古日乃湖盆沉积物发育土壤盐分与碳酸钙积累机制

干旱区湖泊是维持生态脆弱区环境平衡的重要载体,随着环境变化和人类对水土资源的不合理利用,我国干旱区湖泊日渐萎缩、干涸直至消失。湖泊干涸过程中,地下水位持续下降,风积物不断加积,土壤演化过程随之发生变化,但关于湖泊沉积物发育土壤演化特征的研究十分匮乏。本研究结合土壤发生学和地球化学方法分析了古日乃湖盆沉积物发育土壤的盐分与碳酸钙积累特征与机制。结果表明：盐分积累是古日乃湖盆土壤形成的主要特征,盐化土壤表层水溶性盐含量、Na~+浓度和钠吸附比分别为13.15～650.50 g·kg^-1、186.9～12 114.7 mmol·L^-1、22.3～890.5(mmol·L^-1)^1/2,土壤具有高含盐量、高Na~+浓度与高钠吸附比,表现出强度盐化特征。古日乃湖盆干涸,土壤积盐过程由现代盐化向残积盐化演化,盐分类型由氯化物型、氯化物-硫酸盐型向硫酸盐-氯化物型、硫酸盐型转变。借助于与Ca地球化学行为相似的Sr同位素组成分析,表明土壤碳酸钙以次生碳酸钙为主,其占比超过碳酸钙总量的80%;土壤碳酸钙主要来源于母质和...     

含结构体工程堆积体土壤侵蚀研究

为探究野外实际调查中常见的含结构体工程堆积体土壤侵蚀过程,设计含结构体工程堆积体和对照组2种试验材料（对照组为不含结构体工程堆积体,后文中对2种试验材料简称为结构体和堆积体）,通过室内模拟降雨试验,研究了结构体和堆积体坡面径流侵蚀特征与雨强和场次的关系。结果表明：（1）初产历时随雨强和场次的增加而减小,结构体对初产历时有延缓作用,这与结构体的土壤特性和下垫面特征有关;（2）平均径流率和平均流速均随雨强和场次的增加而增大,堆积体平均流速和平均径流率分别是结构体的1.11~1.22,1.11~1.37倍,而结构体流速和径流率快速增加和趋于稳定的时间均较堆积体提前,且用时更短;（3）雨强对侵蚀速率、流速和径流率的贡献率较大,场次与侵蚀速率负相关,各条件下结构体的侵蚀速率均大于堆积体,且侵蚀速率和总侵蚀量分别是堆积体的1.03~2.15,1.36~2.63倍;（4）径流功率能够更好地描述结构体和堆积体侵蚀动力过程,结构体发生侵蚀的临界径流剪切力和径流功率均小于堆积体。     

Primary Growth Parameters of Three Alfalfa Cultivars Adapted to Highland Climatic Conditions

An irrigated field study was conducted to determine the relative importance and inter‐relationships of growth parameters of three dormant alfalfa (Medicago sativa L.) cultivars grown in the highlands of Eastern Anatolia, Turkey, in 2000–2003. The fast‐growing cultivar Savas had the greatest dry matter (DM) yield at the final sampling date with the greatest mean crop growth rate. In addition to a greater relative growth rate (RGR), this cultivar had more stem branching and greater leaf area in the canopy, which resulted in greater leaf area index (LAI) and greater leaf area duration. Despite the considerable increase in leaf area ratio (LAR: leaf area per unit shoot DM), the reduction in RGR of all cultivars over time was the result of a large decline in net assimilation rate (NAR) due to increasing specific leaf area (SLA). Intracultivar variation in the RGR of alfalfa is mainly determined by NAR and SLA, and both were significantly higher for Savas than the other two cultivars. The relative importance of NAR and SLA to RGR changed due to increasing self‐shading as the LAI of the canopy increased, creating a trade‐off between NAR and SLA.     

不同形态工程堆积体产流产沙对比研究

通过室内模拟降雨试验,研究了二维平面和三维锥状两种堆积体坡面在不同砾石含量条件下的产流产沙特征。结果表明:(1)坡面流速和单位面积径流率随产流时间呈“快速增大—缓慢增大—稳定波动”的变化过程;(2)平均流速和单位面积平均径流率随砾石含量的增加而减小;砾石含量相同时,二维平面坡面的流速和径流率大于三维锥状坡面;(3)二维平面坡面剥蚀率随产流时间呈“稳定—减小—稳定波动”的变化过程;三维锥状坡面剥蚀率呈“增大—稳定波动”的变化过程;(4)单位面积侵蚀量随砾石含量的增加先增大后减小;砾石含量相同时,二维平面坡面的侵蚀量大于三维锥状坡面。     

工程堆积体坡面砾石分布及含量概化

为室内试验中更好地模拟工程堆积体,利用图像分析法和经典统计学方法对6大典型水蚀区的368座工程堆积体中粒径D1cm的坡面砾石的分布和含量进行概化分析,得到工程堆积体下垫面上中下坡位砾石含量的概化区间。结果表明:工程堆积体坡面各粒径砾石含量大多服从正态分布,且山区和平原丘陵区之间的砾石总含量有显著性差异。工程堆积体坡面砾石重力分选作用明显,且随着砾石粒径的增加,分选程度增大。在室内进行工程堆积体下垫面设计时,山区堆积体的砾石总含量宜设置在50%~60%,其中,细粒砾石含量宜设置在20%~30%,中粒砾石含量宜设置在10%~15%,粗粒砾石和巨粒砾石含量宜设置为10%,堆积体上中下坡位坡面砾石含量配比宜设置为1∶1.3∶1.5;平原丘陵区的砾石总含量宜设置在15%~20%,其中细粒砾石、中粒砾石、粗粒砾石、巨粒砾石含量分别宜设置为5%~10%,3%~7%,2%~5%,2%~3%,堆积体上中下坡位坡面砾石含量配比宜设置为1∶1.5∶2.5。     

不同铁源对新西兰肉兔生长性能、血清指标及组织器官铁沉积的影响

为研究饲粮中添加硫酸亚铁、富马酸亚铁、甘氨酸铁络合物和氨基酸铁络合物对新西兰肉兔生长性能、血清免疫和抗氧化指标及肝脏和肾脏铁沉积的影响,试验选用35日龄断奶、体重相近的新西兰肉兔192只,随机分为4组,每组8个重复,每个重复6只兔.对照组铁源及水平为一水硫酸亚铁100 mg/kg,试验Ⅰ组、Ⅱ组和Ⅲ组铁源及水平分别为富...     

Combining Plant Growth with Nutrient Content Measurements as a Method to Compare Nutrient Use by Different Raspberry Cultivars

ABSTRACT

Monthly above-ground destructive sampling and partitioning of the plant into distinct component parts for growth and nutrient element (N, P, K, Ca, Mg, Na, B, Cu, Zn, Fe and Mn) analyses were used to compare elemental compositions in two red raspberry (Rubus idaeus L.) cultivars (‘Willamette’ and ‘Haida’) grown in a uniformly managed field plot. Quantitative measurements showed that the two cultivars had different growth patterns. ‘Haida’ yielded greater fresh berry weight and dry matter content than ‘Willamette’ on a per floricane basis, but, because of fewer ‘Haida’ than ‘Willamette’ floricanes in the plot after standard commercial pruning practices, fresh berry yield was similar for both cultivars on a unit area basis. ‘Haida’ berries ripened slightly earlier than ‘Willamette’. Stem, lateral and leaf growth differed between the two cultivars. Although only whole above-ground accumulation (kg ha-1) of one (Ca) of the ten elements measured was different in the two cultivars, the amounts and patterns of all nutrients in the various plant components of floricanes and primocanes differed in significant ways. In some cases, element concentrations in a specific plant component differed between cultivars while dry matter accumulation differed in the opposite way resulting in the same total accumulation in the cane involved. In other cases, there was greater accumulation in one cane type (primocane vs. floricane) than the other such that there was similar accumulation of that element in the whole plant. For Ca, accumulation in primocanes was greater for ‘Willamette’ than ‘Haida’ whereas there was no difference of accumulation in floricanes which resulted in greater accumulation of Ca in the whole above-ground plant in ‘Willamette’. Maximum accumulation of the elements in floricanes occurred generally earlier in the growing season (July to September) than in primocanes (September to October), and these maxima were frequently at different times for the two cultivars, making comparisons of nutrient compositions in the two cultivars complex. Detailed sampling periodically over the growing season in combination with element analysis of these raspberry plant components as done in this study provided a better basis for comparing nutrients in raspberry cultivars than examining element concentrations of a specific plant component (e.g., leaves) sampled once during the growing season because patterns of nutrients over time in the cultivars differed.     

栗钙土钙积层干扰后物理性质的恢复周期

用对比试验方法，对不同年龄杨树人工林地整地与未整地土壤物理性质进行了研究，揭示了半干旱地区栗钙土钙沉积层破除后的恢复周期，为该地区成功地营牧场防护林提供了基础理论依据，结果表明：经犁沟整地破降钙积层后，０～８０ｃｍ土壤物理性质的１０．９ａ恢复到整地前状态，恢复顺序为土壤含水量〈渗透系数〈总孔隙度〈容重〈硬度，其恢复周期分别为６．５，６．６，８，１２，２１．５ａ４０～８０ｃｍ钙积层部位土壤物理性质周     

两个荔枝品种果皮着色和果肉糖酸积累特点的比较

对妃子笑和紫娘喜两个荔枝品种果皮着色和果肉糖酸积累的特点进行了比较.结果显示:果皮颜色指标a值的变化表明妃子笑和紫娘喜荔枝果皮分别在全红前2周以前和全红前4 d以前迅速转红;果皮颜色指标h值的变化表明两个荔枝品种果皮不断转红.妃子笑和紫娘喜荔枝果肉糖酸比分别在果皮全红前6 d和在果皮全红时最高.紫娘喜荔枝果皮的a值和两个荔枝品种的h值与其花色素苷含量分别呈线性正和负相关,妃子笑荔枝果皮a值与其花色素苷含量的变化趋势相同.妃子笑荔枝果肉糖酸比最高时因果皮花色素苷含量较低和叶绿素含量较高而导致果皮未全红,其果皮全红时因果肉酸含量上升而导致果肉糖酸比下降.     

Soil fulvic acid properties as a means to assess the use of pig slurry amendment

Soil amendment with animal manures is a common practice for either increasing soil organic matter (SOM) and nutrient content or disposing of wastes from intensive animal industries. However, the application of organic amendments that are not sufficiently mature and stable may adversely affect soil properties, especially the content and quality of SOM pools. In this work, the effect of the consecutive annual additions of pig slurry (PS) at rates of 0 (control), 90 and 150 m³ ha⁻¹ per year over a 4-year period on the soil fulvic acid (FA) fraction of SOM was investigated in a field plot experiment conducted under semiarid conditions on a Calcic Luvisol in Toledo province, Spain. The FAs isolated from PS and control and amended soils were characterized for chemical, compositional, structural and functional properties by use of elemental and functional group analysis, and ultraviolet/visible, Fourier transform infrared (FT IR), fluorescence and electron spin resonance (ESR) spectroscopies. PS-FA was characterized by a prevalent aliphatic character, large contents of acidic functional groups, S- and N-containing groups and polysaccharide components, extended molecular heterogeneity, small organic free radical (OFR) contents and small degrees of aromatic ring polycondensation, polymerization and humification. With respect to the control soil FA, the PS-amended soil FAs were characterized by a smaller extraction yield, O and OFR contents and ratios of absorbances at 465 and 665 nm, and larger C, N, S, COOH and phenolic OH contents, C/N ratios and aliphaticity. Statistical analysis of experimental data showed that, with some exceptions, these effects generally increased with increasing cumulative amount of PS applied to soil over time. In conclusion, cumulative PS application to soil over time modifies the content and properties of the FA fraction of SOM. Thus, this material should not be considered as a mature organic amendment and should be treated appropriately before it is applied to soil, so as to increase the degree of humification and enhance its potential as a soil organic fertilizer.