Table of Content

25 April 1992, Volume 3 Issue 2

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Articles

Dynamic study of coarse woody debris in temperate forest ecosystems

Chen Hua, M. E. Harmon

1992, 3(2):  99-104. 

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In this paper, tree mortality, coarse woody debris(CWD)storage, its decomposition rate and role in nutrient cyclings in two temperate forest ecosystems of Changbai Mountain Natural Reserve of China and Andrews Experimental Forests of USAwere studied. Resuits show that CWDis an important component in temperate natural forest ecosystems. Its functional importance varies with forest types and decreases from coniferous forest to mixed forest. Aprimary role of CWDin nutrient cyclings within forest may be to retain nutrients and stabilize ecosystem following major natural disturbances. Global estimation of carbon stored in detritus should include CWDin future, otherwise, it is possible to underestimate 2—16×10¹³kg of global carbon storage in forest detritus, or relative error in system is 2—10%.

Quantitative ordination and evaluation of site quality factors of poplar artificial forest ecosystem

Jin Zhinong

1992, 3(2):  105-110. 

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Major site factors of southern type clones of Aigeiros section were evaluated by multivariate statistical analysis method. The results show that soil availabe water is a major integrated site factor which affects the growth of two clones, its contribution percentage (CP)being44.56% and 34.00% for 1-69/55 and 1-72/58 respectively. The CPof soil physical properties and aeration condition is about 24%, and that of soil nutrient is 10%. The accumulated CPof major site subfaetors including flooding, microtopography, ground water level, management level, soil structure, soil texture, available Kand pHis more than90%. In the end of the paper, table of contribution value including those of site class and quantitative site index is worked out.

Projective and contractive aberrations of shelterbelt porosity estimated by measuring photograph with the help of digitized photographic silhouettes

Zhou Xinhua, Jiang Fengqi, Lin Heming

1992, 3(2):  111-119. 

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Both projective and contractive aberrations of shelterbelt porosity estimated by measuring photograph with the help of digitized photographic silhouettes are further studied on the basis of "Study on random error of shelterbelt porosity estimated by measuring photograph with the help of digitized photographic silhouettes". The regular patterns of "the closer the image of shelterbelt is to main point on a photograph, the less absolute value of projective aberration in the porosity is", and "contractive aberration in the porosity is irrelevant to the location of shelterbelt on a photograph" are expounded,and the fact that absolute value of projective aberration in the porosity is negatively related to both focal length of camera and distance of taking a picture is clarified. Of projective and contractive aberrations in the porosity under crown of the shelterbelt disposed respectively by 3 main patterns of rectangle, triangle and oblique line, the models are established. Based on synthesizing the results of study on the errors in the porosity, a series of measures from calculating the number of observation and taking a picture in field to measuring photograph in laboratory up to calculating the errors are advanced to shrink and restrict all errors in the porosity as far as possible,to emend both projective and contractive aberrations in the porosity under crown of shelterbelt, and to estimate the porosity according to known or given error limit.

Responses of organic free-radicals production of overwintering conifer needles to low temperature and light

Tao Dali, Jin Yuehua, Du Yingjun, Liu Yayan, Liu Guizhen, Zhan Ruiyun

1992, 3(2):  120-124. 

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Overwinter experiment of potted and solar-exposed seedlings showed that Pinus koraiensis sustained most severe injury, Pinus sylestris var, mongolica sustained much less, while Picea koraiensis did not show any irreversible damage, ESRsignals of organic free-radicals(OFR) were detected from needle pieces in dark or under 1200 μmol m^-2s^-1 PFD at various temperatures in May: 1) the more severe the winter injury, the more OFRwere produced; 2) the OFRproduction increased with lowering temperature; 3) strong illumination apparently enhanced the OFRproduction; and 4) as a free-radical scavenger,vitamine Cinhibited the OFRproduction, It is suggested that the winter injury of Korean pine seedlings is related to the action of overloaded OFRand the high production of OFRin the field is dependent on strong solar radiation and low temperature.

Remote sensing analysis of total heat effects of regional shelterbelt system

Zhu Tingyao, Jin Changjie, Xu Jiyan, Chang Xingwu

1992, 3(2):  125-130. 

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In this paper, reflectivity and surface temperature in different biotypes of Zhanggutairegion are analysed in terms of NOAA/AVHRR data, and the effects of shelterbelt system on radiation balance and surface temperature are also studied. The results indicate that the percentage of radiation balance in the shelterbelts for sand fixation increases from 46% to 57% of the total, that of surface effective radiation decreases from 35% to 29%, and the range of surface temperature is also decreased from 13.0—14.0℃ to 2.0—3.5℃ during the daytime.

Climatic-ecological effect of interplanting tallow trees in tea plantations

Ding Ruixing, Huang Xiaolan, Zhou Yajun

1992, 3(2):  131-137. 

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The effect of interplanting tallow trees in tea plantations on microclimatic environment were studied on red soils of Huangshan region, Anhui Province. Tallow trees could appropriately shade the tea trees with the aid of their sparse canopies in summer and autumn. In tea-tallow tree interpiantation, the total solar radiation is lower than the light saturation point of tea trees and the diffuse radiation of is higher than that of pure tea plantation.The ratio of diffuse radiation to direct radiation is 0.78—0.90. The temperature and humidity are regulated and adapted to the growth of tea plant. The roots of tea and tallow trees are able to take water from upper and deep soil layers respectively, and the utilization rate of soil water is increased. Therefore, interplanting tallow trees in tea plantations could keep tea trees from the harm of hot and dry weather in summer and increase the yield and quality of tea. It is suggested that tea-tallow interplantation is an artificial ecological pattern producing green teas of high quality in tea planting area.

Residual effect of phosphorus fertilizer and phosphorus recycling in a farming system Ⅰ Phosphorus uptake by crops, residual effect of phosphorus fertilizer and changes of soil available phosphorus

Shen Shanmin, Yin Xiuyan, Zhang Lu

1992, 3(2):  138-143. 

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The results from a six years field experiment conducted on a calsic cinnamon soil indicated that there was no significant difference between the crop yields from two different ways of applying phosphorus fertilizer——once every six years with high rate and once every year with low rate, the latter gave a little more yields than the former, but was more effective in establishing soil available phosphorus pool. The residual effect from one application of phosphorus seemed to last more than five years on the calsic cinnamon soil, and thus, although the recovery of phosphorus was as low as 7% at the first year of application with high rate, the total recovery in six years was as high as 34%. The proportion of residual phosphorus transfering into soil available phosphorus pool was about 17% after six years of applying phosphorus every year with low rate, but only 2% from one application with high rate.

Structural index systems of agroecosystem and their quantitative methods

Hu Bingmin, Wang Zhaoqian, Wu Jianjun, Li Weiguang

1992, 3(2):  144-148. 

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Proper structural index systems at three levels for classifying agroecosystem and methods for converting various indices into same unit were discussed in this paper. Based on the data obtained from some typical ecological farms in different areas of Zhejiang Province,5 data transformation techniques and effective methods for unifying the dimension of various indices and reducing great disparities in quantity among the indices were studied and discussed.

Predicting analysis of livestock population in semi-agricultural and pastoral area of Yanchi county

Zhou Hailin

1992, 3(2):  149-154. 

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In this paper, the dynamic models for livestock population in rangeland of Yanchi county were established by system dynamic method and grey system theory. With the computer process of model, several sensitive parameters such as total elimination coefficient of basal ewes,wether slaughter rate(C₆), percentage of killing Iambs (P₁)and rate of lamb fur (P₂) are found, by which, it is possible to control the development of Tan sheep and goat populations. The author considers that controlling livestosk population can raise the economic benefits.

Effect of high ambient temperature on sheep in subtropical plains

Ma Weidong, Kang Mengsong, Gao Hong, Huang Guanghui, Zhou Fuzha

1992, 3(2):  155-159. 

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Some physiological and biochemical responses of Kauhu crossbred sheep under high temperature conditions were measured. The body temperature, heart rate (HR) and respiratory rate (RR) of sheep increased with ambient temperature (AT). RRand HRmaximized at 29℃. Below 35℃, the skin temperature was higher than that of wool, and sheep might lose heat through evaporative and nonevaporative ways. The skin temperature was equal to wool temperature at 35℃, its heat being lost only via evaporation. Potassium, sodium, chlorine and cholesterol concentrations in serum under high temperature conditions decreased 19.96, 17.43, 1.22 and 35.51% respectively (p<0.05 or p<0.01), while triiodothyronine and thyroxine increased significantly (p<0.01) and glucose content increased also.

Dynamics of silver carp and bighead carp populations in Qinghe Reservoir I Estimation of production

Dong Shuanglin

1992, 3(2):  160-164. 

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The survival rates of catchable groups of silver carp (Hypophthalmichthys molitrix) and bighead carp (Aristichthys nobilis) were calculated by means of Robson-Chapman formula, and those of noncatchable ones and population production were also estimated. The annual survival rates of noncatchable groups of the fishes were 0.25 in average, and those of catchable ones were 0.32 for silver carp and 0.38 for bighead carp. The total population production of silver carp and bighead carp was 141 and 110 kg/ha respectively. The yield of fishes was 33% and 34% of their production, and 36% of their biomass. The annual coefficients P/Bof fish populations were 1.15 and 1.09 respectively.

Algae in Taipinghu Reservoir and its trophic level

Kuang Qijun, Xia Yicheng

1992, 3(2):  165-168. 

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The algae in Taipinghu Reservoir and its trophic level were investigated during 1985—1986. 175 species of algae are observed. Chlorophyta is the most important group with 87 taxa, representing50% of the total. Bacillariophyta and Cyanophyta are subdominant groups with 34(19.4%) and 33(18.8%) taxa respectively. Other five phyla with 21 taxa are less important, representing11.8% of the algal flora. According to the results of trophic evaluation, this reservoir is a mesotrophic waters with clear water. Two parameters (dominant species and TN) achieve eutrophic level, and the blooms of Microcystis occurred sometimes indicate that the trophic level of the reservoir is transiting from mesotrophy to eutrophy. At present, the overgrowth of algae is limited by low phosphorus concentration (TN 0.012mg/L). In order to avoid further eutrophication, it is important to prohibit the discharge of phosphorus and nitrogenous compound into the reservoir.

Continuous spatial distribution models of biological population and their application

Zhang Wenjun, Shang Hongsheng

1992, 3(2):  169-172. 

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This paper deals with the spatial pattern indices for biological population based on Pearson's Ⅲ type distribution and exponential distrbution. The results show that their precision is higher than that of classical frequency distributions. The judging indices of aggregation and formula for required number of sampling in the case of Pearson-Ⅲ distribution and exponential distribution are presented and successfully used in analysis of the spatial pattern and sampling number for inoculum source of wheat scab. Finally, advantages of the continuous models in application to spatial pattern are discussed.

Two mathematical models in rhizobium ecology

Ding Wu, Li Fudi

1992, 3(2):  173-178. 

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In this paper, leguminous plants grown in both natural heavy loam and sterile sand were studied. The increase of Rhizobium japonicum number conforms to Logistic model using MPNmethod, and a corresponding BASIC program about counting is compiled. There is a mathematical relationship between inoculum rate and nodule occupancy by counting six groups of data, and also, a corresponding BASICprogram about counting is compiled.

Low level SO₂ pollution and green peach aphid's growth and reproduction

Wu Kunjun, Gong Peiyu, Li Xiuzhen, Cao Hongfa, Shu Jianmin, Xiong Yanjun

1992, 3(2):  179-183. 

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The effect of low level SO₂ pollution on aphid, Myzus persicae (Sulzer) was examined with the insects reared on rape leaves exposed to 40 or 80 ppb of SO₂. Compared to those of the aphids fed on leaves fumigated with charcoal-filtered air, nymphs of treated groups developed more faster, their mean relative growth rate (MRGR) in5 days increased by 22.3% and 31.5%, respectively, and the fecundity of adult aphids by 40—90%, resulting in mean elevation of 17% and 27% respectively in intrinsic rate of population increase (r_m). The sensibility of M. persicae and other species of aphids to SO₂ pollution is compared, and the mechanism with which low dose of SO₂ pollution stimulated the growth of certain species of phytophagous insects is suggested.

Effects of simulated acid rain on release and forms of aluminum from main acidic soils

Wang Weijun, Chen Jiafang, He Qun

1992, 3(2):  184-189. 

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The effects of simulated acid rain with different pHvalues on the amount of Al released and the change of Al forms of the main acidic soils in southern China were investigated. The experimental results indicated that acid rain had significant effects on the amount of Al dissolved from soils, especially in pH<4.0, but not on the acidification of soils. Acid rain had different effects in various soil types. Highly weathered acidic soils were more sensitive to acid rain. These were closely related to buffer capacity formed by different consumed mechanisms of H~+ and chemical characteristics of Al ions. It is very important that acid rain affected free Al forms of the soils. After acid rain treatment, exchangeable Al increased slightly and the content of moderately labile Al increased significantly. The trend in decrease of organic matter complexed Al was observed. Based on the results obtained in the present work, it was concluded that Al would be transformed to exchangeable or water soluble forms and entered the ecosystem by the effect of acid rain in the long-run. This is a serious problem.

Effect of treating Pb/Zn mine wastewater with Typha latifolia purification pond system

Ye Zhihong, Chen Guizhu, Lan Chongyu, Li Liuchun

1992, 3(2):  190-194. 

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The results show that Pb/Zn mine wastewater can be effectively purified by the system. Before entering the system, the untreated wastewater contains rather high concentration of total suspended substance (4635mg/L), Pb (1.61mg/L), Zn (1.96mg/L) and Ca(0.022mg/L), its pHis 8.03. After passing through the system, the water quality is obviously improved, with pHdropping to 7.74, suspended substance reduced by 99%, Pb by 90%, Zn by 84% and Cd by 84%; other heavy metals such as Cu,Fe, Al etc.are reduced in different degrees.