and NT. This equation is equivalent to the equation of the model C_t=C₀e^−k₂t+k₁A/k₂(1−e^−k₂t), so that a=C₀e^−k₂t and bA=k₁A/k₂(1−e^−k₂t). Such equivalences thus allow the calculation of k₁ and k₂. NT soil had a lower rate of C loss (k₂ = 0.019 year⁻¹) than CT soil (k₂ = 0.040 year⁻¹), while k₁ was not affected by tillage (0.148 year⁻¹ under CT and 0.146 year⁻¹ under NT). Despite that only three treatments had lack of fit (LOFIT) value lower than the critical 5% F value, all treatments showed root mean square error (RMSE) lower than RMSE 95% indicating that simulated values fall within 95% confidence interval of the measurements. The estimated SOC stocks at steady state (C_e) in the 0–17.5 cm layer ranged from 15.65 Mg ha⁻¹ in CT O/M 0 N to 60.17 Mg ha⁻¹ in NT OV/MC 180 N. The SOC half-life (t_1/2 = ln 2/k₂) was 36 years in NT and 17 years in CT, reflecting the slower C turnover in NT. The effects of NT on the SOC stocks relates to the maintenance of the initial C stocks (higher C_0 remais), while increments in C_crop are imparted mainly by crop additions.     

Interpreting the dependence of soil respiration on soil temperature and water content in a boreal aspen stand

Continuous half-hourly measurements of soil CO₂ efflux made between January and December 2001 in a mature trembling aspen stand located at the southern edge of the boreal forest in Canada were used to investigate the seasonal and diurnal dependence of soil respiration (R_s) on soil temperature (T_s) and water content (θ). Daily mean R_s varied from a minimum of 0.1 μmol m⁻² s⁻¹ in February to a maximum of 9.2 μmol m⁻² s⁻¹ in mid-July. Daily mean T_s at the 2-cm depth was the primary variable accounting for the temporal variation of R_s and no differences between Arrhenius and Q₁₀ response functions were found to describe the seasonal relationship. R_s at 10 °C (R_s10) and the temperature sensitivity of R_s (Q_10Rs) calculated at the seasonal time scale were 3.8 μmol m⁻² s⁻¹ and 3.8, respectively. Temperature normalization of daily mean R_s (R_sN) revealed that θ in the 0–15 cm soil layer was the secondary variable accounting for the temporal variation of R_s during the growing season. Daily R_sN showed two distinctive phases with respect to soil water field capacity in the 0–15 cm layer (θ_fc, 0.30 m³ m⁻³): (1) R_sN was strongly reduced when θ decreased below θ_fc, which reflected a reduction in microbial decomposition, and (2) R_sN slightly decreased when θ increased above θ_fc, which reflected a restriction of CO₂ or O₂ transport in the soil profile.Diurnal variations of half-hourly R_s were usually out of phase with T_s at the 2-cm depth, which resulted in strong diurnal hysteresis between the two variables. Daily nighttime R_s10 and Q_10Rs parameters calculated from half-hourly nighttime measurements of R_s and T_s at the 2-cm depth (when there was steady cooling of the soil) varied greatly during the growing season and ranged from 6.8 to 1.6 μmol m⁻² s⁻¹ and 5.5 to 1.3, respectively. On average, daily nighttime R_s10 (4.5 μmol m⁻² s⁻¹) and Q_10Rs (2.8) were higher and lower, respectively, than the values obtained from the seasonal relationship. Seasonal variations of these daily parameters were highly correlated with variations of θ in the 0–15 cm soil layer, with a tendency of low R_s10 and Q_10Rs values at low θ. Overall, the use of seasonal R_s10 and Q_10Rs parameters led to an overestimation of daily ranges of half-hourly R_s (ΔR_s) during drought conditions, which supported findings that the short-term temperature sensitivity of R_s was lower during periods of low θ. The use of daily nighttime R_s10 and Q_10Rs parameters greatly helped at simulating ΔR_s during these periods but did not improve the estimation of half-hourly R_s throughout the year as it could not account for the diurnal hysteresis effect.     

Genetic diversity and differentiation of cultivated ginseng (<Emphasis Type="Italic">Panax ginseng</Emphasis> C. A. Meyer) populations in North-east China revealed by inter-simple sequence repeat (ISSR) markers

Panax ginseng C. A. Meyer is a medicinally important herb with a long history of cultivation, and includes three cultivated types, viz. garden ginseng (GGS), forest ginseng (FGS) and transplanted wild ginseng (TGS). In the present study, inter-simple sequence repeat (ISSR) markers were employed to investigate the genetic variability in 282 individuals, which corresponded to 16 cultivated ginseng populations. Genetic diversity was high at the species level (h = 0.2886; I = 0.4382; PPB = 98.96%), but relatively lower at the cultivated-type level (GGS: h = 0.2294, I = 0.3590, PPB = 85.42%; FGS: h = 0.1702, I = 0.2559, PPB = 57.29%; TGS: h = 0.2021, I = 0.3125, PPB = 76.04%). The hierarchical analysis of molecular variance (AMOVA) revealed pronounced genetic differentiation among populations (Φ _ST = 53.94%), which was confirmed by the gene differentiation coefficient (G _ST = 0.4910) and low gene flow (N _m = 0.5184). Both Principal Coordinates Analysis (PCoA) and UPGMA cluster analysis supported the clustering of all 16 populations into three groups, corresponding to the three cultivated types, among which there occurred remarkable genetic differentiation (Φ _ST = 37.43%). Pronounced genetic differentiation was also detected among populations within the three cultivated types (GGS: Φ _ST = 40.83%, G _ST = 0.3187, N _m = 1.0691; FGS: Φ _ST = 22.85%, G _ST = 0.2328, N _m = 1.6480; TGS: Φ _ST = 30.68%, G _ST = 0.2540, N _m = 1.4686). Mantel test indicated no significant correlation between geographic and genetic distances at both species and cultivated-type levels (P > 0.05). These findings have profound implications for the sustainable utilization of this precious medicinal herb.     

Perchlorate Depositional History as Recorded in North American Ice Cores from the Eclipse Icefield, Canada, and the Upper Fremont Glacier, USA

Temporal depositional rates are important in order to understand the production and occurrence of perchlorate (ClO₄⁻) as limited information exists regarding the impact of anthropogenic production or atmospheric pollution on ClO₄⁻ deposition. Perchlorate concentrations in discrete ice core samples from the Eclipse Icefield (Yukon Territory, Canada) and Upper Fremont Glacier (Wyoming, USA) were analyzed using ion chromatography tandem mass spectrometry to evaluate temporal changes in the deposition of ClO₄ ⁻ in North America. The ice core samples cover a time period from 1726 to 1993 and 1970 to 2002 for the Upper Fremont Glacier (UFG) and Eclipse ice cores, respectively. The average ClO₄ ⁻ concentration in the Eclipse ice core for the time period from 1970 to 1973 was 0.6 ± 0.3 ng L⁻¹, with higher values of 2.3 ± 1.7 and 2.2 ± 2.0 ng L⁻¹ for the periods 1982–1986 and 1999–2002, respectively. All pre-1980 ice core samples from the UFG had ClO₄ ⁻ concentrations <0.2 ng L⁻¹, and the post-1980 samples ranged from <0.2 ng L⁻¹ to a maximum of 2.6 ng L⁻¹ for the year 1992. A significant positive correlation (R = 0.75, N = 15, p < 0.001) of ClO₄⁻ with SO₄²⁻ was found for the annual UFG ice core layers and of ClO₄ ⁻ with SO₄²⁻ and NO₃⁻ in sub-annual Eclipse ice samples (R > 0.3, N = 121, p < 0.002). The estimated yearly ClO₄⁻ depositional flux for the Eclipse ice core ranged from 0.6 (1970) to 4.7 μg m⁻² year⁻¹ (1982) and the UFG from <0.1 (pre-1980) to 1.4 μg m⁻² year⁻¹ (1992). There was no consistent seasonal variation in the ClO₄⁻ depositional flux for the Eclipse ice core, in contrast to a previous study on the Arctic region. The presence of ClO₄⁻ in these ice cores might correspond to an intermittent source such as volcanic eruptions and/or any anthropogenic forcing that may directly or indirectly aid in atmospheric ClO₄⁻ formation.     

Estimating the component of soil respiration not dependent on living plant roots: Comparison of the indirect y-intercept regression approach and direct bare plot approach

Distinguishing between root and non-root derived CO₂ efflux is important when determining rates of soil organic matter turnover, however, in practice they remain difficult to separate. Our aim was to evaluate two methods for determining the component of below-ground respiration not dependent on plant roots (i.e., basal soil respiration; R_b). The first approach estimated R_b indirectly from the y-intercept of linear regressions between below-ground respiration (BGR) and root biomass. The second approach involved direct measurements of soil respiration from bare plots. To compare the contrasting approaches, BGR and crop biomass measurements were collected throughout the year in a range of agricultural systems. We found that both methods were very closely correlated with each other. Values of R_b determined by the intercept approach, however, were slightly higher than those determined by measurement of bare plots. Both approaches showed a seasonal trend with estimates of R_b lowest in winter months at 0.02 t C ha⁻¹ month⁻¹ for the y-intercept approach and 0.11 t C ha⁻¹ month⁻¹ for the bare plots approach, even after the data had been corrected for the influence of soil temperature. Highest rates of R_b occurred from the height to the end of the crop growing season (0.8-1.5 t C ha⁻¹ month⁻¹). The annual CO₂ efflux due to R_b was estimated to be 8.1 t C ha⁻¹ y⁻¹ from the y-intercept approach and 6.8 t C ha⁻¹ y⁻¹ from bare plots. Annual BGR was 12.1 t C ha⁻¹ y⁻¹. We conclude that both methods provide similar estimates of R_b, however, logistically the bare plots approach is much easier to undertake than the y-intercept approach.     

Methane fluxes from three ecosystems in tropical peatland of Sarawak, Malaysia

Methane fluxes were measured monthly over a year from tropical peatland of Sarawak, Malaysia using a closed-chamber technique. The CH₄ fluxes in forest ecosystem ranged from −4.53 to 8.40 μg C m⁻² h⁻¹, in the oil palm ecosystem from −32.78 to 4.17 μg C m⁻² h⁻¹ and in the sago ecosystem from −7.44 to 102.06 μg C m⁻² h⁻¹. A regression tree approach showed that CH₄ fluxes in each ecosystem were related to different underlying environmental factors. They were relative humidity for forest and water table for both sago and oil palm ecosystems. On an annual basis, both forest and sago were CH₄ source with an emission of 18.34 mg C m⁻² yr⁻¹ for forest and 180 mg C m⁻² yr⁻¹ for sago. Only oil palm ecosystem was a CH₄ sink with an uptake rate of −15.14 mg C m⁻² yr⁻¹. These results suggest that different dominant underlying environmental factors among the studied ecosystems affected the exchange of CH₄ between tropical peatland and the atmosphere.     

Effects of nitrite toxicity on soil bacteria under aerobic and anaerobic conditions

Isolates of a soil Pseudoimonas, as well as other soil bacteria, showed a different sensitivity towards NO^?₂ when grown under aerobic or anaerobic conditions. The tolerance to NO^?₂ was increased in the presence of O₂: for instance, a concentration of $\text{200parts}\text{10}{}^6$ of NO^?₂-N proved to be toxic to a Pseudomonas sp. under anaerobic conditions, whereas over $\text{400 parts}\text{10}{}^6$ were needed aerobically to suppress its growth completely. The addition of NO^?₃ as an electron acceptor for anaerobic respiration did not overcome the inhibitive effect of NO^?₃. The pH range, at which NO^?₂ was utilized anaerobically, was narrowed with increasing NO^?₂ concentration (pH 6.8–8.8 at $\text{70 parts}\text{10}{}^6$ of NO^?₂-N and 7.4–8.5 and $\text{140 parts}\text{10}{}^6$ of NO^?₂-N).Tolerance to nitrite varied considerably among the bacteria tested. Each species was able to overcome the inhibitory effect of NO^?₂ up to a certain concentration, while the length of the lag phase was related to NO^?₂ concentration.     

Emissions of CO2, CH4 and N2O from Southern European peatlands

Peatlands play an important role in emissions of the greenhouse gases CO₂, CH₄ and N₂O, which are produced during mineralization of the peat organic matter. To examine the influence of soil type (fen, bog soil) and environmental factors (temperature, groundwater level), emission of CO₂, CH₄ and N₂O and soil temperature and groundwater level were measured weekly or biweekly in loco over a one-year period at four sites located in Ljubljana Marsh, Slovenia using the static chamber technique. The study involved two fen and two bog soils differing in organic carbon and nitrogen content, pH, bulk density, water holding capacity and groundwater level. The lowest CO₂ fluxes occurred during the winter, fluxes of N₂O were highest during summer and early spring (February, March) and fluxes of CH₄ were highest during autumn. The temporal variation in CO₂ fluxes could be explained by seasonal temperature variations, whereas CH₄ and N₂O fluxes could be correlated to groundwater level and soil carbon content. The experimental sites were net sources of measured greenhouse gases except for the drained bog site, which was a net sink of CH₄. The mean fluxes of CO₂ ranged between 139 mg m⁻² h⁻¹ in the undrained bog and 206 mg m⁻² h⁻¹ in the drained fen; mean fluxes of CH₄ were between −0.04 mg m⁻² h⁻¹ in the drained bog and 0.05 mg m⁻² h⁻¹ in the drained fen; and mean fluxes of N₂O were between 0.43 mg m⁻² h⁻¹ in the drained fen and 1.03 mg m⁻² h⁻¹ in the drained bog. These results indicate that the examined peatlands emit similar amounts of CO₂ and CH₄ to peatlands in Central and Northern Europe and significantly higher amounts of N₂O.