Soil pH,extractable aluminum and tree growth on acid minesoils

Abstract

Paper birch and hybrid poplar were grown in acid minesoils amended with different rates and types of lime. Growth of the trees was correlated with soil pH, Ca, Mg, K, P and three measures of extractable Al ‐ 1 N KCl, 0.01 M CaCl₂ and H₂O extractable Al. Correlations between soil pH and extractable Al and between the three measures of extractable Al were also determined. Soil pH accounted for the largest share of the total variation in root and shoot growth of both species over all soils. Correlations between tree growth and extractable Al for all soils combined were low and generally non‐significant. Significant correlations were obtained between soil pH and extractable Al and between the three measures of extractable Al, however, the relationships varied among soils.     

The profile distribution of total and extractable copper in selected Nigerian soils

Abstract

The profile distribution of total, DTPA‐ and 0.1N HCl‐extractable Cu was determined in 11 Nigerian soil profiles formed from various parent materials including the coastal plain sands, shales, basalt, granite and banded gneiss.

Total Cu ranged from 7 to 72 ppm with a mean of 35 ppm₀ The soils formed from basalt had the highest values while those on coastal plains had the least content. Generally, there was a higher content in the subsoils than in the surface horizons. The total Cu significantly correlated with percent clay and the free oxide contents of Fe and Mn.

DTPA ‐ and 0.1N HCl‐extractable Cu ranged from 0.08 to 2.81 ppm and 0.10 to 7.78 ppm, respectively. Soils on metamorphic rocks gave the highest values of DTPA‐extractable Cu. The DTPA‐extractable Cu ‐was only related to pH but the acid extractable Cu was associated with total Cu, clay, free Fe₂O₃ and MnO₂ contents.     

鸡粪等有机肥料的养分释放及对土壤有效铜、锌、铁、锰含量的影响

采用室内培养法研究鸡粪、牛粪和猪粪等畜禽有机肥料的矿化率和速效氮、磷、钾养分释放特性,并探讨施用有机肥料对土壤有效铜、锌、铁、锰含量的影响。结果表明,鸡粪、牛粪和猪粪等畜禽有机肥料当季(120d)有机碳矿化率分别为87．5％、71．9％和55．4％,碱解氮释放量分别为39．9％、20．6％和35．3％,速效磷释放量分别为24．6％、61．3％和34．8％,速效钾释放量分别为78．8％、36．8％和41．5％。供试条件下土壤有效铜、锰含量增加,但有效锌含量降低,施用鸡粪可使土壤有效铁含量增加,而施用牛粪和猪粪则使土壤有效铁含量降低。     

The profile distribution of total and extractable zinc in selected Nigerian soils

Abstract

The profile distribution of total, DTPA‐ and 0.1 N HC1‐extractable Zn was determined in 11 Nigerian soil profiles formed on various parent Materials including the coastal plain sands, shales, basalt, granite and banded gneiss.

The total content ranged from 9 to 84 ppm. Generally soils developed on igneous rocks contained more Zn than those on sedimenatary deposits. Among the soils on sedimentary rocks, those on shale had more total Zn than those on sandstones. Total Zn was weakly correlated with organic matter but strongly associated vith clay content and free oxides of iron and manganese.

The amounts of Zn extracted by DTPA and 0.1 N HC1 ranged from 0.01 to 10.98 and from 0.23 to 6.25 ppm, respectively. The dilute acid generally removed more Zn from the soils than did the DTPA. The amounts extracted generally decreased vith depth especially vith DTFA extractant. Soils developed on basalt and shales contained the highest amounts of 0.1 N HCl‐extractable Zn while those on basement complex rocks gave the highest values of DTPA‐extractable Zn. Extractable Zn from soils on coastal plain sands remained relatively lev. The extractable Zn was more associated vith organic matter than vith clay content.     

畜禽粪肥对土壤有效铜锌铁锰含量的影响

采用室内培养和DTPA浸提法研究了鸡粪、牛粪和猪粪等有机肥料对土壤有效Cu、Zn、Fe、Mn含量的影响。结果表明,在供试条件下施用鸡粪、牛粪和猪粪均可使土壤中有效Cu、Mn含量增加,但有效Zn含量降低;施用鸡粪可使土壤有效Fe含量增加,而施用牛粪和猪粪使土壤有效Fe含量降低。增加鸡粪施用量,可使土壤中有效Cu、Zn、Fe、Mn含量增加;培养期间有效Cu、Zn含量变化幅度较小,有效Fe、Mn含量变化较大。     

Influence of organic amendments on Fe,Cu, Mn,and Zn availability and clay minerals of different soils

The effects of application of composted olive mill wastewater sludge (A) and depotassified sugarbeet vinasse (V) on total diethylenetriaminepentaacetic acid (DTPA) and sequential extracted micronutrients were investigated. The mineralogy of the fine fraction of soils was also studied. The soils used were a Typic Rhodoxeralf (soil R), a Typic Xeropsamment (soil S), and a Typic Xerorthent (soil C). Fertilization with A and V during 3 years, in general did not significantly affect the total concentration of Fe, Cu, Mn, and Zn versus the control. However, the elements extracted with DTPA generally increased with the organic amendments, more with A than with V. The BCR (European Community Bureau of Reference) sequential extraction indicated that the addition of organic matter generally increased Zn and Mn in the two more available fractions. A great amount of Fe was found in the second and third fractions from the unamended and amended soils. Nevertheless, the sum of the three fractions was enhanced for the organic amendment, except for calcareous soil. The distribution of these elements in the different fractions was significantly affected by the type of soil. The addition of both fertilizers caused modifications in particle size and consequence redistribution of the calcite content between the different fractions.     

Comparison of MnSO4 and MnEDTA for soybeans grown on two soils in the greenhouse

Abstract

A greenhouse experiment was conducted to compare MnSO₄ and MnEDTA as Mn sources. Four soil‐applied rates of each source were applied to two Coastal Plain soils, a Leefield s (pH 6.3) and an Alapaha is (pH 7.0). Plants were grown for 40 days and dry tissue weights were recorded along with leaf contents of Mn, Zn, Fe and Cu. The same ions were extracted from the soil with DTPA. The chelate source caused no differences in either extractable soil Mn or plant Mn between soils or among rates even when added at its highest rate of 2 μgMn/g. The sulfate source increased extractable soil Mn and plant Mn over the various rates but more so for the Alapaha soil than for the Leefield. Plant weights were not different between sources except on the averages for the Leefield soil. However, for the Leefield soil and the sulfate source, plant weights were lower for the check than for intermediate Mn rates due to Mn deficiency and lower for the high Ma rate (50 μg/g) presumably due to toxicity. A correlation coefficient of 0.866** was obtained for soil‐extracted Mn versus plant Mn concentration indicating that the DTPA was a good extractant for these two soils. High correlations between plant and soil Mn versus plant and soil Zn, Fe, and Cu for the chelate source showed that the MnEDTA affected metal ion availabilities other than just Mn. It was concluded that the MnSO₄ was the better source at the rates used and that for these soils the best rate was S μgMn/g applied to the soil.     

Evaluating baseline data for trace elements,pH, organic matter content,and bulk density in agricultural soils in Nigeria

Agricultural soil samples were collected about 1 km apart over 21 km from 32 tilled/cultivated plots of yam, rice, and cassava in urban, rural, and the derelict Enyibga lead-zinc mine (EM) in the Abakaliki area, Nigeria during the rainy season in September, 1992. In the derelict mine, mean elemental contents increased in the order Cd < Ni < Cu < Mn < Pb < Zn; while in the urban, rural, and all soils combined, the order increased as follows: Cd < Cu < Ni < Pb < Zn < Mn. The overall mean distribution of all soils shows Mn and Zn to approach and exceed toxic levels, respectively. In all soils, the total mean concentrations of Cu and Ni are well below toxic levels. The Abakaliki area is less likely to be subjected to Cd-contaminated soils. Pb was excessively high at EM and, moderately high at Mgbowo Street in the urban area, but very less so in the rural areas. The rural agricultural areas of Agbaja, Nkwaegu, and Amaegu, including the isolated Ezza Road as well as the peripheral Expressway had relatively lower levels of heavy metals, pH and organic matter content than the urban conglomeration of Mile 50, Mgbowo Street, and Azuiyiokwu including the derelict mining village of Enyigba and EM; except that Ezza Road had pH and organic matter as high as the densely populated urban cultivated areas. The relationship between bulk density and organic matter was highly dependent on pH.     

Biological, chemical and thermal indices of soil organic matter stability in four grassland soils

The various ecosystem functions of soil organic matter (SOM) depend on both its quantity and stability. Numerous fractionation techniques have been developed to characterize SOM stability, and thermal analysis techniques have shown promising results to describe the complete continuum of SOM in whole soil samples. However, the potential link between SOM thermal stability and biological or chemical stability has not yet been adequately explored. The objective of this study was to compare conventional chemical and biological methods used to characterize SOM stability with results obtained by thermal analysis techniques. Surface soil samples were collected from four North American grassland sites along a continental mean annual temperature gradient, each with a native and cultivated land use. Soil organic C concentrations ranged from 6.8 to 33 g C kg⁻¹ soil. Soils were incubated for 588 days at 35 °C, and C mineralization rates were determined periodically throughout the incubation by measuring CO₂ concentration using an infrared gas analyzer (IRGA) to calculate biological indices of SOM stability. Hot-water extractable organic C (HWEOC) contents were determined before and after incubation as chemical indices. Finally, samples from before and after incubation were analyzed by simultaneous thermal analysis (i.e., thermogravimetry (TG) and differential scanning calorimetry (DSC)) to determine thermal indices of SOM stability. Long-term incubation resulted in the mineralization of up to 33% of initial soil C. The number of days required to respire 5% of initial soil organic carbon (SOC), ranged from 27 to 115 days, and is proposed as a standardized biological index of SOM stability. The number of days was greater for cultivated soils compared to soils under native vegetation, and generally decreased with increasing site mean annual temperature. HWEOC (as % of initial SOC) did not show consistent responses to land use, but was significantly lower after long-term incubation. Energy density (J mg⁻¹ OM) was greater for soils under native vegetation compared to cultivated soils, and long-term incubation also decreased energy density. The temperatures at which half of the mass loss or energy release occurred typically showed larger responses to land use change than to incubation. Strong correlations demonstrated a link between the thermal and biogeochemical stability of SOM, but the interpretation of the thermal behavior of SOM in bulk soil samples remains equivocal because of the role the mineral component and organo-mineral interactions.     

Erosional impact on organic matter content and productivity of selected Iowa soils

From 1983 to 1989 an erosion-productivity study was conducted in Iowa. The primary objective of this project was to determine the effects of accelerated erosion and its interactions with other variables on soil productivity, as measured by corn yields of loess and till-derived soils in Iowa. Multiple regression techniques were used to relate corn yields to erosion and selected soil, climatic, and weather variables. Organic matter content of the soils was significantly correlated with erosion phase. Yields of till-derived soils decreased more with increasing degree of erosion than loess-derived soils. The conclusions are based on data collected at 569 sites located in 44 Iowa counties.     

High clay content accelerates the decomposition of fresh organic matter in artificial soils

Clay is generally considered an important stabiliser that reduces the rate of decomposition of organic matter (OM) in soils. However, several recent studies have shown trends contradicting this widely held view, emphasising our poor understanding of the mechanisms underlying the clay effects on OM decomposition. Here, an incubation experiment was conducted using artificial soils differing in clay content (0, 5, and 50%) at different temperatures (5, 15, and 25 °C) to determine the effects of clay content, temperature and their interaction on fresh OM decomposition. CO₂ efflux was measured throughout the experiment. Phospholipid fatty acids (PLFAs), enzyme activities, microbial biomass carbon (MBC), and dissolved organic carbon (DOC) were also measured at the end of the pre-incubation and incubation periods in order to follow changes in microbial community structure, functioning, and substrate availability. The results showed that higher clay contents promoted OM decomposition probably by increasing substrate availability and by sustaining a greater microbial biomass, albeit with a different community structure and with higher activities of most of the extracellular enzymes assayed. Higher clay content induced increases in the PLFA contents of all bacterial functional groups relative to fungal PLFA content. However, clay content did not change the temperature sensitivity (Q₁₀) of OM decomposition. The higher substrate availability in the high clay artificial soils sustained more soil microbial biomass, resulting in a different community structure and different functioning. The higher microbial biomass, as well as the changed community structure and functions, accelerated OM decomposition. From these observations, an alternative pathway to understanding the effects of clay on OM decomposition is proposed, in which clay may not only accelerate the decomposition of organic materials in soils but also facilitate the SOM accumulation as microbial products in the long term. Our results highlight the importance of clay content as a control over OM decomposition and greater attention is required to elucidate the underlying mechanisms.     

Effect of pH,organic matter content and nitrate on the evolution of ethylene from soils

The evolution of C₂H₄ from soils was stimulated by air-drying, and still more by oven-drying at 105°C. The quantities evolved were closely correlated with organic matter content, with no significant difference in this relationship between grassland and arable soils, or between topsoil and subsoil. In arable soils only, the quantities of C₂H₄ also increased significantly with decreasing pH. No significant relationship could be found between NO₃^? concentrations in fresh soils and the quantities of C₂H₄ evolved, but for air-dried soils (arable only) there was a significant decrease with increasing NO₃^?. Artificial addition of NO₃^? only partially inhibited the evolution of C₂H₄, even at concentrations an order of magnitude higher than those found in the field. At normal soil concentrations the only effect of NO₃^? seems likely to be a short delay in the achievement of the maximum C₂H₄ concentrations.     

硼、锌和铁对龙胆中龙胆苦dan含量和产量的影响

A field experiment of 2-year-old gentian （Gentiana manshurica Kitag.） with application of boron （B）, zinc （Zn）, and iron （Fe） in Taikang County, Heilongjiang Province, was conducted to study the effects of the three microelements on gentiopicroside content in the roots of gentian, uptake of these elements, and root dry weight as well as the ratio of root dry weight to fresh weight. Zinc sulfate, ferrous sulfate, and borax were split sprinkled on 2-year-old gentian on June 26, July 18, and August 25, 2002, with sprinkling water taken as a control. Compared with the control, applying B significantly increased （P 〈 0.05） the gentiopicroside content by 7.9%, and there was a highly significant increase of 22.4% （P 〈 0.01） in the root dry weight. Meanwhile, B content in the shoots of gentian gradually increased from the vegetative to the harvesting period, while Fe decreased at first and then increased. Fc treatment increased the gentiopicroside content only by 4.0% and the content was slightly decreased by the Zn treatment （3.1%） as compared to the control. The three microelements had different effects on the gentiopicroside content and appropriate microelement application could increase active ingredient content of gentian.     

土壤锌、铁、铜、锰形态的分布及其与植物有效性的关系

The distribution of various fractions of Zn,Fe,Cu and Mn in 15 types of soils in China and its relationship with plant availability were studied.Fractions of various elements were found to have some similar characterstic distribution regularities in various types of soils,but various soil types differed to varying degrees in the distribution of each fraction.Soil physico-chemical properties,such as pH,CEC and the contents of OM,CaCO3,free Fe,free Mn and P2O5,were significantly correlated with the distribution of elemental fractions,and a significant correlation also existed between the distribution and plant availability of elemental fractions.Various fractions of each element were divided into two groups based on their plant availability.The correlation between the distribution of combination fractions and plat availability indicated a significantly or an extremely significantly positive correlation for Group I but a significantly or an extremely significantly negative correlation for Group II.Therefore,the fractions in Goup I were primary pools of available nutrients,while those in Group II could hardly provide available nutrients for plants.Decreasing the transformation of corresponding elements into fractions of Group II and increasing the storage capacity of various fractions of Group I were an important direction for regulation and controlling of soil nutrients.However,some Particular soils with too high contents of Zn,Fe,Cu and Mn should be regulated and controlled adversely.     

三江平原白浆土中Fe、Mn、Cu和Zn生物有效性的研究

在三江平原上,测定 42 个小区中玉米、大豆、小麦籽实 Fe、Mn、Cu 和 Zn 含量和土壤中各形态 Fe、Mn、Cu 和Zn含量.通过相关分析和通径分析,探讨了土壤中各形态Fe、Mn、Cu 和 Zn 的生物有效性,旨在为该地区合理施用微量元素提供科学依据.试验结果表明,玉米、大豆和小麦籽实含 Fe、Mn、Cu 和 Zn 量与土壤中有效态和交换态 Fe、Mn、Cu和Zn含量呈显著或极显著正相关.有机态 Fe、Mn、Cu 和 Zn含量与玉米、大豆和小麦籽实Fe、Mn、Cu 和 Zn含量也有很好的相关关系.交换态对有效态 Fe、Mn、Cu 和 Zn 影响最大,其次是有机质结合态.铁锰氧化物结合态 Fe、Cu 对有效态 Fe、Cu 及碳酸盐结合态 Mn、Zn 对有效态 Mn、Zn 具有一定正效应.而残留态 Fe、Cu 对有效态 Fe、Cu 和铁锰氧化物结合态 Mn 对有效态 Mn 产生负效应.     

Examination of thermal and acid hydrolysis procedures in characterization of soil organic matter

Abstract

Differential thermogravimetry (DTG), differential scanning calorimetry (DSC), and stepwise thermogravimetry (STG), together with two acid hydrolysis methods (hydrolysis with hydrochloric acid in a single step, and hydrolysis with sulfuric acid in two steps), were evaluated to determine the quality of four plant materials (Medicago sativa, Eucalyptus globulus, Quercus ilex, and Pinus halepensis) before and after mixing with a red earth. These quality indices were then compared with the same materials in the field, whether their decomposition could be predicted. All the thermal methods gave poor results. In both DTG and DSC, the presence of the mineral matrix gave rise to strong distortions in the spectra. Since the spectrum of any mixture is not simply the sum of the spectra of the two components (organic matter + mineral matter), these distortions could not be corrected by simply subtracting the spectrum of the red earth alone. STG trials also gave poor results, because the presence of the mineral matrix greatly increased the quality indices, and reduced the ability of the method to distinguish between organic matter qualities. In view of our results, the usefulness of thermal methods in the characterization of soil organic matter would seem to be restricted to certain organic horizons (L, F, and perhaps H). In contrast, methods based on acid hydrolysis were comparatively more satisfactory. Their resolution (ability to distinguish organic matter qualities) was much higher than that of thermal methods. However, they were able to distinguish carbon more accurately than nitrogen. The sulfuric acid method, unlike the hydrochloric acid method, was affected by the presence of a mineral matrix. While both methods could be improved, in their present form they seem to operate as good predictors of carbon and nitrogen mineralization.     

The influence of the moisture content,texture and organic matter on the aggregation of sandy and loamy soils

It is generally accepted that water is one of the major factors involved in the aggregation process. This is proved by the change in bulk density of a soil wetted to different water contents and submitted to a certain number of standardized knocks.The water content corresponding to a minimal bulk density, resulting in an optimal aggregation, is called optimal or critical moisture content. The corresponding suction or critical capillary depression is inversely proportional to the particle size and thus will increase as the latter decreases. The pF-value at the critical moisture content ranges between 2.30 for sand and 3.32 for sandy loam.Organic matter also plays an important role in the aggregation process, but has no influence on the critical capillary depression. From a quantitative point of view the organic matter is a better aggregation agent than clay and silt.     

Soil organic matter turnover as a function of the soil clay content: consequences for model applications

Based on a literature review including 201 surface soils from wet, mild, mid-latitude climates and 290 soils from the Lower Saxony soil monitoring programme (Germany), we investigated the relationship between soil clay content and soil organic matter turnover. The relationship was then used to evaluate the clay modifier for microbial decomposition in the organic matter module of the soil-plant-atmosphere model DAISY. A positive relationship was found between soil clay content and soil microbial biomass (SMB) C. Furthermore, a negative relationship was found between soil clay content and metabolic quotient (qCO₂) as an indicator of specific microbial activity. Both findings support the hypothesis of a clay dependent capacity of soils to protect microbial biomass. Under the differing conditions of practical agriculture and forestry, no or only very weak relationships were found between soil clay content and non-living soil organic matter C (humus C). It is concluded that the stabilising effect of clay is much stronger for SMB than for humus. This is in contrast to the DAISY clay modifier assuming the same negative relationship between soil clay content, on the one hand, and turnover of SMB and turnover of soil humus on the other. There is a positive relationship between SMB and microbial decomposition activity under steady-state conditions (microbial growth≈microbial death). The original concept of a biomass-independent simulation of organic matter turnover in the DAISY model must therefore be rejected. In addition to the original modifiers of organic matter turnover, a modifier based on the pool size of decomposing organisms is suggested. Priming effects can be simulated by applying this modifier. When using this approach, the original modifiers are related to specific microbial activity. The DAISY clay modifier is a useful approximation of the relationship between the metabolic quotient (qCO₂) as an indicator of specific microbial activity and soil clay content.     

Contribution of primary organic matter to the fatty acid pool in agricultural soils

Fatty acids as major compounds of soil lipids may affect many soil properties, but the input and turnover rates in soil are largely unknown. The objective of this study was to identify and quantify fatty acids in soils as a result of input from primary sources such as plant residues, farmyard manure and soil organisms, and to evaluate the corresponding turnover- and stabilization processes. The concentrations of n-C_10:0 to n-C_34:0 fatty acids were determined in the Ap horizon of a Phaeozem with long-term cropping of rye and maize and the treatments ‘Unfertilized’ (‘U’) and fertilized with ‘Farmyard manure’ (‘FYM’). The most important primary sources of fatty acids such as rye and maize stubble and roots, soil micro- and mesofauna, and the applied FYM were also investigated. The quantification of fatty acids by gas chromatography/mass spectrometry (GC/MS) showed that long-term FYM application led to larger concentrations of n-alkyl fatty acids in the plots grown with rye (‘U’: 48.1 μg g⁻¹, ‘FYM’: 57.7 μg g⁻¹, **P≤0.01, n=3) and maize (‘U’: 17.0 μg g⁻¹, ‘FYM’: 23.4 μg g⁻¹, ***P≤0.001, n=3). The observed bimodal fatty acid distribution in soils from n-C_10:0 to n-C_21:0 and from n-C_21:0 to n-C_34:0 with a predominance at n-C_16:0 and at n-C_28:0 was apparently due to input from crop residues, soil organisms and FYM. The short-chain lengths may have originated from the investigated primary sources. The major contributors to the long-chain lengths, with a maximum at n-C_28:0, were rye stubble and FYM. A change in mono-culture from rye to maize, 38 years prior to sampling, led to a decrease in fatty acid concentrations by factors of about 2.8 (‘U’) and 2.5 (‘FYM’). Therefore, rye-derived fatty acids and soil tillage had a larger impact on fatty acid pools than the input of primary organic matter. The changes in fatty acid distributions and pools under the consideration of the quantified input of primary organic matter led to the conclusion that the short-chained fatty acids were more rapidly decomposed than the long-chains.