文县杨个体生物量生长规律研究

采用标准木法对文县杨地上部分生物量进行了调查,分析了地上部分各器官生物量与株高、胸径的相关关系,结果表明:文县杨地上部分生物量各器官的比例为树干56.12%、干皮7.8%、叶9.5%、枝21.4%、枝皮5.2%,其大小顺序依次为树干＞枝＞叶＞干皮＞枝皮;地上部分质量、树干质量、树皮质量、叶质量、枝质量等与株高和胸径均呈...     

基于无人机高光谱影像的玉米地上生物量反演

【目的】研究以玉米地上干生物量为研究对象,探讨基于无人机高光谱数据利用人工神经网络法反演生物量的可行性。【方法】在吉林省蔡家镇开展玉米氮肥梯度试验,并进行无人机高光谱数据和地上干生物量获取,共获数据30组。随机选22组数据用于建模,剩下8组用于模型的外部验证。分别基于光谱指数法和BP神经网络算法构建反演模型,比较分析各种方法反演玉米生物量的优劣。【结果】结果表明：和基于光谱指数构建的生物量反演模型相比,BP神经网络模型取得了更好的反演结果。其建模时决定系数为0.99均方根误差为0.08 t/ha,相对均方根误差为3.39%；外部验证时,决定系数为0.99,均方根误差为0.15 t/ha,相对均方根误差为8.56%。【结论】BP神经网络模型可有效提高无人机高光谱遥感反演玉米地上生物量的精度。     

Variations of SOC and MBC observed in an incubated brown loam soil managed under different tillage systems for 12 years

To assess changes in organic carbon pools, an incubation experiment was conducted under different temperatures and field moisture capacity (FMC) on a brown loam soil from three tillage practices used for 12 years: no‐till (NT), subsoiling (ST) and conventional tillage (CT). Total microbial respiration was measured for incubated soil with and without the input of straw. Results indicated that soil organic carbon (SOC) and microbial biomass carbon (MBC) under ST, NT and CT was higher in soil with straw input than that without, while the microbial quotient (MQ or MBC: SOC) and metabolic quotient (qCO₂) content under CT followed the opposite trend. Lower temperature, lower moisture and with straw input contributed to the increases in SOC concentration, especially under NT and ST systems. The SOC concentrations under ST, with temperatures of 30 and 35°C after incubation at 55% FMC, were greater than those under CT by 28.4% and 30.6%, respectively. The increase in MBC was highest at 35°C for 55%, 65% and 75% FMC; in soil under ST, MBC was greater than that under CT by 199.3%, 50.7% and 23.8%, respectively. At 30°C, the lower qCO₂ was obtained in soil incubated under NT and ST. The highest MQ among three tillage practices was measured under ST at 55% FMC, NT at 65% FMC and CT at 75% FMC with straw input. These data indicate the benefits of enhancing the MQ; the low FMC was beneficial to ST treatment. Under higher temperature and drought stress conditions, the adaptive capacity of ST and NT is better than that of CT.     

Effects of selective cutting and timing of herbicide application on growth and development of Cirsium arvense in spring barley

Recently, a new implement for controlling weeds in cereals (CombCut) has been developed. It cuts weeds in growing cereals without damaging them by using the physical differences (in height, stem thickness, straw stiffness and branching pattern) between crops and weeds. To evaluate and compare the effects of selective cutting with different timings of herbicide application on Cirsium arvense in spring barley, a randomised block experiment was conducted in Sweden in 2015–2017, in a field with a naturally occurring C. arvense population. Treatments consisted of control (C), herbicide application at 4–5‐leaf stage of C. arvense (H1), herbicide application at 8–10‐leaf stage (H2) and selective cutting at 10‐leaf stage (S). The treatments were performed in 2015 and repeated in 2016 in the same plots, and a final evaluation was performed in 2017. Compared to the control, S, H1 and H2 were equally efficient in reducing above‐ground biomass production of C. arvense and increasing spring barley grain yield per unit area. The number of C. arvense shoots per area was, however, higher in S compared to H1 and H2. No differences in control effects on shoot number were observed between H1 and H2. Our study indicates that (i) selective cutting (S) reduces C. arvense equally efficient as herbicide application and (ii) early herbicide spraying is as efficient as spraying later in the season.     

Changes in the relationship between species richness and belowground biomass among grassland types and along environmental gradients in Xinjiang,Northwest China

The association between biodiversity and belowground biomass (BGB) remains a central debate in ecology. In this study, we compared the variations in species richness (SR) and BGB as well as their interaction in the top (0-20 cm), middle (20-50 cm) and deep (50-100 cm) soil depths among 8 grassland types (lowland meadow, temperate desert, temperate desert steppe, temperate steppe desert, temperate steppe, temperate meadow steppe, mountain meadow and alpine steppe) and along environmental gradients (elevation, energy condition (annual mean temperature (AMT) and potential evapotranspiration (PET)), and mean annual precipitation (MAP)) based on a 2011-2013 survey of 379 sites in Xinjiang, Northwest China. The SR and BGB varied among the grassland types. The alpine steppe had a medium level of SR but the highest BGB in the top soil depth, whereas the lowland meadow had the lowest SR but the highest BGB in the middle and deep soil depths. The SR and BGB in the different soil depths were tightly associated with elevation, MAP and energy condition; however, the particular forms of trends in SR and BGB depended on environmental factors and soil depths. The relationship between SR and BGB was unimodal in the top soil depth, but SR was positively related with BGB in the middle soil depth. Although elevation, MAP, energy condition and SR had significant effects on BGB, the variations in BGB in the top soil depth were mostly determined by elevation, and those in the middle and deep soil depths were mainly affected by energy condition. These findings highlight the importance of environmental factors in the regulations of SR and BGB as well as their interaction in the grasslands in Xinjiang.     

生物质热解柔性输送装置性能研究

为了解决生物质连续热解装置的螺旋绞龙与热解管因热变形而发生的机械干涉现象,研究了一种用于生物质热解的无轴柔性连续输送装置,设计了该无轴柔性螺旋叶片参数。以稻壳、木屑和黄豆为输送物料,探究了螺距、转速和有轴、无轴等因素对输送性能的影响。结果表明:柔性输送装置的输送能力随着螺距的增加而增强,在中低转速下,物料的处理量随着转速的增加呈线性增加,表明物料的输送量和通过时间可通过调节电机转速实现精准控制;无轴螺旋输送能力比有轴螺旋增加15%~30%,且输送过程平稳,避免了物料在输送装置与输送管之间发生挤压、进而出现死机的现象。     

生物质热解气燃烧装置设计与燃烧特性试验

针对目前生物质热解气中焦油去除困难、焦油能量难以利用等问题,结合现有燃气燃烧器相关技术,开展了生物质热解气直接燃烧技术研究与试验。燃烧器理论耗气量为2~5 m~3/h,通过理论计算确定了燃烧器参数,设计了卧式燃烧室并安装烟气催化裂解装置及烟气检测装置,搭建了热解气燃烧试验平台,并对热解气的燃烧特性进行了试验研究。以花生壳为原料,在碳化温度500℃、滞留时间30 min的条件下进行连续热解碳化,产生的高温热解气直接通入燃烧设备。结果表明,燃烧设备性能较好,热解气燃烧过程稳定,燃烧效率达到98.5%,在催化剂的作用下,燃烧效率提高到98.9%,满足设计要求。     

Relative Efficiency Evaluation on Water Resource Utilization

Water resource allocation was defined as an input-output question in this paper, and a preliminary input-output index system was set up. Then GEM （group eigenvalue method）-MAUE （multi-attribute utility theory） model was applied to evaluate relative efficiency of water resource allocation plans. This model determined weights of indicators by GEM, and assessed the allocation schemes by MAUE. Compared with DEA （Data Envelopment Analysis） or ANN （Artificial Neural Networks）, the mode was more applicable in some cases where decision-makers had preference for certain indicators     

硇洲马尾藻的繁殖特性及体长生物量的季节变动

广东特产的硇洲马尾藻是一种具有食用、药用价值的大型褐藻,有望开发成人工育苗栽培的新种类。2009年7月至2010年6月,原生态定点观察周年各月其体长和生物量等季节变动情况,结果发现,藻体假多年生,异株、异托。8—10月为体止期,11月至翌年4月中旬为生长期,4月中旬至6月初是繁殖期,6月初至7月底为衰老期。自然种群的繁衍和维持以假根再生为主,有性繁殖为辅。假根周年各月均可再生小苗,拔除假根,严重破坏种群繁衍,保留假根的剪收可以使第二年相同面积、同一时间的同种藻体的现存生物量明显增加。分布在水深2 m以内,宽5～10 m的潮间带岩礁上,11月开始加速生长,到5月上旬藻体长度生长达到最大值,原生态藻体的生物量表现出明显的季节变化,基本上与体长生长保持同步增长,最大生物量可达1 280 g/m²,最大单株藻体长1.73 m,最大单株质量可达250 g。     

生物质燃料常温变径成型锥头研究

针对生物质常温闭式成型机的不足,本文引入了开式成型的概念,并在原有闭式成型机液压驱动设备的基础上,改进了成型腔.通过对生物质原料的力学分析,设计了开式成型的变径成型锥头.并使用小刨花、锯末等材料进行验证,探讨了对生物质常温变径成型机成型效果的影响因素,同时确定了较高成型质量时成型腔的压缩比范围.