Through the research of dynamic change in nitrogen discharge with runoff from a small watershed in southern Anhui Province, we found drastic seasonal changes in nitrogen discharge with runoff, which was attributed to the impact of rainfall and fertilizer use. There is a significant linear relationship between nitrogen discharge and rainfall and the amount of fertilizer applied. Equations for prediction of nitrogen discharge were established based on the study. 更多还原 AbstractFilter('EnChDivSummary','ChDivSummaryMore2','ChDivSummaryReset2');

Based on the state of siltation in front of the lock of the Caotanzhuang Water Diversity Project on the Heihe River, analysis was carried out of effects of local scour, siltation and unbalanced silt transportation between the upper and down reaches on its eco environment. For its improvement,some practical engineering measures were brought forward, which are believed to be of great significance in maintaining normal operation of the project and bringing up its economic benefit. 

The development potential and the six factors restricting the development of the Karst Regions in Southwest China have been comprehensively analyzed. Five strategic countermeasures for the development of the region are put forward. 

IFI was introduced and used to analyze the temporal changes in soil fertility in Daxing County,and the factors affecting these changes as well.Results show that soil fertility has been raised as a whole in the past twenty years,and especially was in the 1990’s.Thanks to the adjustment of cropping structure and return of straws,the soil IFI has been increasing steadily and so has the integrated soil fertility in this county.

In line with the ecological engineering principle,such a link addition measure was adopted as raising loaches and paddy eels in lotus fields to form a symbiosis, which benefited both sides in increasing profit and decreasing cost of plant production.Besides the symbiosis could also effectively control lotus root eating Donacia provosti Fairmaire without the aid of pesticides, thus improving both the yields of lotus roots and fish and the eco environment of the lotus fields. Experiments demonstrated that the raising of loaches and eels in mixture yielded more significant effect with the insect control rate and yield increase rate being 83%～99% and 12.7%, respectively,than the raising of loaches or eels alone did being 66%～90% or 59%～85% and 7.6% or 2.3%, respectively.

From the wastewater treatment system of a pesticide plant, a Bacillus strain was isolated, capable of efficiently degrading methyl parathion (MP).It is preliminarily identified as Bacillus cereus J5.The bacteria,however,do not live on MP as the sole carbon and energy source.Experiment results suggest that J5 degrades MP by way of co metabolism.Growing in the medium with glucose as its carbon source, J5 can degrade MP by over 95%.Rate and metabolites of the degradation of MP by J5 were studied by means of TLC,ultra violate scanning and HPLC.

Effects of lanthanum on the growth and some other physiological indices of rape (Brassica juncea),such as biomass,chlorophyll content,nitrate reductase,root activity,were studied in a solution culture experiment.The results showed that the biomass,chlorophyll content,nitrate reductase activity and root activity increased when 0 03～3 mg/kg La ³⁺ was sprayed or added into the culture solution,and decreased,but POD activity,when more than 30 mg/kg La ³⁺ was added.The critical concentration of lanthanum to rape was suggested to be 30 mg/kg.

The following mechanisms of nitrogen fertilizers suppressing atmospheric methane oxidation in soils by methanotrophs have been reviewed:(1) competition between ammonium and methane for MMO’s active sites;(2) toxicity of metabolites such as organic acids and NO ₂ ^- to methanotrophs;(3) methanotrophs suffering physiological lack of water due to addition of nitrogen fertilizer into the soil fixing free soil water; and (4) nitrogen turnover in soils.Based on the research reports available in the world, the mechanism of ammonium suppressing atmospheric methane oxidation is supposed to be that both methanotrophs and ammonium oxidizing bacteria compete for limited amount of oxygen in soil air, if the amount of nitrogen added to the soil exceeds the soil capacity.What we have proposed successfully explains the reason why exogenous nitrogen can suppress atmospheric methane oxidation, that is, there exists a dynamic balance between ammonium oxidizing bacteria and methanotrophs in non fertilized soils called natural soils, but a large amount of nitrogen added to the soil will stimulate the activity and growth of ammonium oxidizing bacteria, which, in turn, outdoes methanotrophs in competition for limited oxygen in the soil and becomes dominant bacteria as compared with methanotrophs. So it is very difficult for methanotroph to outgrow ammonium oxidizing bacteria again and maintain the previous balance in fertilized soils, and however they can arrive at new balance,at which there are less methanotrophs but more ammonium oxidizing bacteria compared with that before nitrogen application. This may be the reason why soils fertilized with ammonium will gradually lose the ability to oxidize atmospheric methane.

Besides serious soil erosion,the Three Gorge Region is faced with a series of environmental issues,such as diminishing biodiversity,degrading functions of the ecosystem,aggravating agricultural non point source pollution,expanding polluted zone ashore and deteriorating water quality.Based on a comprehensive eco environment evaluation index system,and similarity and dissimilarity of the eco environmental issues in different areas of the Three Gorge Region,clustering analysis was made.Results showed that the 19 counties(cities)in the region could be sorted into 7 groups of areas.

By analyzing Landsat images of tidal saltmarsh and conducting necessary field investigations,studies were carried out on superficial variation of Spartina alterniflora,planted pioneer vegetation on the beach,as indicator of the succession of vegetation community from pioneer vegetation community to inning vegetation community.The study helps fully understand the forming process of saltmarshes along the coast of Jiangsu Province and facilitates rational exploitation and protection of coastal saltmarsh environment.

With the effects of competition for light and nutrients and the microbial interference ruled out among plants, allelopathic effects of Alternanthera philoxeroides,Trapa spp., Ceratophyllum demersum and Lemna minor on Scenedesmus arcuatus Lemm were examined in comparison with that of Eichhornia crassips .The results showed that the test plants reduced,in varied degree, the population of the algae by stimulating destruction of its chlorophyll a and increasing of its MDA content and inhibiting of its SOD activity.The water in which the plants were cultured also showed similar allelopathic effect.But the allelopathic effect was not as effective as that of Eichhornia crassips .It seems that the allelopathic effect of aquatic higher plants on the algae was somewhat a common phenomenon.

The research was to probe into effects of three kinds of organic fertilizers on nitrate accumulation in greenhouse vegetable and salt content in soil with several species of leafy vegetable.The results indicated that the average content of nitrate ions in celery from three different organic fertilizer treatments was 2 133 mg/kg,1 617 mg/kg lower than that from CK receiving special vegetable fertilizer (as comparison).Among the three organic fertilizer treatments,the treatment of Dasanyuan bio organic fertilizer had the lowest nitrate ion content in celery, being about 1 803 mg/kg,1 947 mg/kg lower than that in CK.Salt content (EC) in soil was also the lowest in the treatment of Dasanyuan bio organic fertilizer,being 0 079 S/m in the 0～10 cm layer of soil,about 0 024 S/m lower than in CK,and being 0 055 S/m in the 10～20 cm layer of soil,about 0 010 S/m lower.According to the above results,applying organic fertilizers in greenhouse culture can decrease effectively nitrate content in leafy vegetables and salt accumulation in soil.

Outstanding progress has been achieved in eco environment construction in the upper reaches of Changjiang River in the past ten years,but problems with its old management system still exist.The reform in the economic system has been sped up in China during the recent years,forcing us to enhance our effort and import new systems in bringing the eco environment construction on to a road of socialization and industrialization.This is a new task under the socialist market economic system.An integrated reform is needed for industrializing the eco environment construction under the current economic system.The breaking point in achieving this goal is to optimize the structure of distributing economic benefits and let the stakeholders/erectors enjoy true benefits.

Based on the fieldwork,the current situation of nature reserve construction in Xuzhou Prefecture has been analyzed, and the corresponding construction strategies are proposed.

Rurban areas, as a kind of landscape ecosystem usually called ecotone, have their own unique structure, highly instable and fragmented. A case study on rural landscape planning was mainly focused on principles and methodology of landscape planning for a typical ecotone. 

On the basis of the brief introduction to the origin and connotation of land rearrangement,effects of the rearrangement on the rural eco environment were elaborated and several eco environment issues raised for concern in the process of land rearrangement. 

Nuisance free vegetable is of most important significance to the life quality of people, its production base must be established at first.The status quo of environmental pollution in Chongqing was investigated.According to the related national environmental quality standards and food standards,criteria for evaluating quality of nuisance free vegetables and environment of their production base in Chongqing have been put forward.