吉林省黑土某些微量元素环境地球化学特征

根据吉林省第二次土壤普查资料 ,对黑土中微量元素B、Cu、Fe、Mn、Mo和Zn的全量、有效态含量、它们在土壤剖面中的迁移分布等环境地球化学特征及其影响因素进行了研究 ,得出如下结论 :①吉林省黑土B、Mn、Mo、Zn的全量缺乏 ,Cu、Fe的全量略低 ;②黑土B、Cu、Zn的有效态含量缺乏 ,其中Zn严重缺乏 ;③黑土剖面中 ,B、Cu、Fe、Mn、Mo、Zn等微量元素全量与有效态含量分布相似 ,均以淋溶层最低 ,表层和淀积层较高 (Mo的全量除外 )。微量元素有效态含量剖面分布中淀积层层次较深 ,表层富集程度稍强 ;④黑土中B、Fe、Mn、Mo、Zn的有效态含量与土壤有机质含量呈显著的正相关 ;B、Mo的有效态含量与 pH值呈显著正相关 ,而Cu、Fe、Mn、Zn的有效态含量则与pH值呈负相关 ;黑土B、Cu、Fe、Mn、Mo、Zn有效态含量与其全量均达到显著相关水平。根据吉林省黑土中微量元素全量和有效态含量分布的特点 ,需施用微量元素肥料 ,增加黑土中微量元素的含量 ,促进该地区农业的可持续发展     

湘北丘岗地区红壤和水稻土微量元素的有效性研究

本文对湘北丘岗区土壤微量元素Cu、Zn、B、Mo、Mn和Fe的有效性进行了研究 .结果表明 ,该区大面积土壤缺Zn、缺B ,也有部分土壤缺Cu和Mo,而有效Mn含量较为丰富 .微量元素有效性与成土母质的关系极为密切 ,土壤 pH、有机质含量及土壤质地也是影响微量元素有效性的重要因素     

青岛崂山茶园土壤微量元素有效量及其影响因素研究

青岛市崂山茶种植区土壤调查研究表明,茶园土壤中6种主要微量元素(Zn、Cu、B、Mn、Fe、Mo)的有效量多大于其缺素临界值,有效态铜、锌、锰含量均处于高水平,钼中等,硼较低.统计分析表明,土壤中Zn、B、Mn等元素全量与有效量间具显著正相关性,Fe呈显著负相关性,说明全量并不是有效量的完全控制因素;pH值与有效态Zn、Cu、B、Fe和Mo均有一定的负相关关系,表明土壤酸性增强(酸化)会增加这类元素的生物有效性;有机质含量与有效态Zn、Cu、B、Fe和Mo呈正相关性,说明有机质较高有利于土壤元素活化.     

湖州市土壤微量元素含量与有效性评价

本文研究了湖州地区水稻土、红壤和潮土三种主要土壤类型的土壤微量元素Fe、Mn、Cu、Zn、B、和Mo的有效态含量,并对各微量元素的有效态含量满足作物生长需要的状况进行评价。结果表明:湖州市土壤大面积缺钼,部分土壤缺锰、硼,而土壤有效态铜、锌含量比较丰富,土壤有效铁含量则极其丰富。最后对该市水稻土、红壤和潮土三种主要土壤类型的土壤微量元素含量与成土母质、pH、土壤有机碳之间的关系进行分析研究。     

基于遗传算法的番茄缺素叶片图像特征选择

在基于计算机视觉技术对无土栽培番茄营养元素缺乏智能识别研究中，如何选择出对缺素叶片分类能力强的特征项组合是识别诊断面临的关键问题，文章利用遗传算法对提取的缺素叶片图像众多颜色和纹理特征项进行优化选择，以达到诊断识别用的信息最优，实验表明，经过优化的特征组合明显优于人工选择的特征组合分类能力。     

风沙土酿酒葡萄基地养分资源特征与生物有效性

本文应用化学分析、吸附试验和生物诊断方法 ,系统研究了风沙土营养元素的丰缺状况及营养元素的有效性和对酿酒葡萄幼苗的影响 .结果表明 :养分含量受质地影响较大 ,缓效营养元素和速效营养元素则随质地变粘而增加 .在分析土壤对营养元素的吸附固定时发现 :土壤对锌、铜、硫和硼的吸附较弱 ,各种营养元素的固定率随着营养元素吸附液浓度的提高而增加。研究养分生物有效性后认为各种营养元素缺乏的次序为 :P >N >Fe>K >Mg >Zn >S >Mn >B >Cu .研究养分对酿酒葡萄幼苗生长发育的影响后发现 :各种营养元素在一定范围内对酿酒葡萄生长发育均有明显的影响 ,但铜肥对植株生长发育具有抑制作用 .而且 ,干红品种 (赤霞珠 )对于营养元素的吸收利用比干白品种 (白诗南 )强 .     

辽宁省水田土壤硅素肥力状况的初步研究

通过田间调查、田间试验和室内分析,研究了辽宁省不同类型水田土壤的硅素肥力状况,结果表明,醋酸-醋酸钠(pH4)缓冲液法测定的辽宁省水田土壤的有效硅含量不能准确反映土壤的供硅能力,淹水培养法的测定过程同水稻的生长过程相似,测定出的水浸态硅含量同硅肥的增产效果密切相关,因此,这种方法的测定结果可以用于评价水田土壤的供硅能力;田间试验结果表明,合理施用硅肥可提高水稻的产量,增产幅度和水浸态硅含量的关系可用CateandNelsen校验曲线进行描述;通过该曲线初步确定的辽宁省硅素丰缺的临界标准为水浸态硅含量80mg/kg;根据初步确定的临界标准,辽宁省绝大多数的水田土壤硅素缺乏,合理施用硅肥将成为辽宁省水稻产量提高的重要措施之一。     

典型黑土pH值变化对营养元素有效态含量的影响研究

采用室内培养实验的方法,控制典型黑土样品的酸碱度值,探讨典型黑土中Cu、Zn、Mn、P和Fe等营养元素有效态含量与pH值的关系。结果表明:pH值变化0.5个单位左右,有效态铜含量变化约0.5～1倍;有效态锰含量变化约3～5倍;有效态锌含量变化9～15倍之多;有效态磷含量变化约1.5～2倍;有效态铁含量变化约3～4倍。说明精确掌握土壤的酸碱度值对于土壤诊断、合理施肥、提高作物产量和实现土地的可持续利用都具有重要的理论与实践意义。     

氮肥对啤酒大麦Zn、Mn、Fe、Mo 营养效应的研究

以黄褐土为基质进行盆栽试验。结果表明，啤酒大麦植株体内Zn、Mn、Fe、Mo含量、积累量及其吸收速率等，因施N水平及生育期的不同而差异很大，从而影响其产量和品质。经统计分析，以施N0.08～0.12g/kg土为最佳。     

江西省农田土壤有效硫现状研究

采集了江西 1 6个县市 9种主要母质的 6 0 9个农田耕层土样进行了土壤有效硫含量测定 .统计结果表明 :平均值为 2 6 7mg/kg ,缺硫和潜在缺硫样点占 39 1 % .按地区分 ,以赣南、赣东北山区缺硫最严重 ,有效硫小于 1 2mg/kg的样点占 2 6 6 %～ 4 4 7% ,其次是丘陵地区 ,有效硫小于 1 2mg/kg的样点占1 0 0 %～ 1 9 0 % .按母质分 ,以石英岩、花岗岩发育的土壤最缺 ,约占 50 %～ 6 0 % ,其次是红砂岩、泥质岩 ,缺硫为 30 %～ 4 0 % ,这些是江西省急需施用硫肥的土壤 .水稻土以黄砂泥田、麻砂泥田、红砂泥田、鳝泥田等土属有效硫缺乏面积最大 ,全省水稻土有效硫缺乏的面积约为 1 0 3 8万hm2 ,约占水稻土面积的 34 % .     

Early estimation of rice area using temporal ERS-1 synthetic aperture radar data a case study for the Howrah and Hughly districts of West Bengal,India

The characteristic temporal backscattering signature of rice crop grown under flooded condition was used to estimate rice acreage for a region in West Bengal, India. To date ERS-1 Synthetic Aperture Radar (SAR) data, one acquired within 30 days of transplantation and another after 30-40 days was found to be optimum for early estimation of rice acreage. The rice crop was found to be distinctly separable from forest, tree vegetation, village/urban areas. Misclassification of rice was observed mainly with water, waterlogged areas and fallow fields.     

Spectral features associated with nitrogen,phosphorus, and potassium deficiencies in Eucalyptus saligna seedling leaves

Nitrogen (N), phosphorous (P) and potassium (K) deficiency symptoms were induced in Eucalyptus saligna seedlings. Leaves of these seedlings were measured radiometricaly in order to characterize spectrally the symptoms. It was used the SPECTRON SE-590, linked to a LICOR integrating sphere, running at 0.4 to 0.09 mu m spectral range. The results indicated that only the symptoms related with K deficiency could be spectrally detected in the visible region. The time lag from the beginning of the experiment was fundamental to characterize the symptoms, due to the synergism of the symptoms related with mineral deficiencies. The SPECTRON SE-590 fine spectral resolution proved unnecessary to spectrally characterize the symptoms.     

盆栽水稻水分消耗检测系统的研制

为了准确检测纸膜覆盖对水稻植株蒸腾、地表蒸发和耕层渗漏的影响，本试验研制了盆栽条件下的水稻水分消耗检测系统，它由动态电阻应变仪、输出面板、计算机或万用表、土槽传感器、渗漏传感器、种植作物的土槽、水箱、漏斗、土槽，水箱配重、吊索和机架等组成。该系统的特点是，通过配重平衡了系统的静态质量，能对静态质量较大，但质量的动态变化值很小的质量变化动态系统进行实时检测，结构简单、造价较低。标定试验结果表明，研制的系统精度和灵敏度较高。该系统可以用于其他作物的水分消耗及其他类似质量动态变化系统的检测。     

Use of RADARSAT‐1 data and a digital elevation model to assess flood damage and improve rice production in the lower part of the Chi River Basin,Thailand

In Thailand, flooding due to seasonal monsoon conditions frequently destroys a substantial amount of rice production, the most important agricultural activity of the country. Taking the 2001 monsoon flooding that hit the Lower Chi River Basin as an example, we developed a new method for accurately assessing damage to flood‐affected paddies. A RADARSAT‐1 image acquired during peak flooding was combined with a 30‐m digital elevation model (DEM) to develop a ‘flood‐level‐determination’ algorithm for estimating floodwater depth. Based on the elongation capability of the rice varieties, a water depth of 80 cm was used to separate ‘non‐damaged’ from ‘damaged’ paddy areas, indicating that about 60% of the paddy fields in the flooded areas were non‐damaged paddies. To minimize the loss of rice and maximize farmers' incomes, a map of rice varieties appropriate for the damaged paddy areas was produced, combining the flood‐affected paddy map with the flood frequency map. Our results demonstrate the potential of using single‐date RADARSAT‐1 data and a DEM to provide accurate and economic means of assessing flood damage to rice fields that can be used to improve rice production.     

Use of ENVISAT/ASAR wide-swath data for timely rice fields mapping in the Mekong River Delta

Because of the importance of rice for the global food security and because of the role of inundated paddy fields in greenhouse gases emissions, monitoring the rice production world-wide has become a challenging issue for the coming years. Local rice mapping methods have been developed previously in many studies by using the temporal change of the backscatter from C-band synthetic aperture radar (SAR) co-polarized data. The studies indicated in particular the need of a high observation frequency. In the past, the operational use of these methods has been limited by the small coverage and the poor acquisition frequency of the available data (ERS-1/2, Radarsat-1). In this paper, the method is adapted for the first time to map rice at large scale, by using wide-swath images of the Advanced SAR (ASAR) instrument onboard ENVISAT. To increase the observation frequency, data from different satellite tracks are combined. The detection of rice fields is achieved by exploiting the high backscatter increase at the beginning of the growing cycle, which allows the production of rice maps early in the season (in the first 50 days). The method is tested in the Mekong delta in Vietnam. The mapping results are compared to existing rice maps in the An Giang province, with a good agreement (higher than 81%). The rice planted areas are retrieved from the maps and successfully validated with the official statistics available at each province (R² = 0.92). These results show that the method is useful for large scale early mapping of rice areas, using current and future C band wide-swath SAR data.     

Remote sensing of rice crop areas

Rice means life for millions of people and it is planted in many regions of the world. It primarily grows in the major river deltas of Asia and Southeast Asia, such as the Mekong Delta, known as the Rice Bowl of Vietnam, the second-largest rice-producing nation on Earth. However, Latin America, the USA, and Australia have extensive rice-growing regions. In addition, rice is the most rapidly growing source of food in Africa. Rice is therefore of significant importance to food security in an increasing number of low-income food-deficit countries. This review article gives a complementary overview of how remote sensing can support the assessment of paddy rice cultivation worldwide. This article presents and discusses methods for rice mapping and monitoring, differentiating between the results achievable using different sensors of various spectral characteristics and spatial resolution. The remote sensing of rice-growing areas can not only contribute to the precise mapping of rice areas and the assessment of the dynamics in rice-growing regions, but can also contribute to harvest prediction modelling, the analyses of plant diseases, the assessment of rice-based greenhouse gas (methane) emission due to vegetation submersion, the investigation of erosion-control-adapted agricultural systems, and the assessment of ecosystem services in rice-growing areas.     

Towards an operational system for regional-scale rice yield estimation using a time-series of Radarsat ScanSAR images

This paper demonstrates that Radarsat ScanSAR data can be an important data source of radar remote sensing for monitoring crop systems and estimation of rice yield in large areas in tropical and sub-tropical regions. Experiments were carried out to show the effectiveness of Radarsat ScanSAR data for rice yield estimation in the whole province of Guangdong, South China. A methodology was developed to deal with a series of issues in extracting rice information from the ScanSAR data, such as topographic influences, levels of agro-management, irregular distribution of paddy fields and different rice cropping systems. A model was provided for rice yield estimation based on the relationship between the backscatter coefficient of multi-temporal SAR data and the biomass of rice. The study indicates that the whole procedure can become a low-cost and convenient operational system for large-scale rice yield estimation which is difficult for conventional methods.     

The relationship between land-surface temperature and rice quality in Tottori prefecture,Japan

Numerous studies have suggested that rice quality in Japan is affected by high temperatures during the ripening period, especially in summer. On the assumption that land-surface temperature (LST) can be substituted for air temperature, we examined rice quality using LST satellite data from the Moderate Resolution Imaging Spectroradiometer (MODIS) during the ripening stage (August) in Tottori prefecture. Rice quality in Tottori was very low compared with Japan as a whole and to neighbouring prefectures. LST was correlated with minimum and average air temperatures in August at six meteorological stations in Tottori. Rice quality decreased with increasing LST, and the threshold LST value when the quality of rice was less than 50% was 307 K (33.9 °C). The spatial distribution of LST in August indicated that LST values over 307 K were widespread, especially in coastal and lowland areas, and areas with the highest rice quality corresponded with intermountain regions that had LSTs less than 307 K.     

Analysis of the applicability of multi-temporal full polarimetric airborne L-band SAR scattering to paddy rice field mapping

ABSTRACT

A Synthetic Aperture Radar (SAR) is an all-weather imaging system that is often used for mapping paddy rice fields and estimating the area. Fully polarimetric SAR is used to detect the microwave scattering property. In this study, a simple threshold analysis of fully polarimetric L-band SAR data was conducted to distinguish paddy rice fields from soybean and other fields. We analysed a set of ten airborne SAR L-band 2 (Pi-SAR-L2) images obtained during the paddy rice growing season (in June, August, and September) from 2012 to 2014 using polarimetric decomposition. Vector data for agricultural land use areas were overlaid on the analysed images and the mean value for each agricultural parcel computed. By quantitatively comparing our data with a reference dataset generated from optical sensor images, effective polarimetric parameters and the ideal observation season were revealed. Double bounce scattering and surface scattering component ratios, derived using a four-component decomposition algorithm, were key to extracting paddy rice fields when the plant stems are vertical with respect to the ground. The alpha angle was also an effective factor for extracting rice fields from an agricultural area. The data obtained during August show maximum agreement with the reference dataset of estimated paddy rice field areas.     

Mapping paddy rice with multitemporal ALOS/PALSAR imagery in southeast China

Mapping rice cropping areas with optical remote sensing is often a challenge in tropical and subtropical regions because of frequent cloud cover and rainfall during the rice growing season. Synthetic aperture radar (SAR) is a potential alternative for rice mapping because of its all-weather imaging capabilities. The recent Phased Array-type L-band SAR (PALSAR) sensor onboard the Advanced Land Observing Satellite (ALOS) acquires multipolarization and multitemporal images that are highly suitable for rice mapping. In this pilot study, we demonstrate the feasibility of this sensor in mapping the rice planting area in Zhejiang Province, southeast China. High-resolution ALOS/PALSAR images were acquired at three rice growing stages (transplanting, tillering and heading) and were applied in a support vector machine (SVM) classifier to map rice and other land use surfaces. The results show that, based on the 1:10 000 land use/land cover (LULC) survey map, the rice fields can be mapped with a conditional Kappa value of 0.87 and at user's and producer's accuracies of 90% and 76%, respectively. The large commission error primarily came from confusion between rice and dryland crops or orchards because of their similar backscatter amplitudes in the rice growing season. The relatively high rice mapping accuracy in this study indicates that the new ALOS/PALSAR data could provide useful information in rice cropping management in subtropical regions such as southeast China.