Beta-Glucosidase Activity in Paddy Soils of the Taihu Lake Region, China

The profile distribution of β-gulcosidase activity in twelve typical paddy soil profiles with high productivity in the Taihu Lake region of China were investigated. Activities of β-gulcosidase in the plow layers were in the range of 52.68- 137.02μg PNP g^-1 soil h^-1 with a mean of 89.22μg PNP g^-1 soil h^-1. However, most plow layers ranged from 70 to 110 μg PNP g^-1 soil h^-1. The profile distribution of β-gulcosidase activity in the 12 soil profiles decreased rapidly with soil depth, with activity at the 60 cm depth only about 10% of that in the surface layers （0-15 cm or 0-20 cm）. In these soil profiles, β-gulcosidase activity was significantly positively correlated with soll organic carbon and arylsulphatase activity. Meanwhile, a significantly negative correlation was shown between β-gulcosidase activity and soil pH.

Residual Levels and New Inputs of Chlorinated POPs in Agricultural Soils from Taihu Lake Region

Selected persistent organochlorine pesticides (OCPs), including 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) and its principal metabolites 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) and 1,1-dichloro-2,2-bis(p-chlorophenyl)e- thane (DDD), hexachlorocyclohexane (HCH) and its isomers (α-,β-, γ-, and δ-HCH), hexachlorobenzene (HCB), endo- sulfan, dieldrin, and endrin were quantified to determine current levels of organochlorine pesticides, to assess the eco- toxicological potential, and to distin…

Assessment of Nitrogen Pollutant Sources in Surface Waters of Taihu Lake Region

The nitrogen （N） pollution status of the 12 most important rivers in Changshu, Taihu Lake region was investigated. Water samples were collected from depths of 0.5-1.0 m with the aid of the global positioning system （GPS）. The seasonal variations in the concentrations of different N components in the rivers were measured. Using tension-free monolith lysimeters and ^15N-labeled fertilizer, field experiments were carried out in this region to determine variations of iSN abundance of NO3^- in the leachate during the rice and wheat growing seasons, respectively. Results showed that the main source of N pollution of surface waters in the Taihu Lake region was not the N fertilizer applied in the farmland but the urban domestic sewage and rural human and animal excreta directly discharged into the water bodies without treatment. Atmospheric dry and wet N deposition was another evident source of N pollutant of the surface waters. In conclusion, it would not be correct to attribute the N applied to farmlands as the source of N pollution of the surface waters in this region.

Research Progresses on Diversity of Quality Traits of Rice Landraces in Taihu Lake Region

It has a long history of rice cultivating in Taihu Lake region, with abounds rice landraces resources. The research on the genetic diversity of rice landraces resources can provide some reference for the protection and utilization of high-quality germplasm resources and breeding of new varieties. In this study, we reviewed the concepts of genetic diversity, research methods, genetic diversity of quality traits of rice landraces in Taihu Lake region and summarized the relevant utilization value of the rice landraces from Taihu Lake region.

Contribution of Geographic Information Systems in Protection Zones Delineation around a Surface Water Resource in Adzope Region (Southeast of Côte d’Ivoire)

Adzope’s Municipal Artificial Lake which serves as a drinking water supply to the population is prone to pollution due to human activities and increasing urbanization. Thus, it is essential to protect this surface water supply for sustainable use. The objective of this study is to determine the protection zones around this water reservoir in order to preserve the stored water quality. To achieve this, a methodological approach based on a Geographic Information System (GIS) was adopted. This methodological approach first consisted to assess the water reservoir vulnerability to pollution according to certain hydrological parameters (slope, land use, soil type, runoff, and drainage network density) and then to determine the protection zones according to the different vulnerability classes. After the scoring of different parameters, a weight was assigned to each, from the multi-criteria method (AHP). The combination of the weighted parameters in the GIS enabled to establish the water reservoir vulnerability indexes map. The vulnerability map established subsequently presents five (5) vulnerability classes in the watershed: very low (12%) and low (23%) in the North and South of the study area, moderate (32%) disseminated throughout the study area, high (20%) and very high (13%) particularly in the West and North of the water reservoir and in the East of study area. This water reservoir vulnerability map is potentially influenced by the land use parameter according to the sensitivity analysis test. The different vulnerability classes then allowed the delimitation of three protection zones (Zone 1, Zone 2 and Zone 3) around the water reservoir. The immediate protection zone (Zone 1) has a width between 100 and 450 m around the water reservoir with a surface of 1.16 km2. The delimitation of this immediate protection zone takes into account the high and very high vulnerability classes near the water reservoir. The width of protection zone 2 varies from 350 m to 1 km around protection zone 1 with a surface of 5.38 km2. The protection zone 3 covers the rest of the high vulnerability areas contiguous to protection zone 2 with a total surface of 5.69 km2.

Phosphorus losses via surface runoff in rice-wheat cropping systems as impacted by rainfall regimes and fertilizer applications

Phosphorus（P） losses from agricultural soils contribute to eutrophication of surface waters. This field plot study investigated effects of rainfall regimes and P applications on P loss by surface runoff from rice（Oryza sativa L.） and wheat（Triticum aestivum L.） cropping systems in Lake Taihu region, China. The study was conducted on two types of paddy soils（Hydromorphic at Anzhen site, Wuxi City, and Degleyed at Xinzhuang site, Changshu City, Jiangsu Province） with different P status, and it covered 3 years with low, high and normal rainfall regimes. Four rates of mineral P fertilizer, i.e., no P（control）, 30 kg P ha^（–1） for rice and 20 kg P ha^（–1） for wheat（P_（30＋20））, 75 plus 40（P_（75＋40））, and 150 plus 80（P_（150＋80））, were applied as treatments. Runoff water from individual plots and runoff events was recorded and analyzed for total P and dissolved reactive P concentrations. Losses of total P and dissolved reactive P significantly increased with rainfall depth and P rates（P〈0.0001）. Annual total P losses ranged from 0.36–0.92 kg ha^–1 in control to 1.13–4.67 kg ha^–1 in P150＋80 at Anzhen, and correspondingly from 0.36–0.48 kg h^–1 to 1.26–1.88 kg ha^–1 at Xinzhuang, with 16–49% of total P as dissolved reactive P. In particular, large amounts of P were lost during heavy rainfall events that occurred shortly after P applications at Anzhen. On average of all P treatments, rice growing season constituted 37–86% of annual total P loss at Anzhen and 28–44% of that at Xinzhuang. In both crop seasons, P concentrations peaked in the first runoff events and decreased with time. During rice growing season, runoff P concentrations positively correlated（P〈0.0001） with P concentrations in field ponding water that was intentionally enclosed by construction of field bund. The relative high P loss during wheat growing season at Xinzhuang was due to high soil P status. In conclusion, P should be applied at rates balancing crop removal（20–30 kg P ha^–1 in this study） and at time excluding heavy rains. Moreover, irrigation and drainage water should be appropriately managed to reduce runoff P losses from rice-wheat cropping systems.

环太湖地区文化景观的时空层积与特征解译研究——以常州为例

太湖地区以太湖为中心,形成碟形洼地,位于长江三角洲的南部。常州作为太湖平原西北部的区域中心,是早期有人类开发历史记载的重要地区,自古即为运河沿线重要的交通枢纽。通过系统梳理文化景观特征与时空演变,为现代文化景观的保护传承与发展提供理论基础。以地域文化景观这一视角重新审视常州地区,将其理解为融合了自然系统与人文系统的层状体系复合系统,借助文化景观的研究思路,以朝代更迭为时间线索,从历时性、共时性两个维度逐层揭开常州地域文化景观体系中各要素的发展情况,探索古代人地关系的动态演变,并从时空层积、空间特征、关联性内因三个方面进行分析解译。在大运河文化带战略框架下和在快速城镇化进程中,为沿运城市的文化复兴和高质量城乡营建提供一定借鉴意义。

基于生物多样性保护的常州市太湖治理对策分析

新时代,常州市深入贯彻习近平生态文明思想,以打造人与自然和谐共生的现代化常州为目标,全面开展生物多样性保护工作,扎实推进太湖治理。本文梳理常州市生物多样性保护取得的成效,分析存在的问题,并提出以生物多样性保护推进太湖治理的对策建议,将太湖治理成效以生物多样性不断丰富的形式直观呈现给人民群众,为太湖治理提供新思路。

环太湖地区高质量发展时空收敛特征分析

运用综合评价方法测度环太湖地区高质量发展水平,使用σ收敛、β收敛模型回归分析环太湖地区之间在时间上的纵向收敛趋势和内在影响机制,发现2005年至2021年期间,环太湖地区高质量发展呈现逐渐增长趋势;环太湖五市之间的高质量发展指数的差距逐年缩减,存在σ收敛;环太湖五市之间高质量发展指数发生显著的β收敛,经济发展水平较低的城市,如湖州、嘉兴,正以较快的速度追赶苏州、无锡、常州,并以超过15%的速度趋同;低碳绿色发展是促进环太湖地区高质量发展收敛的重要因素。

太湖渔洋山水源地近岸生态修复工程探索

从江苏省苏州太湖渔洋山水源地饮用水水源保护区的实际情况出发,分析水源地现状问题,研究确立水源地近岸生态修复措施,建设风浪削减和蓝藻拦截、鱼贝螺控藻引导水下生态修复工程、水下森林生态修复工程和长效管理等措施,确保饮用水水源地水质达标和长效安全。

太湖设防水位变化对区域防洪的影响研究

太湖位于太湖流域中心位置,是流域的洪水集散地,其设防水位是评判流域防洪形势的重要特征水位之一,也是部署流域防汛工作的重要依据之一。近年来的流域性洪水中,太湖水位多次突破原设防水位,对区域防洪产生了较大影响。本文采用太湖流域河网一维水量水质模型,分析研究太湖设防水位的变化对区域防洪的影响。结果表明,太湖设防水位与上游区域洪水位呈正相关,与下游区域洪水位呈负相关。太湖设防水位的升高,使得上游区域超特征水位的幅度和历时逐渐增大,特别是对湖西区和长兴平原的影响更为明显。

北京水源保护区绿化废弃物资源化利用方式初探

鉴于绿化废弃物外运成本高,增加城市垃圾量和碳排放,处理不当会造成环境污染的情况,本文结合团城湖调节池实践项目,分析水源保护区不同区域空间、不同月份及不同类型绿化废弃物的产量,对其绿化废弃物收集利用的方法及处理工艺进行探索,实现取之于园、用之于园,生态消纳,保护环境。以期为其他水源保护区探究绿化废弃物资源化利用的工艺、流程及方法,提供一定借鉴。

长期不同施肥对太湖地区典型土壤酸化的影响

以太湖地区典型土壤黄泥土上26年的长期肥料定位试验为例,研究不同施肥处理对研究区耕作层土壤(0～15 cm)酸化特征及酸化速率的影响。试验采用裂区设计,主区为不施有机肥处理(C)和施有机肥处理(M),副区为不同无机肥及秸秆施用处理。研究结果显示,不同施肥处理对土壤pH和土壤酸碱缓冲容量有显著影响,增施有机肥的主区处理pH显著低于不施有机肥处理,但对应的土壤酸碱缓冲容量略有上升;副区单施尿素处理和尿素增施水稻秸秆处理pH较不施尿素对照分别下降了0.45、0.66个单位,酸碱缓冲容量分别下降1.52、0.95 mmol kg-1;各试验处理的酸化速率为H+0.61～1.74 kmol hm-2a-1,单施尿素处理高于不施尿素处理,而尿素增施有机肥或水稻秸秆的大于单施尿素处理,以尿素配施有机肥和水稻秸秆处理最高。相关分析表明,各处理土壤pH与外源氮输入量、土壤全氮及速效氮存在显著的依变关系。尿素对土壤的酸化影响与有机肥及水稻秸秆存在差异,前者在降低土壤pH的同时还导致土壤酸碱缓冲容量的降低,而增施有机肥及水稻秸秆处理土壤缓冲容量保持稳定甚至提升,但其各自对土壤酸化的具体贡献率等还需进一步研究。

太湖渔业发展及区域设置与功能定位

渔业是太湖的重要功能之一。太湖渔业主要以自然捕捞和围网养殖为主。目前太湖自然渔业捕捞强度及东太湖湾围网养殖的超常规发展,给湖泊生物资源带来巨大影响。依据太湖生物资源现状和分布,借助太湖遥感解译图像,定位设置太湖各类生物资源恢复与保护的功能区域,包括东部的资源保护核心区、缓冲区(湿地生态景观带)和西部的生态恢复区等。其管理目标是太湖水环境、渔业资源和生物多样性及环湖湿地、自然景观的保护,加快太湖生态恢复进程,促进旅游业和渔业的健康发展,实现太湖渔业资源的有序利用和可持续发展。

太湖地区湖水与河水中溶解N_2O及其排放

水体是N2 O排放的重要来源 .2 0 0 0 0 9～ 2 0 0 1 0 9,每月 2次采样 (重复 3次 )连续监测太湖地区太湖和大运河水体N2 O排放通量和水中溶解的N2 O浓度 ,还同时监测不同深度水样中的N2 O浓度 .结果表明 ,太湖N2 O N的年均排放通量为 3 5 3 μg/(m2 ·h) ,而大运河已高达 1 2 2 5 μg/(m2 ·h) .太湖湖水中溶解N2 O N浓度为 0 3 6μg/L ,大运河河水中浓度高达 1 1 3 1 μg/L ,浅水型水体是N2 O排放的源 .结果还表明 ,不同深度水中N2 O浓度差异不明显 ,而时间差异显著 .水面N2 O的排放通量和水中溶解的N2 O浓度呈显著正相关关系 ,二者又都与水温呈显著正相关 .

太湖地区湖、河和井水中氮污染状况的研究

连续监测了 2 0 0 0年 9月至 2 0 0 1年 9月太湖、大运河和井水中的N污染状况。结果表明 ,太湖水体中无机氮年均浓度达 1.14mg·L-1,已超过水体富营养化的浓度下限 ;大运河和井水分别达 7.16mg·L-1和 15 .84mg·L-1;井水中NO-3 -N浓度高达 15 .4 7mg·L-1,超过WHO所规定的生活饮用水NO-3 -N浓度上限的 5 0 %。试验结果还表明 ,河水中氮污染源以NH+ 4 -N为主 ,浓度高达 5 .6 3mg·L-1,占无机氮(NO-2 -N含量很低 ,忽略不计 )的 79% ;而井水中无机氮以NO-3 -N为主 ,占 98%。湖、河及井水中不同深度水样的分析结果表明 ,NO-3 -N和NH+ 4 -N浓度差异不显著 ,但其随时间变化差异明显。

填闲作物甜玉米对太湖地区设施菜地土壤硝态氮残留及淋失的影响

为控制我国南方太湖地区设施蔬菜管理体系中夏季休闲期氮素淋失,减轻其对地下水污染的风险,本田间试验在太湖地区设施菜地夏季揭棚休闲期种植填闲作物(甜玉米),研究了不同施氮条件下甜玉米填闲处理对土壤硝态氮含量、电导率和pH变化的影响,并通过收集淋洗液的方法观测了甜玉米对土壤氮素淋洗及对下茬作物莴苣产量的影响。结果表明:与休闲相比,甜玉米填闲处理可使表层0～10 cm土壤硝态氮含量从251.4 mg kg-1下降至143.5 mg kg-1,0～50 cm土壤硝态氮残留减少4.19%～30.72%;种植甜玉米可显著降低土壤(0～10 cm)电导率,降幅达30%以上,但对pH影响不显著。从减少氮素淋洗角度看,甜玉米填闲处理虽不影响淋洗液体积,但可使农民习惯施氮量条件下淋洗液中总氮浓度从102.6 mg kg-1降低至53.7 mg kg-1。与休闲相比,甜玉米填闲处理可减少总氮淋洗30.4%,且对下茬莴苣产量无显著影响。在南方设施菜地夏季休闲期,利用种植填闲作物甜玉米的方式降低土壤氮素淋失风险是较直接有效的措施。

太湖流域坡地茶园径流流失规律

在太湖流域坡地茶园进行小区试验,研究自然降雨条件下坡地茶园径流流失的基本规律。结果表明,在常规种植条件下,茶园的平均年径流水量为98.29L·m-2,随径流流失的氮素量为11.685kg·hm-2,其中硝态氮(NO3--N)流失量为8.918kg·hm-2,占总氮的76.320%;可溶性总磷(TDP)流失量为0.128kg·hm-2,磷酸根(PO43-)流失量为0.104kg·hm-2,占磷总流失量的65.823%;径流携带泥沙量为181.13kg·hm-2,其中泥沙携带氮为0.272kg·hm-2,泥沙携带磷为0.030kg·hm-2;氮、磷流失系数分别为1.008%和-0.087%,氮、磷肥流失率分别为5.686%和0.190%。说明试验区域坡地茶园径流量少,氮、磷流失较少,产生农业面源污染的风险较小。

不同轮作模式对太湖地区大棚菜地土壤氮淋失的影响

为控制太湖地区设施菜地氮素淋失,减小地下水污染风险,本研究选取2种轮作模式,即芹菜-番茄-莴苣(模式1)和金花菜-番茄-莴苣(模式2),2种轮作模式下分别设置2个施氮量水平,即习惯施氮(N1)和减量施氮(N2),研究不同轮作模式和施氮水平对设施菜地全年氮素淋洗的影响,并观测了不同轮作模式下土壤硝态氮含量、电导率和pH的变化。结果表明,与模式1相比,模式2可分别使N1和N2处理的淋洗液中的NO3--N平均浓度降低了36%和38%,进而使全年总氮淋洗量减少了41%和38%,但淋洗液体积不变。模式2结合减量施氮(N2)对设施菜地氮素淋失阻控效果最佳,全年总氮淋失量为63.0 kg/hm2,而年经济效益最高,可达51.9×104Yuan/hm2,最大经济效益提高29%。一年三季蔬菜收获后,N1处理下模式2的土壤硝态氮含量(0—20 cm)为189.2 mg/kg,而模式1的高达269.3 mg/kg。因此模式2可分别使N1和N2水平下的土壤硝态氮含量减少30%和26%,同时也显著降低了土壤pH和电导率(P<0.05)。在太湖地区,选择需氮量较少的作物进行合理优化轮作(如金花菜-番茄-莴苣轮作模式),是减少设施菜地氮素流失的有效手段,且具有较好的经济效益。