Table of Content

10 September 1990, Volume 11 Issue 03

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RESEARCH ON THE CO_2 FLUX DENSITY AND THE WATER USE EFFICIENCY OF WHEAT CANOPY

Yu Huning Liu Xuan(Agro-ecosystems Experiment Station,Inst.of Geography,Academia Sinica)

1990, 11(03):  18-22. 

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The CO_2 content in the air and the wheat canopy and the CO_2 flux density of wheat canopy has been measured with a infrared CO_2 analyser system. Photosynthetic rate and the water use efficiency of the canopy has been calculated in this paper. The relationship of CO_2 flux density between net radiation, wind speed and the exchange coefficient has been analysed and the results are quite satisfy.

THE CHARACTERISTICS OF TURBULENCE NEARBY THE MODEL SHELTERBELTS

Zhu Tingyao Guan Dexin Kong Fanzhi(Institute of Applied Ecology, Academia Sinica, Shenyang)Yin Jiefen Wang Xinying(Environmental Sciences Center, Beijing University)

1990, 11(03):  22-26. 

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The distribution of turbulent intensity (ε=u'~2~(1/2)/u) and friction velocity (V_(?)=-u'w'~(1/2)) nearby the model shelterbelts is studied in this paper according to the wind tunnel experiment. The distribute characteristic is where there is decreased velocity there must be increased turbulent intensity and the maximum of ε/ε_0 is 200% more behind the model shelterbelt. The relative friction velocity (V_(?)/V_(?)0) is increased in the leeward the maximum is about 200% but it is decreased very much in the trianglar position nearby the model shelterbelt.

A STUDY ON INSUFFICIENT ILLUMINATION DURING THE TILLERING STAGE OF RICE

Li Lin Zhang Gengsheng Ji Fujian Chao Yiandong (Jiangsu Academy of Agricultural Sciences)

1990, 11(03):  40894-408. 

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The climatic regularity of insufficient illumination in rice area of Huainan in Jiangsu Province was showed, based on analysing indexes of insufficient illumination during the tillering stage of rice. And it was expounded that, because of insufficient illumination during the tillering stage of rice, the ratio of carbonhydrate and nitrogen contens in rice plants was imbalanced, values of a+b and a/b of chlorophyll in rice leaves changed notably, and photosynthesis was hindered. Therefore, it was caused that the number of tillers and dry weight decreased, the height of plant increased, the duration of gowth lengthened, and the degrees of disaster were different with various illumination levels