水土保持生态自然修复与生态文明建设

水土资源是人类发展与文明的根基,如何整治日趋恶化的生态环境、防止水土流失、恢复和重建受损的生态系统成为生态文明建设的关键.水土保持生态自然修复是一个费省效宏的水土流失综合防治办法,水土保持生态修复是实现资源节约型、环境友好型社会的重要途径,也是建设生态文明与美丽中国目标实现的重要载体.在分析水土保持生态自然修复与生态文明建设相互关系的基础上,概括我国水土保持生态自然修复的成效与经验,明确水土保持生态自然修复工作需要亟待加强的几个领域,提出未来实施水土保持生态自然修复工作的若干发展策略.     

再论商品型生态农业

商品型生态农业能够实现人与自然关系的协调发展,实现“人－自然－社会”关系的合理化,并是农业生产与水土保持措施相结合的有效途径,因而黄土高原建设商品型生态农业具有重要的现实意义。     

总结新经验 寻求新突破——关于对广安等地水土保持新机制的调研

广安市在开展“长治”工程大示范区建设中 ,统筹协调 ,综合开发 ,创新机制 ,产生了良好的经济效益、生态效益和社会效益 ,对全省开展水土保持工作具有许多重要启示。广元市因地制宜发展庭园水土保持 ,积极实践“项目到村”和“以土方换水方” ,为新形势下调动群众和社会的力量参加水土保持生态建设 ,探索出了新的途径 ,取得了良好效果     

基于关键指标的水保时空大数据多维可视化研究与实现——以陕西省“水土保持一张图”指标体系建设为例

开展“水土保持一张图”建设是“十四五”期间推进智慧水保发展的重要任务之一。为了科学准确把握关键性指标、高效综合应用水土保持时空大数据、简明生动展示水土保持行业态势及成果,基于陕西省水土保持信息化资源,通过建立“水土保持一张图”的关键指标体系,构建时空大数据管理平台,对全量水土保持数据的可视化方法进行了研究并最终得以实现。建设的陕西省“水土保持一张图”实现了二、三维地图展示、多元化数据统计、感兴趣时空筛选及全量化详情查询等功能,可支撑各级水行政主管部门监测业务运行状态、查看业务管理成效、推测业务发展趋势,服务水土保持智慧化模拟和精准化决策,有助于推进陕西全省水土保持行业健康、高质量发展。     

水土保持与建设美丽中国的思考

中共十八大提出了建设美丽中国的宏伟蓝图,而水土保持是建设美丽中国的重要基础和主要内容。基于此,从水土保持生态建设角度,对美丽中国进行了自然和社会等方面的探讨,分析了水土保持在美丽中国建设中的功能和作用,就现状和发展进行了思考,提出了政策建议。     

论资源环境保护与水土保持方案审批

 科学发展观是我们统领发展的指导思想。国家提出加快建设资源节约型社会和环境友好型社会的目标,开发建设项目水土保持方案的审批应成为转变经济增长方式、实现社会转型的重要手段。在新形势和新的历史发展时期,应根据国家“十一五”规划纲要确定的产业发展政策、区域主体功能定位,从注重单个项目水土流失防治技术的战术层面向注重流域或区域的资源环境保护的战略层面转变,针对不同情况给予审批、暂缓审批或不予审批,发挥水土保持调节经济发展的作用。水行政主管部门要加强水土保持方案的技术评估机构建设,强化水土保持监测工作,为国家掌握水土资源、生态环境、水土流失动态变化,调整经济发展政策,提供技术支撑和科学依据。     

水土保持实现两个转变的战略探讨

<正>实现“两个转变”,是我国实现今后15年奋斗目标的关键所在.水利部党组从实际出发,研究制定了深化水利改革的具体措施,要求积极推进五大体系建设,做好“水利第一”这篇文章.水土保持既是基础设施,又是基础产业,“九五”期间,党中央和国务院对水土保持工作提出了更高的要求,每年治理水土流失面积5万km~2.面对世纪之交的历史使命,水土保持工作必须深化改革,走出一条有中国特色的水土保持持续、快速、健康发展的路子,实现水土流失治理开发利用方式和经营管理方式的转变,向提高水土资源利用效益的方向发展.水土保持实现“两个转变”,必须以改革为动力,构建与市场经济体制相适应的运作机制,大力发展高效小流域经济,努力提高水土资源利用效益.     

铁岭市水土保持信息数字化管理系统研究

过去由于种种原因,水土保持信息主要靠手工或简单计算机操作进行统计和汇总。没有从总体上做到数据采集标准化,数据应用智能化,使大量的原始数据得不到应有的存储和利用,造成资源浪费。“数字生态”工程关键在于应用水土保持生态现代化、信息化工程技术,从宏观上解决生态“海量数字”规模化、系统化的管理、分析、决策的问题,能够从大局上变“实体生态”为“数字生态”和“模型生态”,系统能够涵盖各行政区、流域、生态保护区的自然状况、社会经济状况、水土流失及治理状况、土地利用情况、植被覆盖情况等。可以实时地监测过去或今后的水土保持林草措施、工程措施及耕作措施的实施状况,同时还可以在图形上查阅各项措施的具体内容。初步实现了水土保持生态信息资源数字化管理。     

搞好水土保持 加快鄱阳湖生态经济区建设

水土保持是生态经济区建设的基础,不搞好水土保持,生态经济区难以形成,即使一时建好,也无法长久保住;水土保持是生态经济区建设的重要载体,通过实施工程技术、生物技术,美化山水田林路,实际上就是在生态经济区里栽树种草美化环境。生态经济区建设是水土保持的目的,人们通过水土保持保护自然、改造自然的根本目的是利用自然、欣赏自然,建设美好的家园;生态经济区建设是水土保持的最终保证,只有将自然资源转化为经济资源,才能推动经济可持续发展,水土保持才有投入保证,水土保持才能真正实现;生态经济区建设为水土保持开辟了新的途径。针对抚州市水土保持和生态经济区建设特点,提出了搞好水土保持,加快生态经济区建设的对策。     

水土保持高质量发展助推贵州省创建生态文明建设先行区

水土保持高质量发展是贵州省创建生态文明建设先行区的基础保障，在阐述贵州省“十三五”期间(2016—2020年)水土保持工作发展情况的基础上，剖析了贵州省水土保持工作存在的问题，提出构建水土保持生态文明评价体系、水土流失长效防治机制、现代化水土保持监督管理体系，以及培植水土保持优势产业、引导社会多元化投入等水土保持高质量发展路径，以建设良好的生态环境，助推贵州省创建生态文明建设先行区，为贵州经济高质量发展提供前提和基础。     

Mechanisms of persistence of low numbers of bacteria preyed upon by protozoa

Tetrahymena pyriformis cultures were maintained when transferred serially in solutions containing 10⁵ to 10⁷Klebsiella pneumoniae cells.ml^?1, bacterial numbers that were observed to persist in the presence of protozoa. The number of cells of one strain of K. pneumoniae surviving predation in solution was essentially the same in the absence of an alternative prey as in the presence of a second K. pneumoniae strain. Toxins deleterious to protozoa did not appear as the animal consumed the bacteria. T. pyriformis reduced the abundance of Escherichia coli from about 10⁸ to 10⁶.ml^?1. but the latter number persisted for 15 days; however, in solutions containing chloramphenicol, the abundance of E. coli fell to 590 cells. ml^?1 in 15 days. In solutions containing the antibiotic, T. pyriformis reduced the Rhizobium sp. population from more than 10⁶ to less than 10³ cells in 10 days and K. pneumoniae from more than 10⁸.ml^?1 to zero in 18 days. An appreciable decline in abundance of these bacteria did not occur in the antibiotic-amended liquid free of protozoa. T. pyriformis did not greatly reduce Rhizobium sp. numbers when both were added to irradiated soil, but the predator caused the bacterial population to decline from 4 × 10⁸ to fewer than 10⁵.g^?1 in 16 days in chloramphenicol-treated soil. Colpoda sp. inoculated with Rhizobium sp. into soil sterilized by autoclaving only reduced the prey abundance from 10⁹ to 10⁸.g^?1, but the protozoan caused the bacterial population to fall to about 100.g^?1 in 15 days in the presence of the antibiotic. The population of Rhizobium sp. added to nonsterile soil dropped from in excess of 10⁸ to 6 × 10⁶.g^?1 in 29 days. but it declined to 550. g^?1 in the same period when chloramphenicol was also introduced. It is concluded that the ability of these bacteria to maintain themselves in solution and in soil is governed by their capacity to reproduce and replace the cells consumed by predation.     

Evidence of Long-Range Transport of Pollutants from the Size-Fractionated Ionic Composition of Aerosols in the Jeju Island of Korea

The ionic composition of total suspended particulate (TSP) and fine (PM_2.5) fractions was investigated from an 1,100 site in the middle of Mt. Halla in Jeju Island, Korea from March to November 2006. The sum concentrations of cation and anion species in TSP fraction were 205 ± 170 and 183 ± 164 neq m^?3, respectively, while those for PM_2.5 as 118 ± 129 and 88.5 ± 89.3 neq m^?3, respectively. In TSP, the concentration of the major ions changed in the order of SO₄ ^2? > NH₄ ⁺ > Ca²⁺ > Na⁺ > NO₃ ^? > Mg²⁺ > K⁺ > Cl^?, while its PM_2.5 counterpart as NH₄ ⁺ > SO₄ ^2? > Ca²⁺ > NO₃ ^? > Na⁺ > Mg²⁺ > K⁺ > Cl^?. Inspection of the temporal variabilities of ionic components indicated that most ions peaked in spring or fall months. The back trajectory analysis showed that the atmospheric composition of the major ionic species was affected fairly sensitively by long-range transport from China under the favorable meteorological conditions. In contrast, the lowest ionic concentration levels were seen most abundantly, when air masses passed from South Sea. Hence, the analysis of ionic concentration data suggests that their distributions are controlled by the combined effects of various source processes including the most prominent Chinese origin and the meteorological condition favorable for such transport.     

Simulation of the Mathematical Model of Composting Process of Sewage Sludge

An integrated model was developed to simulate the temporal change and spatial variation of temperature and spatial distribution of TM (total mass) and MC (moisture content) of the final compost for composting process of sewage sludge. The model included biodegradation kinetics of organic matter and balance equations of energy and mass. First-order assumption was applied to describe the biodegradation process with correction functions of temperature, oxygen, MC, and FAS (free air space). The transfer process was considered in balance equations of energy and mass. A finite difference method was used to solve the model. Two trials of 0.21 m³ were run to estimate parameters and evaluate the simulation. The model could predict TM and VS (volatile solid) of the final compost well, temporal trend of oxygen concentration and water removal, and also a good fitting of the temporal and spatial change of temperature. H_rx (reaction enthalpy of biodegradable volatile solid) and η_BVS (mass fraction of biodegradable volatile solid) were considered the most sensitive parameters based on the sensitivity analysis. Future research was suggested to focus on reasonable humidity assumption, measuring accurate value of thermodynamics and kinetics parameters of sewage sludge, and simulating the composting process with different aeration modes and turning of the pile.     

Change of hydrophysical properties of clayed minerals due to the influence of soluble salts

It was revealed that the influence of soluble salts on the hydrophysical properties of clayed minerals depends on the nature of minerals, the properties and state of salt (in solution or sorbing), and the region of fundamental hydrophysical characteristics (FHCH). The treatment of clayed minerals by NaCl, MgCl₂, Ca(CH₃COO)₂, and ZnCl₂ solutions increased their water-retention in the range NaCl > MgCl₂ > Ca(CH₃COO)₂ ≈ ZnCl₂. Pb(CH₃COO)₂ decreased the water-retaining ability of clayed minerals in all the FHCH range. A differential characteristic of the action MgCl₂, Ca(CH₃COO)₂, and ZnCl₂ on smectite is decrease of capillary water deduction.     

水稻幼苗根系吸收NO3-对细胞膜电位的影响

利用玻璃微电极技术测定了扬稻6号(籼稻)幼苗根尖细胞在吸收不同NO3-浓度(0.01、0.02、0.1、0.2、0.5、1.0和2.0.mmol/L)过程中膜电位的变化。结果表明,1)水稻根系吸收NO3-引起膜的去极化,去极化到一定程度后出现复极化;有小部分水稻根表现为超极化。在0.01～1.0.mmol/L范围内,去极化大小随外界NO3-浓度的增加而增加,且差异显著(P0.05)。0.01.mmol/L.NO3-产生较小的去极化,平均为3.8.mV;0.5.mmol/L.NO3-产生了最大去极化,平均为40.2.mV;当外界NO3-浓度大于1.0.mmol/L时膜电位去极化大小呈下降趋势。根系吸收不同浓度的NO3-而使膜电位去极化的进程符合Michaelis-Menten动力学。2)复极化有部分复极化和完全复极化两种。超极化也有两种:一种是膜电位先超极化,后缓慢复极化;另一种是先出现一个小的去极化,然后是较大幅度的超极化。3)运输蛋白抑制剂PGO抑制了根系吸收NO3-而产生的膜电位的响应。4)对于经CaSO4溶液预培养的水稻来说,C2+主要引起膜电位超极化。     

太行山低山丘陵区不同植物群落物种多样性研究

 通过样地法对小浪底水库库区山地生态系统不同群落间的Shannon-Wiener指数(H′)、Simpson指数(D1)、Margalef物种丰富度(D2)、种间相遇概率(P)和Pielou均匀度指数(Jsw)等多样性指数进行研究,利用统计方法分析不同群落的物种多样性指数与其所处环境的关系。结果表明:1)物种多样性指数和丰富度指数与群落类型有密切关系,同一类型的群落中,多样性指数随演替时间表现出复杂的关系;2)土壤含水量对H′、P、Jsw、D1等呈极显著的正相关性,土壤厚度与H′、D1、P呈显著正相关性;多样性指数与坡度无相关性;土壤有机质、速效氮、速效磷等养分指标与多样性指数H′、D1有显著的正相关;3)多样性指数H′与乔木、灌木群落生物量表现为正相关关系,草本群落与D1相关性不显著;4)乔木林群落的恢复时间与Jsw、H′呈正相关关系,其余多样性指数(P、D1、D2)与恢复时间关系不显著(P>0.05);恢复时间每增加10a,群落物种数平均增加约6种;5)物种多样性指数H′与灌木的盖度和高度呈极显著正相关性;有些单优群落随高度增加和盖度提高,多样性指数反而表现出降低;6)草本植物群落的高度和盖度与物种丰富度指数D2与呈显著的负相关关系,与H′相关性不显著。     

两种退耕还林模式对土壤微生物优势类群的影响

以两种退耕还林模式的桦木林地、苦竹林地和农耕地(对照)为对象,对各样地土壤微生物优势类群数量的季节性动态变化、垂直分布特征及其与土壤酶活性的相关性进行了研究。结果表明,土壤微生物的优势类群为微球菌属(Micrococcus)、芽孢杆菌属(Bacillus)、链霉菌属(Streptomyces)、游动放线菌属(Actinoplanes)、酵母菌(未定属)、木霉菌属(Trichoderma)这6类。两种退耕还林模式下土壤优势微生物类群数量存在差异,春、夏、秋三季均为苦竹林所占比例最大,冬季为桦木林最大。两种林地和农耕地土壤微生物优势类群数量季节性变化规律为微球菌和酵母菌在夏、冬季较大,春、秋季较少;芽孢杆菌在秋季最大,夏季最小;游动放线菌与木霉菌数量在四季中变化不大;链霉菌是夏季最高,冬季最少。各优势微生物类群数量的垂直分布特征表现为微球菌、游动放线菌、木霉菌随土壤层的加深其数量逐渐降低,芽孢杆菌、链霉菌数量则随土壤层的加深而逐渐增加,酵母菌随土壤层的加深其数量减少,但趋势不明显。两种林地对各优势微生物类群数量的根际效应为:链霉菌和木霉菌的R/S值大于1,酵母菌的R/S值小于1,微球菌和游动放线菌在桦木林的R/S值大于1而在苦竹林小于1。在优势微生物类群和土壤酶之间,微球菌与转化酶,芽孢杆菌与纤维素酶,木霉和游动放线菌与过氧化氢酶,酵母与脲酶呈显著正相关关系。     

Effect of rate of nitrapyrin and source of N on soil pH and response of burley tobacco

Abstract

A field experiment was conducted on Maury silt loam soil (Typic Paleudalf) during 2 years to determine the effects of rate of nitrapyrin and source of N fertilizer on soil pH and response of burley tobacco (Nicotiana tabacum L.cv.^xKy‐14'). All sources of N were applied at the rate of 280 kg N ha^‐1. The information was needed to increase the efficiency of N fertilizer use and improve the growth and safety of tobacco.

Results indicated that application of a NO₃ ^‐source of N fertilizer or low rates of nitrapyrin (0.56 to 2.24 kg ha^‐1) decreased surface soil acidification and the concentration of plant Mn, while plant dry weight early in the growing season was increased. The early growth benefits noted for .nitrapyrin did not lead to increased cured leaf yields or value. Cured leaf yield and value were highest in plots receiving Ca(NO₃)₂, followed by KH₄NO₃, then urea.

Concentration of protein N, total alkaloids, and total volatile nitrogenous bases of cured leaves increased and NO₃ ^‐‐N decreased as rate of nitrapyrin increased. Total N concentration of cured leaf, however, was not significantly affected by nitrapyrin application, indicating that the proportion of absorbed N as NH₄ ⁺increased as nitrapyrin rate increased.     

The effect of organic matter on the structure of soils of different land uses

In this study, the soil structure of two soils (Haplic Chernozem and Eutric Fluvisol) of different land uses (forest, meadow, urban and agro-ecosystem – consisted of four crop rotations) in Slovakia was compared. The soil aggregate stability was determined with a dependence on the chemical composition of plant residues. The quantity and quality of the organic matter was assessed through the parameters of the C and N in size fractions of dry-sieved and water-resistant aggregates. The soil structure of the forest ecosystem was evaluated as the best of all of forms of land use. Differences in the soil structure under the grass vegetation of a meadow (natural conditions) and urban ecosystem were also recorded. The agro-ecosystem was characterised by a higher portion (55.95%) of the most valuable (agronomically) water-resistant aggregate size fraction of 0.5–3 mm. Values of the carbon management index showed that the larger water-resistant aggregates were, the greater were the changes in the organic matter (r = ?0.680, P < 0.05). In addition, a smaller content of dry-sieved aggregates of the 3–5 mm size fraction was observed with higher contents of soil organic carbon (SOC) (r = ?0.728, P < 0.05) and labile carbon (C_L) (r = ?0.760, P < 0.05); there were also greater changes in the soil organic matter and vice versa, higher contents of SOC (r = 0.744, P < 0.05) and C_L (r = 0.806, P < 0.05) greater contents of dry-sieved aggregates of size fraction 0.5–1 mm. The soil structure of agro-ecosystem was superior at a higher content of cellulose (r = ?0.712, P < 0.05) in the plant residues. The higher content of cellulose and hemicellulose in the plant residue of a previous crop was reflected in a smaller C_L content in the water-resistant aggregates (r = ?0.984, P < 0.05). A correlation was observed between a high content of lignin in the plant residue and a smaller SOC content in the water-resistant aggregates (r = ?0.967, P < 0.05). Lastly, a higher content of proteins in the plant residues (r = 0.744, P < 0.05) supported a greater content of dry-sieved aggregates of the 0.5–1 mm size fraction.     

Localisation of nitrate in the rhizosphere of biochar-amended soils

A wheat seedling rhizobox approach was used to differentiate between the rhizosphere and non-rhizosphere (bulk) soil amended with low and high rates of biochar (20 and 60 t ha⁻¹ vs. control). Nitrate (NO₃⁻) was added as the main nitrogen (N) source because emerging biochar research points to reduced NO₃⁻ loss through leaching and gaseous loss as nitrous oxide. The rhizosphere under the different treatments were distinct (P = 0.021), with greater soil-NO₃⁻ and biochar-NO₃⁻ contents in the high biochar treatment. Biochar addition increased wheat root length ratio (P = 0.053) and lowered root N uptake (P = 0.017), yet plant biomass and N content were similar between treatments. The results indicate localisation of NO₃⁻ within the rhizosphere of biochar-amended soils which has implications for NO₃⁻ loss and improved nitrogen use efficiency.