Chinese Journal of Agrometeorology

Multi scale Periodic Analysis and Trend Prediction for Precipitation Dynamics in Coastal Tidal Flat Region

YU Shi peng,YANG Jing song,WANG Xiang ping,YAO Rong jiang,LIU Guang ming

2013, 34(04): 377-383. doi:10.3969/j.issn.1000-6362.2013.04.001

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For the sake of identifying the multi scale periodic characteristics of annual and seasonal precipitations and forecasting the precipitation trend in coastal tidal flat region, two kinds of the most popularly used continuous wavelet transforms, Morlet and Mexican Hat wavelet transforms, were conducted based on the long term precipitation series covering 59 years from 1953 to 2011 in coastal Dongtai county. By comparing the two wavelet analysis results,it was proved that Morlet wavelet transform performed better in revealing the local features of coastal precipitation periodicity and increasing the periodic significance level.The results showed that the dominant periodic oscillations involved in coastal annual and seasonal precipitation appeared at inter decadal time scales.The annual and summer precipitation had the similar first,second and third dominant periods of 24,16 and 9 years respectively,and the spring,autumn and winter precipitation had the 16,23 and 17 years dominant periods respectively.The significant precipitation periodicities at interdecadal time scales in the studied area matched the corresponding precipitation periodicity in the whole Jianghuai Area,while the poor significance in precipitation periodicities at inter annual time scales in the studied area didn't match because of the special geography location in coastal region.Further precipitation trend prediction,based on the revealed dominant periodicities in coastal precipitation,showed that the coastal annual and summer precipitation in subsequent 8-12 years, the spring and winter precipitation in subsequent 8 years and the autumn precipitation in subsequent 11-12 years might be in relatively low periods.The present study can be helpful for extending the research field of application mechanism in wavelet analysis,and can provide theoretical basis for the research of climate change and agriculture development in coastal region under the background of coastal reclamation and global climate change.

Spatial temporal Distribution of Precipitation in Gansu Province Last 42 Years

WANG Hong xia,LIU Xiao ni,LI Chun bin,REN Zheng chao,PAN Dong rong,WEI Jing qiong

2013, 34(04): 384-389. doi:10.3969/j.issn.1000-6362.2013.04.002

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The basis of meteorological data of annual average precipitation and its trend from 1970 to 2011 in Gansu province was analyzed for spatial interpolation and cross validation, and the spatial temporal variation of precipitation was analyzed further by using methods of IDW, OK, CK, Microtopographic Factors and Analytic Method Based on Multiple Regression and Residues (M AMMRR), improved MAMMRR (I AMMRR). The results showed that I AMMRR, combining with climatic factor, longitude and latitude, altitude and micro terrain factor (slope, aspect) to interpolate based on OK, significantly improved simulation accuracy of precipitation, which was the most suitable interpolation method for arid and semi arid area. Annual average precipitation had a downward trend from southeast to northwest during last 42 years in Gansu province. Accordingly, the distribution of climatic zone varied from humid region , semihumid region to semiarid region and arid region. Meanwhile, the area of arid region was the largest,accounting for 43% of the total area. Apart from Qilian mountain, middleeastern Hexi corridor and north mountains, annual precipitation in Gansu province decreased during last 42 years. Precipitation in summer showed a decreasing trend while increased in winter. Precipitation variation indicated zonal distribution in spring and autumn. The results detailed the distribution of the precipitation in Gansu province, which could provide the basis for adjustment of agricultural structure, the development of characteristic agriculture and precision agriculture.

Ecosystem Respiration and Carbon Sink Strength of the Aalpine Weeds Meadow in Qinghai Tibetan Plateau under Grazing Gradient

WU Qi hua,LI Ying nian,LIU Xiao qin,LI Hong qin,MAO Shao juan

2013, 34(04): 390-395. doi:10.3969/j.issn.1000-6362.2013.04.003

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In order to discuss the variation of the ecosystem respiration, soil respiration and carbon sink strength under grazing gradient, the biomasses in alpine weeds meadow lying to the north slope of Qilian mountain were observed from May, 2010 to December, 2011. Meanwhile the respiration of ecosystem and soil were tested by the static chamber. Results showed that(1)the respiration of ecosystem and soil had an exponential relationship with 5cm soil temperature significantly（P＜0.01）. The Q10 values of ecosystem respiration under light, moderate and heavy grazing were 4.28, 4.16 and 4.43 and the Q10 values of soil respiration were 3.33, 3.24 and 3.44, respectively.(2)Ecosystem respiration and soil respiration were higher in summer and lower in winter，carbon released from ecosystem respiration were 854.64, 909.79 and 811.70g·m-2·y-1 and released from soil respiration were 564.24, 606.92and 534.56g·m-2·y-1 respectively under light, moderate and heavy grazing; there was no significant difference of the carbon released between different grazing intensity.(3)Total net primary productivity which was 766.65, 707.75 and 570.36gC·m-2·y-1, carbon sink which was 351.93, 261.68 and 177.46gC·m-2·y-1 respectively under light, moderate and heavy grazing both reduced with grazing pressure. The alpine weedy meadow was a carbon sink whether under light grazing or heavy grazing, and carbon sequestration potential was huge. The results provide a basis for understanding the characteristics of carbon cycle of alpine weedy meadow in Qinghai Tibetan plateau.

Effect of Biochar on CH4 and N2O Emissions from Early Rice Field in South China

MENG Meng, LV Cheng wen, LI Yu e, QIN Xiao bo, WAN Yun fan, GAO Qing zhu

2013, 34(04): 396-402. doi:10.3969/j.issn.1000-6362.2013.04.004

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The methane and nitrous oxide emissions from rice field which added biochar as fertilizer in South China were measured from field experiments, by using of static chambergas chromatography method. Six treatments including traditional farming (CK), BC1 (5t·ha-1 biochar), BC2 (10t·ha-1 biochar), BC3 (20t·ha-1 biochar), RS (rice straw return), and RI (rice straw return with inoculants) were designed. The results showed that compared to CK, RS and RI, the treatments with biochar incorporation inhibited the greenhouse gas (methane and nitrous oxide) emissions intensity significantly. The comprehensive emission intensity of BC3 was 0.98kg CO2eq·kg-1, which has the lowest emissions among all the treatments. According to this study, the more biochar added, the lowest average (22.11mg·m-2·h-1) and seasonal total methane emissions (93.21kg·ha-1) were found. While the emissions of nitrous oxide had the opposite trend, i.e. the lowest biochar application had the highest average and seasonal emissions which were respectively 285.65μg·m-2·h-1 and 1.07kg·ha-1. But this emission was still less than the CK treatment (368.13μg·m-2·h-1 and 1.13kg·ha-1). In addition, this study also found that the highest biochar application(BC3) had the highest rice yield, which stood at 7152.58kg·ha-1.In conclusion, BC3 was the optimal management which had the best effects on emission reduction and rice production.

Interactive Effects of Elevated Carbon Dioxide and Water on the Growth and Development of Winter Wheat

JIANG Shuai,JU Hui,LV Xiao xi,HAO Xing yu,FENG Yong xiang,HAN Xue,WANG He ran

2013, 34(04): 403-409. doi:1000-6362.2013.04.00

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In order to find out the influence of water conditions on the CO2 fertilization，free Air CO2 Enrichment (FACE) system was conducted to research the interaction of the CO2 fertilization and water conditions. Winter wheat was treated with two atmospheric CO2 concentrations: elevated carbon dioxide(550μmol·mol-1) and ambient carbon dioxide(400μmol·mol-1) and two levels of soil moisture: high moisture (75% soil field capacity)and low moisture(55% soil field capacity) to observe the photosynthesis parameter, transpiration, dry matter accumulation and yield components. The results showed that elevated atmospheric CO2 decreased significantly stomatal conductance and transpirationrate, but significantly increased net photosynthetic rate, water use efficiency, yield per plant. The elevated CO2 dramatically benefited for the growth and development of winter wheat and its yield formation. Compared with the high moisture environment, low moisture condition decreased stomatal conductance and transpiration rate,increased net photosynthetic rate, water use efficiency, dry matter accumulation and yield component under elevated CO2.Thus, the elevated CO2 partly reduce the deleterious effects of water stress on the winter wheat. It is much more beneficial for the CO2 fertilization under low moisture environment.

Combined Effects of Elevated O3and Shading on Leaf Photosynthetic System of FieldGrown Winter Wheat

ZHENG You fei,HU Hui fang,WU Rong jun,XU Wei min,SUN Jian,LI Jian

2013, 34(04): 410-418. doi:10.3969/j.issn.1000-6362.2013.04.006

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To assess the gas exchange parameters,chlorophyll,accumulation of assimilation products and antioxidation system of winter wheat (Triticum aestivuml Yangmai13) under elevated O3 and reduced solar irradiance,five field experiments were conducted inside open topchambers (OTC).Five treatments (CK,T1,T2,T3and T4) were designed as follows:CK consisted of nature O3 concentration and nature solar irradiance,T1 of 100nL·L-1 O3 concentration and 40% of nature solar irradiance,T2 of 100nL·L-1 O3 concentration and 60% of nature solar irradiance,T3 of 100nL·L-1 O3 concentration and 80% of nature solar irradiance,T4 of 100nL·L-1 and no shading.The results showed that O3 stress caused intercellular CO2 concentration increasing,leaf photosynthetic rate,chlorophyll (chl) and carotenoid (Car) decreasing;O3 and shading composite treatment accelerated the net photosynthetic rate declining,while it could relieve chlorophyll (chl) and carotenoid (Car) falling.The photosynthetic rate descending were caused by nonstomatal factors under the two kinds of circumstances.O3 stress significantly increased leaf soluble sugar and total free amino acids,the soluble protein was significantly reduced;Under O3 and shading composite treatment,leaf soluble sugar no longer increased,and soluble sugar and soluble protein content declined,while the total free amino acid content continues to increase as the shading intensified.Carbon metabolism was planted major supersession under O3 stress,adding the weakened radiation to ozone stress changed the metabolism of plants,the main metabolism converted Carbon into nitrogen metabolism.O3 stress increased leaves malondialdehyde content(MDA),catalase (CAT),peroxidase(POD),superoxide dismutase (SOD) activity;Under O3 and shading composite treatments,leaves MDA decreased significantly,CAT,POD,SOD content was significantly higher,it indicated that increased antioxidant enzymes of plant could not completely eliminate excessive reactive oxygen species,leading to accumulation of reactive oxygen species,which resulted in the increase of membrane permeability under O3 stress,reduced solar irradiance relieved the damage of ozone on plants in a certain extent.

Distribution of Precipitation in Inner Mongolia and its Impact on Potato Irrigation Amount

HU Qi, PAN Xue biao,SHAO Chang xiu,ZHANG Dan,YANG Ning

2013, 34(04): 419-424. doi:10.3969/j.issn.1000-6362.2013.04.007

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Potato is the dominant crop in Inner Mongolia, its growth and yield is mainly restricted to water conditions. Studying the distribution of precipitation in Inner Mongolia and water requirement rules during potato growth period can provide the basis for the rational distribution of potato producing in Inner Mongolia and rational utilization of water to achieve stable yield. Based on the daily meteorological data of 46 meteorological stations from 1961 to 2010, authors calculated the effective precipitation and its distribution in Inner Monglia, evapotranspiration(ET) during potato growth period and irrigation amount in different rainfall years. The results showed that the effective precipitation was 25-240mm during potato growth period and its spatial distribution was non uniform. ET was 300-700mm and 400mm ET contour started from northern Hulun Buir, across northern Xilin Gol league, east to Hinggan league. As for the irrigation amount,there was an increasing trend from east to west and the irrigation amount contours were distributed by longitude. Hulun Buir and northern Hinggan league, east to the 1500m3/ha irrigation amount contour, were suitable for planting potato, where effective precipitation could basically meet potato water requirement in normal years. On the other hand, it was not suitable for planting potato in western and northern Inner Mongolia, where effective precipitation was insufficient to support potato producing. Compared to normal years, dry years had less precipitation and more ET, and the potato irrigation amount increased by an average of 40.4%.

Analysis on the Simulation Adaptability of ORYZA2000 Model for Rice with Different Sowing Date in Anhui Province

HAO Yu, JING Yuan shu, MA Xiao qun, GENG Li ning, YANG Shen bin

2013, 34(04): 425-433. doi:10.3969/j.issn.1000-6362.2013.04.008

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Simulation was conducted in Xuancheng, Anhui by using of ORYZA2000 model based on observed data of two rice varieties (Liangyou-6326, Nanjing-44) under three different sowing date (May 5,15,25), daily meteorological data as well as soil data during the period from 2010 to 2011. Observed data in 2010 was specified as calibration data set to calibrate model parameters, while observed data in 2011 were classified as validation data set to estimate rice development stages, leaf area index, biomass and yield. The results showed that most rice growth stage development rate of Liangyou-6326 was slightly higher than that of Nanjing-44, the basic nutrition and reproductive stage growth rate of Liangyou-6326 in the third sowing date was largest. However, the growth rate of spike differentiation stage of Nanjing-44 was less, the simulated value of rice growing period was smaller than measured value, the difference was 2~7d. Furthermore, the normalized root mean square error (NRMSE) of different development stages ranged from 3.4% to 7.5%. While the NRMSE of other rice parameters were 16%-22% for aboveground biomass, 20%-25% for green leaves biomass, 17%-21% for stem biomass, 19%-25% for panicle biomass, 24%-26% for leaf area index, 6%-13% for final biomass, and 5%-14% for yield. Over all,ORYZA2000 model could be applied to obtain satisfied simulations of rice growth, development stages and dynamic process of dry matter accumulation on the basis of crop parameter calibration.

Assessment Indices of Climate Suitability and Division for Jatropha curcas in Guizhou Province

GU Xiao ping,YU Fei,MA Jian yong,LOU Yan ping

2013, 34(04): 434-439. doi:10.3969/j.issn.1000-6362.2013.04.009

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As one of the most high quality raw material for biodiesel,Jatropha curcas has the natural advantages such as outstanding potential on economic and ecology,but their growth depended on meteorological conditions strongly.To avoid introduce blindly,the authors adopted the agro meteorological analysis and geographic information system (GIS) technology,achieved climatic suitability division for Jatropha curcas,which based on observed meteorological data of 85 stations in Guizhou from 1961 to 2009,and combined with the data of field observation.According to the annual temperature (Tmean),>10℃ accumulated temperature (∑T）,sunshine hours (H),extreme minimum temperature(Tmin)and the average temperature in the coldest month（Tcold）,the regionalization standard of the climate suitability of Jatropha curcas was established in Guizhou.Based on GIS spatial analysis function,refinement climatic division which was under grid interval of 100m×100m and accurated to villages (towns) in Guizhou was finished.Jatropha curcas planting distribution,including suitable area,sub suitable area and unsuitable area,was developped.The suitable area of Jatropha curcas was mainly located in south and north Pan River,the sub suitable area was mainly distributed in the subtropical area of Guizhou,and the unsuitable area mainly focused on the central and northern Guizhou.The results could provide the scientific evidence for Jatropha curcas on work safety layout.

Estimating Model for Rice Flowering Habit with Different Rice Varieties

HU Ning, CAO Ming hui, JIANG Xiao dong, HU Ji chao, YAO Ke min

2013, 34(04): 440-446. doi:10.3969/j.issn.1000-6362.2013.04.010

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10 varieties including sterile lines, indica rice and japonica rice, were chosen as experimental materials.The daily and hourly flowering percentage of single panicle,first flowering panicles in each day and total flower amount were measured.The theoretical flowering percentage was modeled by using the normal distribution function,and the stepwise regression was established to calculate the departure of flowering percentage considering the effect of temperature, humidity, precipitation and sunshine duration. Then the diurnal variation of the population flowering habit could be simulated by the daily and hourly flowering percentage, first flowering panicles in each day and total flower amount. The results showed that rice flowering habit was mainly decided by the genetic characteristics of varieties. Japonica rice had an obvious peak of flowering percentage during 11:48am-12:22pm and a longer flowering period for 7.7d. While the flowering peak of indica rice was earlier than that of japonica rice (9:36am-10:53am) and they had a shorter flowering period for 6.0d. The sterile lines had not obvious peak of flowering percentage and its flowering period was 7.0d between japonica rice and indica rice. Moreover, the meteorological factors would change the rule of rice flowering mentioned above, which led to the ralative departure of daily and hourly flowering percentage in-16.85% to 28.78% and -66.88% to 95.03%, respectively. Especially for indica rice and sterile lines,the departure was sensitive to the meteorological factors, which was showed in the correlation coefficient P<0.05 and P<0.01.Therefore, with considering the meteorological factors,the precision of flowering amount for a single panicle would be improved, which was also better to estimate the population flowering amount. It was positive to master the biological characteristics of rice flowering, understand the effect of meteorological conditions on rice flowering habit, which could provide a basis reference to understand rice hybrid breeding and male sterile line.

Validation and Adaptability Evaluation of CERESRice Model in the Jianghan Plain

CAO Xiu xia, AN Kai zhong, CAI Wei, SU Rong rui, YAO Feng mei

2013, 34(04): 447-454. doi:10.3969/j.issn.1000-6362.2013.04.011

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Daily weather records and observations from paddy rice field experiments at two sites in Jianghan plain (Wuhan and Jingzhou) were used to calibrate and validate the recently released version 4.5 of CERESRice model.The experiments included singleseason rice and doubleseason early rice and late rice.The model was firstly calibrated using the GLUE parameter estimation calculator and trial and error method as a complement, then validated through comparing the observed dynamic leaf area index (LAI) and biomass, development stage (flowering and maturity), total above ground biomass and grain yield with that of simulated. The results showed that the model performed well in development stage simulation, the errors between simulated and measured flowering and maturity date was no more than 3 days, with early rice the most accurate and late rice the least accurate, owing to the differences in photoperiod sensitivity. The simulated and observed of dynamic LAI and biomass during the growing stage showed a consensus trend, with the Index of Agreement(D) of 0.98 and 1.0 respectively, although slight difference existed in specific data. The predicted and observed grain yields and total aboveground biomass were also very close on the whole, with the relative Root Mean Square Error (RMSE) of 8.72% and 5.91% respectively, but a relative large RMSE of 11.6% for late rice for the chilling injury during the flowering stage. The results suggested that the CERES Rice model was able to simulate rice production with good performance in the Jianghan plain under a normal weather condition. This research supports the model application in the Jianghan plain for operational use, such as crop phenology prediction, as well as meteorological effect assessment and yield forecasting provided that effect of extreme weather condition on yield formation was taken into consideration.

Comparison of Risk Assessment on Climatic Drought for Rice Based on Two Methods in Sichuan Province

WANG Ting,YUAN Shu jie,WANG Peng ,YOU Chao

2013, 34(04): 455-461. doi:10.3969/j.issn.1000-6362.2013.04.012

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Based on the data of daily precipitation,daily mean temperature and the data of rice growth stages of 159 sites in Sichuan province from 1960 to 2010,taking the precipitation anomaly percentage and the relative moisture index as drought index respectively,the probability of each climatic drought level during the rice tillering stage,jointing booting stage and headingflowering stage in Sichuan province was analyzed.The rice climatic drought disaster risk model was constructed with two indexes and assessed the climatic drought risk during whole growth season in Sichuan province.The results showed that the high risk growth stages of rice climatic drought was at rice jointing booting stage and heading flowering stage,there was some differences in the risk zoning between the results of precipitation anomaly percentage and relative humidity index,but the risk distribution trends were similar.From whole rice growth stage,higher risk areas were mainly concentrated in Sichuan basin and northwestern of Sichuan,and the risk of drought in southern was smaller.The research results could help to reduce the losses caused by the drought on rice production,to provide a scientific basis for the rice drought assessment and the development of disaster prevention and mitigation measures.

Spatial temporal Variation of Sterile type Chilling Damages at Rice Booting Stage in Northeast China in Last 50 Years Based on Meteorological Model

FENG Xi yuan, GUO Chun ming, CHEN Chang sheng,LIU Shi

2013, 34(04): 462-467. doi:10.3969/j.issn.1000-6362.2013.04.013

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To provide the basis for predicting sterile type chilling damage, taking rice shell rate from 1961 to 2010 in Northeast China as a basic data of sterile type chilling damage, the distribution and variation of sterile type chilling damage at rice booting stage in Northeast China in last 50 years was analyzed by using of the methods of cumulative curve and Wavelet analysis. The results showed that the steriletype chilling damage at rice booting stage was mainly distributed in the northeast of Jilin and southeast of Heilongjiang. In Jilin province, chilling damage was increasing before 1972 and decreasing during 1973-1981,then increasing during 1982-1985 and decreasing during 1986-2001, increasing since 2002. The situation in Heilongjiang province was similar to in Jilin province, but it was not changed obviously in Liaoning province. There was periodic variation with 24 years and 16 years in Heilongjiang province,24 years and 8 years in Jilin province, but there was not obvious period in Liaoning province. There was an evident that sterile type chilling damage at rice booting stage was increasing in Northeast China after the beginning of the 21st century.It was estimated that the upward trend of sterile type chilling damage could be up to 2016 in Heilongjiang province and Jilin province, but not obvious in Liaoning province.

Critical Temperature and Integrated Climatic Index of Low Temperature Injury for Loquat in Fujian Province

YANG Kai,LIN Jing,CHEN Hui,WANG Jia yi,CHEN Bin bin,MA Zhi guo

2013, 34(04): 468-473. doi:10.3969/j.issn.1000-6362.2013.04.014

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According to actual observation data of temperature in mountain area and the investigation results of loquat yield reduction caused by the low temperature injury in Fujian province, the critical temperature of loquat yield reduction caused by the low temperature injury was determined as 1.0℃(inside thermometer screen), and then by comparing the temperature data of township automatic weather station and city county meteorological station, the actual critical temperature of low temperature injury was determined as 3.0℃.According to the daily climatic data of winter from 1992 to 2009 and relative meteorological yield of loquat in Fujian, the disaster inducing factors for low temperature injury of loquat was determined, the factors included extreme minimum temperature, the sum of daily numbers for ≤3.0℃, the maximum sustained days of low temperature injury for ≤3.0℃, and the accumulated temperature for ≤3.0℃. By using the method of principal component analysis to simplify comprehensively four disaster inducing factors, the integrated climatic index of low temperature injury evaluation of loquat was obtained, and the index classification was determined by combining relative meteorological yield with the index. The trial calculation in Putian showed that the integrated climatic index of low temperature injury was significantly negatively correlated with the relative meteorological yield of loquat（P＜0.05）. The results had practical reference value for evaluation low temperature injury degree of loquat in Fujian province.

Analysis on Frost Index and Hazard Risk in Ningxia

LI Hong ying, ZHANG Xiao yu, CAO Ning, ZHANG Lei, ZHANG Yu lan

2013, 34(04): 474-479. doi:10.3969/j.issn.1000-6362.2013.04.015

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Based on daily minimum temperature data of 23 meteorological observation stations during 1981 to 2010 in Ningxia Hui Autonomous Region, the characteristics of frost scope, frequency, intensity and hazard risk was analyzed by using mathematical statistics and spatial analysis methods. The results showed that the frost scope became narrow in last 30 years, and slight frost scope was significantly larger than that of moderate and severe frost, the slight frost frequency increased generally, and had no obvious differences in different areas, the frequency of moderate and severe frost decreased and space differences were significant. Frost strength was obviously regional, in which strength indices of slight frost and moderate frost were smaller in the north central, larger in the south and north, and strength indices of the severe frost were generally small. Frost hazard risk was generally higher in the south than in the north, the frost hazard risk was the highest in Longde and Xingren region, and it was the lowest in the north and central region. The results could provide an important basis for regional disaster prevention and mitigation.

Meteorological Data Reconstruction and Changing Characteristics of Haze Days during Last 51 Years in Huzhou

LI Hong quan,CHEN Zhong yun,CHEN Shi chun,LUO Li nan,LIU Shuang xi

2013, 34(04): 480-485. doi:10.3969/j.issn.1000-6362.2013.04.016

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Based on observed data,including visibility,relative humidity and weather phenomena,from Huzhou national basic meteorological station from 1961 to 2011,the haze days data was reconstructed by using of two daily average methods.The optimal reconstructed result was analyzed.The results showed that the meteorological data of haze days reconstructed by the daily average method had certain reference value.Among which 3 times a day on average as the average daily value to reconstruct the meteorological data sequence was welldistributed and accorded with the changing rules of weather phenomenon.And it had a good correlation and correspondence degree with the records from surface meteorological observed data.The haze days increased obviously,and haze days on different levels increased as well.The severe haze days were increased significantly.The haze days and its different levels were highest in winter and lowest in summer.Haze days in four seasons showed increasing trend,among which the days in autumn increased obviously,followed by the winter and summer was slowest.Monthly variation of haze days and haze days on different levels showed a"V"distribution,and the peak value appeared in December and the bottom was in July.Haze days in each month showed increasing trend,and in October particular.The research results could provide a basis for scientific understanding of haze and some references for ecological construction and atmospheric environmental governance.

Effects of Enhanced UVB Radiation and Notillage on Canopy Reflectance Spectroscopy of Winter Wheat

XU Jia ping, JIANG Xiao dong, LI Ying xue, CAO Chang, ZHAO Tu xiang, LIU Cheng, CHANG Liang,DAI Jun mei

2013, 34(04): 486-492. doi:10.3969/j.issn.1000-6362.2013.04.017

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In order to investigate the effects of two tillage patterns i.e. no tillage (Z) and deep plowing (C) on winter wheat canopy spectral reflectance and its first order derivative spectra under enhanced 20% UVB radiation, a field experiment was conducted, by simulating enhanced UVB radiation and using FieldSpec Pro FR. The experiment was designed to two levels of UVB radiation i.e. control (N, ambient) and enhanced (U, 20%) and thus four treatments: ZU，ZN，CN，CU. The results showed that canopy spectral reflectance could monitor well the combined effects of enhanced UVB radiation and different tillage patterns. For four treatments, their differences mainly in near infrared spectra and filling stage was the best period to monitor wheat growing. In filling stage, enhanced UVB radiation led to the significant decrease of canopy spectral reflectance in nearinfrared spectra, meanwhile the reflectance under Z treatment were much lower than that under C treatment.Since no tillage could delayed leaf senescence,the nearinfrared reflectance under Z treatment usually suffered smaller influence from enhanced UVB radiation than that under C treatment.For the firstorder derivative spectra of winter wheat canopy, the four treatments appeared obvious discrepancy in flowering and filling stages. Enhanced UVB radiation caused the significant decline in the red peak height. Red peak height under Z treatment was much lower, the red spectrum position was closer to the red spectrum and had multiple peaks compared with C treatment. The results could provide theoretical reference for applying canopy reflectance spectroscopy into the monitor of winter wheat growing under different tillage patterns.

Rubber Planting Area Extraction in Xishuangbanna Region Based on HJ1CCD Remote Sensing Image

YU Ling xiang,ZHU Yong,LU Wei kun,LI Xaio qing,ZHAO Ze,LI Chun li

2013, 34(04): 493-497. doi:10.3969/j.issn.1000-6362.2013.04.018

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The rubber plantation area in Xishuangbanna was extracted by the supervised classification method from the HJ remote sensing images in the 1st leafumbrella of rubber tree color to stable stage with specific spectral features.This method solved the spectral differences problem of supervised classification caused by age,species and farming.The non extractive features ware removed before supervised classification which effectively reduced the number of categories and workload.Analysis showed that the classification accuracy was up to 97.6% which reflected preferably rubber cultivation distribution in Xishuangbanna.It was a good model for the promotion and application of domestic satellite.

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