河南烟区烤烟叶片含钾量低的原因初探

温室盆栽和大田试验结果揭示．烟叶评吸质量与烟叶含钾量呈正相关。尽管河南植烟土壤含钾量高于南方红壤，但其所产烟叶含钾量却远低于红壤。造成这种现象的主要原因包括土壤水分不足钾素迁移速度低，补充速度赶不上吸收速度的需要；土壤固相对钾的固定，河南烟区上镶中过量的钙对钾吸收的拮抗等。盆栽试验表明烤烟缺钾临界值为烤烟收获后土壤速效钾含量小于150mg／kg。通过调节土壤水分状况，选用吸钾能力高的烤烟品种和调节烤烟的生理活性可以有效地提高烟叶含钾量。     

Impact of cover crops in vineyard on the aroma compounds of Vitis vinifera L. cv Cabernet Sauvignon wine

This study compared the influence of different cover crops with clean tillage on wine aroma compounds of 5-year-old Cabernet Sauvignon vines. White clover, alfalfa, and tall fescue were used in the vineyard and compared with clean tillage. Aroma compounds of wine were analysed by solid-phase microextraction gas chromatography–mass spectrometry (SPME-GC/MS). Forty-seven volatile compounds were identified and quantified. Wines made from grapes grown with various cover crops had higher levels of aroma compounds. Ethyl acetate, isoamyl acetate, ethyl octanoate, ethyl hexanoate, phenylethyl acetate, isoamyl alcohol, linalool, citronellol, β-damascenone, α-ionone, and 5-amyl-dihydro-2(3H)-furan were the impact odorants of sample wines. Wines from cover crop also had higher contents of these impact odorants than the control. For different cover crops, alfalfa sward yielded the highest levels, followed by the tall fescue treatment. According to the data analysis of aroma compounds and sensory assess, permanent cover crop may have the potential to improve wine quality.     

浅议保墒灌溉技术新体系及其理论基础

从干旱半干旱地区发展起来的较为成熟的保墒技术得到启迪,提出了“保墒灌溉”这一新理念。初步探讨了保墒灌溉提出的现实背景、基本理论基础、今后应该研究的重点以及该领域研究的重大意义,以期为我国节水事业的发展起到抛砖引玉的作用。     

Spatial variability of Soil Nutrients and Influencing Factors in a Vegetable Production Area of Hebei Province in China

This study was conducted to determine soil nutrient spatial variability and the factors influencing it in a vegetable production area using traditional statistics and geo-statistics. The study area encompassed 55 ha and consisted of 182 farmer's plots belonging to six production groups in the Yutian county of China. Two hundred and seventeen soil samples were collected on a 50×50-m grid at depths of 0–20 cm prior to the plots being sown for cabbage. Vegetable production history, including varieties, rotation systems and fertilizer use, at the sampling sites was also examined. Soil pH, organic manure (OM), NO₃⁻–N, available P, K, Zn, and other nutrients and particle size were measured. The results showed that N, P, K and Zn were the main limiting nutrient factors in the soil. Distinct semi-variance structures of spatial variability were observed for soil NO₃⁻–N, available P, K and Zn, with the range of spatial correlation being 204–348 m. Significant spatial distribution similarity was found for soil NO₃⁻–N, P, K and Zn, with relatively high contents of all these nutrients in some areas of the study area and relatively low contents in other areas. The correlation of soil NO₃⁻–N, P and K content with vegetable production history and fertilizer application rates (N, P₂O₅ and K₂O) suggested that vegetable variety and history of fertilizer use are important factors to be considered in the development of a soil nutrient management program in the study area.     

Application of solar thermal desorption to remediation of mercury-contaminated soils

Solar thermal desorption at temperatures up to 500 °C is an innovative technology applied to the removal of mercury and arsenic from soil polluted by mining operations. As the soil is heated in a low and high-temperature solar system, the pollutant vapor pressure rises, producing mass transfer to the gas phase, which is then extracted by vacuum pumps and blower systems.In the UPC low-temperature experiments, removal of mercury from the polluted soil was as much as 76%. The experimental results show that volatilization of mercury is only significant when the temperature is above approximately 130 °C, which agrees with the predominant mercury solid phases detected. PSA middle-temperature experiments, showed that when soil and mine waste samples were heated to 400-500 °C, mercury elimination was significant (41.3-87%). However, the results from heating to 320 °C or below 300 °C, indicated little or negligible removal, possibly, because the fluid dynamics in the fluidized-bed module and the presence of cinnabar and pyrite rich-Hg as dominant mineral phases.These results show the potential for efficiently removing mercury and other pollutants from solid matrices (soil, waste, etc.) at low temperatures.     

Synthesis and characterization of a novel soil stabilizer based on biodegradable poly(aspartic acid) hydrogel

A novel soil stabilizer based on poly-amino acid - polyaspartic acid (PASP) and its copolymer which modified by xanthan gum (XG) was studied to increase soil particle compressive strength and resistance to wind erosion. Due to its unique property, the stabilizer aggregated individual soil particles and formed crust. The sample compressive strength increased from 0.175 to 0.612 MPa and the wind erosion modulus reduced from 22.43 to 10.56 g·m⁻²·min⁻¹ after the 1% PASP hydrogel was applied by 1.67 Lm⁻² (1 cm of crust). The soil water content was higher than the control due to the polymer’s excellent water-retaining property. The polymer had no negative influence on seed germination and growth. The biodegradability experiment showed that PASP was easy to biodegrade and therefore it was safe to apply in the field. This work was presented at 13 ^th YABEC symposium held at Seoul, Korea, October 20–22, 2007.     

多钻孔竖直U型埋管换热器传热研究

以地源热泵地下U型埋管四钻孔换热器为研究对象,利用有限元计算方法,编制程序,模拟分析了系统运行时间及钻孔顺序排列和交叉排列时钻孔间距和布置形式对土壤温度场的影响。结果表明:随着运行时间的增长,热干扰现象越强烈,热干扰主要发生在钻孔之间,在两钻孔中间影响最大;从土壤能源利用均衡性角度来讲钻孔交叉排列的形式优于顺序排列的形式。     

浅层地埋管热交换器换热能力分析

采用自主研发的浅层地下岩土热物性测试平台,通过模拟冬夏季取放热实际运行工况,对不同工况下地源热泵地埋管热交换器的换热能力进行了实际测试,分析了地埋管换热器与周围地下岩土之间的换热状况,确定了该地区地源热泵系统地埋管换热器冬夏季工况下的实际单位延米换热量。同时,根据测试数据推算出了该地区地下岩土的综合导热系数,体积热容等热物性参数,为该地区地源热泵系统的模拟分析以及设计施工提供了依据。     

煤田土壤热红外发射率特征及其有机质估算模型

利用傅立叶热红外光谱仪探测煤田土壤的光谱数据和土壤有机质含量数据,分析了原始光谱发射率的特征,求算原始发射率的一阶、二阶导数,分别建立原始发射率、一阶导数、二阶导数与有机质之间的模型,检验和评价了每个模型的适用性。结果表明：(1)土壤的有机质含量随着地表地物类型和周边环境的不同而存在明显差异;(2)无论有机质含量存在多大的差异,热红外光谱发射率随波长的增加的而变化的趋势不变;但土壤热红外光谱的发射率在8-11.5 um范围内最敏感,有机质含量的大小会对其敏感性产生影响;(3)一阶导数、二阶导数的发射率与有机质的相关性明显优于原始发射率数据,发射率数据的导数处理能够有效的增强与有机质之间的相关性,且在该研究区发射率数据的二阶导数与有机质含量相关性最高;(4)一阶导数和二阶导数的热红外光谱发射率与有机质含量之间的拟合函数效果均较为良好,尤其二阶导数发射率的指数函数效果最佳;一阶导数的多元逐步回归拟合模型预测能力略优于线性函数模型。     

水泥土复合式支挡结构探讨

探讨用于基坑支挡的水泥土复合式结构的应用，即对其设计计算方法和设计理论中的一些相关问题提出自己的看法。