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Table of Content

    10 August 1997, Volume 18 Issue 04
    论文
    The Growth Expression of Transition type Wheat Varieties Under Early Sown Conditions of Non transitional Zone in China
    Cao Guangcai Wu Dongbing (Institute of Crop Breeding and Cultivation, CAAS, Beijing 100081) Yu Meiling Liu Yongqing (Institute of Crop Breeding, Inner Mongolia Academy of Agri. Sci.)
    1997, 18(04):  . 
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    The wheat ecological experiment was conducted during 1988 ̄1990. Transition type wheat varieties were sown in early spring in Heihe, Huhhot, Lanzhou, Urumqi and in early winter in Kunming and Guiyang in southwest China. All the wheat sown grew normally. In comparison with the local spring wheat varieties, the maturity period was very close with little variations. During the 3 growth phases of vegetative growth, vegetative reproductive growth and reproductive growth, the transition type wheat varieties demonstrated a “two long and one short” phenomenon (long short long) in Heihe, Huhhot, Lanzhou and Urumqi, while those in Kunming and Guiyang demonstrated a “three long” phenomenon. There was a wide temperature range for field vernalization, ranging from 0℃ to 15℃ in daily mean temperature. Before inflorescence, the day length requirement was not strict. There existed a great significant negative correlation between the days from tillering to heading and the “average” light temperature accumulation, displaying a temperature light interaction effect. Under certain temperature ranges, the days between heading and maturity had significant negative correlation with daily mean temperature. In comparison with spring type wheat varieties, transition type wheat varieties had higher 1000 grain weight. It was concluded from the results of experiment that the transition type wheat varieties had a fairly wide ecological adaptability in terms of growth and development.
    Studies on the Cooling Tolerant Basis of Rice Plant in Cold Area Ⅱ. Effect of Cool Temperature at Young Microspore Stage on the Fertility of Spikelets in Rice Plant
    Wang Lianmin (Crop Cultivation research Institute of Heilongjiang Academy of Agricultural Sciences, Harbin 150086)
    1997, 18(04):  . 
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    A pot experiment was carried out to study the effect of cool temperature at young microspore stage on the fertility of spikelets in rice. Results showed that cool temperature (12℃, 15℃, 16℃) treatment for 4 ̄7 days delayed the heading, flowering and ripenning stages of Hejiang No.19 and Longing No.1 significantly, increased the soluble sugar content in leaves and ears and greatly decreased the seed setting percentage of spikelets. The seed setting percentage of spikelets on primary branches was similar to that of spikelets on second branches under the conditions of low temperature.
    Climate Change and Its Effects on Summer Harvesting Crops in Hubei Province
    Feng Ming (Hubei Agrometeorological Center, Wuhan 430074)
    1997, 18(04):  . 
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    Through detailed analysis on climate change in the period of 1981 ̄1994 in Hubei Province, it was found that the yearly mean temperature in this province was getting lower gradually which was different from the results of study on the globe and other palces of China. The climate getting warmer in winter and getting cooler in summer was the main features in Hubei Province. There was a demarcation line of air temperature change near 111°E. Air temperature was getting warmer in winter and is getting cooler in summer on the east of the line. Air temperature dropped at all seasons on the west of the line. The yields of wheat and oil rape were affected by the climate change. The effects of climate change were more obvious in east than in west. It was favourable for high yield of wheat in the 1980’s when the precipitation and the rain days were reduced in April and May.
    A Summary of Research on the Agricultural Decision Support System
    Cao Yonghua (Agrometeorological Institute, Chinese Academy of Agricultural Sciences, Beijing 100081)
    1997, 18(04):  . 
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    An agricultural decision support system was developed on the basis of the agricultural information crop simulation model and the agricultural expert system. It is usually divided into three scales: field, farm, and region. At present it is developing toward a group decision supoort system and a network decision support system.
    Measurement and Simulation of Evaporation from a Bare Sand Soil
    Wnag Huixiao (Institute of Geography, Chinese Academy of Sciences, Beijing 100101)
    1997, 18(04):  . 
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    An experiment was carried out in 1993 in Sonning Farm, Reading University, UK to evaluate the use of micro lysimeter method for direct measurements of evaporation from a sand soil. A good relation between evaporation and water content of topsoil and the topsoil water content could be used to infer soil evaporation. A numerical model SWEAT was used to simulate evaporation, soil water, and soil temperature and the hydrological characteristics of soil and time dependent weather data were used as input. The difference between the simulated cumulative evaporation and that measured using micro lysimeter in 18 days was less than 0.7mm. The difference of stored water in the profile of 0 ̄23cm between simulation and measurement was less than 4mm. It was concluded that micro lysimeter is an effective way to measure soil evaporation except rainy days. SWEAT mode can be used to simulate bare soil evaporation rate accurately and the water content profiles.
    Effects of Sod Culture on the Environment of Citrus Orchard, the Yield and Quality of Citrus Fruits
    Li Guohuai Zhang Wencai Hu Dewen Liu Jihong (Department of Horticulture, Huazhong Agricultural University, Wuhan 430070)
    1997, 18(04):  . 
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    The experiment was carried out in 1993 ̄1995 in satsuma citrus ( Citrus unshiu Marc. cv. Kamei) orchard to study the effects of sod culture on the environment of citrus orchard and yield and quality of citrus fruits. Bahia grass ( Paspalum notatum Flugge) was planted as sod which was cut down to cover the floor under trees in summer. The results showed that the ecological enviroment in citrus orchard was improved by sod culture. The leaf photosynthetic rate of citrus trees was raised, the percentage of fruit setting and yield was increased, and the quality of fruits was improved in sod plot.
    The Effect of Latitude and Altitude on Grain filling Period, 1000 Kernel Weight and Plant Height of Medium Maturing Maize Varieties in Southwest China
    Huo Shiping Xu Minglu Yan Qingjiu (Institute of Agricultural Sciences, Wanxian City, Sichuan Province, Wanxian City 634000)
    1997, 18(04):  . 
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    The variations of grain filling period, 1000 kernel weight, plant height and ear height with latitude and altitude were studied using 6 medium maturing maize varieties grown in Southwest China. The results indicated that the relationships of the above 4 traits with latitudes and altitudes could be described by dualistic linear regression equations, which are able to predict more than 90% variations. When altitudes remained unchanged, each increment of one degree in latitudes resulted in an additional increase of 1.13±0.038d for grain filling period, 9.82±0.081g for 1000 kernel weight, 8.22± 0.941 cm for plant height and 3.40±0.508 cm for ear height; When latitudes remained unchanged, each increment of 100 m in altitudes made the grain filling period 1.33±0.149 d longer, and 1000 kernel weight, palnt height and ear height were not significantly increased. The results were highly uniform among years and varieties.
    Water Use Efficiency and its Optimization in Wheat
    Zheng Youfei Wan Changjian Yan Jingyi Liao Zhihong (Nanjing Institute of Meteorology, Nanjing 210044)
    1997, 18(04):  . 
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    According to the data measured in field , a composite index of water use effciency (WUE)-P/E was analysed in wheat. The variation of WUE was resulted from the joint effects of photosynthesis and transpiration. The main factors affecting the variation of WUE are solar light intensity, relative humidity, stomatal conductance and the fertility of soil. It is shown that the phenomenon of “midday depression” in crops is an adaptive adjustment for optimization of WUE.
    The Relationship Between the Dymamics of Oil Accumulation in Seed of Oil Sunflower and Temperature Conditions
    Wang Yanfei Xiang Lijun Yu Bocheng Hu Qilin Jia Zuochen (Institute of Economic Crops, Xinjiang Academy of Agricultural Sciences, Urumgi 830000)
    1997, 18(04):  . 
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    The relationship between the dynamics of oil accumulation in seeds of early maturity and medium maturity varities of oil sunflower was studied in 1994~1995 in 4 different regions. The results showed that the temperature in the early filling period was the most important factor to oil content. The higher the temperature was the higher the oil accumulated the accumulative rate of oil content was in early stage after flowering, but lower in late stage after flowering. The accumulative peak period of oil content was different in different regions. There was a significant positive correlation between the accumulation of oil content and the accumulated temperature in the flowering period and diurnal range of temperature.