长江中游土壤潜沼化现状及其利用

讨论了长江中游地区土壤潜育化沼泽化现状,土壤渍害的原因及其危害,并总结提出了一些改良措施。该地区土壤潜育化沼泽化十分普遍,四湖地区处于这种状况下的水稻土达84%,洞庭湖地区达51%,内外排水不畅是产生土壤渍害的重要原因。土壤渍害的产生极为频繁,并强烈影响作物的产量。从整个区域出发,综合考虑水利设施的规划以及因地制宜、因时制宜采取合理而有效的土壤改良措施,是改造潜沼化低产土壤的原则。     

江汉平原湿地农业技术体系探讨

以十多年来江汉平原农业地理和涝渍地开发研究实践为基础,综合国内外湿地研究新成果,首次提出了建立中国南方湿地农业技术体系的构想。针对本地区涝渍灾害严重和生态脆弱化突出的实际,重点探讨了湿地农业关键技术和建立湿地农业开发模式的问题,湿地农业的关键技术主要有涝渍地农业小区综合整治开发规划与实施;涝渍地排水改良技术;涝渍地土壤肥力特征及改良技术;适生生物资源的发现、引进与鉴定;主要作物抗涝渍的机理及抗渍高产栽培;涝渍地作物病虫草害的发生规律及综合防治技术;涝渍地生态环境异化评价与生态恢复技术。基于江汉平原实际,今后湿地农业必须在国土整治与水资源合理分配、调控技术、选择与培育湿地特色产业和恢复优美环境与确保食物安全等方面进行重点攻关研究。     

江汉平原温地农业技术体系探讨

以十多年来江汉平原农业地理和涝渍地开发研究实践为基础，综合国内外湿地研究新成果，首次提出了建立中国南方湿地农业技术体系的构想。 地本地区党政军渍灾害严重和生态脆弱化突出的实际，重点探讨了湿地农业关键技术和建立湿地农业开发模式的问题，湿地农业的关键技术主要有涝渍地农业小区综合整治开发规划与实施；涝渍地排水改良技术；涝渍地土壤肥力特征及改良技术；适生生物资源的发现、引进与鉴定；主要作物抗涝渍的机理及抗渍高产栽培；涝渍地作物病虫草害的发生规律及综合防治技术；涝渍地生态环境异化评价与生态恢复技术。基于江汉平原实际，今后湿地农业必须在国土整治与水资源合理分配、调控技术、选择与培育湿地特色产业和恢复优美环境与确保食物安全等方面进行重点攻关研究。     

三峡工程对长江中游地下水动态和土壤潜育化的影响

通过对长江中游四湖地区地下水动态观测数据分析得出，长江对沿岸平原地下水影响程度随距离蛎而逐渐减弱，用遥感技术和实地调查，确定了潜育化、沼泽化土壤在四湖和洞庭湖地区分布以及潜在威胁面积，并依此分析了三峡工程对土壤潜育化沼泽化的影响。在大量调查和田间试验的基础上，提出了适用于当地潜育化沼泽化土壤的改良利用途径。     

涝渍地农业综合整治开发示范区规划探讨

通过中日合作项目“湖北省江汉平原四湖涝渍地综合开发计划”两个涝渍地综合开发示范区的有关实践，对该区涝渍地开发规划方法进行了系统探讨。研究表明，江汉平原涝渍地大体上可分成以河流冲积物为主和以湖积与冲积共同作用形成的两类地区，两者在地貌、土壤结构、耕作方式和经济发展阶段上存在较大差异，应该区别对待；“单元水系”可作为涝渍地区域综合开发最基层的区域单元。水土资源存在的巨大潜力和障碍应作为规划的出发点，其开发模式可借鉴日本“农田综合整备”的理论与实践；田间土地整治及其附属物设施建设的技术标准应以我国近20年来关于涝渍地排水的工程标准为主，适当参照世界先进国家标准。数量化理论I可作为规划前对涝渍地微域土地进行综合评价的一种合适方法；鉴于涝渍地开发的阶段性，对现阶段涝渍地开发效果的评价指标的选择，应在农田的物理结构改变效果、农业深度开发与结构调整效果和综合经济效益效果等3方面取得平衡。以第一方面的评价为重点，给出了一个相应的评价体系。     

三峡工程对长江中游地下水动态和土壤潜育的影响

通过对长江中游四湖地区地下水动态观测数据分析得出，长江对沿岸平原地下水影响程度随距离增大而逐渐减弱。用遥感技术和实地调查，确定了潜育化、沼泽化土壤在四湖和沿庭湖地区分布以及潜在威胁面积。并依此分析了三峡工程对土壤潜育化沼泽化的影响。在大量调查和田间试验的基础上，提出了适用于当地的潜育化沼泽化土壤改良利用途径。     

湿地农田低产土壤改良利用研究

系统地阐述了四湖地区湿地农田低产土壤的分布、成因、类型、特性及障碍因素，并着重对采取“三沟”配套排水、增肥调养、使用释氧化物、选手抗逆良种及轮作养地等综合改良利用技术的试验研究对果作了系统分析。     

江汉平原涝渍地域分异规律研究

通过五年研究，澄清了江汉平原涝渍灾害形成的原因。根据微地貌特点和涝渍状况将江汉平原涝渍地域土地分为7种类型：洲滩平地季节性洪涝地域，淤高平地季节性暗渍地域，中间平地季节性渍害地域，低湿平地渍害地域，滨湖平地涝渍地域，湖泊水面调蓄地域，碟形洼地涝渍圈。江汉平原涝渍微地域分异和演变规律主要表现在6个方面：(1)在平面上与河流呈水平带状分布；(2)在空间上呈梯度分布；(3)碟形洼地涝渍特征呈同心圆分布；(4)涝渍微地域随时间推移发生有序地演变；(5)人类活动越来越成为江汉平原涝渍地域分异的主导因素；(6)江汉平原涝渍微地域与涝渍灾害呈显著的相关性。根据江汉平原涝渍微地域涝渍发生特征，提出了因地制宜、分区开发的指导思想，并选点进行了实证开发示范，取得了显著成效。     

长江中游潜沼化土壤的限制因子及其对策研究

研究表明，地下水和单一的种植结构与利用方式，是长江中游地区潜沼化土壤生产力的主要限制因子，在调查和田间试验的基础上，在国家目前难以实现配套水利工程设施的条件下，提出了以生物措施为主，结合小型工程措施进行综合改良利用，治渍改土的切实可行的方案，在优化农业结构的前提下，比较了诸多优化模式，通过田间试验，筛选出诸如退田还湖，种植水生经济植物，垄稻沟鱼及各种轮作方式，同时适当引进耐潜作物品种，实行配方施肥     

江汉平原中低产土壤及其改良利用

在分析江汉平原中低产土壤形成原因的基础上，将其分为涝渍、漏瘠和粘结三种类型，提出了五条改良利用措施：１、渔农复合，增强调蓄能力；２、抗旱治渍、协调水气；３、增肥调养，增肥地力；４、选择适当作物品种和优良耕作栽培模式；５、综合治理、系列配套。     

稻鸭、稻鱼共作对稻田P素动态变化的影响

以稻鸭和稻鱼生态系统为研究对象，通过大田试验研究了稻田P的动态变化及转化规律，及其对环境的影响。结果表明，施P后土壤和田面水P含量立即达到最大值，一周后迅速降低。相对于空白（CK），养鸭处理（RD）和养鱼处理（RF）田面水总P浓度、溶解P浓度、土壤速效P含量和水稻吸P量显著增加，而土壤全P含量有所增加。研究还表明，水稻吸P量与田面水溶解P、土壤速效P显著相关。对田面水P素径流流失的潜在环境效应分析表明，施P后的一周左右是控制P素流失的关键时期；由于养鸭养鱼能提高稻田P含量，在稻鸭、稻鱼共作期间，要注意避免农田排水和防止因降雨引起的田面水外溢。同时，由于鸭子和鱼能提高土壤有效养分含量，降低化肥的施用量，进而降低了化肥损失所造成的环境危害。     

论水稻土肥力进化与土壤质量——以太湖地区为例

太湖地区是我国古老农业区之一。在六七千年之前先民已开始种植水稻 ,随着耕作培肥措施不断加强 ,与土壤肥力进化同步伴随着耕作轮作制的不断演进 ,由轮荒———沤田———水旱轮作———三熟制的变化 ,土壤基础肥力稳步提高 ,稻麦单位面积产量逐年上升。该区水稻土历经数千年的耕肥与平田整地等人为活动 ,在起源土壤背景上发育成五类水稻土 ,这五类水稻土经过培肥改良均达到水旱轮作高产稳产阶段 ,尽管地力上还存在不同程度的差异 ,这不能不说是人为定向培育的成果。在一般情况下 ,土壤质量是由土壤肥力决定的 ,基础肥力高低是农业生产优质高产低耗的关键 ,在评价土壤质量时必需首先予以关注。当然 ,随着工业的发展 ,土壤污染所波及的农产品超标问题 ,也应在评价土壤质量时予以关注 ,并作为评价因素在综合评价体系中占有应有的份量     

长期有机物循环对红壤稻田养分及水稻生长的影响

通过长期有机物循环的定位试验,研究了长期有机物循环利用对红壤稻田养分供应及水稻生长发育的影响,目的是了解长期有机物循环利用后土壤养分含量变化、水稻生长特性及两者的相关性。结果表明有机物循环明显提高了土壤有机质含量,并使土壤养分维持在一个相对较高的水平上。有机物循环处理的土壤有机质,全N、全P和全K及其有效部分的平均含量分别比无循环处理提高了445％、347％、175％、94％,特别是碱解N,速效P和速效K含量提高显著,有机物循环处理比无循环处理提高达469％、452％和347％。有机物循环利用提高了水稻分蘖数和叶面积指数,使水稻群体的透光率减少。有机物循环处理平均单叶净光合速率比无循环处理高68％,蒸腾作用比无循环处理高50％,最终表现为干物质积累量及稻谷产量的增加。对长期有机物循环利用后的红壤稻田养分指标与水稻生长指标进行逐步回归分析后发现,土壤中速效P及有机质含量的增加是促进水稻生长的主要因素.     

稻田种养结合循环农业模式生态环境效应实证分析——以南方稻区稻-鱼模式为例

稻田种养结合循环农业模式生态环境效应明显,其主要体现在节肥、节药、抑草、改善土壤和水体等方面上。本文根据对南方稻区的入户调查数据和2001-2009年中国统计年鉴、中国农村统计年鉴、中国农业统计年鉴相关统计数据及化肥农药使用量的技术标准,实证分析了稻田种养结合循环农业模式的节肥、节药的生态环境效应。调查分析显示,稻-鱼模式下农户化肥使用量比常规水稻种植模式的使用量要减少15.21%,农药使用量要减少40.17%;相关性分析表明南方稻区稻-鱼种养结合模式的稻田面积占水稻生产总面积的百分比与化肥、农药使用量之间呈负相关关系,相关系数分别为-0.407 2和-0.979 9。可以看出,在稻-鱼的稻田生态系统中,土壤和水体的改善以及有害生物的减少,形成了鱼类对化肥和农药的替代关系,在稻谷产量不变甚至增产以及增加鱼类产出的情况下,农户大幅度减少了化肥和农药的使用量,因此实施扶持稻田种养结合循环农业模式策略,是改善稻区农业生态环境的重要途径。     

稻鸭、稻鱼共作对稻田P素动态变化的影响

以稻鸭和稻鱼生态系统为研究对象，通过大田试验研究了稻田P的动态变化及转化规律，及其对环境的影响。结果表明，施P后土壤和田面水P含量立即达到最大值，一周后迅速降低。相对于空白（CK），养鸭处理（RD）和养鱼处理（RF）田面水总P浓度、溶解P浓度、土壤速效P含量和水稻吸P量显著增加，而土壤全P含量有所增加。研究还表明，水稻吸P量与田面水溶解P、土壤速效P显著相关。对田面水P素径流流失的潜在环境效应分析表明，施P后的一周左右是控制P素流失的关键时期；由于养鸭养鱼能提高稻田P含量，在稻鸭、稻鱼共作期间，要注意避免农田排水和防止因降雨引起的田面水外溢。同时，由于鸭子和鱼能提高土壤有效养分含量，降低化肥的施用量，进而降低了化肥损失所造成的环境危害。     

Investigating options for attenuating methane emission from Indian rice fields

The development of methods and strategies to reduce the emission of methane from paddy fields is a central component of ongoing efforts to protect the Earth's atmosphere and to avert a possible climate change. It appears from this investigation that there can be more than one strategy to contain methane emission from paddy fields, which are thought to be a major source of methane emission in tropical Asia. Promising among the mitigating options may be water management, organic amendments, fertilizer application and selection of rice cultivars. It is always better to adopt multi-pronged strategies to contain CH4 efflux from rice wetlands. Use of fermented manures with low C/N ratio, application of sulfate-containing chemical fertilizers, selection of low CH4 emitting rice cultivars, and implementation of one or two short aeration periods before the heading stage can be effective options to minimize CH4 emission from paddy fields. Among these strategies, water management, which appears to be the best cost-effective and eco-friendly way for methane mitigation, is only possible when excess water is available for reflooding after short soil drying at the right timing and stage. However, in tropical Asia, rice fields are naturally flooded during the monsoonal rainy season and fully controlled drainage is often impossible. In such situation, water deficits during the vegetative and reproductive stage may drastically affect the rice yields. Thus, care must be taken to mitigate methane emission without affecting rice yields.     

The Challenges and Solutions for Cadmium-contaminated Rice in China: A Critical Review

The wide occurrence of Cd-contaminated rice in southern China poses significant public health risk and deserves immediate action, which arises primarily from extensive metal (including Cd) contamination of paddies with the fast expansion of nonferrous metal mining and smelting activities. Accumulation of Cd in rice grains can be reduced by removing Cd from the contaminated paddy soils, reducing its bioavailability, and controlling its uptake by rice plants. Although a range of measures can be taken to rehabilitate Cd-contaminated lands, including soil replacement and turnover, chemical washing, and phytoremediation, they are either too expensive and/or too slow. Various amendment materials, including lime, animal manures, and biochar, can be used to immobilize Cd in soils, but such fixation approach can only temporarily reduce Cd availability to rice uptake. Cultivation of alternative crops with low Cd accumulation in edible plant parts is impractical on large scales due to extensive contamination and food security concerns in southern China. Transgenic techniques can help develop rice cultivars with low Cd accumulation in grains, but little public acceptance is expected for such products. As an alternative, selection and development of low-Cd rice varieties and hybrids through plant biotechnology and breeding, particularly, by integration of marker-assisted selection (MAS) with traditional breeding, could be a practical and acceptable option that would allow continued rice production in soils with high bioavailability of Cd. Plant biotechnology and breeding can also help develop Cd-hyperaccumulating rice varieties, which can greatly facilitate phytoremediation of contaminated paddies. To eliminate the long-term risk of Cd entering the food chain, soils contaminated by Cd should be cleaned up when cost-effective remediation measures are available.     

Foliar and root uptake of 134Cs, 85Sr and 65Zn in processing tomato plants (Lycopersicon esculentum Mill.)

Rice is a staple food in Japan and other Asian countries, and the soil-to-plant transfer factor of 137Cs released into the environment is an important parameter for estimating the internal radiation dose from food ingestion. Soil and rice grain samples were collected from 20 paddy fields throughout Aomori Prefecture, Japan in 1996 and 1997, and soil-to-polished rice transfer factors were determined. The concentrations of 137Cs, derived from fallout depositions, stable Cs and K in paddy soils were 2.5-21 Bq kg(-1), 1.2-5.3 and 5000-13000 mg kg(-1), respectively. The ranges of 137Cs, stable Cs and K concentration in polished rice were 2.5-85 mBq kg(-1) dry wt., 0.0005-0.0065 and 580-910 mg kg(-1) dry wt., respectively. The geometric mean of soil-to-polished rice transfer factor of 137Cs was 0.0016, and its 95% confidence interval was 0.00021-0.012. The transfer factor of 137Cs was approximately 3 times higher than that of stable Cs at 0.00056, and they were well correlated. This implied that fallout 137Cs, mostly deposited up to the 1980s, is more mobile and more easily absorbed by plants than stable Cs in the soil, although the soil-to-plant transfer of stable Cs can be used for predicting the long-term transfer of 137Cs. The transfer factors of both 137Cs and stable Cs decreased with increasing K concentration in the soil. This suggests that K in the soil was a competitive factor for the transfers of both 137Cs and stable Cs from soil-to-polished rice. However, the transfer factors of 137Cs and stable Cs were independent of the amount of organic materials in soils.     

Lead in paddy soils and rice plants and its potential health risk around Lechang lead/zinc mine, Guangdong, China

As part of a project on phytoextraction of lead (Pb) in paddy soils around a lead/zinc (Pb/Zn) Mine in Lechang of Guangdong Province, South China, the concentration distribution of Pb in paddy soil-rice system was investigated, and its potential health risk to animal/human was evaluated. Total and diethylenetetraminepentaacetic acid (DTPA)-extractable Pb in soils averaged 1486 and 268 microg/g, respectively. According to sequential extraction procedure, soil Pb occurred primarily in the residual, carbonate and exchangeable fractions (30.2%, 26.7% and 19.1%, respectively). Lead extracted by the gastric juice simulation test (GJST) was 1068 microg/g and accounted for 75.4% of the total concentration. Mean Pb concentrations of 419 microg/g in rice root, 69.1 microg/g in whole straw, 51.0 microg/g in part straw (without two leaves near above the root), 44.9 microg/g in stalk, 21.9 microg/g in hull, 13.2 microg/g in grain with hull and 4.67microg/g in grain without hull (namely, unpolished rice) were found. Lead concentrations in both soil and rice plant were far above the corresponding tolerable levels. Lead daily intakes by local residents were 2.6 mg for adults and 1.2 mg for children, which were much higher than the allowable level. Thus, Pb in this area might pose a potential health risk to the local population.