中性盐和pH对红壤、砖红壤胶体交换性酸的影响

In the present work, the exchangeable acidity of a red soil colloid and a latosol colloid at different pH during reacting with four neutral salts was measured. The results show that the exchangeable acidity increased with increasing amounts of the neutral salts added, and the relation between them was almost linear. When the amount of the neutral salt added was lower than a certain value, the slope of the line was high, and the slope turned low when the amount exceeded that value, so there was a turning point in each line. The addition amounts of the neutral salts for the turning points were affected by the cation species of the neutral salts, but pH had less effect on them. After the turning points occurred, the exchangeable acidity of the red soil colloid still gradually increased with the addition amounts of the neutral salts, but that of the latosol colloid did not increase any more. The exchangeable acidity in NaClO₄, KClO₄ and NaCl solutions increased at first, and then decreased with increasing pH, that is to say, peak values appeared. The peak positions of the exchangeable acidity in relation to pH changed with neutral salt solutions and were affected by the surface characteristics of the soil colloids, but not affected by the amounts of the neutral salts added. The exchangeable acidity in the Ba(NO₃)₂ solution increased continuously with increasing pH. The exchangeable acidity of the red soil colloid was obviously larger than that of the latosol colloid.     

滨海土壤盐分动态集成预报模型及其应用

本文提出了以GM(1,1)模型拟合发展趋势、傅里叶变换提取周期分量和AR(p)模型模拟随机过程的集成预报模型,并用于黄河三角洲人工草场群落土壤盐分的定量研究中.经理论和应用检验证明该模型能以较高的精度模拟或预报土壤盐分在较长时期内的动态变化过程.方法简单,计算工作量小,并优于传统的单一预报模型.     

胀果甘草原生境土壤盐分特征分析

 通过野外调查采样和土样化学测定,分析胀果甘草原生境下土壤盐分的特征。结果表明:研究区土壤盐分普遍较高且表聚作用明显,土壤表层0～10 cm土层盐分均值高达32+.08g/kg,属典型的强度盐渍化土;土壤盐分组成中,含阳离子Ca2+、Na+、Mg2+、K+和阴离子Cl-、SO24、HCO-3,不含CO2-3,土壤盐分的特征因子为Ca2+、C1-、SO2-4、NaCa+,其盐渍类型主要为硫酸盐-氯化物型,重碳酸盐是土壤盐分的次要成分;该生境土壤中在整个垂直剖面上Ca2+的含量丰富,属典型钙质土。     

Methyl parathion degradation and metabolism in soil: Influence of high soil-water contents

Mineralization of [¹⁴C]methyl parathion (MP) in Cecil sandy loam was considerably reduced when soil-water content was near saturation. Despite the fact that amounts of MP residue in soil held at 10?0 kPa after 35 days were about the same, larger amounts of metabolites were accumulated and higher amounts of non-extractable ¹⁴C-activity were formed in soil held at ? 2.5 kPa than held at ? 6 kPa. Three principal metabolites, p-nitrophenol (PNP), p-aminophenol (PAP) and a water-soluble polar product ($\text{R}{}_{\mathrm{?}}\text{= 0}$), were detected in soil held at ? 2.5 kPa but only PNP and PAP were detected in soil held at ? 6 kPa. The major metabolite PNP behaved like parent MP, in that it was rapidly mineralized in soil held at ? 6kPa. Much slower mineralization was observed in soil held at ? 2.5kPa.     

Influence of soil factors on the soil enzyme inhibition by Cd

A comparative study was conducted on the toxicity of Cd to alkaline phosphatase activity (ALP) and dehydrogenase activity (DHA) in 18 top soils with contrasting soil properties representative of 14 major soil types in China. Soil pH and carbonate content, soil organic matter, and cation exchange capacity (CEC) largely affected the Cd toxicity on two enzyme activities; with the soil pH having only minor effect on the median ecological dose values based on total Cd concentrations (ED_{50 T}). The values of ED_{50 T}/ED_{50 W} (based on water-soluble Cd content) of alkaline phosphatase and dehydrogenase were strongly influenced by pH and CEC contents, which explained up to 71% of the variation for alkaline phosphatase, 82% of the variation for dehydrogenase, and also were significantly correlated with the parameter K_F derived from Freundlich adsorption isotherms. This study suggests that the values of ED_{50 T}/ED_{50 W} could be useful to evaluate the buffer capacity of soils which protects soil enzymes from harmful effects of heavy metal.     

质地对土壤热性质的影响研究

土壤热性质是水热迁移研究中的重要参数之一。根据非稳态条件下热流方程的差分解和实测土壤温度资料计算了不同质地土壤的热扩散率，并得出了质地影响下的土壤导热率关系式。研究结果表明，对特定土壤而言，土壤导热率与含水率之间可建立幂函数关系；砂粒、粉粒和粘粒含量对土壤热性质有不同程度的影响；不同质地土壤的热性质与土壤水吸力之间存在良好的定量关系；此外，含盐土壤的导热率可表示为浓度的幂函数关系。     

Soluble salts dynamics in the soil under different climatic conditions

The dynamics of soluble salts concentration in the soil was investigated at seven research stations in Israel that represent four climatic regions: Mediterranean, semi-arid, mildly arid and arid. Measurements were taken in different seasons from soils that were developed on hillslopes, which are consisted of hard calcareous rocks. The relationship between the soluble salts content and rainfall was found to be non-linear. An abiotic threshold, which is characterized by a sharp change in the soluble salts content, exists around 200 mm isohyet: sites that receive less than 200 mm rainfall are characterized by significantly high soluble salts content whereas sites that receive more than 200 mm are characterized by very low soluble salts content. Each side of this abiotic threshold expresses typical behavior that can be defined as “environmental signature”. At the “dry” side of the threshold temporal heterogeneity, rate of change, potential of change and differences between layers are higher than those at the “wet” side of the threshold.     

可溶性盐对土壤pH测定的影响及消除初探

在我国大量施肥的背景下,最近几十年农田土壤酸化速率加快,尤其是设施栽培体系土壤。在淋洗强度较弱的情况下,土壤可伴随有次生盐渍化现象,而可溶性盐的存在对土壤p H(H2O)(用水浸提土壤测得的p H)的测定有显著影响。由于p H是酸化评估的重要指标之一,有必要深入探究农田土壤常见可溶性盐对p H(H2O)测定的影响。本研究中,为精确评估积盐农田土壤的酸化状况,以潮土、褐土、水稻土和红壤为研究对象,研究了农田土壤尤其是设施土壤中常见六种可溶性盐(Ca(NO3)2、KNO3、Mg SO4、K2SO4、Ca Cl2、KCl)对土壤p H测定的影响;并以硝酸钾为研究对象,对比分析了四种消除可溶性盐对p H(H2O)测定影响的方法,这四种方法分别为:用石灰位代替p H(H2O);用0.01 mol L-1Ca Cl2浸提代替水浸提;先用模型计算出盐分对p H(H2O)测定的影响,然后从p H(H2O)中减去;用蒸馏水或50℃的50%酒精溶液将土壤中可溶性盐洗除后风干再测定p H(H2O)。结果表明:10 g kg-1可溶性盐的存在可使土壤p H下降0.09~0.87个单位,可溶性盐浓度及土壤电导率(EC)均与p H、△p H(p H的下降程度)之间具有显著的自然对数相关性。同种土壤,不同盐类对p H测定的影响程度不同,强弱顺序因离子组成和土壤类型而异,总体表现为硝酸盐和氯化物对p H测定的影响高于硫酸盐,氯化钙的影响程度高于钾盐及硝酸钙和硫酸镁,三种钾盐之间差异不明显;同种盐类,四种土壤受盐分影响的程度强弱顺序为:褐土水稻土潮土红壤。四种方法均可以减弱或消除硝酸钾对p H测定的影响,6.9 g kg-1硝酸钾施入土壤中可使土壤p H下降0.24~0.71个单位,消除影响后,硝酸钾仅可使土壤p H下降-0.38~0.19个单位。四种方法的简单有效程度为:石灰位0.01 mol L-1Ca Cl2浸提测定p H模型拟合计算洗盐处理。消除可溶性盐对p H测定的影响可以使积盐的农田土壤酸化评估更为精确,使土壤酸化风险预测更为准确,有利于制定合理有效的风险应对措施。     

Influence of halogen salts on the production of the ochratoxins by Aspergillus ochraceus Wilh

The first report of the biological production of bromo ochratoxin B by Aspergillus ochraceus Wilh. is presented as well as a study of the influence of potassium bromide, potassium iodide, potassium fluoride, and potassium chloride on the production of ochratoxin A and ochratoxin B. Potassium fluoride and potassium iodide inhibited the growth of the fungus, whereas potassium chloride substantially stimulated the production of ochratoxin A in shaken solid substrate fermentation on whole wheat or shredded wheat, generally giving a high yield of ochratoxins. Increasing levels of potassium bromide led to a decline in ochratoxin A production and an increase in bromo-ochratoxin B, ochratoxin B, and 4-hydroxy ochratoxin B. Nevertheless, A. ochraceus was much less versatile in the bromo analogues than other fungi, which produce metabolites containing chlorine. Analysis included aminopropyl solid-phase extraction column cleanup followed by quantitative analysis on reversed-phase HPLC using fluorescence detection and employing N-(5-chloro-2-hydroxybenzoyl)phenylalanine as an internal standard.     

滨海盐碱地基盘法造林试验

为研究推广基盘法造林技术在我国沿海盐碱地区的应用,以唐山市南堡盐场重盐碱地为研究对象,通过基盘育苗、修筑台田、挖排水沟、铺隔离层、客土穴移植树苗等综合措施,探讨滨海盐碱地基盘法造林技术。结果表明：种基盘具有一定阻隔盐碱的作用,其出苗率降序排列依次为Ⅲ、Ⅳ、Ⅱ、Ⅰ,即以客土、草炭、蛭石和珍珠岩体积比为5：1：2：2的种基盘出苗率最高,且蛭石和珍珠岩组合占优势的基盘配方出苗率高于草炭占优势的基盘配方;台田以南北两条“十”字式（炉渣）的排盐阻盐效果最好,炉渣隔离层比建筑垃圾隔离层的排盐阻盐效果要好;客土穴起到了较好的改土阻盐效果,大部分移植树苗成活。研究结果可为滨海盐碱地造林提供改土阻盐技术支持。     

Influence of the soil composition on the effects of benzoxazinoid allelochemicals on two soil nontarget organisms

Seven selected benzoxazinoid allelochemicals and synthetic reference compounds were tested for their lethal and sublethal effects in different field soils and standard soil on Folsomia candida and Poecilus cupreus by applying standard laboratory test procedures. The higher microbial activity in the field soils was most probably responsible for the reduced effects of test compounds on F. candida in the majority of all tests, whereas the higher organic carbon content in field soils was likely the reason for the reduced effects of test substances on P. cupreus.     

Influence of exchangeable potassium on soil erodibility

Abstract. Regular application of slurry manure in large quantities is thought to degrade soil structure and increase erodibility. One hypothesis links this to the large input of potassium which increases the exchangeable potassium percentage (EPP) and, thereby, dispersion. The effect of EPP on erodibility was quantified in three experiments. In the laboratory, eleven rainfall experiments were conducted using a silty topsoil from a typic Hapludalf which was fertilized to EPPs of 4 to 18%. Field rainfall experiments on 22 Inceptisols and Alfisols were used to examine whether the long-term application of monovalent cations (Na⁺, K⁺ and NH₄⁺) with slurry manure had changed soil properties, especially erodibility. In addition, erodibilities of 32 soils determined with natural and simulated rains were taken from literature. The experiments on these 65 soils together covered a wide range of soils, slopes and rainfalls. Dispersion by a large percentage of highly hydrated ions (K⁺, Na⁺) reduced the infiltration rate faster, caused runoff up to 5 min earlier, and increased sediment concentrations by 15g/l compared to low EPP soils. These changes increased soil erodibility of the Universal Soil Loss Equation (USLE) by 0.021 t × h/N × ha (where N = Newtons) for each 1% increase in EPP + ESP (exchangeable sodium percentage). The ESP contributed little to this increase as ESP was less than 1/10 of EPP in the experiments.
Fields with long-term manure application had similar chemical, physical and microbiological soil properties as fields without slurry manure except for slightly greater pH (+ 0.6) and P (+ 17 mg/kg) values. We conclude that, as long as the potassium input and output are balanced, the long-term use of slurry manure does not increase erodibility.     

Influence of microwave radiation on soil bacteria

Cultures of different soil bacteria were used in the experiment. Both the suppression and the stimulation of the growth were observed for different bacterial species under the impact of microwaves. Spore suspensions responded to microwave radiation upon a shorter time of exposure than suspensions of vegetative bacterial cells. The influence of microwave radiation on the biomass accumulation and the intensity of other physiological processes in different species of streptomycetes led to changes in the number and activity of these microorganisms in the soil microbial complex. Changes in the capacity of streptomycetes for assimilation of substrates under the impact of microwaves were identified by the method of multisubstrate testing.     

Influence of earthworm middens on the distribution of soil microarthropods

Summary Earthworm middens and non-midden soil were sampled for microarthropods in a mowed recreational field and and adjacent woodlot site. Samples were taken in fall 1983 and spring 1984. The earthworm middens of the mowed field supported a higher density of micrarthropods (especially Collembola and prostigmatid mites) than adjacent non-midden soil. This positive midden effect in the mowed field was more pronounced in the fall than in the spring. Woodlot earthworm middens examined in the fall had lower densities of microarthropods (especially oribatid mites) than adjacent non-midden soi, but in the spring woodlot middens supported greater densities of microarthropods (especially Collembola) than adjacent, non-midden soil.     

Influence of dispersion treatments on the properties of soil colloids

The identification and characterization of clay minerals in the soil have been carried out on the clay fraction separated from a dispersed soil suspension. The process of dispersion includes the replacement of exchangeable divalent cations with H-ions by the dilute acid treatment, the removal of organic matter with hydrogen peroxide, and the dissolution of free iron oxides with reducing and/or chelating agents.     

黑土区土壤侵蚀厚度对土地生产力的影响及其评价

为了研究黑土区土壤侵蚀厚度对土地生产力的影响,采用盆栽试验,人为剥离黑土表层0、5、10、15、20、25和30 cm土壤以模拟侵蚀厚度不同的耕层土壤,分析土壤侵蚀厚度对土壤理化性质、大豆生物性状和水分利用效率等指标的影响。并对TOPSIS(technique for order preference by similarity to ideal solution)模型进行改进,用于评价侵蚀厚度不同的土壤的土地生产力。结果表明:土壤全N、碱解N、全P、速效P、有机质含量和土壤田间持水率均随侵蚀厚度的增加而递减,土壤容重随侵蚀厚度的增加而递增。土壤侵蚀厚度对大豆生长有显著影响,随着侵蚀厚度的增加,大豆减产率呈"S型"曲线递增,产量、耗水量呈"Z型"曲线递减,水分利用效率呈指数曲线关系递减。改进的TOPSIS模型对不同侵蚀厚度下土地生产力的评价结果较为理想,计算的土地生产力指数随土壤侵蚀厚度的变化呈"Z型"曲线,与大豆产量的变化趋势相同,且二者呈指数函数关系,决定系数达0.996,均方根误差为0.65。研究结果可为黑土区土壤侵蚀防治提供理论依据。     

Influence of carbon amendments on soil denitrifier abundance in soil microcosms

It is known that carbon (C) amendments increase microbial activity in anoxic soil microcosm studies, however the effects on abundance of total and denitrifier bacterial communities is uncertain. Quantitative PCR was used to target the 16S rRNA gene for the total bacterial community, the nosZ functional gene to reflect a broad denitrifier community, and functional genes from narrow denitrifier communities represented by Pseudomonas mandelii and related species (cnorB_P) and Bosea/Bradyrhizobium/Ensifer spp. (cnorB_B). Repacked soil cores were amended with varying amounts of glucose and red clover plant tissue (0–1000 mg C kg^? 1 of soil) and incubated for 96 h. Carbon amendment significantly increased respiration as measured by cumulative CO₂ emissions. Inputs of red clover or glucose at 1000 mg C kg^? 1 of soil caused increased abundance in the total bacteria under the conditions used. There was about an approximate 2-fold increase in the abundance of bacteria bearing the nosZ gene, but only in treatments receiving 500 or 1000 mg C kg^? 1 of soil of glucose or red clover, respectively. Additions of ≥ 500 mg C kg^? 1 soil of red clover and ≥ 250 mg C kg^? 1 of glucose increased cnorB_P-gene bearing denitrifiers. Changes in abundance of the targeted communities were related to C availability in soil, as indicated by soil respiration, regardless of C source. Applications of C amendments at rates that would occur in agricultural soils not only increase microbial activity, but can also induce changes in abundance of total bacterial and denitrifier communities in studies of anoxic soil microcosms.     

Influence of cultivation on soil nitrogen pools

Abstract

Exchangeable NH₄, organic N, and fixed NH₄, were followed in three soil layers (0–25, 25–50, and 50–75 cm) of plots under conventional and minimum tillage in a 10—year field experiment. The main effect of both tillage treatments was a marked increase of fixed NH₄ during the first two years which was attributed to the heavy application of N fertilizers because soils were not fertilized prior to the experiment. Due to spatial variability of soil composition, a statistically significant increase over the 10—year was observed for total and fixed NH₄ only in the surface layer of conventionally tilled soils, probably due to thorough mixing caused by intense cultivation. In this layer the organic N pool did not appear to vary with the years, while the fixed NH₄ pool was influenced by N fertilization. A general trend was a uniform increase of the ratio between fixed NH₄ and total N. Under conventional tillage, the trend was similar for the three soil layers while the reduced amount of fixed NH₄ present in the upper soil layers (0—25 and 25–50 cm) was assumed to be caused by root absorption. Under minimum tillage, the increase of fixed NH₄ ratio was limited to the first 50 cm of soil, and was less pronounced in the top layer where maximum root accumulation is generally expected to be present. The data support the importance for crops of the fixed NH₄ pool.