Analysis on reasons for the Yellow River''''s dry-up and its eco-environmental impacts

ＡｎａｌｙｓｉｓｏｎｒｅａｓｏｎｓｆｏｒｔｈｅＹｅｌｏｗＲｉｖｅｒ’ｓｄｒｙｕｐａｎｄｉｔｓｅｃｏｅｎｖｉｒｏｎｍｅｎｔａｌｉｍｐａｃｔｓＧａｏＹａｎｃｈｕｎＩｎｓｔｉｔｕｔｅｏｆＧｅｏｇｒａｐｈｙ，ＣｈｉｎｅｓｅＡｃａｄｅｍｙｏｆＳｃｉｅｎ...     

Numerical experiments for the impacts of temperature and precipitation variation on the growth and development of winter wheat

The growth process of winter wheat was simulated by CERES-wheat model assuming the daily temperature increase -1, 0,1, 2℃ and daily precipitation increase -20, -10, -5, 0, 5, 10, and 20 percent, respectively. The case study site is Zhenjiang City of Jiangsu Province in the east China. Simulation results show that the impacts of temperature variation on winter wheat is stronger than that of precipitation. Climate warming would speed development rate and shorten phonological period. In general, the adverse effect of climate change on grain yield is greater than that of its beneficial effect, especially when the climate becoming cooler and dryer. The increase of temperature and decrease of precipitation would reduce the plant extractablc soil water content.     

The curve of ion exchange ratio(%)-pH of the interaction between suspended particles with Cd(Ⅱ) in the Yellow River

Ｔｈｅｃｕｒｖｅｏｆｉｏｎｅｘｃｈａｎｇｅｒａｔｉｏ（％）ｐＨｏｆｔｈｅｉｎｔｅｒａｃｔｉｏｎｂｅｔｗｅｎｓｕｓｐｅｎｄｅｄｐａｒｔｉｃｌｅｓｗｉｔｈＣｄ（Ⅱ）ｉｎｔｈｅＹｅｌｏｗＲｉｖｅｒＹａｎｇＨｏｎｇｗｅｉ，ＪｉａｏＸｉａｏｂａｏ，Ｇｕ...     

Impacts of climate change on development rate and production of corn in the northeastern China

In this paper, the impacts of climate change on development rate and production of corn in the northeastern China are discussed. The results show that the higher the temperature is, the faster the development rate will be. And the more the precipitation is, the slower the development rate will be. Of which, air temperature is the controlling factor of corn development rate. The influences of development rate on corn yield are remarkable. The impacts of development rate on production in first and last periods are great, and small in the middle two periods. The development rate is positive by relate with corn production from sowing to emergence stage and negative during other periods. So, it is very important to arrange a suitable sowing time for com cultivating in the northeastern China.     

Simulated seasonal movement of precipitation zone in rainy season over China and its change on CO2-doubling

In this paper, an investigation of simulated monthly precipitations from April to September is made. Though the precipitations are sometimes overestimated or underestimated, the geographical advance and recession of precipitation zones are well simulated by the UKMO global climate model with a simple mixed-layer ocean. Main characteristics of large-scale precipitation distribution are changed less on CO₂-doubling, but the change is significant in some regions. The change in precipitation threatens us while the dry region is imposed by rainfall defect or the wet region by abundant rainfall induced by CO₂-doubling.     

Electrokinetic chemical characteristics of humic and dannic acids effecting on the natural water and its coagulation

Taking streaming current(SC)as the electrokinetic parameter,this paper demonstrated the electrokinetic chemical characteristics of humic and dannic acids(HA and DA)in suspensions including turbid water,coagulated water and HA or DA contained water.Accordingly, the studies were carried out for determining the relationship between streaming current and zeta potential ζ(expressed by eleetrophoretie mobility EM)in above water conditions.In addition,the mechanisms of HA effecting on streaming current within or after coagulant addition and the electrokinetic detection principles for HA or DA were also investigated on experiments and theoretical analysis.The results indicated that the change of SC like ζ presented meaningful information concerning the degree for destabilization of a particulate suspension,and HA or DA in water could remarkably decrease the effect of inorganic coagulant upon streaming current,which is in accordance with their influence on coagulation.     

Characteristics for the hybrid cell Foaz obtained from the  protoplast fusion between yeast and photosynthetic bacteria in soybean processing wastewater

The optimal pH and temperature, maximum specific degradation rate, half rate constant and flocculation rate for the hybrid cell Foaz were measured in the reaction for the degradation of soybean processing wastewater(SPW) in this study. The optimal pH and temperature for Foaz in SPW were the same as those of its parental strains Saccharomyces cerevisiae Y9407 and Rhodobacter sphaeroides P9479, but the flocculation rate, the maximum specific degradation rate and the half rate constant for Foaz were higher than those of its parental strains. The results suggest that the characteristics of the inter kingdom fusant Foaz constructed from the protoplast fusion between the eukaryote cell yeast S.cerevisiae and the prokaryote cell photosynthetic bacteriaR. sphaeroides may favor degrading organic pollutant in SPW and removing biomass from the effluent.     

Study on the proposed environmental guidelines for Cd, Hg, Pb and As in soil of China

This paper deals with the soil-environmental standard. According to the current situation of researching on the soil-environmental quality guideline at home and abroad, and on the basis of the foundations and principles of enacting the soil-environmental standard, the soil environment quality guideline values of Hg, Cd, Pb and As were suggested.     

Analysis and improving ways for water condition in winter wheat field of dryland in subhumid areas of the Loess Plateau

Based on the soil moisture data from the locating experiments from 1986—1990, and using the water balance method, the water supply and demand state in the field of winter wheat, and the ways for improving water condition in dryland of dry subhumid area of the Loess Plateau were studied. The results suggested that a low precipitation satisfying ratio of 42.9%—58.8% appears in the growing period of winter wheat, and the yield, to a great extent depended on the water that was stored in deep soil layer in the previous rainy season. The filed trial results showed that tillage in the summer fallow period,straw cover, soil moisture regulation with adequate fertilization, crop rotation and proper cropping system could be the efficient ways for improving the water condition,and for the exploitation and utilization of natural water resources(both precipitation and soil water) in the winter wheat field of dryland. 