近红外光谱技术与常规方法检测紫花苜蓿品质的对比研究

从黑龙江省国家牧草产业技术体系绥化综合试验站的试验田中采集的10 种（每种取7 个样品）紫花苜蓿样品分别采用近红外光谱技术和常规化学测定法,对其含有的粗蛋白（CP）、中性洗涤纤维（NDF）、酸性洗涤纤维（ADF）、脂肪（FAT）、灰分（ASH）、干物质（DM）成分进行了测定,并将测试结果用SPSS 软件进行配对T值分析比较,结果表明：两种方法的X ± S 相近,|t|<0.05,P>0.05,差异不显著。分别计算两种方法的标准偏差（S）和相对标准偏差（RSD）,发现近红外分析方法的值均小于常规化学分析方法。试验结果表明：基于与常规化学方法的比较,近红外方法可以作为一种新的检测方法被使用,值得广泛应用于各种牧草饲养品质的测定与推广。     

基于吸收、透射和反射光谱预测水稻叶绿素含量研究

选择基于吸收率和透射率的叶绿素含量定量反演波段组合,构建叶绿素含量光谱估测模型寻找基于吸收、透射和反射光谱预测叶绿素含量的波段。以3个水稻品种临稻11,圣稻13和阳光200为材料,进行田间实验。比较水稻叶片吸收、反射及透射光谱曲线和一阶导数光谱曲线,发现440、480、630nm和681nm为叶绿素吸收峰的实际发生波段位置,其中630nm波段处的叶片光谱吸收率(A)、透射率(T)和反射率(R)之间相关性最好。比较三者之间的相关性,吸收率与透射率的相关性最强。630nm波段处的叶片光谱吸收率、透射率和反射率与叶绿素含量之间的相关性均达到极显著水平。回归分析表明基于440、480nm和681nm3个波段光谱吸收率线性模型,440、480nm和630nm3个波段光谱透射率线性模型估测叶绿素a含量,480、630nm和681nm3个波段光谱透射率线性模型估测叶绿素b含量,与单独使用630nm光谱变量估测叶绿素含量比较,在4个生育期估测精度均有显著提高,其中以叶绿素a和叶绿素总量的估测效果最好。     

Stabilization Properties of Aged refuse in Semi aerobic and Anaerobic Landfills

The stabilization properties of aged refuse in five year old semi aerobic and anaerobic landfills were compared, such as volatile solid (VS), total organic carbon content (TOC), humic matters, and so on. It was found that VS and TOC content in aged refuse were obviously lower than those in fresh refuse after five years disposal. However, the VS and TOC content of aged refuse in semi aerobic landfill were slightly lower than anaerobic ones, whilst the difference was not significant. Surface settlements of semi aerobic landfills were higher than that of anaerobic ones (P<0.05). Moreover, there was negative correlation between VS content and surface settlements. Both leachate and water recycling methods did not lead to significant VS content difference, while leachate recycling would cause obviously uneven surface settlement. Biological degradable materials (BDM) value of aged refuse in semi aerobic landfill and anaerobic one was similar. Furthermore, BDM value increased with the increase of air pipe distance and depth. The greater the air pipe distance is, the bigger the difference of BDM value between the layers is. In addition, total extraction ratios of humic matters and HA/FA in semi aerobic and anaerobic landfill aged refuse had no significant differences.     

基于反射光谱的山核桃幼苗氮素营养状况分析

山核桃(Carya cathayensis)是世界著名的干果之一,也是重要的木本油料作物,其油味清香、营养丰富,是优良的休闲保健食品.山核桃长期以来产量不稳、大小年现象明显,通过肥水管理、病虫害防治等有效管理措施,大部分产区大小年现象都明显趋缓,产量逐年上升(黎章矩,2003).我国山核桃研究起步较晚,在其营养方面的研究甚少.     

滚珠丝杠的温升及热变形对策

对滚珠丝杠的温升及热变形的对策进行了探讨,提出解决温升和热变形的方法,为滚珠丝杠的设计、安装、使用和维修提供参考.     

小麦叶片氮含量与冠层反射光谱指数的定量关系

本文以3种蛋白质类型的小麦品种在不同施氮水平下的3年田间试验为基础，研究了小麦叶片氮含量与冠层反射光谱的定量关系。结果显示，不同试验中拔节后叶片氮含量均随施氮水平呈上升趋势，同时冠层光谱反射率在不同施氮水平下存在明显差异。对于低、中、高籽粒蛋白质含量的品种，叶片氮含量与冠层反射光谱的归一化植被指数NDVI (1 220, 710)和红边位置均有密切的定量关系，决定系数在0.80左右。对于不同品质类型小麦品种，均可利用统一的回归方程描述其叶片氮含量随反射光谱参数的变化，对于低蛋白类型品种，采用单独的回归系数即可提高叶片氮含量估测的准确性。本研究确立的小麦叶片氮含量与冠层反射光谱的定量关系可用于不同的小麦品种、生育时期和施氮水平，为小麦氮素营养的监测诊断与精确施肥等提供理论依据和技术途径。     

浅析南方丘陵地区土地平整中的表土问题及对策

土地平整工程是土地整理项目的核心内容,但是,南方丘陵地区土地平整中出现不科学的工程措施导致的表土破坏的潜在问题却一直没有引起重视。在此,针对南方丘陵地区土地整理中土地平整工程的特点及现状,总结土地平整从规划设计到项目实施表土保护问题并进行分析,提出加强表土保护的相应措施。     

利用辐射度模型模拟玉米冠层辐射分布

随着遥感研究的深入和计算机技术的提高,地面目标二向性反射分布函数（BRDF）的研究不断深入,计算机模拟模型因其对植被结构的细致描述并能更真实模拟光线与植被冠层之间的相互作用,受到越来越多的学者重视。本文以2000年在中国科学院栾城生态系统试验站测量的夏玉米为例,在对玉米三维结构进行实地测量的基础上,利用扩展的L系统对生长期的玉米进行建模,进而应用基于真实结构场景的辐射度模型(RGM)计算了玉米场景的二向性反射率因子（BRF）,对模拟结果与实测结果进行了分析与比较,结果显示两者之间具有较好的一致性。证明了辐射度模型用于植被冠层光辐射分布模拟是行之有效的,可以为波谱库提供可靠的多角度数据,并为进一步冠层辐射分布的研究工作奠定了基础。     

Variability in energy partitioning and resistance parameters for a vineyard in northwest China

Grapevines are extensively grown in the semiarid and arid regions, but little information is available on the variability of energy partitioning and resistance parameters for the vineyard. To address this question, an eddy covariance system was applied to measure energy balance over a vineyard in northwest China during 2005-2006. Result indicated that 2-year average Bowen ratio (β) of vineyard was 1.0, canopy resistance (r_c) 289.3 s m⁻¹, aerodynamic resistance (r_a) 9.7 s m⁻¹ and climatological resistance (r_i) 117 s m⁻¹. This implied that the annual energy was split almost equally between sensible heat and latent heat. Compared to the corresponding values in other ecosystems reported by Wilson et al. [Wilson, K.B., Baldocchi, D.D., Aubinet, M., Berbigier, P., Bernhofer, C., Dolman, H., Falge, E., Field, C., Goldstein, A., Granier, A., Grelle, A., Halldor, T., Hollinger, D., Katul, G., Law, B.E., Lindroth, A., Meyers, T., Moncrieff, J., Monson, R., Oechel, W., Tenhunen, J., Valentini, R., Verma, S., Vesala, T., Wofsy, S., 2002. Energy partitioning between latent and sensible heat flux during the warm season at FLUXNET sites. Water Resource Research 38, 1294-1305.], the vineyard had a higher β, r_c and r_i than deciduous forests, corn and soybean, and grassland. Such difference was mainly attributed to (1) serious water stress in 2005, which resulted in a greater r_c up to 364.4 s m⁻¹; (2) sparse canopy with row spacing of 2.9 m and plant spacing of 1.8 m; (3) warm-dry climate and high attitude (1581 m) along with higher r_i and lower psychrometer (54 Pa K⁻¹) in the arid region of northwest China. These characters of vineyard revealed varying process of energy partitioning and surface resistance, and provided a scientific basis in understanding and modeling water and energy balance for the vineyard in the semiarid and arid regions.     

Estimation of litchi (Litchi chinensis Sonn.) leaf nitrogen content at different growth stages using canopy reflectance spectra

The estimation of crop nitrogen status in fresh vegetation leaf using field spectroscopy is challenging due to the weak responses on leaf/canopy reflectance and the overlapping with the absorption features of other compounds. Although the spectral indices were proposed in the literature to predict leaf nitrogen content (LNC), the performance of selected spectral indices to estimate the LNC is often inconsistent. Moreover, the models for nitrogen content estimation changed with the growth stage. The goal of this study was to evaluate the performance of published indices, ratio of data difference index (RDDI) and ratio of data index (RDI) developed by band iterative-optimization algorithm in LNC estimation. The correlation analysis, linear regression and cross validation were used to analyze the relationship between spectral data and LNC and construct the best performed estimation model. The study was conducted by the data of five growing seasons of litchi from the orchards in Guangdong Province of China. Results showed that the relationship between chlorophyll (Chl) related spectral indices and LNC varied with the growth stage. Even in flower bud morphological differentiation stage and autumn shoot maturation stage, there were not significant correlations between the proposed spectral indices and LNC. Besides it is difficult to estimate the LNC by the general model across the growth stages due to the integrated effects of cultivar, biochemical, canopy structure, etc. The band iterative-optimization algorithm can improve the sensitivity of spectral data to LNC to some extent. The optimal RDDI performed better than other indices for the synthetic dataset and the dataset in each growth stage. And the sensitive bands selected in the optimal indices at each growth stage are not consistent, which are not only related to the Chl absorption but also other biochemical components, such as starch, lignin, cellulose, protein, etc. In general, the LNC can be estimated by the optimized CR-based RDDI indices in autumn shoot maturation stage, flower spike stage, fruit maturation stage, and flowering stage with the R² > 0.50 and RMSE < 0.14. Although there were the significant relationship between RDIs and RDDIs in flower bud morphological differentiation stage, the highest R²s of the model developed by RDDIs and RDIs were less than 0.50 in cross validation. This study indicated that the applicability of canopy reflectance to estimate litchi LNC was closely related to the growth stage of litchi. Growth stage-specific models will be preferred for estimating litchi LNC estimation.