Climate Change and Dryland Agricultural Ecosystem Management

asin, have more obvious differences with the region far from the river. Riparian zone has many
functions such as reducing river pollution, providing wildlife and plant ecology and improving the
river environment, etc, but it is very sensitive to river changes, is the area most likely to lose
biological diversity. So it has great importance to research distribution of riparian vegetation for
protecting ecological environment and evaluating river ecosystem health.
The distribution of riparian vegetation is affected both by terrestrial environment and river, so factors
of the distribution of riparian vegetation must be considered from both above, the major impact of the
river on the vegetation is providing nutrients and moisture, and also vegetation can indicate the
environment well. Environmental interpretation of classification and sorting not only compare
objectively and quantificationally the distribution pattern of plant communities and environmental
information, but also can get the relationship between community type distribution and environmental
gradients, which has important ecological significance. But the researches of Heihe River have not be
concerned with the distribution of riparian vegetation , impact of environmental factors and vegetation
indicator species of environment.
In this paper, clustering and canonical correspondence analysis(CCA) were used to classify and sort
riparian vegetation of Heihe River Basin, and also vegetation indicator species of environment were
got to discuss the response of riparian vegetation for the environmental impacting, and to determine
the vegetation indicator species as specific environmental signal directives
Spatial variation of water requirement for spring wheat in the
middle reaches of Heihe River basin
Wang Yao1, Zhao Chuanyan1,∗, Tian Fengxia2, Wang Chao2
1 Key Laboratory of Arid and Grassland Ecology with the Ministry of Education, Lanzhou University, Lanzhou
730000, China
2. Key Laboratory of Western China's Environmental Systems with the Ministry of Education, Lanzhou University,
Lanzhou 730000, China
Abstract: Sustainability of irrigated agriculture depends primarily on the efficient management of
irrigation water. Understanding crop evapotranspiration (ETc) is essential in planning the most
effective use of water resources in the arid northwest China. The objective of this study is to map the
spatial distribution of water requirements and analyze the relationship between the spatial variation of
water requirement and main meteorological factors in the Heihe river basin. First, reference crop
evapotranspiration (ET0) was calculated using Penman-Monteith equation with daily data obtained
from 14 meteorological stations in and around the study area. Secondly, the crop coefficients (Kc) of
spring wheat in different growing stages were adjusted according to the investigation data. Finally, we
estimated the spatial distribution and variation trend of the water requirement of spring wheat in the
middle reaches of Heihe river basin with the technology of Geographical information system. From
the study, the results can show that the trend of crop evapotranspiration (ETc) gradually increased
from southwest to northwest,the ETc varies from 544 mm to 769 mm during the entire growing
∗ Corresponding author: ZHAO Chuanyan, Email: nanzhr@lzb.ac.cn
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