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1.
中国水稻土的粘土矿物 总被引：1，自引：0，他引：1
应用X射线衍射法、差热分析法和化学分析法,鉴定了中国主要水稻土区的近六十个土壤标本。粘粒系小于2微米的部分。水稻土的粘土矿物组成与其母质有密切关系,在一般情况下,它继承了母质的矿物组成。不同母质发育的水稻土的主要粘土矿物组成可见表17。水稻土形成过程中粘土矿物组成的变化可分为三种不同的情况:富有含钾矿物的母质发育成水稻土时脱钾作用明显,粘土矿物有较大的变化。中量含钾矿物的母质发育成水稻土后,粘土矿物组成的变化很小。没有含钾矿物的砖红壤发育的水稻土,在成土过程中有明显的复硅和复盐基作用,在老水稻土中,三水铝石减少,同时出现了濛脱类矿物。水稻土表层与心土层的粘土矿物组成,只有少数土壤有明显差别,大多数看不出差别来。水稻土的潜育层与其上部土层比较起来,除氧化铁含量有显著减少以外,粘土矿物组成基本上是相同的。因此潜育作用的实质主要是部分游离氧化铁的还原,淋失,而粘土矿物并未遭受特别强烈的破坏。根据粘土矿物的异同,暂时将中国水稻土分为四个地理区:以高岭类(三水铝石)为主的华南水稻土区,也就是热带和南亚热带双季稻地区,以高岭类(云泰、濛脱类)为主的华中水稻土区,也就是中亚热带双季稻地区,以濛脱类和云泰(高岭类)为主的长江中、下游水稻土区,也就是北亚热带稻麦两熟地区,以云泰(濛脱类)为主的华北水稻土区。由于水稻土的粘土矿物组成仍受其前身——地带性土壤的影响,因此上述各区的粘土矿物组成,也反映出地带性的特征。 相似文献
2.
水蚀风蚀交错区土壤养分特征与土壤质地及水分关系 总被引：4，自引：0，他引：4
黄土高原水蚀风蚀交错区在强烈的水蚀风蚀作用下,土壤养分流失严重,土壤退化明显。但不同的土地利用方式,这种退化规律有较大的差异。以位于黄土高原水蚀风蚀交错区的六道沟小流域为研究区,分析坡耕地和荒草坡地土壤养分特征,探讨土壤养分与土壤质地及水分的相关性。结果表明:(1)水蚀风蚀交错区各养分含量都较低,其养分含量表层均高于下层,坡耕地高于荒草地;土壤各养分上下层比值越大,土壤的供肥持续能力越差;(2)坡耕地土壤养分含量表现出与坡地水土流失相似的规律,从坡顶部到坡底呈现先减小后增大的趋势;(3)土壤水分含量影响土壤质地变化,并与土壤有机质和全氮关系最好,与有效态氮的关系较密切;(4)土壤养分含量与土壤质地的吸附作用有关,组成物质越细,吸附能力越强,但这种吸附能力还与不同粒级组成的比重有关,其机理有待于进一步研究。 相似文献
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5.
新疆阿勒泰山区土壤形成特征有有机物质积累特征、粘化特征、钙积特征、盐积特征和相应的化学组成及粘土矿物特征。ba值0.99~2.41,粘粒Sa 3.53~4.84,Saf 2.63~3.57,土壤淋溶风化程度不高,R2O3在山地棕色针叶林土、山地灰色森林土中略有移动,粘土矿物以蒙脱石、伊利石为主。本区山体高大,土壤垂直分布完整,东西差距显著,具有温带荒漠草原土壤垂直分布的典型特征,在干旱中温带的山地土壤中有代表性。 相似文献
6.
长期定位施肥对非石灰性潮土粘土矿物组成及主要理化性质的影响 总被引：1，自引：0，他引：1
土壤粘土矿物中层状硅酸盐与氧化物共存及晶质和非品质共存。土壤中含钾的粘土矿物主要有水云母、蛭石和绿泥石等。这些粘土矿物影响土壤钾素的固定和释放，进而影响土壤钾的生物有效性。有研究表明，土壤中的层状硅酸盐矿物彼此之间存在着一种相互演变的关系。例如在云母风化初期，通常会出现水化云母，在钾比较丰富的条件下，就会出现伊利石；水化云母进一步风化并释放出更多的钾以后，则形成蛭石和蒙脱石。相反，蛭石和蒙脱石在吸收了钾离子并脱水后，也可以向伊利石及云母类矿物转变。 相似文献
7.
长期定位施肥对非石灰性潮土钾素状况的影响 总被引：12，自引：7，他引：12
利用22年肥料长期定位试验,研究施肥对土壤钾素状况的影响。结果表明,1978年到2000年,土壤钾素收支平衡的状况为:氮钾肥处理钾盈余57.72kg/hm2,氮磷钾肥处理钾亏缺192.90kg/hm2。以氮钾肥处理提高土壤中水溶性钾、非特殊吸附钾、特殊吸附钾、矿物钾最多,依次分别比对照提高5.49倍、1.13倍、2.47倍和1.11倍。氮磷钾肥和氮钾肥处理在土壤中积累各形态钾总量分别占施钾量的19.18%、20.01%。氮钾处理和氮磷钾处理土壤速效钾和土壤缓效钾含量高,在土壤剖面中分布以0—20cm含量高,20cm以下逐层降低。用X-射线衍射测定长期施钾和不施钾的土壤粘土矿物组成为:氮磷钾处理土壤粘土矿物中蒙脱石峰值高;而氮磷处理土壤粘土矿物中蛭石峰值高。 相似文献
8.
黄土高原水蚀风蚀交错区治理的重要性与紧迫性 总被引：32，自引：0，他引：32
在全国范围划分水蚀、风蚀和冻融侵蚀三大侵蚀类型区基础上 ,提出进一步划分水蚀风蚀交错区的必要性及重要意义。黄土高原的强烈侵蚀中心出现在水蚀风蚀交错区 ,该区为黄河粗泥沙的主要来源区 ,生态环境脆弱 ,自然灾害频繁。该区又为世界级大型煤田蕴藏地 ,将建成我国 2 1世纪的能源重化工基地。强化水蚀风蚀交错区综合治理 ,对治黄及西部地区开发具有重大意义。 相似文献
9.
植物根系强化黄土土层化学风化速率的作用 总被引：4，自引：0，他引：4
黄土的风化主要为植物群落根系的物理作用及其所引起的生物化学作用。利用原状土柱淋滤实验装置及大型挖掘剖面壁法,在陕北黄土丘陵沟壑区进行野外实验研究,定量分析了林、草和农地土壤化学风化的剖面特征及动力学过程。研究结果表明,黄土土层的化学风化具有明显的垂直剖面分异特征,即风化速率随土层深度增加而递减。土壤化学风化的动力学过程可划分为急剧减小和稳定状态两个阶段。不同植被类型土壤风化速率及主导风化矿物组合类型的剖面差异主要受制于直径≤1mm的须根在剖面中的缠绕分布特征。植物根系对土壤风化作用的强化效应为油松林群落>白草群落;油松林群落和白草群落根系显著提高矿物风化速率的稳定土层深度范围分别为0～45cm和0～30cm,有效根密度分别在17根/100cm2和60根/100cm2以上。 相似文献
10.
根据河北省第一次全国水利普查成果,对张承地区土壤侵蚀面积、类型、强度、水土保持效果进行了分析,得出如下结论:张承地区是河北水土流失最为严重的地区,土壤侵蚀面积排前三位的区(县)分别为围场县、丰宁县和康保县;水力侵蚀占主导地位,风力侵蚀集中分布在河北坝上地区;土壤侵蚀区可分为风蚀为主水蚀为辅区、风蚀水蚀交错区、水蚀为主风蚀为辅区和水蚀区4个分区;轻度侵蚀面积最大,中度侵蚀次之,强烈、极强烈、剧烈侵蚀面积较小,并逐级减少;1995—2011年水土流失面积呈现逐年减少的趋势,并根据坝上高原区、冀北山地区和冀西北黄土丘陵区的地貌类型特点,提出土壤侵蚀防治建议。 相似文献
11.
Ambani R. Mudau Hintsa T. Araya 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2019,69(1):26-35
Baby spinach is rich in phytochemicals that provide great benefits to consumers’ health. The study aim was to investigate the effect of the growth harvest stage, postharvest storage duration and temperature on quality of baby spinach leaves. A 3?×?5?×?3 factorial experiment was laid out in a randomised complete block design with four replicates per treatment. The treatments were arranged as follows namely: stage I [28 days after sowing (DAS)], stage II (35 DAS)and stage III (42 DAS), and leaves were kept up to 12 d at three different temperatures – 4, 10 and 20°C. The study demonstrated that the overall appearance and odour were both well maintained in the leaves of baby spinach harvested at stage II. The baby spinach harvested 28 DAS led to higher content of iron [1.13?mg?g?1 dry weight (DW)], magnesium (14.4?mg?g?1 DW), and zinc (0.17?mg?g?1 DW). The highest level of total antioxidant activity (0.43?mg?g?1 DW) and flavonoids (12?mg?g?1 DW) after 12 d of storage was observed in baby spinach leaves at stage I when stored at 4°C. Therefore, baby spinach leaves harvested 28 DAS and store at 4°C for 6 d improved shelf life and nutraceutical quality. Thus, early harvest of fresh produced baby spinach harvested in order to attain high phytochemical and mineral content when stored at low temperature (4°C) without exceeding 6 days is recommended. 相似文献
12.
LI Zhao-Jun XIE Xiao-Yu ZHANG Shu-Qing LIANG Yong-Chao Institute of Agricultural Resources Regional Planning Chinese Academy of Agricultural Sciences Key Laboratory of Crop Nutrition Fertilization Ministry of Agriculture of China Beijing 《土壤圈》2011,(2)
Extensive worldwide use of oxytetracycline (OTC),a member of the tetracyclines,has resulted in its accumulation in soils,posing a potential risk to food production and safety.A pair of OTC-sensitive (Heyou 1) and OTC-tolerant (Yannong 21) wheat (Triticum aestivum L.) cultivars was compared hydroponically at 0.01,0.02,0.04,and 0.08 mmol L-1 OTC in terms of wheat growth and photosynthesis.Biomass and shoot length decreased significantly with the addition of OTC,with the decreases in dry biomass and shoot leng... 相似文献
13.
采用x射线衍射分析方法,对辽宁地区发育于不同母质上的古红土的粘土矿物特性进行了研究,结果表明:辽宁各种母质发育的古红土的粘土矿物中都含有伊利石、1.4nm过渡矿物和高岭石,片麻岩和千枚岩发育古红土中还含有较多量的蛭石,第四纪水成沉积物发育的古红土中含有少量的蒙脱石。辽宁古红土粘土矿物的组成反映了不同于现代成土环境的古环境特征,现代的环境条件对古红土的某些性质已经产生了影响。在辽宁各种母质发育的古红土的粘土矿物组成中,1.4nm过渡矿物的地位比较突出,片麻岩发育的古红土的蛭石含量也很突出,有着不同于南方和黄土高原的特点。从土壤发育程度上讲,相似母质发育的辽宁古红土低于南方红壤,同黄土高原古土壤的发育程度基本相当。 相似文献
14.
土壤抗生素污染对小麦生长和光合参数的影响 总被引：5，自引：0，他引：5
Extensive worldwide use of oxytetracycline (OTC),a member of the tetracyclines,has resulted in its accumulation in soils,posing a potential risk to food production and safety.A pair of OTC-sensitive (Heyou 1) and OTC-tolerant (Yannong 21) wheat (Triticum aestivum L.) cultivars was compared hydroponically at 0.01,0.02,0.04,and 0.08 mmol L-1 OTC in terms of wheat growth and photosynthesis.Biomass and shoot length decreased significantly with the addition of OTC,with the decreases in dry biomass and shoot length being 5.61%-13.75% and 3.33%-8.57% larger,respectively,for Heyou 1 than Yannong 21.Photosynthesis of Heyou 1 was suppressed by OTC as indicated by the significant decreases in photosynthetic rate (PN),transpiration rate (TR),and stomatal conductance (GS) and the significant increase in intercellular CO 2 concentrations (CI),at all OTC levels.Stomatal limitation (LS) and water use efficiencies (WUE) of Heyou 1 also increased significantly,but not at 0.08 mmol L-1 OTC.However,photosynthesis of Yannong 21 was suppressed by OTC only at high OTC levels from 0.02 to 0.08 mmol L-1 as indicated by the decreases in PN,GS,TR,and LS;at 0.01 mmol L-1 OTC,PN,CI,GS,and TR significantly increased.It was noted that WUE of Yannong 21 was not affected by OTC addition.The results from this hydroponic test suggested that OTC had a potential risk to crop growth through inhibition of photosynthesis,requiring further confirmation with soil tests. 相似文献
15.
Muñoz-Pallares J Corma A Primo J Primo-Yufera E 《Journal of agricultural and food chemistry》2001,49(10):4801-4807
Modification of the chemical and structural properties of zeolites has led to the preparation of an optimized zeolitic dispenser for insect attractants such as n-decanol and trimedlure. The impact of zeolite variables such as the framework Si/Al ratio, nature of compensating cation, nature and strength of acid groups, and pore dimensions on the kinetics of emission has been studied, and the results are as follows. Zeolite pore dimensions and the presence or absence of acid sites have the greatest effect on the rate of release, decreasing with decreasing pore diameter and increasing acidity. Further tuning of the release characteristics is achieved by controlling the polarity and the polarizability of the framework by increasing the Si/Al ratio and nature of the compensating cations, i.e., the higher the polarizability and the lower the polarity, the slower the release of attractants. 相似文献
16.
Color-generating reactions of protein-bound lysine with carbohydrates were studied under thermal as well as under physiological conditions to gain insights into the role of protein/carbohydrate reactions in the formation of food melanoidins as well as nonenzymatic browning products in vivo. EPR spectroscopy of orange-brown melanoidins, which were isolated from heated aqueous solutions of bovine serum albumin and glycolaldehyde, revealed the protein-bound 1,4-bis(5-amino-5-carboxy-1-pentyl)pyrazinium radical cation (CROSSPY) as a previously unknown type of cross-linking amino acid leading to protein dimerization. To verify their formation in foods, wheat bread crust and roasted cocoa as well as coffee beans, showing elevated nonenzymatic browning, were investigated by EPR spectroscopy. An intense radical was detected, which, by comparison with the radical formed upon reaction bovine serum albumin with glycolaldehyde, was identified as the protein-bound CROSSPY. The radical-assisted protein oligomerization as well as the browning of bovine serum albumin in the presence of glycolaldehyde occurred also rapidly under physiological conditions, thereby suggesting CROSSPY formation to be probably involved also in nonenzymatic glycation reactions in vivo. 相似文献
17.
该文对蔗渣在温和条件(75～95℃)下转化制备5-氯甲基糠醛(5-CMF)的一锅法反应进行了研究,考察了AlCl3、LiCl、NaCl、KCl、MgCl2、CaCl2、BaCl2、CrCl3、NiCl2和FeCl3的催化效果,并利用GC-MS、1HNMR和FT-IR对目标产物进行了表征。研究结果表明:供试用的金属氯化物都具有一定的催化效果,其中AlCl3的催化效果明显优于碱金属、碱土金属和过渡金属氯化物;以AlCl3为催化剂,考察了反应温度、反应时间和AlCl3浓度对5-CMF产率的影响。得到反应的最佳条件为反应温度85℃,反应时间3h和AlCl3质量浓度为6.0g/L。在最优反应条件下5-CMF的产率为72%。该研究结果,对利用各种纤维素废弃物,开发潜在的生物汽油具有重要价值。 相似文献
18.
Stijn Spaepen Joost Van Durme Frederik Das Sebastian Maurer-Stroh Frederic Rousseau Joost Schymkowitz Jos Vanderleyden 《European Journal of Soil Biology》2009,45(1):81-87
2,6-Dibromophenol (DBP) was reported as an auxin-like molecule using molecular quantum similarity measures. In this study, the auxin activity of this molecule and its chlorinated homologue is further determined using a bacterial biosensor: the auxin-inducible ipdC promoter of Azospirillum brasilense. We were able to demonstrate that DBP can induce gene expression, but to a lesser extent than the auxin indole-3-acetic acid (IAA) and that DBP is not an antagonist for the IAA signalling pathway. To investigate the role of the bromine groups, the molecule 2,6-dichlorophenol (DCP) was also tested for gene expression induction. However, no induction could be observed. In a second part, DBP and other molecules were modelled in the auxin-binding pocket of the plant auxin receptor TIR1 to evaluate theoretical binding energies. Both DBP and its chlorinated homologue DCP are not strong ligands compared to other known auxins such as IAA. The importance of a carboxylated side chain for optimal binding (and probably auxin activity) was demonstrated. 相似文献
19.
Jean-François Ponge 《Biology and Fertility of Soils》2015,51(6):645-648
20.
The agricultural use of pesticides leads to diffuse pollution whereby the various contaminants of the soil infiltrate into
the groundwater reaching lakes and drinking water aquifers. Due to the extensive application of these chemicals, their leaching
presents a high environmental risk.
Since the adsorption coefficient (K) characterizes the soil / water partitioning [1] and is also representative for leaching,
the first step in understanding of the environmental fate of a pollutant is to study its adsorption properties. Weak binding
to the soil constituents (low K) leads to groundwater pollution, while a strong binding (high K) results in surface water
pollution through the erosion of the soil.
Acetochlor is a widely used herbicide all over the world. Similar to other organic pollutants, the environmental fate of this
chemical is strongly related to its adsorption properties.
Static adsorption equilibrium measurements were carried out at 25°C on different types of Hungarian soils (chernozem, brown
forest and sandy soil) characterized by varying amounts of organic matter and pH values.
Acetochlor solutions were prepared in the presence of nitrate and phosphate ions (0.1 mol/L sodium nitrate and 0.1 mol/L phosphate
uffer, pH=7) which are constituents of fertilizers occurring in high concentrations in the environment. In order to appreciate
their effect, adsorption studies were also performed in pure aqueous medium. The equilibrated liquid was analyzed after centrifugation
by two different methods (Total Organic Carbon measurement, High Performance Liquid Chromatography).
Isotherms obtained under different conditions, as well as on various soils, exhibit a similar shape, thus indicating a two-step
adsorption process. The plots cannot be interpreted according to the classes of isotherms suggested by Giles (H-, L- and C-type,
[2]). The adsorption coefficients were estimated from the initial slope of the curves. These values were determined not only
by the type of the soil, but also by the composition of the aqueous media.
Due to the low value of the adsorption coefficients, the acetochlor is a rather mobile pollutant of the soil posing a potential
danger to the aquatic environment.
The organic matter adsorption coefficients (Kom) [3] were also calculated and they were approximately identical for soils of high organic matter. For the chernozem and brown
forest soils, the values of the K and Kom parameters are increasing in the order from water < phosphate buffer < sodium nitrate.
For soils of low organic content, the similarity of the Kom values cannot be expected (due to the hyperbolic nature of the equation) as the data really indicate it for the adsorption
behavior of the sandy soil. Here, the organic matter plays a less important role and the adsorption is controlled by the solute
/ inorganic substance interactions. This conclusion is nicely proved by the adsorption of the acetochlor on quartz resulting
thereby in a similar plot being obtained for the soils.
According to the hypothesis presented here, the first step of the isotherms is controlled by the solute / surface interactions
while the solute / adsorbed solute interactions are operating in the second step of the isotherm. The role of the organic
matter in this region of the isotherm is probably negligible.
The comparison of the adsorption coefficients leads to the conclusion that the presence of nitrate and phosphate ions enhances
the adsorption of acetochlor on the soils containing a high percentage of organic matter. As these ions are present in the
environment due to the extensive use of fertilizers, they may increase the acetochlor pollution of water by erosion. This
conclusion corroborates those earlier observations that reported frequent acetochlor contamination of the surface waters [4–5].
As the organic matter content of the soils plays an important role in the acetochlor adsorption, humic substances must have
a strong influence on the transport of this compound. Experiments to obtain adsorption isotherms of further pesticides and
the development of a quantitative model are in progress. 相似文献