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1.
不同异位发酵床垫料的粪污处理能力比较研究   总被引:3,自引:1,他引:2  
为了比较不同垫料的猪粪水消纳能力,本试验利用微生物异位发酵床技术,以锯末和稻壳为垫料,比较分析不同垫料配比的发酵工艺、发酵产物的理化性质及粪污消纳能力的差异。结果表明:在垫料含水量为70%的情况下,各垫料均能正常发酵。垫料温度整体呈先升高后降低的趋势,各垫料的55℃以上高温期均维持了20天以上,其中稻壳垫料的最高温度达到了69.5℃。垫料发酵过程中为弱碱性,随着发酵时间的增加,不同垫料的有机碳含量变化均不大,但氮含量不断减少,磷和钾含量有所上升。锯末垫料的粪污消纳能力是稻壳垫料的2倍,锯末比稻壳更适合用做发酵床的垫料。  相似文献   

2.
Utilizing relative dynamic elastic modulus and weight loss of concrete as evaluation indices, the frost resistance of concrete with 0.45 water-cement ratio and different recycled aggregate replacement proportions was studied in the water and 3.5% sodium chloride solution. The mass proportions of recycled aggregate are 25%, 50% and 75%, respectively. Furthermore, the frost resistance of the modified concrete with 5% and 10% rubber powder volume fractions replacing fine aggregates was studied. The results show that: the frost resistance of concrete decreases with the increase of recycled aggregate, when the recycled aggregate mass fractions are 25% and 50%, its influence on the frost resistance of concrete is little, and mixing rubber powders can effectively improve the frost resistance of concrete; when the recycled aggregate mass fraction reaches 75%, its effect on the frost resistance of concrete is significant, and mixing rubber powders has certain improvement effect, but compared with the benchmark group of concrete the maximum freeze-thaw cycles decreases more than 30%. In water frozen test, the weight loss is small and the relative dynamic elastic modulus loss is quite obvious. The frost resistance is better when adding 5% volume fraction of rubber powders. In salt frozen test, the main characteristic is the weight loss exceeds the requirements. The frost resistance is better when adding 10% volume fraction of rubber powders. The improvement effect of rubber powder to the frost resistance of concrete in salt solution is much better than that in water.  相似文献   

3.
Prehardening of winter rape, i.e. its early growth in a reduced day temperature (+12°C) from emergence to the beginning of cold acclimation at chilling temperatures (the 1st stage of cold acclimation), has a beneficial influence on frost resistance. In earlier studies it has been demonstrated that during prehardening, plants formed leaf rosettes and increased the photosynthetic efficiency at chilling temperatures. In the present study investigations were carried out on the effect of prehardening on the growth rate of the plants during the 1st stage of cold acclimation, and the progress of selected physiological processes occurring during this stage and resulting in increased frost resistance. It has been demonstrated that a greater inflow of photoassimilates during the 1st stage of cold acclimation results in greater increments of the dry mass of prehardened plants. These plants show also a distinct inhibition both of the elongation growth and the rate of expanding new leaves. The acquired energy is thus spent to a greater extent on the processes associated with increasing frost resistance, and not on growth. In prehardened seedlings, during the 1st stage of cold acclimation, there have been observed in leaves a higher rate of both water content decrease and drop in the osmotic potential of the cell sap and water potential in the tissues. Also an increased accumulation of soluble sugars and free proline was noticed. However, the beginning of these processes was not observed during the prehardening period. Prehardening stimulated the effectiveness of the 1st stage indirectly through changes leading to the increased amount of available energy and enabling the utilisation of the greater part of acquired energy in the cold acclimation process.  相似文献   

4.
A number of lands were occupied by discarding the dredged sludge in the yard as waste materials.The Aeration Vacuum rapid Mud Water Separating (AVMWS) technique was appropriate for discarding yard with high water content and high clay particle content sludge.This technique could quickly reduce the volume of the sludge and accelerate the turnover use of the yard.In addition,the technique could overcome the clogging problem when pumping water from high water content, high clay particle content dredged sludge.Through the sampling particle size distribution tests after AVMWS and conventional vacuum pumping model tests, it was found that in the AVMWS tests the fine grained soil run off, coarse particles accumulated, and arching structure layer was formed.However, in the conventional vacuum pumping tests, fine particles did not lost and there was clogging without arching structure layer.The layer could protect the internal loss of the fine particles and ensure a high permeability of the soil at the same time.And the mechanism was explained as well.  相似文献   

5.
This investigation focuses on influence of ultra low temperature on frost resistance of cementitious material by freeze thaw cycles test in which liquid nitrogen was applied as ambient medium. The appearance, mass and strength change before freeze thaw recycle and after were measured, respectively. Micro structure of cementitious material before and after freeze thaw recycle was tested by using scan electron microscope (SEM). It is found that, under the condition of ultra low temperature, frost resistance of concrete is better than that of mortar. And the frost resistance of concrete increased with the improvement of concrete strength. The SEM results reveal the structure defect is produced clearly when specimen freeze in liquid nitrogen and thawed in water. It is concluded that freeze thaw recycle with ultra Low temperature is an effective quick method to evaluate the frost resistance of cementitious material because destroying progress was accelerated and experimental time was redned.  相似文献   

6.
沟垄和覆膜连作种植对马铃薯生长、产量及品质的影响   总被引:3,自引:0,他引:3  
为了探明不同沟垄覆膜连作种植对马铃薯生长特征及品质影响的差异,以当地主栽品种‘新大坪’为试验材料,研究了平畦不覆膜(CK)、平畦覆膜(T1)、全膜双垄垄播(T2)、全膜双垄沟播(T3)、半膜沟垄垄播(T4)、半膜膜侧种植(T5)6种栽培模式连作种植对马铃薯生长、产量及品质的影响。结果表明,与CK相比,沟垄和覆膜栽培能显著促进连作马铃薯生长,且T3处理促进作用最大;并能显著提高连作马铃薯产量,增产幅度为1.5%~29.8%,其中T2处理产量最高。沟垄和覆膜处理马铃薯薯块氨基酸总量和还原糖含量较CK存在显著差异,其中CK的氨基酸总量最高,T4的还原糖含量最高;而薯块干物质、蛋白质及淀粉含量差异未达到显著水平。  相似文献   

7.
In faba bean, field based winter-hardiness is a complex trait that is significantly correlated to frost tolerance. Frost tolerance could be used to indirectly select for faba bean winter-hardiness. The aim of this study was to identify putative QTL associated with frost tolerance and auxiliary traits and to quantify the efficiency of marker assisted selection. Thus, 101 recombinant inbred lines derived from the cross between two frost tolerant lines were tested for their hardened and unhardened frost tolerance and for their leaf fatty acid content in both treatments. Significant differences among the RIL were observed for all studied traits. For frost tolerance, five putative QTL were detected; three for unhardened frost tolerance that explained 40.7% (8.6% after cross-validation, CV) of its genotypic variance and two for hardened frost tolerance that explained 21.8% (1.0% after CV). For fatty acid content, three QTL were detected for oleic acid content in unhardened leaves that explained 62.9% (40.6% after CV) of its genotypic variance. This fatty acid was significantly correlated with unhardened frost tolerance. The unbiased genotypic variance explained enabled to draw realistic prospects of MAS for frost tolerance. In this study, combined MAS was more efficient than classical phenotypic selection and was expected to be higher on larger populations at early generations. Moreover, favourable alleles inherited from the exotic line BPL 4628 could be introgressed to European winter-hardy beans for further improvement.  相似文献   

8.
The effect of cold acclimation on the water status and the fate of carbohydrates was studied in white clover (Trifolium repens L., cv Huia) subjected to chilling and/or freeze-thaw cycles. Treatments were applied in a controlled environment, with a constant photoperiod, for 6 weeks to plants either acclimated or non-acclimated to low temperature.

Cold acclimated plants had a higher concentration of starch in the stolons at the end of the acclimation period than non-acclimated plants (54 vs. 15 mg g−1 DW). During the experiment, the leaves of cold acclimated plants subjected to frosts maintained a higher relative water content (RWC) than did leaves of plants not acclimated for which we observed a strong dehydration of 80%.

Under chilling, cold acclimated plants demonstrated an osmotic adjustment. We showed that only 30–40% of the variation of the osmotic potential was explained by variation in free sugar concentration, suggesting that compounds other than carbohydrates participated in the osmotic regulation.

Chilling increased the carbohydrate content and frost decreased the starch concentration in non-acclimated plants only.

We showed in white clover that the cold acclimation contributed to frost and chilling tolerance by the maintenance of the hydration of tissues. We demonstrated that osmotic adjustment was not completely explain by the accumulation of free sugars.  相似文献   


9.
武威市霜冻变化特征及其对农作物的影响   总被引:1,自引:1,他引:0  
为增强气象为农服务能力,减少霜冻造成的损失,笔者以1961—2015年武威市各县(区)霜冻和农作物生育及产量资料为基础,分析了霜冻特征及灾害发生的概率和影响。结果表明:(1)55年来武威市各县(区)初霜日推迟17~23天,终霜日提前20~29天,无霜期延长天数达39~48天;变异系数:无霜期终霜日初霜日;(2)终霜日60年代到90年代多为正距平,21世纪以来多为负距平;而初霜日和无霜期60年代到90年代多为负距平,21世纪以来为正距平;60、70年代距平变幅较大;(3)从霜冻出现时平均地面最低气温看,发生重霜冻害概率民勤9%,凉州2%;发生中霜冻害概率民勤7%,凉州7%,古浪2%;而发生轻霜冻害概率民勤84%,凉州91%,古浪98%;(4)霜冻对喜温作物春玉米的影响明显大于春小麦,且春玉米三叶—七叶期是霜冻危害最敏感的时期,初霜日越早、无霜期越短,春小麦、春玉米和粮食作物易受早霜冻害影响产量;而终霜日越晚,农作物遭受晚霜冻害风险提高。  相似文献   

10.
干旱胁迫对杂种马褂木形态特征的影响   总被引:1,自引:1,他引:0  
杂种马褂木(Liriodendron chinense×L. tulipifera)是一种生长快、材质好、树形美、观赏价值高的优良树种,现已广泛应用于园林绿化和用材林培育。为了了解杂种马褂木的抗旱性,笔者对南京市8年生的杂种马褂木在夏季干旱条件下的生长情况进行了调查研究。结果表明,杂种马褂木具有较强的抗旱性,但是在严重的干旱胁迫下,杂种马褂木叶片含水率和叶绿素含量明显降低,叶片发生黄化和脱落。在下蜀黄土上,如果土壤含水率低于12%,杂种马褂木会出现明显的叶片黄化和脱落现象,故在土壤含水率降低到12%之前有必要补充水分。  相似文献   

11.
土壤含水量对牡丹光合特性的影响   总被引:23,自引:4,他引:23  
以盆栽牡丹朱砂磊为试材,研究了5种土壤相对含水量(SRWC)对牡丹光合特性的影响。结果表明,随着土壤水分胁迫程度的增加,光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)逐渐下降,表观量子效率(AQY)、CO2羧化效率 (CE)、光饱和点降低;光补偿点及CO2补偿点升高。干旱胁迫下,光合速率的下降是气孔因素与非气孔因素双重作用的结果:轻度干旱胁迫下(土壤相对含水量55%-40%)气孔限制是光合速率下降的主要原因,而严重干旱胁迫下(土壤相对含水量20%)非气孔限制是光合速率下降的主要原因。牡丹光合作用的最适SRWC为70%左右。  相似文献   

12.
早生抗寒优质茶树新品系“茶农1号”的选育   总被引:3,自引:1,他引:3  
以经N+离子诱变后的槠叶齐茶种子为原始材料,经系统选种和无性繁殖,育成了早生优质抗寒茶树良种茶农1号。经1998—2003年品种比较实验,结果表明:该品系春季萌发期特早,与对照皖农95相比,同期萌展值大0.39~0.96,与福鼎大白茶相比,同期萌展值大0.35~0.57;鲜叶中生化成分含量丰富,其中多酚含量28.22%、氨基酸含量1.51%,咖啡碱含量4.81%,水浸出物含量44.82%,茶多糖含量1.55%;各成分比例协调,绿茶品质佳,尤以香气和滋味表现突出;抗寒性强,对倒春寒的抗性也强。实验结果提示:N+注入是一种有效的茶树良种选育方法。  相似文献   

13.
The frost resistance of steel fiber reinforced concrete (SFRC) was studied based on the fast freeze thaw tests in water and in a 3.5% sodium chloride solution, with different mass fraction of steel fiber in concrete at 0%, 0.5%, 1.0%, 1.5% and 2.0%, respectively. The effects of the number of freeze thaw cycles and the volume fraction of steel fiber on the mass lose rate, the splitting strength loss rate and the dynamic modulus of elasticity of SFRC were analyzed. The reinforcement mechanism of the steel fiber under the action of freeze and thaw was also discussed. Moreover, mercury intrusion method and SEM analysis were carried out to study the pore size distribution features and the performance of microstructure on the impact of frost resistance of SFRC. The results show that adding an appropriate amount of steel fiber into concrete can reduce the pore porosity and improve the compactness of concrete. Furthermore, the presence of steel fiber proves to shrink the porosity and improve evidently the frost resistance of concrete. It is also shown that the steel fiber content has a great influence on the frost resisting property of SFRC. The best performance of SFRC can be achieved when the volume fraction of steel fiber is 1.5%.  相似文献   

14.
不同土壤含水量对菲油果幼苗生长及生理生化特性的影响   总被引:1,自引:0,他引:1  
为了探索菲油果幼苗生长所需的最适土壤水分条件,对所试材料的耐性进行初步研究,采用不同梯度的土壤水分含量(20%、40%、60%、80%)分别对1年生菲油果扦插苗进行栽培处理,正常管理作为对照。通过对菲油果幼苗生长特性及生理生化特性,如过氧化物酶(POD)和超氧化物歧化酶(SOD)的活性等指标的测定,研究菲油果幼苗对不同土壤含水量的耐受特性,并探索菲油果适宜生长的水分含量区间。结果表明,在不同含水量处理下,菲油果幼苗均可以生长;当水分含量高于80%时出现淹水胁迫,表现为茎干生长过快,其POD、SOD活性也随着胁迫时间的延长表现为持续上升;水分含量低于20%时出现干旱胁迫,菲油果则表现出生长受到抑制,POD、SOD酶活则随着胁迫的加剧,均出现先降低后增加的趋势。菲油果在40%~50%的土壤质量含水量范围内生长最为健壮;所试材料在一定时间内(50天)对不适宜的含水量具有一定耐性。  相似文献   

15.
以转铜锌超氧化物歧化酶(Cu/Zn SOD)和抗坏血酸过氧化物酶(APX)基因甘薯(TS)及未转基因甘薯(NT)为实验材料,研究在旱后复水条件下转基因甘薯及未转基因甘薯抗氧化防御系统变化。结果显示,连续36h胁迫条件下,TS和NT的SOD活性都先降低后升高,但TS的SOD活性始终高于NT。胁迫至24h时,TS的SOD活性约为NT的1.2倍,复水后二者SOD活性都下降。持续胁迫时,TS的APX活性先升高后降低,NT与之相反,复水后TS和NT的APX活性都是先升高后降低,复水12h,TS的APX活性是NT1.5倍。在水分胁迫条件下,TS抗氧化物质AsA、CAR增长速度较快,复水后,TS中的AsA含量仍显著高于NT水分胁迫条件下TS的膜质受伤害程度要轻于NT,胁迫24h,复水12h,NT的MDA含量均约为TS的1.2倍。实验结果表明,同时转入SOD、APX抗氧化基因后,在胁迫及复水条件下转基因甘薯的抗氧化系统可以更好的对植株体进行保护及修复。  相似文献   

16.
黄土高原杨树人工林的细根生物量与碳储量研究   总被引:1,自引:0,他引:1  
闫美芳  王璐  郭楠 《中国农学通报》2015,31(35):146-151
为了解细根生长、周转及其对土壤碳库的贡献,以太原地区杨树人工林(Populus tomentosa)为研究对象,采用连续取土样法及分解袋法,研究了细根(< 2 mm)的垂直分布、季节动态、年生产量及碳储量。结果表明:0~40 cm土层细根生物量为241.8 g/m2,其中活细根生物量为168.0 g/m2,约占细根总生物量的69.5%。细根主要集中于0~10 cm土层,且随土层加深而递减。细根生物量还具有明显的季节变化,最大值出现在8月,最小值出现在4月。细根年分解量为35.3 g/m2,年死亡量为98.2 g/m2。细根年生产量估计为216.6 g/m2,年周转率为1.29次。0~40 cm土层细根总碳储量为97.4 g?C/m2,每年由于细根死亡向土壤碳库输入的碳量约为39.6 g?C/m2。土壤全氮含量和土壤含水量是影响细根垂直分布的主要因素,而细根季节动态与土壤水分及气候特点密切相关。由于本研究区地处黄土高原,土壤水分短缺是导致细根生产量偏低的主要原因,且影响细根周转及其向土壤有机碳库的碳输入。  相似文献   

17.
霜监测模型的探讨——以湖南省为例   总被引:1,自引:1,他引:0  
为了实现基于区域气象站观测资料进行霜的精细化监测和利用高分辨率数值预报产品开展霜的精细化预报,运用湖南省97个地面气象观测站建站至2012年4月逐日最低气温、降水量、相对湿度、风速、日照、总云量、天气现象资料,在全面分析了霜形成的气象条件的基础上建立了湖南省霜监测模型,开展了霜监测模型误差比对分析。结果表明:在日最低气温小于等于3℃条件下,分段考虑不同气象要素临界阈值对霜模拟准确率的提高有较大作用;建立的霜监测模型与霜观测结果的误差小于通用监测指标;霜监测模型模拟的的初霜日、终霜日、无霜期、霜日与观测值空间分布形态、年代际变化趋势都较为一致;该模型可用于开展霜的监测、预报。  相似文献   

18.
弹性波作用下渗流多孔介质微粒运移分析是对目前静态流体或稳态多相渗流中微粒运移/捕集的补充,通过分析弹性波对微粒剥离运移捕集过程的影响,建立弹性波作用下微粒运移模型,得到对微粒运移效果和储层物性变化的影响规律。由推导得到的弹性波作用下微粒剥离临界速度可知,当微粒与孔喉半径的比值越小时弹性波导致的振荡附加力影响越大,临界速度与流体粘度、微粒/孔喉半径比成负相关,与基质胶结程度、结构力、微粒半径、微粒密度成正相关。弹性波作用下微粒运移模型需同时考虑多孔介质渗流速度的变化,此时微粒剥离释放速率增加,但随着波衰减和时间延长而降低,微粒在孔隙表面沉积滞留速率先上升后下降,喉道堵塞的速率有所上升,说明弹性波作用下微粒的剥离和悬浮能力增加,但亦增加了微粒在微细孔喉"架桥"堵塞的可能性。研究结论对岩石物理学和工业化波动处理涉及的储层物性研究具有一定指导意义。  相似文献   

19.
Frost tolerance is a main component of winter-hardiness and improving it would promote faba bean (Vicia faba L.) cropping in cool-temperate regions. In many species, leaf fatty acid composition was found to be related to frost tolerance. The objective of this study was to determine, in a representative sample of genotypes, the effect of hardening on leaf and stem (1) frost tolerance and (2) fatty acid composition, and to seek correlations between them. First leaf, second leaf and stem of 31 faba bean genotypes were analyzed after hardening and without hardening. High frost tolerance of known winter genotypes and several experimental lines was shown. Hardening had a significant, positive effect on frost tolerance of all three organs. Stems were on average more frost tolerant than leaves. Hardening induced significant changes in the fatty acid composition: oleic acid decreased significantly in leaves by 3.24% and in stems by 1.77%, whereas linolenic acid increased in leaves by 6.28% and in stems by 9.06%. In stems, correlations between frost tolerance and fatty acid composition were not significant. Correlation coefficients strongly indicated that non-hardened oleic acid content, changes in oleic acid and in linoleic plus linolenic acid content in leaves partly explained their frost tolerance; 0.347 (P < 0.1) < |r| < 0.543 (P < 0.01). The results corroborate the importance of using genetic differences in the fatty acid metabolism in breeding grain legumes for frost tolerance.  相似文献   

20.
香菇精粉喷雾干燥工艺研究   总被引:2,自引:0,他引:2  
鲜香菇经清洗、破碎打浆、胶磨、均质、加热后喷雾干燥,可得富含香菇营养成分的香菇精粉。通过对影响喷雾干燥效果的因素进行研究,得到了最佳的工艺参数,即物料需经均质处理,雾化器频率为70Hz,蠕动泵转速为25r/min,进风温度220℃,料水比为1∶1.5。在此条件下,香菇精粉得率为9.47%,固形物回收率为72.9%。香菇精粉水分含量为5.1%,灰分含量为7.7%,蛋白含量为31.4%,多糖含量为19.0%。  相似文献   

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