喀斯特湿地转变为农用地对土壤有机硫形态及芳基硫酸酯酶活性的影响

【目的】土壤有机硫形态及芳基硫酸酯酶活性能敏感地反映土壤硫库的变化,厘清喀斯特湿地转变为农用地后不同土地利用方式下土壤有机硫形态和芳基硫酸酯酶活性的变化特征及其影响因素,对喀斯特湿地土地合理利用和土壤质量管理具有重要意义。【方法】以典型桂林会仙喀斯特天然沼泽湿地为对照(沼泽湿地),以由其转变而来的5种土地利用方式,即水稻田、旱地、果园、养殖地和弃耕地为研究对象,采集0—10、10—20、20—30和30—40 cm共4个土层的样品,分析各形态有机硫含量及芳基硫酸酯酶活性。【结果】1)与沼泽湿地相比,5种土地利用方式的土壤全硫储量、酯键硫、碳键硫以及残渣态硫含量均呈降低趋势。5种土地利用方式土壤碳键硫、酯键硫和残渣态硫占有机硫的比例分别为39.08%～63.54%、22.91%～34.28%、13.55%～28.46%,与沼泽湿地相比,酯键硫和残渣态硫占比降低,碳键硫占比升高(P<0.05)。2)沼泽湿地土壤有机硫含量范围在158.41～442.18 mg/kg,全硫含量范围在180.22～510.83 mg/kg,全硫平均值为345.53mg/kg,低于世界土壤全硫含量均值(70...     

太湖水稻土中的芳基硫酸酯酶活性

选取了 1 2个太湖地区的水稻土表土及其剖面 ,分析芳基硫酸酯酶活性变化。耕作层芳基硫酸酯酶活性平均为PNP 1 60 μgg- 1h- 1。大多数土壤其酶活性在PNP 1 0 0～ 2 0 0 μgg- 1h- 1之间。最低值和最高值分别为PNP 75 ,31 5 μgg- 1h- 1。犁底层土壤芳基硫酸酯酶活性明显低于耕作层 ,60 %的土壤其酶活性低于PNP 5 0 μgg- 1h- 1。犁底层酶活性与耕作层酶活性之间没有相关性。土壤芳基硫酸酯酶活性与土壤有机碳有显著正相关 (R2 =0 .5 33) ;与土壤pH关系较为复杂 ,在pH小于 5 .2时 ,随pH升高 ,酶活性增加 ,大于 5 .2时 ,酶活性则明显下降。除个别土壤外 ,大多数土壤芳基硫酸酯酶活性沿剖面下降 ,在大于 60cm的土层中基本上没有芳基硫酸酯酶存在。不同土壤芳基硫酸酯酶活性的剖面分布有所不同。根据酶活性变化下降趋势 ,其剖面分布基本上可以归结为四个类型。     

土壤芳基硫酸酯酶及其活性和农业措施影响

硫是作物生长发育的必需营养元素,但土壤的缺硫现象日益严重,土壤硫营养逐渐成为作物产量和质量的重要限制因子。土壤芳基硫酸酯酶能酶促土壤有机硫的矿化,在硫素的生物化学循环和植物的硫营养中具有重要的作用,是反映土壤质量的一个重要生物学指标。本文在阐述土壤芳基硫酸酯酶的重要作用、来源、存在方式等的基础上,综述了国内外该酶对农业技术措施的响应的研究,为不同农业管理制度下土壤芳基硫酸酯酶活性的调节提供参考。     

长期不同施肥下紫色土有机硫和芳基硫酸酯酶活性变化特征

  【目的】  基于长期定位试验,探究施入含硫肥料的不同处理土壤总硫与有机硫含量变化,以及不同施肥处理土壤总硫与有机硫的变化趋势,为硫素的合理施用提供理论依据。  【方法】  长期定位试验位于重庆市北碚区西南大学国家紫色土肥力与肥效监测基地,始于1991年,至本研究取样时已连续进行了22年,一年两季,水稻?小麦轮作。选择试验中的7个处理:不施肥 (CK),施用氮磷钾 (硫酸钾,NPK_S),有机肥单施 (M),氮磷钾配施有机肥 (MNPK_S),氮磷钾与稻草还田配合施用 (SNPK_S),含氯化肥氮 (氯化铵)、磷、钾 (氯化钾) 与秸秆还田配施 (SNPK_Cl)和永久休闲 (F)。取0—20 cm土样,测定了全硫、有机硫以及3种形态有机硫含量以及芳基硫酸酯酶活性。  【结果】  1) 与1991年原始土壤相比,除CK的全硫和有机硫含量显著降低外,其余处理均显著增加,且土壤全硫含量除M和NPK_S处理间差异不显著外,其他处理间均差异显著,由高到低为MNPK_S > SNPK_S > M和NPK_S > F > SNPK_Cl。土壤有机硫在全硫中的占比也发生了变化,CK处理中有机硫含量显著下降,其他处理均显著增加 (P < 0.05)。MNPK_S和SNPK_S处理有机硫含量增加最多,但是MNPK_S处理有机硫在全硫中的占比只有73.3%,而SNPK_S为92.2%。另外,M和F处理有机硫含量差异不显著,但都显著高于SNPK_Cl和NPK_S处理 (P < 0.05)。SNPK_Cl处理的有机硫含量虽然显著低于MNPK_S、SNPK_S、M和F处理,但有机硫的占比 (90.3%) 与SNPK_S处理相当,而NPK_S处理的有机硫含量虽然高于CK和初始土壤,但显著低于F处理和含有机肥处理的土壤 (P < 0.05)。2) 与CK相比,其他施肥处理0—20 cm土层中碳键硫、酯键硫、残渣态硫含量均有所增加,且不同施肥处理之间差异达到显著水平。与初始土壤相比,包括F在内的所有处理中碳键硫和酯键硫含量增加,其中MNPK_S处理的碳键硫的增加量显著高于其他处理,增加了31.1 mg/kg;酯键硫增加量最大的处理是SNPK_S,增加了37.05 mg/kg;而残渣态硫除MNPK_S处理增加了52.2 mg/kg和F处理增加了11.65 mg/kg外,其余处理均减少,以CK减少最多 (46.62 mg/kg)。3) 与初始土壤相比,土壤芳基硫酸酯酶的活性除SNPK_Cl处理减少了 8.19 μg/(mL?h)和F处理减少了7.80 μg/(mL?h)外,其余处理都有不同程度的增加,增加最大的处理是SNPK_S,增加了37.77 μg/ (mL?h),其次是M处理,增加了33.91 μg/ (mL?h)。  【结论】  长期施用化肥、有机肥、化肥与有机肥配施都显著增加了紫色土壤有机硫中碳键硫、酯键硫的含量,降低了残渣态硫含量,因而显著提高了硫的有效性。不施肥,不论是否休闲,均降低土壤中有机硫的有效性。含氯化肥也能提高土壤硫的有效性,并且含氯化肥与有机肥配合施入土壤,一定程度上提高了有机硫的比例。但长期施用含氯化肥会降低芳基硫酸酯酶活性,在施肥的时候尤其是长期施入含氯化肥,应该密切关注土壤中pH的变化问题。     

磁场对中国东北主要土壤酶活性的影响

Soil enzyme activities as affected by applied magnetic field were studied with three main soils (brown soil,black soil and albic soil) collected from Northeast China,Appropriate intensities of magnetic field could obviously enhance the activities of hydrogen peroxidases,invertases,amylases and phosphatases in the three soils,although the effect varied with types and water regimes of the soils.Increasing times of magnetic treatment could multiple its good effect on the activities of hydrogen peroxidases in soils.     

双氰胺对土壤酶活性的影响

本文选用沈阳市东陵区天拄山耕作棕壤,采用室内培养试验研究了双氰胺对土壤酶活性的影响情况。双氰胺对土壤中性磷酸酶活性的影响主要在培养的前20天,表现为显著的抑制作用;对土壤脲酶活性的影响主要在培养的第20、30天时表现为显著的抑制作用;对土壤过氧化氢酶活性的影响在培养的第30天时表现为显著的激活作用;对土壤转化酶活性影响不大。     

酚酸化合物对土壤酶活性和土壤养分的影响

研究了酚酸化合物对连作西瓜土壤酶活性和土壤养分的影响。结果表明,添加外源酚酸入土刺激了土壤酶活性,土壤过氧化氢酶活性、脲酶活性均比对照提高,土壤呼吸强度增加,施入酚酸化合物2周时,500.mg/kg浓度的苯丙烯酸和对羟基苯甲酸土壤呼吸强度分别比同期对照增加了22.5%和20.0%;处理4周时,750.mg/kg浓度的苯丙烯酸和对羟基苯甲酸脲酶活性分别比对照提高了34.4%和29.0%。苯丙烯酸和对羟基苯甲酸类酚酸化合物降低了土壤碱解氮、速效磷、速效钾含量,有机质含量也降低,250.mg/kg苯丙烯酸处理2周时,碱解氮、速效钾、速效磷和有机质含量分别比对照降低了9.6%,18.4%,20.7%和11.0%。     

不同耕作措施对土壤酶活性的影响

对华北平原不同耕作措施对土壤酶活性的影响进行了研究,结果表明:随着土层的增加,除秸秆深耕还田外其他三个处理下磷酸酶、转化酶活性均显著降低,而过氧化氢酶活性则呈升高趋势。其中秸秆免耕还田下过氧化氢酶、磷酸酶、转化酶活性均显著高于其他三个处理,秸秆旋耕还田下过氧化氢酶和磷酸酶活性次之,而秸秆深耕还田下转化酶活性则显著高于秸秆旋耕还田,深耕秸秆不还田处理下各种酶活性均处于最低。     

兽药磺胺间甲氧嘧啶对土壤呼吸及酶活性的影响

为评价兽药污染对土壤生态环境造成的潜在环境风险,采用室内培养的方法,研究了兽药抗生素磺胺间甲氧嘧啶对黄潮土土壤微生物呼吸及土壤酶活性的影响。结果表明,磺胺间甲氧嘧啶可显著影响土壤呼吸强度,抑制率和激活率分别可达72%和254%,药物对土壤酶活性的影响小于其对土壤呼吸强度的影响。在添加磺胺间甲氧嘧啶的前11 d,其对脲酶活性的影响主要以抑制作用为主;药物对蔗糖酶活性的影响较为明显,最大抑制和激活率可分别达到18%和30%;磺胺间甲氧嘧啶作用于过氧化氢酶和磷酸酶主要表现为激活效应,最大激活率分别为17%和25%。在试验浓度范围内,土壤微生物呼吸及酶活性的抑制率或激活率呈现一定的波动性。     

Examination of ester sulfates in Podzolic and Regosolic soils using an immobilized arylsulfatase reactor

The enzyme kinetics of an immobilized arylsulfatase reactor were examined. We found that the optimum operating conditions for the reactor were pH 7.0 and 25°C, using p-nitrophenyl sulfate in acetate buffer. The Michaelis constant (K _m) of immobilized arylsulfatase was 5.29 mM, compared with a K _m of 2.18 mM for soluble arylsulfatase from the same source (Helix pomatia). Since arylsulfatase hydrolyzes organic ester sulfate linkages, the immobilized arylsulfatase reactor was used to examine ester sulfate compounds in two soils subjected to different fertility management schemes. Soil samples were obtained from the Ap horizons of a Podzol from S-amended wheat plots and a Regosol from dykeland hayfield plots which had received additions of NH₄NO₃ and compost. The distribution of S in these soils was examined in the fall of 1993 and the spring of 1994. Soil organic matter was extracted and separated into three molecular weight fractions (<500, 500–10 000, >10 000). There was no difference in the ester sulfate content for the >10 000 fraction of control and S-amended Podzol soils; however, the S-amended samples had significantly higher quantities of hydrolysable ester sulfates than controls for the 500–10 000 range, indicating that S amendments resulted in the incorporation of ester sulfate into this lower molecular weight fraction. Both control and NH₄NO₃ treatments to the Regosol showed significantly higher quantities of hydrolysable ester sulfates in the >10 000 fraction, while compostamended plots showed no difference between the >10 000 and 500–10 000 fractions due to suspected microbial degradation of high molecular weight organic S compounds in the compost. Since there was no significant effect of sampling time, this study indicated that naturally occurring low molecular weight ester sulfate compounds accumulate in soil and persist during storage. Hydrolysable ester sulfates constituted 35–55% of the hydriodic acid-reducible S in these different soils and probably represent an important and easily mineralizable portion of total ester sulfates.     

Abiontic enzymes in arctic soils: Influence of predominant vegetation upon phosphomonoesterase and sulphatase activity

Abstract

The level of phosphomonoesterase and sulphatase enzyme activity in Arctic soils subjected to an environmental gradient established by snow patch water melt was examined. Within the environmental gradient, distinct zones of vegetation had been established and could be delineated on the basis of dominant plant growth form. Phosphomonoesterase and sulphatase activity levels were not only influenced by the presence of the plant, but also by the dominant vegetation. The levels of activity for each abiontic enzyme differed with respect to vegetative zone. Although soil moisture and water movement could be implicated as influencing the level of enzyme activity within the environmental gradient, their exact role was not apparent. Various factors associated with water movement and soil moisture level and their possible influence upon phosphomonoesterase and sulphatase activity levels are discussed. In comparison to Virginia temperate soils dominated by single physiognomic vegetation, the levels of phosphomonoesterase and sulphatase activity were generally higher, whether expressed on a dry weight basis or a volume basis. Based upon the higher levels of enzyme activity, mineralization of organic matter by abiontic enzymes may be a major route by which phosphorus and sulphur are replenished in some Arctic soils.     

Chemical and microbial properties in contaminated soils around a magnesite mine in northeast China

We measured soil chemical and microbial properties at a depth of 0–20 cm among mine tailings, abandoned mined land, contaminated cropland, and uncontaminated cropland around a magnesite mine near Haicheng City, Liaoning Province, China. The objective was to clarify the impact of Mg on the soils. We found that soluble Mg²⁺ concentration and pH were significantly higher in contaminated soils (266–345 mg kg⁻¹ and 9·9–10·3, respectively) than in uncontaminated soils (140 mg kg⁻¹ and 7·1, respectively). Soil nutrients (total N, total P, mineral N, available P and soluble Ca) and microbial biomass C and N decreased as pH and soluble Mg²⁺ concentration increased. In addition, an increase of microbial metabolic quotient and a decrease of N mineralization rate were found in contaminated soils. Soluble Mg²⁺/Ca²⁺ ratios in contaminated soils were 3·5–8·9‐times higher than in uncontaminated soils. Our results indicate that soil contamination in such magnesite mine regions is characterized by high pH, Mg²⁺ concentration and soluble Mg²⁺/Ca²⁺ ratio, and low microbial activity and N and P availability. Future soil amelioration in the magnesite regions should consider applying acid ameliorants to neutralize high pH and applying calcareous ameliorants to increase Ca²⁺ concentration. Copyright © 2011 John Wiley & Sons, Ltd.     

我国一些主要土壤铁锰结核中氧化锰矿的矿物学特征

X－ray diffraction and selective chemical dissolution methods were used to investigate the composition of Mn oxide minerals in Fe-Mn nodules of several main types of soils in China.The changes of relative intensity of X-ray diffraction patterns were studied both before and after chemically selective dissolution.It was found that lithiophorite was a common Mn oxide in all examined Fe-Mn nodules.Todorokite,however,was a predominant Mn oxide in Fe-Mn nodules ,Todorokite,however,was a predominant Mn oxide in Fe-Mn nodules in cal-aquic vertisols of Linyi,Shandong Province,The Fe-Mn nodules of arp-udic Luvisols in Wuhan and Zaoyang,Hubei Province,contained birnessite and vernadite. Hollandite was found in Fe-Mn nodules of alt-udic Ferrisols of Yizhang,Hunan Province,;arp-udic Luvisols of Zaoyang,Hubei Province,and cal-aquic Vertisols of Linyi,Shandong province,The Fe-Mn nodules in alt-udic Ferrisols of Guiyang,Hunan Province,had a few coronadites.Mineralogy of Mn oxide minerals in soil Fe-Mn nodules was related to soil environment,soil types and quantities of relevant cations     

甘肃省几种主要农田土壤肥力监测结果

对甘肃省几种主要耕种农田土壤肥力连续5年的定位监测结果进行分析。结果表明:农田土壤耕层有机质、全氮、速效磷均比第二次土壤普查值增加,速效钾均比普查值下降;施肥结构不合理,土壤耕层养分盈亏量为氮盈余,磷富积,钾亏缺。     

Modeling of the fine‐scale temperature response of arylsulfatase activity in soil

Fine‐scale (1.0–2.2 °C) temperature dependence of soil arylsulfatase activity (arylsulfate sulfohydrolase, EC 3.1.6.1) was measured at 0 to 75 °C in a Danish sandy, arable soil. Assays were done with field‐moist soil samples in the absence of toluene as plasmolytic agent – a procedure that primarily measures the extracellular enzymes. The aim was to evaluate the use of temperature models to describe the temperature response of soil arylsulfatase activity. In addition, we searched for increases in activity at high temperatures (e.g., 50–60 °C), which might be associated with unmasking (exposure) of intracellular enzymes. Arylsulfatase activities ranged from 1.1 to 60.3 μg p‐nitrophenol (g dry weight soil)^–1 h^–1, with an optimum temperature at 58.1 °C. The temperature response below 58.1 °C could be described by the Arrhenius equation (r² = 0.978, n = 83) and the simple Ratkowsky equation (r² = 0.977, n = 83). The expanded Ratkowsky equation, which covered the entire temperature range (0–75 °C), was less satisfactory (r² = 0.958, n = 90) because the model underestimated the reaction rates near the optimum temperature. The activation energy (E_a) calculated from the Arrhenius equation was 42.2 kJ mol^–1. This was higher than previously found for other soils (16.5–34.7 kJ mol^–1), possibly due to the use of toluene in these studies. Further analysis of the temperature response showed that no increase in activity occurred due to potential unmasking of intracellular enzymes by disintegration of bacterial cell membranes at high temperatures. Thus, the use of high incubation temperatures did not facilitate the differentiation between intra‐ and extracellular enzyme activity.     

华北旱地土壤硫施用量指标

Fifteen upland soils collected from the major arable areas in North China were used to assess the availability of soil sulfur (S) to plants in a pot experiment. Soils were extracted with various reagents and the extractable S was determined using turbidimetric method or inductively coupled plasma atomic emission spectrometry (ICP-AES), respectively. In addition, mineralizable organic S, organic S, N/S ratio, sulfur availability index (SAI) and available sulfur correction value (ASC) in soils were also determined. The S amount extracted by 1.5 g L^-1 CaCl₂ was nearly equivalent to that by 0.25 mol L^-1 KCl (40 ℃), and both of them were slightly smaller than that by 0.01 mol L^-1 Ca(H₂PO₄)₂ solution, as measured by turbidimetric method or ICP-AES. The extractable S measured by turbidimetric method was consistently smaller than that by ICP-AES. All methods tested except that for organic S and N/S ratio produced satisfactory results in the regression analyses of the relationships between the amounts of S extracted and plant dry matter weight and S uptake in the pot experiment. In general, 0.01 mol L^-1 Ca(H₂PO₄)₂-extracted S determined by ICP-AES or turbidimetric method and 0.25 mol L^-1 KCl (40 ℃)-extracted S determined by ICP-AES appeared to be the best indicators for evaluation of soil available S.     

Gypsum amendment improves native grass establishment on saline-alkali soils in northeast China

Abstract. Soil salinity and alkalinity reduce plant production and alter species composition of meadow grasslands in western Jilin Province, China. This study was designed to compare the survival and growth of three grass species ( Aneumlepidium chinense, Puccinellia tenuijlora and Hordeum brevisubulatum ) transplanted into saline-alkali soils in the field, and to evaluate the effects of gypsum amendments on soil properties and growth of these species. Gypsum treatments decreased soil pH, electrical conductivity, and chloride and sodium levels; water infiltration and calcium levels were increased. Survival of grass transplants was increased by gypsum treatments. Tiller number and height, and grass yields were all increased by the application of gypsum. Improvements in plant growth and survival with gypsum treatment appeared to be due to reduced chloride levels and increased Ca availability in the soil, and to changes in soil structure leading to improved infiltration rates. Revegetation of salinelalkaline soils in this region would be improved by application of gypsum in the range of 14–19 t/ha.     

我国主要菜区土壤盐分、酸碱性和肥力状况

从全国主要菜区采取1201个典型菜田耕层土壤样品,对主要菜区土壤盐分、酸碱性和肥力（OM、NO3--N及速效P和K）状况进行了研究。结果表明,（1）全国温室和大棚菜田土壤次生盐渍化严重,土壤硝酸根的积累是引起土壤次生盐化的重要原因之一,而土壤硝酸盐积累是氮肥过量施用所致。全国主要菜区温室和大棚土壤电导率高于蔬菜正常生长土壤电导率临界值（600 ?s/cm）的土样数分别占其总土样数的28.1%和29.3%,居于超高盐度水平（≧1000 ?s/cm）的土样数分别占9.5%和14.9%。温室和大棚土壤电导率与土壤硝态氮含量之间均呈极显著的正相关（温室:n = 285, r = 0.76**;大棚:n = 348, r = 0.86**）。（2）全国主要菜区土壤有机质含量普遍处于中低水平,土壤有机质含量低于其临界值（20 g/kg）的土样数占总土样数的36.9%,处于高含量水平（≧40 g/kg）的仅为10.0%。（3）温室和大棚土壤硝态氮和速效磷大量积累,对生态环境构成了严重威胁。全国主要菜区温室和大棚土壤硝态氮含量居于高含量水平（≧150 mg/kg）的土样数分别占其总土样数的33.0%和30.7%,土壤速效P含量居于高含量水平（≧150 mg/kg）的土样数分别占其总土样数的59.3%和35.3%。（4）北方温室和大棚菜田土壤酸碱度中性化明显,北方主要菜区温室和大棚土壤pH值（分别平均为7.2和7.3;温室:n = 270,大棚:n = 143）显著低于露地土壤（平均7.7,n = 155）。