淹水在苏打盐碱土形成过程中的作用——苏打盐碱土形成原因的探讨

苏打盐碱土在我国松嫩平原西部地区广泛分布,它以透水性差,碱性强为主要特点,是世界上最难治理的一类障碍性土壤。近年来,该区土壤苏打盐碱化程度日益加剧,面积不断增加,亟待治理,而弄清苏打盐碱土形成的主要原因是有效治理的前提。本文对松嫩平原西部苏打盐碱土形成原因,从土壤地表景观格局、物理特征和化学性质方面进行了系统归纳与总结,概述了淹水对土壤盐分以及生物的影响,发现由于特殊的地形地貌,该区土壤过去经常处于淹水状态,长期的排水不畅导致区域内水分运动以上行为主,积盐作用强烈,淹水在苏打盐碱土形成和导致盐碱化加剧过程中起到了重要作用。文章同时从3方面提出了苏打盐碱土治理的有效对策与途径。     

环渤海盐碱地区农业资源分布特征与农业持续发展模式初探

综合分析了河北省沧州市运河以东环渤海盐碱地区农业资源分布特征及经济发展状况,提出该区应依据资源与经济的梯级分布布局及开展盐碱地梯级开发治理的战略,利用与保护并举,实施生物措施与工程措施相结合,发展特色、优质和高产高效农业,促进该区农业的持续高效发展。     

环渤海盐碱地区农业资源分布特征与农业持续发展模式初探

综合分析了河北省沧州市运河以东环渤海盐碱地区农业资源分布特征及经济发展状况,提出该区应依据资源与经济的梯给分布布局及开展盐碱地梯级开发治理的战略,利用与保护并举,实施生物措施与工程措施相结合,发展特色、优质和高产高效的农业,促进该区农业的持续高效发展。     

松嫩平原西部盐碱土旱作改良研究进展与展望

土壤盐碱化已成为世界上重要的环境问题之一;同时,盐碱土也是一种重要的后备土壤资源。松嫩平原西部是世界上三大片苏打盐碱地集中分布地区之一。通过回顾松嫩平原西部盐碱土旱作改良发展历程,分析了旱作改良的主要措施与效果及存在的问题,并结合目前国内外相关研究的前沿和热点问题,提出了松嫩平原西部盐碱土旱作改良的展望。建议重点进行旱作改良后的盐渍化动态监测、评估与预警,生物与盐分互作机制,盐碱土障碍治理、修复与农业资源高效利用的优化管理和生态环境效应等方面的研究。     

盐碱区适应性农作制度与技术探讨——以河北省滨海平原盐碱区为例

土壤盐渍化是影响干旱半干旱区农业持续发展的重要因素,国内外对盐碱土的治理改良已经开展了大量工作且取得了丰硕成果.分析盐碱地治理改造的主要经验,最为有效的措施就是以灌排为主的水利工程措施,通过抽提地下水,降低地下水位,发展灌溉,淡水淋盐,大面积的盐碱土地得到改良治理.     

NaCl胁迫下作物对离子的吸收及分配

盐渍化土壤在世界上分布广泛,在我国也有很大的面积。为了开发利用盐渍化的土地资源,传统的治理途径是采用工程和农业措施相结合的方法。然而,近年来越来越多的研究表明,发掘利用现有的生物资源,应用现代生物技术,通过培育抗盐品种来提高植物抗盐性也是开发利用盐碱土的一个重要方面。本文通过对作物耐盐品种和盐敏感品种的比较,综述了盐胁迫下粮食、果树、蔬菜及棉花等作物对K+、Na+、Ca2+、Mg2+等离子吸收及分配的影响,并提出了进一步的研究方向。     

加强盐碱土改良,促进农业持续发展

本文通过对盐碱土的“盐、碱、旱、涝、瘦”多项障碍因素的综合治理技术的应用，及从区域整治着眼，结合流域治理的双重措施，改善土壤肥力状况，增强排灌能力，建立了良好的农业生态系统，为持续农业发展打下坚实的基础。     

辽东山区泥石流初步研究

辽东山区是我国泥石流分布的重点地区之一。文章概述了该区泥石流的基本条件,提出该区特大暴雨是泥石流形成的触发条件;物理风化和断裂构造是形成泥石流松散固体物质的重要过程;岩性、植被条件对泥石流的影响比较突出。最后指出该区泥石流治理应以近期工程措施,远期森林植被等生物措施为主的治理原则。     

三峡库区坡耕地运用生物埂治理水土流失技术的研究

阐述了三峡库区耕地构成及其水土流失成因,研究了该区坡耕地运用生物埂治理水土流失技术,并提出该区减少水土流失、防止农业面源污染的对策与措施     

西藏黑河地区盐碱土的概述

西藏高原黑河地区的盐碱土多分布在高山草原带内陆流域以及湖泊洼地中,在拉莎、日喀则、林芝等地区的农地中间亦有零星的盐斑分布。该区气候比较干旱,年降雨量为150-300毫米,而蒸发量为降雨量的10倍左右。     

Forms and profile distribution of soil Fe in the Sanjiang Plain of Northeast China as affected by land uses

Purpose  

Since the mid-1950s, the wetlands in Sanjiang Plain of Northeast China have experienced greater changes in land use under which the mobility of soil Fe could be changed giving definite effects on the biomass production of adjacent regions. The aim of this work was to investigate the effects of land use change on the characteristics of soil Fe vertical distribution with a focus on evaluating the effects of cultivation on the soil Fe mobility in Sanjiang Plain.     

荒漠地区土地开垦对土壤团聚体稳定性及碳固定的影响

[目的]研究土地开垦前后土地利用方式对该地区土壤团聚体稳定性及有机碳的响应机制,为艾比湖湿地保护区的荒地开垦和植被恢复及农业生产提供科学理论依据。[方法]选取新疆艾比湖流域未开垦的天然林地(CK)和开垦后人工种植的枸杞地、葡萄地、棉花地、苜蓿地共5种不同土地利用类型下,探究荒漠生态系统土地开垦后的土壤结构和有机碳含量的变化规律。[结果]荒漠地区土地开垦对土壤团聚体稳定性及碳固定有显著的影响。土地开垦后,人工种植地块大团聚体(>0.25 mm)含量和团聚体稳定性均显著高于CK,其中棉花地力稳性大团聚体含量最高(>87%);枸杞地水稳性大团聚体含量最高(>79.7%),不同人工耕作模式均增加了大团聚体含量。0—30 cm土层人工种植地块不同团聚体粒级有机碳含量分别为5.91～15.46,5.50～10.70,8.12～16.11,6.90～13.67 g/kg,均显著高于CK(3.91～8.73 g/kg),主要分布在0.25～0.5 mm粒级,各人工土地利用方式下土壤团聚体有机碳含量均显著增加,且枸杞地有机碳含量增加最显著。[结论]该区域土地开垦后种植枸杞的耕作模式更有...     

土壤微食物网对旱改水不同稻作年限土地利用变化的响应

Land use changes affect belowground ecosystems.During the past few decades,land use in Northeast China has changed considerably,and the area of paddy fields has increased rapidly from upland.In this study,soil characteristics and soil biotic community in paddy fields with different years of rice cultivation were measured to examine the effects of land use change from upland to paddy fields on soil micro-food web.The upland maize fields were selected as control and the microbial community composition was characterized using phospholipid fatty acids (PLFAs) analysis.The microbial biomass (total PLFA),bacteria biomass,and fungi biomass were higher in the 20-40-year (late-stage) than 1-10-year (early-stage) paddy fields.The abundances of total nematodes and bacterivores were lower in the early-stage than late-stage paddy fields.The abundance of herbivores was the highest in the early-stage paddy fields but that of omnivore-predators was the highest in the late-stage paddy fields.Structural equation model indicated that soil food web was developed and structured after 20 years of paddy cultivation.Our results suggested that soil micro-food web may be a good indicator for soil development and stabilization of paddy fields following land use change.     

东北3省人类活动与水土流失关系的演进

受人类对土地过度垦殖及不合理耕作利用的影响,水土流失正在成为制约我国东北地区耕地可持续利用和粮食生产的主要因素。在对历史资料甄别与整理的基础上,分析近代以来东北3省区人口、土地利用变化及其与水土流失关系的演变。结果表明：到20世纪中期,东北地区人口压力达到60-70人/km^2,伴随着生活方式的转变,机械化技术的应用,林草湿地被垦殖,森林覆盖率降到30%,垦殖率达30%,使区域性水土流失问题日益严重。     

Maize (Zea mays L.) yield and soil properties as affected by no tillage in the black soils of China

A four-year tillage experiment on maize was conducted in the high latitude region of Northeast of China. The main objective of this study was to investigate the effects of different field tillage practices on maize grain yield, soil physical properties, and soil water and temperature dynamics in Northeast of China. The tillage practices included moldboard plow tillage (MOT), rotary tillage (ROT), reduced tillage (RET), combined tillage (COT), and no tillage (NOT). The surface soil water content at depths of 0–20 cm was higher under NOT compared with other tillage practices, but not different at the deeper soil depths in 2011. The soil temperatures under NOT and RET were lower than those under moldboard plow tillage and ROT at depths of 5 and 15 cm, respectively, measured at 9:00 am in 2005. From the hourly dynamics of soil temperature, the differences among the tillage practices mainly appeared during the daytime (from 8:00 am to 7:00 pm). Among all the practices, the average daily soil temperature under ROT was the highest, while that under NOT was the lowest. MOT, ROT, and RET had higher soil accumulative infiltration compared with NOT and COT. The surface soil bulk density under NOT was higher than or equal to that under the other four tillage practices. The maize yields under NOT were the lowest among all the tillage practices for three years straight. Meanwhile, the yields under MOT were the highest, which were about 47%, 61%, and 38% higher than those under NOT. NOT practice is not recommended for use in spring-planted maize under the high latitude humid cool climate Mollisol region in Northeast of China.     

The impact of cultivation practice and wheelings on runoff generation and soil erosion on the South Downs: some experimental results using simulated rainfall

Abstract. The quantitative effects of different cultivation practices and wheelings on the generation of runoff and soil loss on the South Downs were assessed experimentally with a small drip-type rainfall simulator and rainfall intensities of 42.5 and 23.3 mm/h. Runoff volumes generated by different cultivation practices and between wheeled and non-wheeled areas were significantly different. Amounts of soil lost from different cultivation treatments and from wheelings were less consistent. Less runoff and erosion occurred from shallow cultivated land than from conventionally ploughed and cultivated land. Runoff is further increased by rolling ploughed land after drilling and along tramlines compressed by wheelings. Under high intensity rainfall, considerable runoff can be generated from stubble, especially from wheeled areas.     

Effects of reforestation and deforestation on soil properties in humid mountainous areas: a case study in Wolong Nature Reserve, Sichuan province, China

Abstract. Natural secondary succession, forest planting and agricultural practices after deforestation affect soil properties in many ways. During the last 50 years, land uses have greatly changed in the mountainous areas in southwestern China as the result of deforestation and cultivation. A study was initiated in Wolong Nature Reserve, Sichuan province to elucidate the complex relationships in a humid mountainous region. Soil properties under six typical land use types (natural forest, grassland, shrub, secondary forest, cultivated land and reforested land) were compared. Significant differences between land uses were found for soil bulk density (BD), total nitrogen (TN), soil organic carbon (SOC), available phosphorus (AP) and available potassium (AK). Cultivated land had the lowest levels for most soil properties compared to other land uses and shrubland had a higher SOC, TN and available nitrogen (AN) than other land uses. Soils under grassland and shrub contained the greatest carbon mass (TC). Further studies on reforested land indicated that soil properties could be changed by length of reforestation. The SOC and TN in particular showed a linear relationship with years since reforestation. The results suggested that in an area of China where the climate favours secondary succession, 'leave nature as it is' is a better choice than the policy 'change farmland to forest land ', especially for the mountainous regions where there is lack of labour and financial support.     

东北黑土旱田改稻田对土壤团聚体微生物群落功能多样性的影响

为了解东北黑土旱田改种稻田后土壤团聚体中微生物群落功能多样性的变化,将东北黑土旱田(种植玉米为主)改种为稻田(简称“旱改稻”),采用Biolog-Eco微平板技术,研究了“旱改稻”后不同粒径土壤团聚体微生物的多样性指数以及其对碳源利用能力的变化。结果表明,“旱改稻”显著增加了黑土土壤水稳性微团聚体数量,增加了不同粒径土壤团聚体内有机碳(SOC)的含量。旱田和稻田不同粒径土壤团聚体内的土壤微生物群落平均颜色变化率(AWCD)表现为旱田淤泥+粘土>旱田大团聚体>旱田微团聚体>稻田大团聚体>稻田淤泥+粘土>稻田微团聚体。“旱改稻”明显降低了各粒径土壤团聚体微生物的多样性指数以及碳源利用能力,尤其对氨基酸与碳水化合物最为明显。主成分分析结果表明,旱田和稻田不同粒径土壤团聚体微生物群落功能多样性差异显著。综上,“旱改稻”明显改变了黑土土壤团聚体微生物群落功能多样性,降低了以碳源为底物的土壤微生物代谢活性。本研究结果为东北黑土区土壤可持续利用提供了理论参考。     

"绿色"引领下东北地区秸秆产业发展长效机制解析

东北地区秸秆产出总量大、积温低,是中国秸秆综合利用的重点和难点区域,推进东北地区秸秆综合利用对于保护黑土地、促进农业绿色发展具有重要意义。该研究在总结农业绿色发展内涵的基础上,结合东北地区秸秆利用现状、主要问题和发展需求,分析了"绿色"引领下秸秆产业发展的总体思路。通过文献调研,研究了以美国等为主的直接还田肥料化利用方式、以韩国等为主的种养结合饲料化利用方式,以丹麦等为主的发电供热能源化利用方式,结合东北地区秸秆利用主要成效与典型做法,阐释了"绿色"引领下东北地区秸秆产业发展长效机制的构成要素及其内在关联,绘制了秸秆产业发展长效机制框架图,并从技术装备研发、法规政策创设、市场主体培育、公共服务与市场监管等方面进行了解析。提出了基于产业发展长效机制的全要素、多维度秸秆利用模式构建原理,并示例说明了利用模式构造基本过程与方法。该研究可为推动东北地区秸秆高质高效利用提供基础支撑和决策参考。     

Influence of three different land management practices on soil mite (Arachnida: Acari) densities in relation to a natural soil

Intensification of agricultural practices is leading to an increased rate of severe soil degradation in the central area of Argentina, with large areas being converted to arable lands. The application of different management practices to soil impacts edaphic mite populations by altering the organic inputs and by influencing the soil microhabitat. The objective of this paper was to evaluate the influence of three different land management practices on soil mite density in temperate agroecosystems of Córdoba, Argentina, in comparison with a natural soil. Standard abiotic soil properties were also analyzed. Six samples per plot and per sampling date were taken at bimonthly intervals from August 1999 to June 2001. A gradient of increasing soil degradation was evident in physical, chemical and physicochemical soil properties from natural to agricultural plots. Total mite density decreased as soil cultivation increased. However, different responses to land management were observed when comparing the different suborders of mites. Oribatida and Mesostigmata were more sensitive to the agricultural practices than Prostigmata and Astigmata. Densities of the last two suborders seemed to be unaffected by soil cultivation in some periods. Oribatida, Mesostigmata and pooled mite density showed a hump-backed relationship with management intensity, with a maximum in the cattle management. It is concluded that the influence of soil cultivation on soil mites as a whole was negative, with more intensively managed systems tending to reduce mite density, although different suborders were differentially affected by agricultural intensification. We suggest that the reduction of total mite, Oribatida and Mesostigmata densities in the high-input managements is mainly explained by the perturbations produced by conventional agricultural practices and by environmental soil conditions present in the intensively managed sites that were unfavorable for these groups of mites. The implication of the changes reported in mite abundances on soil processes is discussed.