盐度降低间歇曝气动态膜生物反应器净化水产养殖废水的效果     

洪俊明  卢芳芳  尹娟 《农业工程学报》2012,28(11):212-217

采用间歇曝气动态膜生物反应器(DMBR)处理不同盐度下的水产养殖废水,研究盐度对有机物降解和反硝化过程的影响。结果表明:当盐度在0～35g/L范围内,随着盐度的提高,由于盐度对微生物的抑制作用,在含盐条件下有机物降解和反硝化效率下降,间歇曝气动态膜生物反应器对水产养殖废水化学需氧量CODMn的去除率从89.5%下降到75.5%;出水总氮TN去除率从89.9%下降到74.4%。通过对有机物降解速率常数和反硝化速率常数的动力性模拟,CODMn降解速率常数和硝态氮NO3--N的降解速率常数随盐度的提高呈线性下降的趋势,其线性回归模型的决定系数分别为0.9838、0.9665。盐度对水产养殖废水反硝化过程的抑制作用要大于有机物降解过程。  相似文献   

MODELLING THE EFFECT OF VEGETATION COVER AND DIFFERENT TILLAGE PRACTICES ON SOIL EROSION IN VINEYARDS: A CASE STUDY IN VRÁBLE (SLOVAKIA) USING WATEM/SEDEM     

J. Lieskovský  P. Kenderessy 《Land Degradation \u0026amp; Development》2014,25(3):288-296

Vineyards represent one of the most erosion‐prone types of cultivated land. Because of this, cultivation practices are very important in reducing the soil erosion risk in vineyard regions. The aim of this paper was to assess the impact of various management practices on soil loss in vineyards. Effects of tillage, hoeing, rotavating and grass cover were evaluated in small vineyards located in southwestern Slovakia in the Vráble viticultural district. Erosion and deposition rates were estimated using the levelling method. This method is based on an evaluation of variability of the soil surface against vineyard poles measured between the year of pole insertion and the year of measurement. On the basis of the measured data, a WATEM/SEDEM distributed soil erosion model was calibrated, and the total soil loss from the vineyards under different management conditions was estimated. The model shows rather good performance in modelling soil erosion, but at the same time, it shows lower reliability in modelling soil deposition. Downslope tilled vineyards were the most eroded; the erosion in rotavated vineyards is somewhat reduced. The most protective tillage system is hoeing. Considerably lower soil loss was estimated with the use of vegetation cover between vine rows, which is in accordance with agro‐environmental schemes supporting use of grass cover as an erosion prevention measure in vineyards. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Detecting ALS and ACCase herbicide tolerant accession of Echinochloa oryzoides (Ard.) Fritsch. in rice (Oryza sativa L.) fields     

《Crop Protection》2014

Inconsistent control of Echinochloa oryzoides has been reported repeatedly by farmers in the major rice growing area of Turkey. Greenhouse studies confirmed the existence of cross and multiple herbicide tolerance of E. oryzoides accessions including acetolactate synthase (penoxsulam, bispyribac-sodium) and acetyl CoA carboxylase (cyhalofob-butyl) inhibiting herbicides. Comparison of 95% lower confidence intervals of ED₉₀ derived from log-logistic dose–response curves, and twice the recommended field rates of the herbicides showed some, but not distinct separation of susceptible and tolerant accessions. We used a novel method to separate heterogeneous data without a priori knowledge of grouping into more than one group. On the basis of the distribution of ED₉₀ it was possible to identify two distinct groups of the 172 accessions tested, 78% were not controlled by ALS inhibitors (penoxsulam, and bispyribac-sodium) at recommended field rates; and 38% were not controlled by the ACCase Inhibitor (cyhalofob-butyl) at twice the field rates. The effective response level of ED₉₀ resulted in 64 and 14 tolerant accessions to ALS and ACCase, respectively. Fourteen accessions showed multiple resistances to ALS and ACCase Inhibitors.Some of the accessions were strongly tolerant to both herbicide modes of action and had 100% survival even at 6 times the recommended rates. Most of these tolerant accessions were from Marmara region, predominantly in Edirne and Balıkesir, which are the regions without any crop rotation.  相似文献   

玉米抗茎倒伏能力相关性状与评价研究进展   总被引：1，自引：0，他引：1  

赵雪  周顺利 《作物学报》2022,(1):15-26

茎倒伏造成玉米产量和品质下降,收获成本增加,籽粒生理成熟后无法继续田间站秆脱水,影响玉米机械化籽粒收获。关于玉米抗茎倒伏相关的性状,前人从植株形态、节间形态、解剖结构和化学成分等方面进行了大量研究,但结果不完全一致,同时这些性状对茎秆抗倒性作用大小的定量研究较少。本文综述了玉米抗茎倒伏能力的评价方法和指标、茎秆力学测定方法、抗茎倒伏能力相关性状的分析方法及其影响因素,提出了抗茎倒伏能力相关性状及评价研究中存在的问题和需要进一步关注的内容,希望为进一步研究玉米抗茎倒伏相关性状及其评价方法,培育抗倒伏品种和优化栽培措施提供参考。  相似文献   

惠州市古树名木衰败死亡原因及保护探析     

巫添辉 《林业科技情报》2014,46(3):18-20

古树名木,指的就是在人类发展历史中保存下的具有文化、历史或科研价值的树木的总称。作为我国珍稀的植物资源,古树名木是我国优质的文化遗产,具有非常高的收藏和观赏价值,但是,由于各种原因的影响,古树名木衰败死亡,使我国遭受重大的历史文化遗产损失,我们应当及时采取有效策略,来保护古树名木,本文针对惠州市古树名木衰败死亡的原因和保护措施,做了深入的分析和探讨,以飨读者。  相似文献   

Excel在导线测量计算中的应用     

何如伟 《林业调查规划》2014,(2):17-22

阐述电子表格软件Excel在罗盘仪闭合导线测量、极坐标导线测量、测绳丈量中的数据输入、角度格式转换、平差及面积计算等方法及步骤,并列出了相应函数和公式。结果认为,用Excel处理数据具有直观、美观,易于输入和修改,工作效率高,便于导入CAD或GIS软件环境等优点。  相似文献   

Technical Research for Detector of Grain Moisture Content Based on Error Compensation     

Dong Yu-de  Yang Xian-long  Ye Fei  Pan Kai  Jin Xing-chi  Shi De-cai 《东北农业大学学报(英文版)》2014,21(3):76-83

According to the existing method including testing the frequency and establishing the relationship between moisture content and frequency, a corresponding instrument was designed. In order to further improve the accuracy and rapidity of the system, a new approach to describe the relationship between the measurement error and the temperature was proposed. The error band could be obtained and divided into several parts（based on the range of temperature） to indicate the error value that should compensate the grain moisture content for the changes in temperature. By calculating the error band at the maximum and the minimum operating temperatures, as well as by determining the error compensation value from the error band based on the measurement moisture content, the final effective result was derived.  相似文献   

基于PLC的空压机远程监控系统的设计与实现     

李慧玲  罗敏  罗春晖 《湖南农业大学学报(自然科学版)》2014,(3):55-57

省级政府投融资平台公司在城镇化建设中发挥着重要作用,其投融资风险问题亦逐渐引起重视。基于平台公司的投资收益会随着市场等宏观环境的变化而波动的考虑,将平台公司的项目投资资产视为金融资产而度量其风险状况。考虑单笔投资的情形,建立极值理论和SV-t模型的相结合平台公司一维融资风险动态VaR模型;进而考虑多笔投资间的非线性关系,结合Copula函数和蒙特卡洛模拟思路,建立平台公司多维融资风险度量模型。所构建的模型避免了传统研究的强主观性,并实现了投资风险的实时、动态度量。  相似文献   

五华三黄鸡生长发育规律及产肉性状分析     

钟福生 《湖南农业大学学报(自然科学版)》2014,40(1):56-59

五华三黄鸡是广东省特有的地方优良肉用家禽品种。为给五华三黄鸡的保种选育提供参考依据,于2011年5月至2012年5月对公母混养的60只五华三黄鸡进行饲喂试验, 测定其体重、体尺、屠宰性能等指标。结果表明：五华三黄鸡生长发育比较缓慢,210日龄的鸡的平均体重为1 022.5 g,其体斜长和胫长较长,胸深较深;公鸡的屠宰率为88.71%,母鸡的屠宰率为92.63%;公鸡的全净膛率为63.14%,母鸡的全净膛率为60.93%;公鸡的腿肌率为23.67%,母鸡的腿肌率为19.61%;公鸡的腹脂率为0.58%,母鸡的腹脂率为0.63%;对屠宰性能进行邓肯检验的结果显示,公、母鸡的屠宰率差异有统计学意义(P<0.01),活重、半净膛率、全净膛率、腿肌率差异也有统计学意义(P<0.05),而其他各性状间的差异无统计学意义(P>0.05)。  相似文献   

一种玉米苗期冠层叶绿素车载 动态诊断光谱指数     

李树强  李民赞 《广东农业科学》2014,41(2):171-174

为了使用车载平台对玉米叶绿素含量进行快速预测,优化车载系统测量结果,提出了一种适用于玉米 苗期车载动态预测冠层叶片叶绿素含量的光谱指数MPRI,构建了相应的叶绿素含量预测模型,结合空间插值对其 空间分析能力进行了分析和评估。结果表明院基于车载动态获取的冠层光谱指数MPRI,对于单点位置的冠层叶绿素 预测效果较好,模型决定系数R2约为0.81;对于动态测量,车载动态获取信息中的玉米冠层MPRI 值能够通过定值 阈值较为准确地被识别,利用其构建的玉米冠层叶片叶绿素含量预测模型具有较好的单点预测效果。结合反距离加 权插值法进行空间分析,能够得到较佳的空间预测效果,空间分布预测偏差小于7%的数据占总数据量的85%。基于 光谱指数MPRI 构建的车载动态预测冠层叶绿素预测模型具有较好的单点预测效果,结合GPS 位置信息进行空间 分析能够得到较佳的空间预测效果,为车载系统动态测量提供了新的思路。  相似文献