Non-point source pollution in Indian agriculture: Estimation of nitrogen losses from rice crop using remote sensing and GIS     

Abha Chhabra  K.R. ManjunathAuthor VitaeSushma PanigrahyAuthor Vitae 《International Journal of Applied Earth Observation and Geoinformation》2010

The paper presents a detailed understanding of nitrogenous fertilizer use in Indian agriculture and estimation of seasonal nitrogen loosses from rice crop in Indo-Gangetic plain region, the ‘food bowl’ of the Indian sub-continent. An integrated methodology was developed for quantification of different forms of nitrogen losses from rice crop using remote sensing derived inputs, field data of fertilizer application, collateral data of soil and rainfall and nitrogen loss coefficients derived from published nitrogen dynamics studies. The spatial patterns of nitrogen losses in autumn or ‘kharif’ and spring or ‘rabi’ season rice at 1 × 1 km grid were generated using image processing and GIS. The nitrogen losses through leaching in form of urea-N, ammonium-N (NH₄-N) and nitrate-N (NO₃-N) are dominant over ammonia volatilization loss. The study results indicate that nitrogen loss through leaching in kharif and rabi rice is of the order of 34.9% and 39.8% of the applied nitrogenous fertilizer in the Indo-Gangetic plain region. This study provides a significant insight to the role of nitrogenous fertilizer as a major non-point source pollutant from agriculture.  相似文献   

应用NOAA/AVHRR数据测算局地水稻种植面积方法研究   总被引：29，自引：3，他引：29  

李郁竹  曾燕 《遥感学报》1998,2(2):125-130

本文采用在模糊监督分类中增加迭代过程的方法－－模糊监督分类一迭代法,在分解混合像元的基础上,利用ＡＶＨＲＲ数据求算水稻种植面积。根据稻田与旱地存在温度差异的特点,在分析ＡＶＨＲＲ数据统计特征的基础上,增加了第３和４两通道参加模糊监督分类,从而增加了分类橡元值矢量维数,增强了对水稻的鉴别能力。反采用的迭代法是收敛具有效的,经本方法输出的水稻种植面积百分含量图与实际水稻分布十分吻合,测算出的面积值与Ｔ  相似文献   

Impacts of temperature on rice yields of different rice cultivation systems in southern China over the past 40 years     

《Physics and Chemistry of the Earth》2015

The impact of climate change on rice yield in China remains highly uncertain. We examined the impact of the change of maximum temperature (T_max) and minimum temperature (T_min) on rice yields in southern China from 1967 to 2007. The rice yields were simulated by using the DSSAT3.5 (Decision Support System for Agro-technology Transfer)-Rice model. The change of T_max and T_min in rice growing seasons and simulated rice yields as well as their correlations were analyzed. The simulated yields of middle rice and early rice had a decreasing trend, but late rice yields showed a weak rise trend. There was significant negative correlation between T_max and the early rice yields, as well as the late rice yields in most stations, but non-significant negative correlation for the middle rice yields. An obviously negative relationship was found between T_min and the early and middle rice yields, and a significant positive relationship was found between T_min and the late rice yields. It indicated that under the recent climate warming, the increased T_max brought strong negative impacts on early rice yields and late rice yields, but a weak negative impact on the middle rice yields; the increased T_min had a strong negative impact on the middle rice yields and the early rice yields, but a significant positive impact on the late rice yields. It suggested that it is necessary to adjust rice planting date and adapt to higher T_min.  相似文献   

基于MODIS数据的水稻种植面积提取研究进展   总被引：6，自引：0，他引：6       下载免费PDF全文

于文颖  冯锐  纪瑞鹏  张玉书  陈鹏狮  赵先丽  武晋雯 《气象与环境学报》2011,27(2):56-61

概述了水稻种植面积监测遥感数据源的应用变化、特征指数和时相选取以及遥感分类方法的发展,分析了MODIS影像在水稻种植面积遥感提取技术方面的研究进展及发展方向。结果表明：MODIS具有高光谱、高时间分辨率、多时相等特点,在大尺度上提取水稻种植面积上,可提高作物识别和监测的精确度与工作效率,节约成本,有着其他遥感数据无法相比的优势,应用MODIS数据提取水稻种植面积,取得了较好的效果。水稻遥感的最佳时相可以选择移栽期和孕穗期,利用对水体和植被较为敏感的波段或植被指数（如NDVI、LSWI和EVI）进行水稻识别,并提取种植面积。传统的遥感图像分类方法如监督分类和非监督分类,算法成熟、操作简单,是目前应用较多的方法;近年来发展起来的分类新方法,如决策树分类法、专家系统分类法、神经网络分类法,支持向量机法等,能够更准确地提取目标地物,对图像分类有不同程度的改进,在实际应用中通常和传统分类方法结合起来使用;多时相分析法与高时间、高分辨率多光谱影像的结合可以获取较高精度的作物种植面积数据,与传统分类方法相比有较大提高。利用MODIS对单一的或大面积的水稻种植面积提取效果较好,但对于地块破碎的种植面积估算尚难达到满意的结果,添加其他的辅佐数据如高程、坡度等,并结合MODIS数据的多时相特点分类等方法,可提高遥感影像分类的精度。  相似文献   

Satellite-based investigation of flood-affected rice cultivation areas in Chao Phraya River Delta,Thailand     

《ISPRS Journal of Photogrammetry and Remote Sensing》2013

The occurrence of catastrophic floods in Thailand in 2011 caused significant damage to rice agriculture. This study investigated flood-affected rice cultivation areas in the Chao Phraya River Delta (CRD) rice bowl, Thailand using time-series moderate resolution imaging spectroradiometer (MODIS) data. The data were processed for 2008 (normal flood year) and 2011, comprising four main steps: (1) data pre-processing to construct time-series MODIS vegetation indices (VIs), to filter noise from the time-series VIs by the empirical mode decomposition (EMD), and to mask out non-agricultural areas in respect to water-related cropping areas; (2) flood-affected area classification using the unsupervised linear mixture model (ULMM); (3) rice crop classification using the support vector machines (SVM); and (4) accuracy assessment of flood and rice crop mapping results. The comparisons between the flood mapping results and the ground reference data indicated an overall accuracy of 97.9% and Kappa coefficient of 0.62 achieved for 2008, and 95.7% and 0.77 for 2011, respectively. These results were reaffirmed by close agreement (R² > 0.8) between comparisons of the two datasets at the provincial level. The crop mapping results compared with the ground reference data revealed that the overall accuracies and Kappa coefficients obtained for 2008 were 88.5% and 0.82, and for 2011 were 84.1% and 0.76, respectively. A strong correlation was also found between MODIS-derived rice area and rice area statistics at the provincial level (R² > 0.7). Rice crop maps overlaid on the flood-affected area maps showed that approximately 16.8% of the rice cultivation area was affected by floods in 2011 compared to 4.9% in 2008. A majority of the flood-expanded area was observed for the double-cropped rice (10.5%), probably due to flood-induced effects to the autumn–summer and rainy season crops. Information achieved from this study could be useful for agricultural planners to mitigate possible impacts of floods on rice production.  相似文献   

基于残差周期修正的辽宁省粮食产量灰色预测     

江和文  赵铭  郭婷婷  张丽敏  孙卓  高井宝 《辽宁气象》2011,(3):51-55

基于1971—2005年辽宁省主要粮食作物水稻和玉米的全区平均单产资料,根据产量数据的多周期和波动性特点,采用周期修正残差值方法,构建了辽宁省粮食产量灰色预测模型,采用正弦曲线拟合残差序列,对模型的残差进行周期修正,预测精度提高。结果表明：预测＂十二五＂期间,辽宁省水稻在2013年以后出现小幅度下降,而单产绝对值仍处于一个相对较高的水平。玉米单产至2014年呈持续增产趋势,2015年略有下降,单产波动幅度较小。以2006—2009年实际产量数据对模型进行检验,效果较好。水稻单产预测模型精度为一级,玉米单产预测模型精度为二级。该模型对于大灾年份的粮食产量预测精度较差,但可反映其趋势。  相似文献   

基于MODIS数据的水稻种植面积提取研究进展     

于文颖  冯锐  纪瑞鹏  张玉书  陈鹏狮  赵先丽  武晋雯 《辽宁气象》2011,(2):56-61

概述了水稻种植面积监测遥感数据源的应用变化、特征指数和时相选取以及遥感分类方法的发展,分析了MODIS影像在水稻种植面积遥感提取技术方面的研究进展及发展方向。结果表明：MODIS具有高光谱、高时间分辨率和多时相等特点,在大尺度上提取水稻种植面积上,可提高作物识别和监测的精确度与工作效率,节约成本,有着其他遥感数据无法相比的优势,应用MODIS数据提取水稻种植面积,取得了较好的效果。水稻遥感的最佳时相可以选择移栽期和孕穗期,利用对水体和植被较为敏感的波段或植被指数（如NDVI、LSWI和EVI）进行水稻识别,并提取种植面积。传统的遥感图像分类方法如监督分类和非监督分类,算法成熟、操作简单,是目前应用较多的方法。近年来发展起来的分类新方法,如决策树分类法、专家系统分类法、神经网络分类法,支持向量机法等,能够更准确地提取目标地物,对图像分类有不同程度的改进,在实际应用中通常和传统分类方法结合起来使用;多时相分析法与高时间、高分辨率多光谱影像的结合可以获取较高精度的作物种植面积数据,与传统分类方法相比有较大提高。利用MODIS对单一的或大面积的水稻种植面积提取效果较好,但对于地块破碎的种植面积估算尚难达到满意的结果,添加其他的辅佐数据如高程、坡度等,并结合MODIS数据的多时相特点分类等方法,可提高遥感影像分类的精度。  相似文献   

Simulation Study of the Climate Change Impact on the Rice and its Adaptability in Ningxia Province     

Wang Lianxi  Liu Jing  Li Qi  Qian Rui 《地球科学进展》2013,28(11):1248-1256

Yinhuang Irrigation District in Ningxia, as the top rice production area of high quality and quantity, has a long history in rice planting. The studies of the effective measures for the rice production replying the climate change were very important for reducing the harm of the future climate change and crop supply safety in Ningxia Province. Based on the coupling of the PRECIS model and the crop model CERES Rice, the effects of climate change on the rice production and growth stage in Yinhuang Irrigation District in Ningxia Province were simulated and evaluated, and the adaptability measures of rice production were studied. The results showed that the CERES Rice model had the preferable simulation capability, and the modified PRECIS model also could preferably simulate the required climate parameter. The crop model simulation results showed that the climate change had some influence on the rice production and growth stage in Yinhuang Irrigation District. The rice production goes down under future climate change scenarios in Ningxia Province. The trend of reduction of 2050s is more apparent than that of 2020s under the same scenarios,but the spatial change trend is similar. The extent and range of reduction of A2 scenario are wider than that of B2 scenario in the same period, but spatial change trend is different. For the change of growth stage, there has no obvious change in the north and the central part of the Yinhuang Irrigation District. The duration in 2050s shortens more obviously than that of 2020s under the same scenario, and the duration under B2 scenario shortens more obviously than that under A2 scenario in the same period. The results of adjusting the sowing date and the rice variety parameter G4 showed that the negative impact of climate change on the rice production can be reduced by sowing date advance in Yinhuang Irrigation District in Ningxia Province. There has obvious difference for the optimal G4 values of different region in Yinhuang Irrigation District, and the rice production can also be effectively upraised by adjusting the rice variety characteristic and cultivating the heat resistant rice varieties. The optimal G4 values can mitigate the damage of climate change on the rice production in Yinhuang Irrigation District in Ningxia Province.  相似文献   

Rice Husk Ash as a Low Cost Adsorbent for the Removal of Methylene Blue and Congo Red in Aqueous Phases     

Anirban K. Chowdhury  Anupam D. Sarkar  Amitava Bandyopadhyay 《洁净——土壤、空气、水》2009,37(7):581-591

Adsorption is of significant importance for effluent treatment, especially for the treatment of colored effluent generated from the dyeing and bleaching industries. Low cost adsorbents have gained attention over the decades as a means of achieving very high removal efficiencies to meet effluent discharge standards. The present article reports on batch investigations for color removal from aqueous solutions of Methylene Blue (MB) and Congo Red (CR) using Rice Husk Ash (RHA) as an alternative low cost adsorbent. The performance analysis was carried out as a function of various operating parameters, such as initial concentration of dye, adsorbent dose, contact time, shaker speed, interruption of shaking and ionic concentration. Performance studies revealed that a very high percentage removal of color was achievable for both dyes. The maximum percentage removal of MB was 99.939%, while 98.835% removal was observed for CR. These percentage removals were better than existing systems. Detailed data analysis indicated that adsorption of MB followed the Temkin isotherm, while CR followed the Freundlich isotherm. These isotherms were feasible within the framework of experimentation. Batch kinetic data, on the other hand, indicated that pseudo second order kinetics governed adsorption in both cases. Sensitivity analysis further indicated that the effects of initial dye concentration, shaker speed, pH and ionic strength had no noticeable effect on the percentage dye removal at equilibrium. Batch desorption studies revealed that 50% acetone solution was optimum for CR, while desorption of MB varied directly with acetone concentration.  相似文献   

基于环流和海温的稻曲病指数长期预报模型研究     

刘文菁  徐敏  徐经纬  任义方 《气象科学》2018,38(5):659-665

稻曲病属于典型的"气象型"病害,为了提前预报出适宜稻曲病发生的气象等级与提供足够的防治准备时间,根据中长期天气预报原理,充分考虑大气环流和太平洋海温对区域气象条件影响的滞后性,利用近40 a的江苏逐日气象观测资料、大气环流指数和海温资料,采用空间拓扑原理和最优相关普查等统计方法,挑选出了对综合稻曲病指数影响最显著的预报因子,并通过滑动平均和主成分识别等检验方法确保预报因子的稳定性和独立性,最终分别建立了基于大气环流因子和基于海温因子的综合稻曲病指数长期预报模型。经过检验,两种模型的模拟效果均理想,能提前一个月预报出综合稻曲病指数以及对应的发病气象等级。  相似文献