基于冠层光谱和BP神经网络的水稻叶片氮素浓度估算模型

[目的]快速、准确地诊断水稻叶片氮素营养状况,为水稻氮肥精准管理提供依据。[方法]以江西省农科院8种不同施肥处理的晚稻为研究对象,于主要生育期同步测定了水稻冠层光谱反射率及叶片全氮浓度(Leaf Nitrogen Concentration,LNC),系统分析了原始光谱反射率、一阶微分光谱、"三边"参数以及由350～1 350nm两两波段组合的差值(SD (Rλ1,Rλ2))、比值(SR (Rλ1,Rλ2))及归一化(ND(Rλ1,Rλ2))光谱指数与水稻LNC的相关关系,筛选出敏感参数,并以之为自变量构建了水稻LNC的传统预测模型,另外构建不同指标个数的多元线性与BP神经网络模型,并对模型进行验证。[结果](1)水稻LNC与一阶微分光谱在751nm处的相关性最高(r=0. 822);(2)"三边"参数中的红边面积SDr与LNC的相关性较高(r=0. 687);(3) 750nm附近的红边波段与近红外波段差值组合、550nm附近的绿光波段与近红外波段的比值及归一化差值组合与水稻LNC的相关性较高,以SD (R752,R751)、SR (R534,R1 350)和ND (R534,R1 349)表现最好,相关系数分别为0. 827、-0. 790和0. 788;(4)传统回归模型中以SD(R752,R751)构建的一元线性模型最佳(RC2=0. 665、RV2=0. 750、RMSEV=0. 4%、RPD=2. 034);(5)利用5个指标((R'751、SDr、SD (R752,R751)、SR (R534,R1 350)、ND (R534,R1 349))经逐步回归筛选出的2个指标SD ((R752,R751)和SR (R534,R1 350))构建预测水稻氮素的BP神经网络模型,预测效果最佳,其验证参数值分别为R2=0. 859、RMSEV=0. 302%和RPD=2. 669。[结论]基于单指标构建的传统线性模型计算过程简单但精度略低,而基于2个指标(SD (R752,R751)、SR (R534,R1 350))构建的BP神经网络模型预测精度高于该2指标构建的多元线性模型,表明在指标适合的情况下,BP神经网络对氮素具有较好的预测能力,是一种快速准确估算水稻叶片全氮浓度的方法。     

氮肥与磷肥质量检验的方法

作物的生长都必须依靠土地中必要的肥料和营养完成发育周期,合理地使用氮肥和磷肥,可以促进作物的生长发育,增加产量,能够改善土壤和农作物品质。近年来大多数土地中的含氮、磷素不均衡,损耗流失比较严重,不易在土壤中积累,而现代集约型农业又对土壤中的氮肥和磷肥有着过多的损耗。因此,为了生产出能够促进作物生长的好肥料,对氮肥与磷肥质量的检验是非常有必要的。本文针对氮肥和磷肥质量物理检验的方法进行了分析探讨。     

300MW循环流化床锅炉NO_x控制分析

本文从300MW循环流化床锅炉燃烧控制和烟气排放现状出发,对300MW循环流化床锅炉NOx排放超标的原因、现状进行深入分析,探讨了控制NOx达标排放的措施,从而为300MW循环流化床锅炉的安全运行、环保达标排放控制提供参考和积累经验。     

Reduction in nitrogen fertilizer use results in increased rice yields and improved environmental protection

Overuse of nitrogen fertilizer represents a considerable environmental problem globally, but especially in China. Recently, a recent approach on an experimental scale based on the diffusion of the so-called Three-Control Technology (TCT) successfully alleviated the overuse of nitrogen fertilizer in southern China villages in the Guangdong Province, serving as a reference point for other rice-producing countries tackling similar challenges. Here, we assessed the correlation between rice yields and reduction in the use of nitrogen fertilizer following the introduction of TCT. Our study was based on the collection of primary data from 248 households randomly selected from four rice-growing areas of Guangdong Province, China. Our results show that TCT significantly improved the efficiency in the use of nitrogen. Crucially, participating farmers, including both full adopters and partial adopters, were found to fundamentally change their application practices of nitrogen fertilizer, resulting in major improvements in the local soil and water systems.     

基于双尺度低NO_x燃烧技术的电站锅炉改造

近年来环境污染问题日益严重,其中电力企业在NOx排放方面对环境的污染尤为突出。为减少环境污染,针对某电厂原有锅炉进行燃烧器的改造,以降低电厂NOx的排放。依据设计方案,以基于炉膛空间尺度和煤粉燃烧过程尺度的双尺度低NOx燃烧技术,对电厂燃烧器进行改造。改造结果表明:基于双尺度低NOx燃烧技术改造后的电站锅炉,其NOx的排放显著降低。     

论合成氨厂含氨尾气达标排放新方法

文章阐述了几种常见的含氨放空气处理方法,从实际角度出发,分析了采用氨加工系统处理含氨放空气在运行中容易出现的问题,并提出了采用填料塔来解决含氨放空气的方法。     

The influence of management decisions and external factors on the dairy farmer's environmentally friendly farming objective: the Green Dairy experience

Ten dairy farms participated in an EU project that aimed to improve nitrogen use and assist with the adoption of more environmentally friendly farming practices. Nitrogen use and management decisions were monitored during 2003, 2004 and 2005. Nine farms improved nitrogen use (nitrogen output relative to input) in Year 2. Four farms maintained or further improved nitrogen use in Year 3. Management decisions and external factors that improved nitrogen use were increasing farm milk output, adopting best management practices for nitrogen use, growing forage crops that required less nitrogen than grass and favourable crop production conditions that rendered large quantities of good quality forage. Decisions that worsened nitrogen use were increasing cow numbers without sufficient management support, the late start of supplementary feeding when grass quality declined, setting the target yield too high, pursuing a higher milk price, less palatable silage and disease. Sufficient slurry storage is essential to improving nitrogen use. The savings from lower nitrogen input and the revenue from milk were in no proportion to the investments required for additional slurry storage, however. The farmers did adopt environmentally friendly practices, but only to the degree their businesses were able to sustain.     

充氮欠平衡水平井技术

欠平衡压力钻井可大大减轻地层伤害,提高油气井产能,增强油气资源的勘探评价能力,显著地增加钻井速度,提高钻井效益。本文详细介绍了胜利油田黄河钻井三公司在墨西哥进行的欠平横钻井施工过程。     

The Environmental Kuznets Curve Hypothesis and Air Pollution in Finland

Abstract

The historiography of mercantilism has been described as a series of disconnected still pictures which reflect the shifting viewpoints of economic thought.¹ However, historians have favoured different concepts of mercantilism not only in response to the shifts of economic science but also because they have held, explicitly or implicitly, different opinions on the problem of how economic ideas are formed and of the role they have played in historical development. The following reexamination of some of those ‘stills’ concentrate on such differences.²     

可编程序控制器在合成氨生产净化工序中的应用

净化工序是合成氨生产过程中最重要的工序,根据净化工艺的控制要求,文章通过对可编程控制器和集散型控制系统进行比较,优化选择可编程控制系统进行配置、设置及组态。从而达到高效、高精度、低成本,满足合成氨生产净化工序工艺的控制要求。