添加尿素和无机盐土对秸秆厌氧消化的影响

向厌氧消化体系加入外源添加剂是一种有效且简单的用于提高产气效率的方法。为了解决秸秆厌氧消化原料转化率低、易酸化、厌氧消化时间长等问题,该文选取尿素和无机盐土作为秸秆厌氧消化的添加剂,研究比较不同添加量对玉米秸秆厌氧消化过程产气特性、发酵环境、微生物活性以及物能转化效率的影响。结果表明,对于出现酸化问题且甲烷菌活性较低的厌氧消化系统,添加尿素和无机盐土有利于缓解酸化并促进微生物生长繁殖,三磷酸腺苷(ATP)峰值时的微生物数量可增加2.76×1011-5.31×1011个/L。添加一定量的尿素和无机盐土可使产气高峰提前,添加10%的无机盐土处理组与纯秸秆处理相比,产气高峰可提前4d;但酸化也会削弱尿素和无机盐土对产甲烷过程的促进作用,添加量越大,削弱效果越显著。研究结果可为秸秆厌氧消化的工程应用提供参考。

无机蒙脱土/琼脂复配体系空心胶囊的制备

研究以无机蒙脱土和琼脂复配体系制备空心胶囊的成型工艺。结果表明:其最优的质量比为无机蒙脱土∶琼脂=70∶30。当溶胶温度为90℃,溶胶时间为40min,养胶时间为40min时,胶液的流动性和蘸胶成型性好,胶囊壁厚达到国家药典的相关规定。

无机交联蒙脱土在催化反应中的应用

对近年来Al、Ti、Fe、Zr-交联蒙脱土用于烷烃芳构化、酯化、选择还原NOx、光催化氧化分解有机污染物、Friedel-Crafts反应和醇胺化等反应的研究结果进行了综述。为进一步提高蒙脱土的热稳定性和催化性能,在单一交联蒙脱土研究的基础上,制备多元交联蒙脱土将成为今后的研究重点。

金沙土遗址裂隙灌浆材料比选室内试验研究

为探究适用于金沙土遗址裂隙加固的灌浆材料,选取了烧料礓石、SH(改性聚乙烯醇)和无机矿物聚合物与金沙遗址试验土拌合制备了三种灌浆材料。通过室内试验,对各种灌浆材料结石体试样的基本物理性能、力学性能及耐久性能进行了详细分析。试验结果表明,无机矿物聚合物灌浆材料具有较低的收缩性,能够有效填充裂隙;同时,其较高的抗折和抗压强度为提升土遗址的力学稳定性提供了可靠保障;在研究的三种灌浆材料中,无机矿物聚合物灌浆材料展现出最佳的耐久性能。因此,建议在金沙土遗址的裂隙注浆加固工程中采用无机矿物聚合物灌浆材料,研究成果将为潮湿环境下土遗址裂隙灌浆材料的选择与应用提供有益的指导。

无机结合料稳定粉土性能分析和研究

无机结合料稳定粉土作为路面基层,可以降低我国西部地区农村公路建设造价。对石灰、水泥稳定粉性土的最佳配合比进行了研究,通过室内试验,对其抗压强度和劈裂强度进行了测试,进而评价了无机结合料稳定粉土的强度和水稳定性。

控制UCS条件下的路基无机结合料改良土动力性能评价

针对湖南省四种不同塑性指数(PI)的路基软土,在控制无侧限抗压强度(UCS)为350 k Pa和700k Pa的条件下,研究了采用粉煤灰、石灰、水泥三种无机结合料进行改良的配比组合方案,并对改良土进行了循环加载试验以评价其动力性能(如回弹模量和累积塑性应变)。研究结果表明,各种结合料组合对提高USC的效果排名为:(石灰+水泥)>水泥>(石灰+粉煤灰)>粉煤灰>石灰,为达到目标UCS,土的塑性指数越大,则改良所需的结合料组合排名越靠前。由于素土类型和改良方案的区别,UCS相近的改良土可能呈现较大差异的回弹模量。在同一UCS控制条件下,改良土回弹模量总体随着水/结合料比例的减小而提高,而累积塑性应变则总体随着该比例的减小而降低,回弹模量、累积塑性应变均与土的PI无明显相关性,在7 d的基础上适当延长养护时间可以有效提高回弹模量,在实际工程中,利用改良土应重视压实后的养护工作。

对无机结合料稳定粉土的配合比与性能试验的探讨

采用合理的固化方式，充分利用当地的材料，以稳定粉性土作为路面基层材料，将会取得非常显著的经济效益，有力地推动当地公路建设持续发展。本文对石灰、水泥等无机结合料稳定粉土的最佳配合比进行探讨，并对其路用性能进行评价。

重铬酸钾容量法测定广东省部分地区土壤中有机质含量的研究

土壤有机质是指土壤中以各种形式存在的含碳有机化合物,是评价土壤养分的重要指标。本文用重铬酸钾容量法来测定广东省部分地区土壤中有机质含量,并对测定结果的进行分析探讨。研究发现广东省内的软土的有机质含量,其数据范围相对集中在1%~2%和2%~3%这两个区域,而且,地区靠近海边的有机质含量相对较高。此研究为实验室长期从事大量样品中有机质测定的提供参考。

新型修复用改性土修补性能试验研究

川渝地区有大量生土墙历史文化建筑,其中很多是全国重点保护文物,由于酸雨的侵蚀,这些文物破坏严重,为保护性修复生土墙历史文化建筑,研究在素土里加入水泥、料姜石、环氧树脂等掺和料,制出一种新型的修复用改性土,利用不同配比的掺和料改性土制成土坯试件,并对土坯进行收缩率、色差及耐水性试验研究,发现按照5%(质量分数,下同)水泥、10%料姜石、3%环氧树脂、82%土进行配比的修复用土,具有收缩率小、色差满足要求及耐水性能好的特点.

蒙脱土对铜离子的吸附缓释性能研究

本文利用蒙脱土对金属离子进行吸附性研究,通过改变缓释环境研究蒙脱土的缓释性能,实验结果表明:无机蒙脱土、有机蒙脱土对Cu^(2+)的吸附量分别为7. 848 g/g和7. 889 g/g。在CuSO_4溶液为0. 05 mol/L的条件下,蒙脱土的吸附率随温度升高逐渐降低,随时间增长逐渐变大,5 min后达到饱和吸附。在碱性环境下,缓释溶液最佳浓度为0. 25 mol/L,最佳缓释时间为30 min,无机蒙脱土、有机蒙脱土对Cu^(2+)的缓释量分别为37. 34μg/m L、97. 29μg/m L。在酸环境下缓释30 min,无机蒙脱土、有机蒙脱土对Cu^(2+)的缓释量分别为1. 429μg/m L、2. 35μg/m L。

生态植树机发展综述

分析了机械化植树造林的必要性,介绍了传统植树机的发展概况及一种新型植树造林机械———生态植树机。这种植树机松土时对土壤的扰动小,这也意谓着种植时其养份损失较小、对土壤破坏程度也小,同时可以大幅度降低能耗、提高植树效益。由于有无机土与腐殖质的混合,使树苗有更高的成活率和生长率。生态植树机对生态的破坏是传统开沟植树机的1/7,其能耗是传统开沟植树机的1/2。

Mixing Alfalfa Straw and Maize Straw to Enhance Nitrogen Mineralization, Microbial Biomass and Enzyme Activity: A Laboratory Study

The quality of straw affects N release after straw retention. As straw with high C： N ratio could result in N immobilization, additional N is needed to compensate N demand of crops. However, more and more N fertilizers have been applied to the soil to improve crop yields in China, which not only increases production cost but also reduces soil quality. Therefore, reasonable application of N fertilizer becomes a key problem after straw retention. This study aimed to assess the effects of applying maize straw with high quality alfalfa straw on mineral N content, microbial biomass and enzyme activity under controlled conditions. The effect of applying maize straw with alfalfa straw was compared with that of maize straw in combination with N fertilizer under the same C： N ratio （25：1）. The laboratory incubation experiment consisted of four treatments： （1） soil with no addition （CK）; （2） soil amended with maize straw （M）; （3） soil amended with alfalfa straw and maize straw with an adjusted C： N ratio of 25：1 （MM）; （4） soil amended with inorganic nitrogen fertilizer and maize straw with an adjusted C：N ratio of 25：1 （MF）. The results showed that application of maize straw leaded to an N immobilization during the 270 d of incubation. Combined application of alfalfa and maize straw and or mineral N fertilizer alleviates the N immobilization and increase soil mineral N content. Compared to MF treatment, MM treatment prolonged N availability during the incubation. MM and MF treatments increased the soil microbial biomass carbon and nitrogen contents, and soil invertase and β-glycosidase activities. There was no difference between MM and M treatment in soil urease activity. MF treatment had significantly negative influence on soil urease activity compared with M treatment. The amount of added N significantly affected mineral N content, soil microbial biomass and enzyme activity. The mixture of alfalfa straw and maize straw sustains higher level of mineral N content, microbial biomass and enzyme activity as it had high N input compared to maize straw in combination with N fertilizer. It is concluded that alfalfa straw may be a better N source than N fertilizer in alleviating N immobilization caused by maize straw retention.

Experiment on Organic Ecotype Soilless Culture of Vegetables

A suitable substrate formula for vegetable cultivation was selected through experimenting on the culture substrate for organic ecotype soilless culture of vegetables, and organic matter content of the substrate was 294% as name that of soil, while the content of N, P and K were 328%, 279% and 192% that of the soil, respectively. Vegetable yield with this substrate was 157%-228% that with the soil.

Effects of Substrates before and after Fermenting Treatment on the Growth,Development and Cut Flower Quality of Lily

[Objective] The aim of this study was to explore the effects of substrates before and after fermenting treatment on the growth,development and cut flower quality of lily.[Method] Oriental lily cultivar ＇Siberia＇ was taken as material to study the effect of using fermentative and unfermented agricultural waste as substrates on the growth,development and cut flower quality of lily.And the physical and chemical properties of substrates before and after fermenting treatment were studied.[Result] The full decomposition of agricultural waste would greatly improve the physical and chemical properties of substrates,such as the fermentative substrates changed to stabilization,the ratio of carbon nitrogen had dropped drastically,the total porosity was increase,the ratio of gas and water was better,and the nutrition elements was increased.Moreover,it could significantly increased the plant height,stem diameter,leaf number,leaf area,leaf fresh weight and so on,as well as expanded the lily roots and significantly improved the rate of cut flower and cut flower quality.[Conclusion] This study had provided theoretically basis for the cultivation of cut lily.

Changes in Phosphorus Fractions, pH, and Phosphatase Activity in Rhizosphere of Two Rice Genotypes

A rhizobox experiment with two phosphorus (P) treatments, zero-P (0 mg P kg-1) and plus-P (100 mg P kg-1) as Ca(H2PO4)2·H2O, was conducted to study the chemical and biochemical properties in the rhizosphere of two rice genotypes (cv. Zhongbu 51 and Pembe) different in P uptake ability and their relationship with the depletion of soil P fractions. Plant P uptake, pH, phosphatase activity, and soil P fractions in the rhizosphere were measured. Both total dry weight and total P uptake of Pembe were significantly (P < 0.05) higher than those of Zhongbu 51 in the zero-P and plus-P treatments. Significant depletions of resin-Pi, NaHCO3-Pi, NaHCO3-Po, and NaOH-Pi, where Pi stands for inorganic P and Po for organic P, were observed in the rhizosphere of both Zhongbu 51 and Pembe under both P treatments. Pembe showed a greater ability than Zhongbu 51 in depleting resin-Pi, NaHCO3-Pi, NaHCO3-Po, NaOH-Pi, and NaOH- Po in the rhizosphere. HCl-Pi and residual-P were not depleted in the rhizosphere of both genotypes, regardless of P treatments despite significant acidification in the rhizosphere of Pembe under zero-P treatment. Higher acid phosphatase (AcPME) activity and alkaline phosphatase (AlPME) activity were observed in the rhizosphere of both Zhongbu 51 and Pembe compared to the corresponding controls without plant. AcPME activity was negatively (P < 0.01) correlated to NaHCO3-Po concentration in the rhizosphere of both Zhongbu 51 and Pembe, suggesting that AcPME was associated with the mineralization of soil organic P.

Effects of Inorganic Sodium Salt in Soil on Concentration of Zinc Ion in Different Patterns

[Objective] The aim was to study on effects of inorganic sodium salt in soil on concentration of zinc ion in different patterns. [Method] Tessier sequential extraction was used to study on effects of inorganic sodium salts （in different species and different concentrations） on concentration of zinc ion in different patterns. [Result] Different inorganic sodium salts had different effects on zinc form. Content of ex- changeable Zn would reduce if Na2CO3 or Na2SO4 was added and the content would increase if NaCI was added. Content of carbonate zinc, which was significantly influ- enced by Na2SO4, would increase if NaCI or Na2SO4 was added, and would decrease if Na2CO3 was added. For Zn bound to Fe-Mn oxides and organic matters, and residual Zn, the contents would decrease if NaCI or Na2SO4 was added and the decrease showed much more significantly if high concentration sodium salts were added. In addition, content of Zn bound to Fe-Mn oxides decreased if Na2CO3 was added. If low concentration Na2CO3 was added, Zn bound to organic matters and residual would increase in content but would lower if high concentration one was added. [Conclusion] The research provided references for measurement of heavy metal ion content in soil in different places.

Soil Inorganic Nitrogen and Microbial Biomass Carbon and Nitrogen Under Pine Plantations in Zhanggutai Sandy Soil

The dynamics of soil inorganic nitrogen （NH4^＋ -N and NO3^- -N） and microbial biomass carbon （Cmic） and nitrogen （Nmic） under 30-year-old fenced Pinus sylvestris L. var. mongolica Litvin （SF）, unfenced P. sylvestris L. var. mongolica Litvin （SUF）, and unfenced Pinus densiflora Siebold et Zucc. （DUF） plantations in the Zhanggutai sandy soil of China were studied during Apr. to Oct. 2004 by the in situ closed-top core incubation method. All mentioned C and N indices in each stand type fluctuated over time. The ranges of inorganic N, Cmic, and Nmic contents in the three stand types were 0.7-2.6, 40.0-128.9, and 5.4-15.2 μg g^-1, respectively. The average contents of soil NH4^＋ -N and Cmic under the three 30-year-old pine plantations were not different. However, soil NO3^ -N and total inorganic N contents decreased in the order of SUF ≥ SF ≥ DUF, the Nmic content was in the order of SF = SUF 〉 DUF, and the Cmic：Nmic ratio was in the order of SUF = DUF 〉 SF. Seasonal variations were observed in soil inorganic N, microbial biomass, and plant growth. These seasonal variations had certain correlations with microbe and plant N use in the soil, and their competition for NH4^＋ -N was mostly regulated by soil N availability. The influence of tree species on inorganic N and Nmic were mainly because of differences in litter quality. Lack of gazing decreased the Cmic：Nmic ratio owing to decreased carbon output and increased the ability of soil to supply N. The soil N supply under the P. sylvestris var. mongolica plantation was lower than under the P. densiflora plantation.

Effect of Continuous Vegetable Cultivation on Phosphorus Levels of Fluvo-Aquic Soils

Soil P status, inorganic P fractions, and P sorption properties were studiedusing sandy fluvo-aquic horticultural soils, which are high in organic matter content for vegetableproduction in comparison with a soil used for grain crop production in Zhengzhou, Henan Province,China P fractions, Olsen-P, and OM were determined at different depths in the soil profile andsorption isotherm experiments were performed Most P in excess of plant requirements accumulated inthe topsoil and decreased with soildepth. Total P, inorganic P, and OM concentrations increased withcontinued horticultural use Olsen-P concentrations in the 0-20 cm depth of horticultural soils were9 to 25 times higher than those of the grain crop soil. A linear transformation of the Langmuirequation showed that the P adsorption maximum (491.3 mg P kg^(-1)) and the maximum phosphatebuffering capacity (162.1 L kg^(-1)) for 80--100 cm were greater in the grain crop soil than thehorticultural soils. Thus, the most immediate concern with excess P were in areas where heavy Pfertilizer was used for vegetable crops and where soil P sorption capacities were low due to sandysoils and high organic matter content.