xiaopinwang@l 63.com 
403 
HYPERSPECTRAL REFLECTANCE AND THEIR RELATIONSHIPS WITH SPRING 
WHEAT GROWTH STATUS CHARACTERISTICS IN RAINED AGRICULTURE 
AREAS OF LOESS PLATEAU 
Wang Xiaoping* Guo Ni Zhang Kai Zhao Hong 
(Institute of Arid Meteorological LAN Zhou CMA , Key Laboratory of Arid Climate Change and Reducing Disaster 
of Gansu Province, Key Open laboratory of Arid Climate Change and Reducing Disaster of CMA, 730020. 
Lanzhou, China) 
KEY WORDS: Spr-wheat; Hyperspectral Reflectance; Growth Satus; Red Edge Parameter; LAI; Chlorophyll; 
ABSTRACT: 
Diagnosis of crop growth and nutrient status is critical for prediction of agriculture yield and quality at Growth stage. Two 
experiments, one in 2006 and one in 2007 were conducted to find out spr-wheat canopy and leaf spectral characters non- 
destructively measurement, and for assessing spring wheat growth status non-destructively at the Experimental Farm (30°53' N, 
104°25' E) of Lanzhou University and Dingxi arid meteorology and agriculture experiment station(35° 32' N,104° 37' E) of 
CMA, China. The experiment included four cultivars (Heshangtou(a), Gaoyuan602(b), Longchun8139(c) and Dingxi24(d) and seven 
levels of denesity (D) application in year 2006 and four spring cultivars, four levels of density(D) and three repetition treatments in 
year 2007. Hyperspectral canopy and leaf reflectance (350-2500 nm) data recorded at various growth stages were measured by an 
ASD Field Spec Pro FR2500 in different stages, and the contents of Leaf area indices (LAI) of spr-wheat, measured by a LAI2000 
plant canopy analyzer, chlorophyll of the leaf, measured by a SPAD502, ground dry biomass, ground fresh biomass and the plant 
height(PH) to the spectra were determined. The results are following: firstly, the spectral differences are clear for the canopy and 
leaves of spr-wheat under different density levels, and the canopy spectral reflectance are gradually getting smaller in the visible 
region and bigger in the near infrared region along with density level increasing at jointing, booting, heading and filling stage, but 
this change is not evidence at ripening stage; secondly, there are obviously difference in four kinds spr-wheat in canopy and leaf 
scales spectral reflectance; thirdly, There are “double peak” phenomena for the spr-wheat at nutrition grown stage. Additionally, 
there were ‘blue shift’ phenomena for the position of red edge (A red ); Fourthly, the relationship between the spectral vegetation 
indices and the biochemical parameters indicated that the LAI have the best relationship with DVI and the relativity are the best 
between the spectral index( A red) and the chlorophyll among the selected spectral index, PVI and FW,plant height (PH) are good 
correlation. This indicated that some right spectral variables would be used to estimate the LAI, FW, the PH and chlorophyll for spr- 
wheat. Furthermore, the correlation of the spectral index and the biochemical properties of vegetation are effected by the different 
cultivars. 
1. INTRODUCTION 
Spring wheat yield is closely related to crop growth status be 
fore the heading stage, Therefore, indicators related to crop 
growth status before heading stage have been frequently em 
ployed in various models to predict grain yield and yield com 
ponents (Cui andLee, 2002; Ntanos andKoutroubas, 2002; 
Casanova et al., 2000). 
remote sensing has attracted a great deal of attention in terms 
of application for crop monitoring. Hyperspectral remote sens 
ing acquiring images in narrow (<10 nm) and continuous spec 
tral bands provides a continuousspectrum for each pixel, unlike 
multi-spectral systemsthat acquire images in a few broad (>50 
nm) spectral bands.Therefore, its data is considered more sensi 
tive to specificcrop variables (Hansen and Schjoerring, 2003). 
Accurate quantitative estimates of biochemical properties of 
vegetation canopies are important applications of remote sens 
ing for terrestrial ecology(Gao, B. -C,etal, 1995).The spr-wheat 
is one of the main grain crops in China and the correlations of 
the output, type and structure of the colony are closely. And 
the canopy for the spring wheat absorption and reflectance the 
sun light is a main factor to effect on the quality and the output 
of the wheat. It provided important evidence for remote sensing 
monitoring growth and estimating the output by observation 
the spectral variable and the relationship among the reflectance 
and biophysical parameters such as the leaf area index (LAI), 
the dry biomass, and wet biomass, the chlorophyll content. The 
report on the estimating the photosynthetical active radiation 
(PAR), the grown state and chlorophyll 
Content using the cotton hyperspectral reflectance data, 
meanwhile, estimating the coefficient of the PAR, the nitrogen 
status are often seen(Sh ibayamaM,1989; Dalezio s N R,2001; 
Pattey E,2001; Thenkabail P S,2000; TangYL,2003), but the 
study on hyperspectral reflectance and red edge character the 
same time for the spring wheat are few. 
The object of this study is to capture the impacts of the species, 
LAI and density on the spectral reflectance and offer the prime 
basis for the growth monitoring and remote sensing estimating 
output.