紫色土中砷、磷的吸附-解吸和竞争吸附

采用批培养法研究了As、P在三峡库区典型土壤紫色土中的吸附-解吸特点及竞争吸附对As、P迁移活化的影响.结果表明：3种紫色土中As、P的吸附-解吸特点相似,等温吸附均符合Langmuir和Freundlich方程,As在酸性、中性和石灰性紫色土中的最大吸附量分别为1428.6、1250.0和1111.1 mg·kg^-1;P在酸性、中性和石灰性紫色土中的最大吸附量分别为322.6、357.1和434.8 mg·kg^-1;As、P吸附动力学过程为先快后慢,均符合一级动力学方程与Elovich方程,快速吸附段符合一级动力学方程,为交换吸附;慢速吸附阶段满足Elovich方程,可能属于深层吸附或专性吸附.As、P竞争吸附试验表明,As、P共存时P的吸附速度和吸附量均增强,而As的吸附速度和吸附量均降低,表明As的存在能明显增强紫色土对P的吸附作用,P的存在则明显抑制紫色土对As的吸附.     

模拟氮沉降下南方针叶林红壤的养分淋溶和酸化

以中国科学院红壤生态实验站林草生态试验区针叶林红壤为研究对象,在恒温(20 ℃)条件下,通过大土柱（直径10 cm、高60 cm）,8个月间隙性淋溶试验模拟研究了不同氮输入量（0、7.8、26和52 mg N/月/柱）对针叶林红壤NO₃^-、NH₄⁺、H⁺和土壤盐基离子(Ca²⁺、Mg²⁺、K⁺、Na⁺⁾淋溶以及土壤酸化的影响.结果表明,土壤交换态盐基总量、Ca²⁺和Mg²⁺淋溶量随氮输入量的增加而增加,土壤交换态Na⁺和K⁺则无明显影响.4种N输入处理的土壤交换态盐基总量净淋溶（淋溶出的盐基与淋洗液累计输入的盐基之差）分别占土壤交换性盐基总量的13.9%、18.6%、31.8% 和57.9％,土壤交换态Ca²⁺净淋溶分别占土壤交换性Ca²⁺总量的19.6%、25.8%、45.3%和84.8%,土壤交换态Mg²⁺净淋溶分别占土壤交换性Mg²⁺总量的4.4%、6.1%、10.9%和17.1%.随氮输入量增加,表层土壤pH值逐渐下降,4种N输入处理的表层土壤pH（KCl）分别为3.85、3.84、3.80和3.75;随氮输入量增加,淋溶液中无机氮、NO₃^-和H⁺逐渐增加.氮沉降可促进针叶林红壤的有机氮矿化,加速养分淋失和土壤酸化.     

山东寿光设施菜地土壤砷含量及形态

通过典型区域采样调查,系统探讨了山东寿光市设施菜地中砷的含量及其形态特征.结果表明: 设施菜地表层(0～20 cm)和亚表层(20～40 cm)土壤中总砷含量分别为8.27、7.93 mg·kg^-1,是对照土壤的1.19和1.23倍,易溶性砷(AE-As)含量分别为0.13、0.06 mg·kg^-1,是对照土壤的1.63和3.00倍; 土壤中的砷主要以残渣态砷(O-As)存在,其含量占总砷的63.0%以上,其他形态砷含量依次为铁型砷(Fe-As)>钙型砷(Ca-As)>铝型砷(Al-As)>AE-As; 随着种植年限的延长,土壤中AE-As含量显著增加,Al-As含量也有不同程度提高,种植15 a设施菜地表层和亚表层土壤中的AE-As含量分别比对照提高了75.0%和150.0%,Al-As含量分别提高了51.6%和190.4%,而Fe-As和Ca-As含量则均有不同程度的下降.     

百菌清对土壤氧化亚氮和二氧化碳排放的影响

在25 ℃、60%WHC（最大持水量）的好氧条件下进行14 d的培养试验，研究杀菌剂百菌清在添加水平为0 mg·kg^-1（CK）、5.5 mg·kg^-1（田间施用量，FR）及110 mg·kg^-1(20FR)和220 mg·kg^-1（40FR）时对酸性、中性和碱性土壤中N₂O和CO₂排放的影响.结果表明：百菌清对N₂O和CO₂排放的影响取决于土壤类型和施用浓度.与对照相比，百菌清在20FR和40FR时显著抑制了酸性土壤N₂O的产生与排放；3种施用量均显著促进了中性土壤N₂O的排放，其中FR水平的促进效果最显著；高浓度（20FR和40FR）的百菌清在培养初期抑制了碱性土壤N₂O的排放，而在培养后期显著促进了N₂O的排放.田间用量的百菌清对土壤CO₂排放量没有明显影响；高浓度（20FR和40FR）时显著促进了酸性土壤CO₂的排放，显著抑制了中性和碱性土壤CO₂的排放.     

添加玉米和水稻秸秆对淹水土壤pH、二氧化碳及交换态铵的影响

通过温室土壤培养试验，研究了不同添加量玉米和水稻秸秆对淹水土壤pH、CO₂及交换态铵的影响.结果表明：在接近中性的土壤中加入秸秆可使土壤pH值降低，4 g·kg^-1玉米和水稻秸秆处理的土壤pH值均与对照差异显著（P＜0.05），而1 g·kg^-1玉米和水稻秸秆处理与对照差异不显著（P＞0.05）.土壤溶液中的CO₂含量随秸秆添加量的增加而增大，1 g·kg^-1玉米和水稻秸秆处理的土壤溶液CO₂含量最大值分别为35.9％和31.9％（v/v），与对照（25.8％）差异达显著水平（P＜0.05），但两者间差异不显著（P＞0.05）；4 g·kg^-1玉米和水稻秸秆处理的土壤溶液CO₂含量最大值分别为54.2％和41.8％（v/v），与对照差异极显著（P＜0.01），两者间差异也达显著水平（P＜0.05）.在不施氮肥的情况下，添加秸秆可降低土壤铵态氮浓度，且铵态氮浓度随秸秆添加量的增加而降低，不同添加量处理间差异显著（P＜0.05）；在施入氮肥的情况下，1 g·kg^-1玉米和水稻秸秆处理提高了土壤铵态氮浓度，而4 g·kg^-1玉米和水稻秸秆处理降低了土壤铵态氮浓度.无论是否施入氮肥，玉米和水稻秸秆处理的土壤铵态氮浓度差异不显著（P＞0.05）.     

脲酶硝化抑制剂对减缓尿素转化产物氧化及淋溶的作用

利用原状土柱模拟试验,研究了脲酶抑制剂氢醌（HQ）,硝化抑制剂包被碳化钙（ECC）和双氰胺（DCD）以及它们的不同组合对尿素转化产物土壤持留、氧化以及淋溶的影响.结果表明,与其它抑制剂处理相比,HQ+DCD组合能有效抑制尿素水解产物的氧化,使其以交换态NH₄⁺的形式在土壤中长时间持留;氧化作用的抑制不仅减少了氧化产物NO₃^-的累积,也降低了NO₃^-淋溶潜势,使其淋入下层土壤的深度仅限在5～10 cm范围内,且淋溶量显著降低.     

水溶性有机质对土壤吸附菲的影响

研究了来源于稻草腐熟物的外源水溶性有机质(DOM)和土壤本身固有的内源DOM对有机碳含量不同的3种土壤吸附菲的影响.结果表明,不同处理土壤对菲的吸附曲线均为线性,其吸附系数(K_d)与土壤有机碳含量(f_oc)正相关.去除内源DOM后,黄棕壤、红粘田和黑土吸附菲的K_d值增加了7.08%～21.4%,增加量(ΔK_d)和增加幅度与f_oc正相关,表明土壤中存在的内源DOM抑制土壤对菲的吸附.而外源DOM对土壤吸附菲的影响与其浓度密切相关.在供试浓度范围(0～106 mg DOC·L^-1)内,红粘田吸附菲的K_d值随加入外源DOM浓度的提高先增大后减小.外源DOM浓度为28 mg DOC·L^-1时,红粘田吸附菲的K_d值增加了19.5%;而当外源DOM浓度≥52 mg DOC·L^-1时,则明显抑制菲的吸附.内源和外源DOM对土壤吸附菲的影响,主要与DOM和菲在溶液中的结合作用、在土壤中的累积吸附效应等有关.     

外源有机质对土壤中菲的增强固定作用

从吸附、解吸、可萃取态残留变化3个方面,研究了外源有机质对粘壤土、砂粉土和粉壤土中菲的增强固定作用.外源有机质为有机商品肥和泥炭.结果表明,施加外源有机质后,供试土壤对菲的吸附等温线仍呈线性,分配作用为土壤吸附菲的主导机制.有机商品肥或泥炭能显著促进供试土样对菲的吸附.施加同量的外源有机质,土壤吸附菲的K_d值的增加幅度与土壤有机碳含量(f_oc)成正比,表明土壤的f_oc越大,外源有机质对菲吸附的促进效果越好.解吸实验表明,施加外源有机商品肥或泥炭能够抑制土壤中菲的解吸,解吸量显著低于原土.经64 d培养,施加外源有机质的3种土壤中的可萃取态残留菲含量降低;由于泥炭的有机质含量高于有机商品肥,施加泥炭的土样中可萃取态残留菲的降幅更大;原土的f_oc越高,外源有机质对菲可萃取性的抑制效果越明显.可见,施加外源有机质可增强土壤中菲的吸附固定、抑制其解吸、并降低其可萃取态残留.     

外源氮对沼泽湿地CH4和N2O通量的影响

三江平原沼泽湿地受到大气沉降、地表径流、农业排水等外源氮素的输入,对湿地生态系统CH₄和N₂O通量有重要影响。采用野外原位施肥试验模拟外源氮输入,设0,60,120,240kgN•hm^-2 4种试验处理,探讨外源氮对沼泽湿地CH₄和N₂O通量的影响。结果表明,外源氮促进了CH₄和N₂O排放。与对照处理比较,各施氮水平CH₄平均排放通量分别增加了181％,254％和155％,N2O排放通量分别增加了21％,100％和533％。外源氮输入对CH₄排放的季节变化形式影响不大,而N²O的季节变化形式随着氮输入表现出波动变化的趋势。不同施氮水平对CH₄排放的促进作用与植物生长阶段和产CH₄的微生物过程密切相关,N₂O排放通量随氮输入量呈指数增加（R²＝0.97,p<0.01）。外源氮通过影响湿地微生物过程来进一步影响CH₄和N₂O的排放。     

有机肥对桃园土壤硝态氮分布的影响

于2004—2005年在北京市平谷区有机桃园设置不同有机肥处理：2年连续施有机肥，年均67 500 kg·hm^-2（T₁）；第一年不施肥，第二年施有机肥135 000 kg·hm^-2（T₂）；第一年不施肥，第二年施有机肥67 500 kg·hm^-2（T₃）；不施肥对照（CK），并于2006年对0～120 cm土层土壤进行取样分析，研究施用有机肥对土壤硝态氮分布和淋失的影响.结果表明：对照土壤中硝态氮分布较均匀，T₁和T₃在0～120 cm土层硝态氮浓度变化呈单峰曲线，其中60 cm以上较高，在60～120 cm逐渐降低；而T₂土壤硝态氮浓度由浅到深逐渐增加，峰值出现在100～120 cm土层，其在60 cm以下土层的硝态氮浓度在所有处理中最高，说明过量施用有机肥易导致硝态氮的淋失.相关分析表明，土壤硝态氮的浓度和分布与多年施氮总量、最近一年施氮量和检测点与树的距离呈显著相关关系，并据此建立了有机肥施用与土壤剖面硝态氮浓度之间的相关模型.     

Accumulating behaviour of Lupinus albus L. growing in a normal and a decalcified calcic luvisol polluted with Zn

Lupinus albus L. is a leguminous plant that is starting to generate interest for the phytoremediation soils showing intermediate metal pollution. Among these metals, Zn causes major phytotoxicity problems and is common in polluted soils of central Spain. The purpose of this study was to explore the nutritional behaviour of this plant species towards increasing Zn concentrations in two calcic luvisol soils: a normal basic soil and a decalcified acid soil. For this purpose the effects of different Zn concentrations on mineral nutrition, growth, nodulation and nitrogenase activity of nodulated Lupinus albus cv. Multolupa plants has been investigated. A 12-week trial was performed in pots under greenhouse conditions. In each soil, four replicate pots were set up per treatment (100, 150, 300, 500 and 700 ppm Zn). Seeds were inoculated with a Bradyrhizobium sp. (Lupinus) strain ISLU-16.

Statistical analysis of data revealed significant effects of soil Zn on grown, plant mineral composition and nodulation. Lupin growth was better in acid soil than in basic soil with the low dose of Zn applied, although plant growth in acid soil was severely affected from 300 ppm Zn, where the pH of the soil was 4.7. Zn application produce nutritional imbalances, especially with the higher dose added. Most of Zn accumulation occurred in the roots in both types of soils. In acid soil, lupin absorbs high amounts of Zn in both root (4650 ppm) and aerial part (3605 ppm), when the doses of Zn applied was 300 ppm. This feature permits Lupinus albus cv. Multolupa to be considered as potential phytoremediator and also for the revegetation of degraded landfill areas with slightly acid or neutral soils polluted with Zn.     

Profile distribution of organic carbon and nitrogen in major soil types in the middle of Qilian Mountains

This paper studied the distribution patterns of organic carbon (OC), total nitrogen (TN), NH4+ -N, and NO3- -N in the profiles of brown calcic soil, grey cinnamon soil, chestnut soil, and alpine meadow soil in the middle of Qilian Mountains. In all test soils, the contents of OC, TN, NH4+ -N, and NO3- -N decreased with increasing soil depth, and the accumulation and decomposition of OC and various N forms differed with soil types. The average content of OC in different soil profiles changed from 14.01 to 41.17 g x kg(-1), and was in the order of grey cinnamon soil > alpine meadow soil > chestnut soil > brown calcic soil; the average content of TN changed from 1.28 to 2.73 g x kg(-1), with a sequence of alpine meadow soil > grey cinnamon soil > chestnut soil > brown calcic soil. The C/N ratio was from 11.33 to 19.22, with the order of grey cinnamon soil > chestnut soil > alpine meadow soil > brown calcic soil. NH4+ -N content changed from 5.80 to 8.40 mg x kg(-1), and was in the order of brown calcic soil > alpine meadow soil > chestnut soil > grey cinnamon soil; NO3- -N content changed from 6.57 to 15.11 mg x kg(-1), being in the order of chestnut soil > alpine meadow soil > brown calcic soil > grey cinnamon soil. The ratio of NO3- -N to NH4+ -N was 1.00-2.69, with the sequence of grey cinnamon soil > chestnut soil > alpine meadow soil > brown calcic soil. The OC and N contents in the same soil types differed significantly with the conditions of climate, vegetation, and topography (e. g. , slope aspect and slope position). Correlation analysis showed that there were highly significant nositive correlations between OC, TN, and NH4+ -N, but these three items had no significant positive correlations with NO3- -N. Furthermore, there were highly significant positive correlations between available K, NH4+ -N, and NO3- -N and between available P and OC, significant positive correlations between available P, TN, and NH4+ -N, but no significant correlations between pH, total K, and total P and OC and N.     

宏基因组技术研究泥岩母质发育的三种不同pH紫色土硝化微生物群落演变规律

【目的】揭示典型农田旱地紫色土硝化微生物的群落组成及其对pH的响应规律。【方法】针对同一母质发育但pH差异显著的3种紫色土,利用宏基因组技术深度测序研究土壤中硝化微生物丰度和群落,包括氨氧化古菌(ammonia-oxidizing archaea,AOA),氨氧化细菌(ammonia-oxidizing bacteria,AOB),亚硝酸盐氧化细菌(nitrite-oxidizingbacteria,NOB)和全程氨氧化细菌(completeammoniaoxidizer,Comammox)。【结果】土壤中硝化微生物的丰度占总微生物的2.130%–6.082%。3种紫色土中AOA、AOB和NOB的相对丰度有显著差异:酸性紫色土中AOA的相对丰度显著大于碱性紫色土,而AOB则相反;NOB的相对丰度在中性紫色土中最高。所有土样中均发现了1种全程氨氧化细菌Candidatus Nitrospira inopinata (Ca. N. inopinata),其在中性紫色土中相对丰度最高,占总微生物的0.203%。3种不同pH紫色土中AOA均以Nitrososphaera为主,NOB均以Nitrospira为主;酸性紫色土中AOB以Nitroscoccus为主,而中性和石灰性紫色土中则以Nitrosospira为主。Pearson相关性分析发现,土壤pH和铵态氮是影响硝化微生物丰度最大的两个因子。【结论】Comammox存在于3种不同pH紫色土中,且偏好中性环境;AOA、AOB和NOB群落结构和相对丰度都存在显著差异,结合相关性分析发现土壤pH和铵态氮是导致差异最重要的两个因子。     

不同磷浓度植株残体降解对紫色土磷素有效性的影响

植株残体降解可直接或间接地影响土壤磷素的有效性,为探讨不同磷浓度植株残体降解对紫色土磷分级体系的影响,结合31P核磁共振分析技术,选取了3种磷浓度不同的植物残体与两种紫色土进行室内模拟培养试验,得出了以下研究结论:(1)添加植株残体显著增强了紫色土呼吸强度,且紫色土分级体系中的活性磷含量均高于对照处理(2)31P-NMR分析结果得知,植株残体的正磷酸盐、磷酸单酯占浓缩液全磷比例的90%以上,高磷植株的正磷酸盐和磷酸单酯含量显著高于中磷和低磷植株,土壤磷素有效性的变化与植株残体的正磷酸盐和磷酸单酯含量有关;(3)紫色土分级体系中的活性磷在0 d含量最高,随着培养周期的延长,土壤磷素有效性会出现降低的趋势;酸性紫色土的累积呼吸强度、分级体系中活性磷(Resin-P、Na HCO3-Pt)所占比例均高于中性紫色土,与土壤钙含量有关。综上所述,植株残体的磷浓度越高,更有利于提高土壤磷素的有效性,本研究结果为农业生产中秸秆还田技术提供了理论参考。     

Soil chemistry and plant distributions in rock habitats of southern Sweden

The vascular plant flora of open land on superficial bedrock in southem Sweden (northwards to 59°N) is described and related to soil chemical properties. including soil acidity (pH), exchangeable Al, Ca, Fe, Mn, Mg, and phosphate, as well as to soil solution pH and concentrations of Al, Ca and Mg, and to the contents of soil organic matter, soil depth and bedrock types (sandstone, gneiss, granites, various dark igneous rocks and limestones). About 120 localities with totally 652 sites (4 m²) have been examined. Experimental evidence for the toxicity of acid soils and mineral nutrient deficiency of neutral and alkaline soils is related to field data. Hydrogen and Al ion toxicity in acid soils and low phosphate solubility in neutral - alkaline soils are identified as major factors limiting the field distributions of rock habitat plants. Some species (e.g., Rumex acetosella and Sedum telephium ) were limited by phosphate also in acid soils. The relative importance of H and Al ion concentrations to plant performance under variously acid soil conditions is discussed, and strong evidence is given for a decisive influence of Al ion toxicity on species diversity at pH-KCI > 4.5. The importance of grazing and former land use is considered briefly and the floristic differences between the western and the eastern half of the study area are discussed originating from differences in general distribution patterns of species and soil chemical properties.     

Impact of soil types on chemical composition of essential oil of purple basil

Purple basil is among the most important basil varieties and its essential oil is used for several purposes including medicinal and aromatic uses. Soil types may impact the plant growth, development, and essential oil composition. Hence, it is important to find the most suitable soil type which may produce basil plants having essential oil with the best composition and concentration. For this reason, plant samples of purple basil that were grown in areas with clay, loamy sand, and sandy-clay loam soil types were collected and evaluated to determine the changes in the yield and essential oil components. Essential oil contents were determined with the Clevenger Device, and essential oil compositions were determined by using GC and GC/MS analysis. The highest essential oil yield according to soil types was obtained from the plant samples that were grown in the loamy sand soil. It was also found that the main compounds present in Arapgir town purple basil were methylcinnamate and linalool that was also present in all Turkish purple basil under all types of soil. According to the soil types, the highest concentration (46.03%) of methylcinnamate was observed in loamy sand soils, and the lowest (42.33%) was obtained from sandy-clay loam soils and found to be significantly different. Data regarding correlations between soil types and essential oil ratios showed that organic matter and P₂O₅ had a significant negative correlation with methylcinnamate. The present study will help researchers and farmers to choose the most suitable soil type to achieve maximum essential oil production from purple basil.     

Variations of soil fertility level in red soil region under long-term fertilization

Based on the long-term (1982-2007) field experiment of "anthropogenic mellowing of raw soil" at the Qiyang red soil experimental station under Chinese Academy of Agricultural Sciences, and by using numerical theory, this paper studied the variations of the fertility level of granite red soil, quaternary red soil, and purple sandy shale soil under six fertilization patterns. The fertilization patterns included non-fertilization (CK), straw-returning without fertilizers (CKR), chemical fertilization (NPK), NPK plus straw-return (NPKR), rice straw application (M), and M plus straw-return (MR). The soil integrated fertility index (IFI) was significantly positively correlated with relative crop yield, and could better indicate soil fertility level. The IFI values of the three soils all were in the order of NPK, NPKR > M, MR > CK, CKR, with the highest value in treatment NPKR (0.77, 0.71, and 0.71 for granite red soil, quaternary red soil, and purple sandy shale soil, respectively). Comparing with that in the treatments of no straw-return, the IFI value in the treatments of straw return was increased by 6.72%-18.83%. A turning point of the IFI for all the three soils was observed at about 7 years of anthropogenic mellowing, and the annual increasing rate of the IFI was in the sequence of purple sandy shale soil (0.016 a(-1)) > quaternary red clay soil (0.011 a(-1)) > granite red soil (0.006 a(-1)). It was suggested that a combined application of organic and chemical fertilizers and/or straw return could be an effective and fast measure to enhance the soil fertility level in red soil region.     

Biological effects of nickel species and their determination in plant and soil

Chemical and biological behaviour of several Ni-forms was studied on different soil types with spinach as a test plant. For the positively charged forms, Ni-ions and Ni-TETREN-ions, extractability increased with decreasing pH and CEC values of the soil. On the other hand, Ni added as EDTA-complex resulted in an extremely high Ni mobility, enhancing extractable Ni in soils having higher pH and CEC values. Speciation of Ni in the saturation extracts of the soils revealed that the transformation of both added positive forms was dependent on the soil characteristics, while Ni added as EDTA-complex mainly remained in the negative form. This altered mobility, accompanied by variable modification of the original chemical form in the soil solution, affected plant uptake and appearance of phytotoxic effects. Speciation in the plant extracts indicated that regardless of the chemical form added to the soil, Ni was only found in neutral and negative complexes. Finally, using ion-pair reversed phase HPLC, Ni-EDTA-ions were quantified in both the soil solution and the plant extract.