New Zealand Journal of Agricultural Research abstracts
Estimating grassland yields using remote sensing and GIS technologies in
China
LI JIANLONG
LIANG TIANGANG*
The State Key Lab. of Arid Agroecology
Lanzhou University
Lanzhou City, China, 730000
CHEN QUANGONG
Gansu Grassland Ecological Research Institute
Lanzhou City, China, 730020
Abstract From green herbage yield, environment, and remote
sensing (RS) data recorded in different grassland types in Fukang County,
Xinjiang from 1991 to 1996, correlation analyses and grassland yield estimates
were obtained using remote sensing and geographic information system (GIS)
technologies. Methods of processing images, analysing information, and linking
of remote sensing data with ground grassland data were explored. Results showed
correlation between fresh herbage yields and ratio vegetation index (RVI) and
normalised difference vegetation index (NDVI) (P < 0.01) in four
grassland types with correlation coefficient (r) >0.679. Fresh
herbage yields correlated better with RVI than with NDVI for lowland meadow,
hill desert steppe, and mountain meadow, but not for plains desert steppe.
Optimum non-linear models for estimating yield were selected from six curves,
and estimated total yields were verified by ground truth large-plot
investigations and statistical analyses. The effects of estimating green
herbage yields using non-linear models were better than those using linear
models in all four grassland regions. The total accuracy of estimating yields
by remote sensing was >75% over large areas in the four grassland types
using a combination of remote sensing and GIS. Remote sensing, along with GIS,
is a new approach to the use, development, and management of grasslands.
Keywords remote sensing technology; grassland; estimating
green yield; geographic information system; pastoralism
New Zealand Journal of Agricultural Research, 1998, Vol. 41: 31-38
0028-8233/98/4101-0031 $7.00/0 (c) The Royal Society of New Zealand
1998
PDF file of entire paper: medium quality (543K); (scanned from paper original: notes about this process)
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