Effect of sewage sludge on nitrogen availability in peat

Summary We studied the effect of incubating peat with lime and sewage sludge in small proportions on biological activity and N mineralization. The peat response was dependent on pH and, in acid peats, on mineralization capacity. In acid peats, the addition of sewage sludge inhibited biological activity. Only the most eutrophic peats (Herbosa) responded with accelerated mineralization. The addition of lime to acid peats favoured organic matter mineralization, shown by a greater CO₂ release. The best results were obtained by adding lime and sewage sludge together. In saline peats, the best N levels were obtained without incubation.     

汞在泥炭上的吸附特征研究

采用批次法研究了汞在三江平原泥炭、吉林双阳泥炭上等温吸附特征及介质pH值、背景离子浓度的影响。实验结果表明:两种泥炭吸附等温线均同时符合Langmuir和Freundlich等温吸附方程,而与Langmuir方程的拟合效果更好; 在溶液汞浓度相同时,温度升高,泥炭对汞的吸附量降低;在相同的条件下,三江平原泥炭对汞的吸附量大于吉林双阳泥炭对汞的吸附量;两种泥炭对汞的吸附量受pH值的影响明显且都在pH 6.0左右具有最大的吸附量;在酸性条件下,吸附介质的pH值升高利于泥炭对汞的吸附;介质的离子浓度升高,可以使两种泥炭对汞的吸附量迅速降低。     

The nitrogen content of particle size fractions separated from peat and its rate of mineralization during incubation

Particle size fractions, varying from 5 to 0.005 mm, were separated from samples of several peat types using a wet sieving technique. In all types, nitrogen content of fractions increased as particle size decreased, the fine fractions (0.15–0.005 mm) accounting for around 43–64% of the total nitrogen. During incubation, fractions from two blanket peats showed a net release of mineral nitrogen, whereas those from raised bog peats were characterized, for the most part, by net immobilization. Amounts of mineral nitrogen released in fractions from any one peat after 28 days incubation at 30°C did not always correlate with either total nitrogen content or C:N ratio. However, better correlations between mineral nitrogen production and total N were obtained for fractions of similar particle size. The proportion of the total nitrogen that was mineralized tended to be higher in coarse fractions > 0.15 mm, blanket peats giving much higher values than samples from raised bogs. Carbon dioxide release also varied with particle size, being highest in large particles and fibres and least in the size range 0.15–0.5 mm. Smaller particles < 0.15 mm, gave intermediate values that were higher in blanket than in raised bog peat.     

Carbon decomposition processes in a peat from the Australian Alps

Carbon dioxide emissions and the mass loss of peat incubated in situ were measured in peat soils in the Australian Alps. The carbon chemistry of incubated peats was characterized using ¹³C nuclear magnetic resonance (NMR). In situ decomposition decreased as a function of increasing alkyl carbon content of the initial organic matter, providing direct evidence of the oft‐cited link between substrate quality and decomposition rates. More mass loss occurred in the bog peat samples than in the dried peat samples. However, at the peat surface, the amount of CO₂ emitted was not significantly different between bog peat and dried peat. Carbon inputs, and therefore the sink or source status, of these peats are yet to be quantified.     

潍坊市土壤大量营养元素有效量及其影响因素

为研究山东省潍坊市土壤大量营养元素有效量分布规律及其影响因素，通过网格化采样，并进行分析测试，获得了碱解氮、有效磷、速效钾等土壤大量营养元素有效量，及对应元素全量、pH和有机质等数据，进行了丰缺空间绘图、相关性和差异性分析。结果表明：碱解氮、有效磷、速效钾含量均具有较强的空间变异性，尤以有效磷变异系数最高。空间分布上，碱解氮以较缺乏区占比最高，有效磷和速效钾以丰富区占比最高。碱解氮、有效磷、速效钾分别在砂姜黑土、潮土、滨海盐土中含量最高，且均与其他土壤类型差异显著。碱解氮、有效磷、速效钾与土壤理化指标关系密切，3种元素有效量均与有机质呈显著正相关；碱解氮与全氮、有效磷与全磷均呈显著正相关；碱解氮、有效磷与土壤pH均呈显著负相关；速效钾与土壤pH呈显著正相关。本研究揭示了大量营养元素有效量在土壤中的本底差异及影响因素，可为土壤肥力的空间调控提供科学依据，助力提升农业生产力水平。     

A Comparative Study of the Use of Organic Carbon and Loss on Ignition in Defining Tropical Organic Soil Materials

Organic soils or Histosols or peats as they are commonly referred to, are characterized by the presence of large amounts of organic soil materials (OSM), which is commonly quantified by the Walkley and Black (1934) (WB) method to determine the soil organic matter (SOM) using a correction factor of 1.724. SOM of Histosols is also identified through a combustion (loss on ignition, LOI) or elemental C-analysis (with a carbon-nitrogen-sulfur (CNS) analyzer with combustion and gas density detector). These methods were established using temperate and boreal peat deposits and here we demonstrate that tropical peat deposits require a modified approach. Typical SE-Asian tropical lowland peat pedons from rain forest and oil palm settings were sampled and the material analysed using a CNS analyzer, WB-C and LOI. The ratios for LOI:CNS-C for the 20 samples yielded values between 2.00–3.09 with a mean of 2.50 while the LOI:WB-C ratio yielded values from 1.75 to 2.58 with a mean of 1.94. A comparison of these values for topsoils and subsoils showed mean ratios (LOI:WB-C) of 1.94 and 1.89 for topsoils and subsoils, respectively. The forest samples had higher LOI:WB-C ratios than the subsoils from oil palm settings (1.94 vs 1.84). These values suggest that the standard factor of 1.724 to correct OSM to SOM for tropical soils is untenable. The values to convert CNS and WB-C values of tropical topsoils/subsoils to SOM or LOI should be 2.5 or 1.9, respectively. Our results indicate a significant difference in the soil organic carbon (SOC) of tropical lowland peats depending on the method used.     

Chemical properties of upland peats influencing the retention of phosphate and potassium ions

Peat samples representing depths of 0–15 cm and 15–30 cm were obtained from 11 upland sites in southern Scotland. Their pH, ash content, cation exchange capacity, phosphate sorption index and contents of 0.1 m hydrochloric acid-extractable iron and aluminium were determined as indicators of the extent to which phosphate and potassium ions would be retained following afforestation and application of fertilizers to these sites. In all soils cation exchange capacities were considerably larger than the quantity of potassium normally applied as fertilizer. Phosphate sorption indices were closely related to the content of extractable iron and aluminium in the peat samples. When expressed on a volume basis, the indices were low compared with those published for mineral soils, and some peats appeared to have almost no capacity to sorb phosphate ions from solution.     

Soil organic matter characterization of temperate peatland soil with FTIR‐spectroscopy: effects of mire type and drainage intensity

Peatlands are an important component of the global carbon cycle because they comprise huge amounts of terrestrial carbon (C). Different conditions during peat formation and secondary peat decomposition affect the quantity and composition of soil organic matter (SOM) in peats. There are few comparative studies on the chemical composition of SOM in temperate peatland soil. This study investigates compositional changes of SOM functional groups in peats and corresponding peat‐forming plants by Fourier transform infrared (FTIR) spectroscopy. Three plant samples and 29 peat samples were taken from seven temperate peatland sites with different genesis and land‐use intensity. Site‐specific differences, such as genesis of the peat, were found to be reflected in the FTIR spectra. In general, there was more variation in FTIR spectra in samples from fens than in those from bogs and peat‐forming plants. The samples from fens have a smaller C–H absorption band than those from bogs and plants, which reflects greater biochemical activity in the minerotrophic than ombrotrophic environments. In addition to peat genesis, drainage and secondary peat decomposition also affect SOM composition substantially. The larger amounts of aliphatic compounds in undrained peats could be explained by selective preservation caused by anaerobic conditions. With increasing drainage of the sites, there was a decrease in the C–H absorption that was accompanied by a relative increase in C=O absorption. These changes in absorption intensities reflect the enhanced aerobic decomposition and mineralization that accompanies drainage and land‐use intensity. However, the ‘degree of peat decomposition’, a diagnostic tool used in the field, is not reflected by OM composition determined by FTIR spectroscopy. Our results contribute to further understanding of changes in SOM composition during peat formation and processes of secondary decomposition caused by drainage.     

风化煤腐殖酸对氮、磷、钾的吸附和解吸特性

研究了风化煤腐殖酸在不同pH值条件下对氮、磷、钾的吸附和解吸特性。结果表明,1)在pH.4～8条件下,随着氮、磷、钾初始处理浓度的增加,腐殖酸对其吸附量和解吸量均呈上升趋势,但解吸率均呈下降趋势;2)在不同pH值的介质溶液中,腐殖酸对氮、磷、钾的吸附和解吸特性不尽相同,其中,在碱性条件下,腐殖酸对氮的吸附和解吸作用较强,在酸性条件下,腐殖酸对磷的吸附和解吸作用较强,而腐殖酸对钾的的吸附和解吸作用在中性条件下更易发生;3)腐殖酸对氮、磷、钾的等温吸附可用Linear、Langmuir和Freundlich三个吸附方程来拟合,相关性达显著或极显著水平,但以Freundlich方程为最优。     

Adsorption of Potassium and Calcium Ions by Variable Charge Soils

Interactions of potassium and calcium ions with four typical variable charge soils in South China were examined by measuring pK-0.5pCa value with a potassium ion-selective electrode and a calcium ion-selective electrode,and pK value with a potassium ion-selective electrode.The results showed that adsorption of potassium and calcium ions increased with soil suspension pH,and the tendency of the pK-0.5pCa value changing with pH differed with respect to pH range and potassium to calcium ratio.Adsorption of equal amount of calcium and potassium ions led to release of an identical number of protons,suggesting similar adsorption characteristics of these two ions when adsorbed by variable charge soils.Compared with red soil,latosol and lateritic red soil had higher adsorption selectivities for calcium ion.The red soil had a greater affinity for potassium ion than that for calcium ion at low concentration,which seems to result from its possession of 2:1 type minerals,such as vermiculite and mica with a high affinity for potassium ion.The results indicated that adsorption of potassium and calcium ions by the variable charge soils was chiefly caused by the electrostatic attraction between the cations and the soil surfaces.Moreover,it was found that sulfate could affect the adsorption by changing soil surface properties and by forming ion-pair.     

Effect of Oxygen on the Adsorption of Pentachlorophenol by Peat from Water

Pentachlorophenol (PCP), a versatile biocide has been extensively used in industry and agriculture. PCP has been designated as a priority organic pollutant by the United States Environmental Protection Agency (USEPA) and its use in consumer products has been banned since 1984. Extensive use of PCP as a wood preservative has led to soil, surface water and groundwater pollution. Batch adsorption studies using peat at various dissolved oxygen (DO) levels in water showed that higher PCP removals can be attained at elevated DO levels. This effect can be quantified by a comparison of the adsorption capacities of peat from linearized Freundlich isotherms developed for different oxygen levels. An increase of approximately 300% in adsorption was observed for an increase in the DO level from 2 to 26 mg L^-1. Thus, molecular oxygen was found to significantly impact the removals of PCP by peat. The increase in adsorptive capacity of peat was not very significant for an increase in DO level from 2 mg L^-1 to 10 mg L^-1.However a rapid increase in adsorptive capacity was observed for an increase in DO level from 10 to 26 mg L^-1.     

改性泥炭对滨海盐渍土的改良作用研究

采用土培的方法,通过泥炭改性处理,研究不同泥炭对滨海盐渍土物理、化学、生物性质的影响,为滨海盐渍土快速改良提供理论依据。研究结果表明:碱改性泥炭的红外图谱特征与原始泥炭相似,但酸改性泥炭在1 710 cm–1处具有明显的特征峰;扫描电镜下,碱改性泥炭颗粒突起最少,表明碱改性泥炭质地相对均一。碱改性泥炭能够显著降低土壤p H,增加土壤团聚体;而原始泥炭提升土壤有机质和增加碱解氮含量方面效果更加明显。碱改性泥炭和原始泥炭均能够提升土壤酶活性,但酸改性泥炭对土壤酶活性存在抑制作用。相关分析结果表明,土壤p H、有效磷、速效钾与过氧化氢酶、蔗糖酶和纤维素酶的活性具有显著相关性(P0.05)。综上所述,在本次试验中,碱改性泥炭对滨海盐渍土改良作用最佳,添加改性泥炭能更有效地消减滨海盐渍土盐、碱、瘦、板、活力差等障碍因子。     

Nutrient Status in Oak Forests in Galicia,Northwest Spain: Foliar and Soil Concentration

The concentration of edaphic and foliar nutrients is an important factor in assessing the nutritional status of an ecosystem. This article presents data on the macronutrients in leaves and topsoil in Quercus robur forests located in northwest Spain. The aim is to evaluate the nutrient level explained by foliar and soil standard values and establish their relationships. We calculated the following nutrients: nitrogen, phosphorus, potassium, calcium, and magnesium. Plots 10 × 10 m were laid out and replicated three times. Soil was collected once per month with three samples from the topsoil, and leaves were collected once every 2 months during the vegetative period. Within the results, we emphasize the absence of nutrient deficiencies. The leaf macronutrient results differed by stand. Soil fertility can be considered low to medium, except for phosphorus and potassium, as compared with soils under pine and eucalyptus. There was no relationship between macronutrients in topsoil and leaves.     

Effect of peat type and ph on breakdown of peat using fourier transform infrared spectroscopy

Abstract

Information on breakdown of peats as evidenced by shrinkage during cropping is generally lacking. The objective of this investigation was to study the breakdown of peat of various degrees of decomposition, effect of pH on breakdown and to relate the compositional changes during breakdown using Fourier Transform Infrared Spectroscopy (FTIR). Incubation studies were used in this investigation. Peat with a higher level of decomposition was less susceptible to breakdown. The pH had a major effect on breakdown with high pH leading to increased rate of breakdown. Lignin content of the peats was somewhat related to breakdown of the peats. The breakdown was also strongly correlated to the changes in the ratio of FTIR spectra of the start and to the end of the incubation particularly the 1600/1060 ratio. The 1600 spectra in mostly lignin 1060 spectra are mostly carbohydrate. There was relative enrichment of 1600 spectra in relation 1060 spectra. Other FTIR spectra ratio changes were also significantly correlated with breakdown. The FTIR technique has the potential to predict breakdown of peats.     

不同原料生物炭对氮、磷、钾的吸附和解吸特性

【目的】通过三种不同原料生物炭 (玉米秆炭、稻壳炭、稻秆炭) 对氮、磷、钾的吸附解吸试验,了解不同材料来源的生物炭对无机养分的吸附和解吸特征,为将其作为添加物来调节有机肥的性质提供参考。【方法】在pH 6.75 ± 0.25、25℃下,采用Langmuir和Freundlich方程对三种不同原料生物炭 (玉米秆炭、稻壳炭、稻秆炭) 氮、磷、钾的等温吸附进行拟合。对吸附养分后的生物炭进行连续5次解吸,前4次采用水浸提,第5次浸提采用1 mol/L KCl浸提氮,0.5 mol/L的NaHCO₃浸提磷,1 mol/L的CH₃COONH₄浸提钾。【结果】1) Langmuir和Freundlich方程均可用来拟合生物炭对氮、磷、钾的等温吸附,Langmuir方程对氮、磷的吸附拟合较好,Freundlich方程对钾的吸附拟合较好。对不同原材料而言,稻秆炭对氮、磷、钾的吸附性能均较好,其最大吸附量q_m分别为 (2.44 ± 0.15) mg/g、(2.91 ± 0.12) mg/g和 (4.97 ± 0.22) mg/g。2) 不同原材料生物炭对氮、磷、钾的单次解吸率和总解吸率具有一定的差异。生物炭对阳离子 (铵根离子和钾离子) 的最大吸附量受阳离子交换量和酸性官能团的数量以及pH_pzc影响,对磷酸根的最大吸附量主要与阳离子交换量和碱性官能团的数量有关。【结论】所试三种生物炭对氮、磷、钾的吸附存在单分子层吸附和多分子层吸附,在单次解吸率和总解吸率上不同原料生物炭存在一定的差异性。在生物炭对氮和钾吸附的总量上,物理性吸附的贡献高于化学吸附;对磷的吸附总量上,化学吸附的贡献高于物理吸附。三种生物炭对氮、磷、钾的固储和缓释能力具有一定的差异,稻秆炭的保肥供肥能力优于玉米秆炭和稻壳炭。     

Growth and Nutritional Disorders of Eggplant Cultivated in Nutrients Solutions with Suppressed Macronutrients

The objective was to evaluate the effects of omitting macronutrients in the nutrients solution on growth characteristics and nutritional status of eggplants. The treatments were complete nutrients solution and solutions with nutrient omission: nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S). The experiment was carried out under greenhouse conditions with three replicates in a completely random design. Plant height, number of leaves per plant, leaf area, relative chlorophyll index, photosynthesis rate, stomatal conductance, dry matter, concentration levels of macronutrients in plant aerial part and root system, and nutritional disorders were evaluated. Omitting elements interfered in the concentration of elements in the various plant tissues and this had as consequences limited vegetative growth, reduced dry matter and led to the development of the typical deficiency symptoms of each element. Although potassium was the most demanded of all elements, nitrogen and calcium were the most growth limiting ones.     

New classification systems for tropical organic-rich deposits based on studies of the Tasek Bera Basin,Malaysia

Most schemes in common use for field and laboratory classification of peats were developed in boreal and humid temperate regions and do not recognize the distinctive features and specific uses of tropical peats, such as those of the Tasek Bera Basin in tropical Peninsular Malaysia. The important aspects of peat texture (morphology of constituents and their arrangement) and laboratory ash content (residue after ignition) need modification to be valuable for classifying these and other tropical peat deposits. In the Tasek Bera Basin, most of the deposits would not be considered as peat according to some classification schemes, even though most have C contents >25%. We propose a new three-group (fibric, hemic, sapric) field texture classification applicable to tropical organic deposits, which is similar to the system of the US Soil Taxonomy. The classification is based on the following factors: (1) visual examination of the morphology of the peat constituents (texture); and (2) estimates of fiber content and matrix (finest fraction of peat consisting of highly humified organic matter and inorganic material). The classification is applicable to all organic deposits with <65% ash (i.e., >35% loss on ignition). We also present a new laboratory classification of organic soils based on ash and C content. The US Soil Taxonomy classifies organic soils as having more than 12–18% organic C, depending on clay content. Ash content and these limits for organic soils allow the discrimination of four main groups: peat, muck, organic-rich soil/sediment and mineral soil/sediment. Peat is defined as having an ash content of 0–55%, muck 55–65%, organic-rich soil/sediment 65–80% and mineral soil/sediment 80–100%. The peat class is further subdivided into very low ash (0–5%), low ash (5–15%), medium ash (15–25%), high ash (25–40%) and very high ash (40–55%) subclasses.     

Geochemistry and geochemical differentiation on major elements in selected peat bog profiles (south-east of Poland)

Abstract

The geochemical differentiation of major elements in various peat bog profiles from Bieszczady Mountains Region (south-east of Poland) was compared to its botanical origin. Peat cores were taken from ombrotrophic, mesotrophic, and oligotrophic peatlands, which were developed in the stream valley of the River San. Twenty-four various peat samples were analysed for peat genus, degree of peat decomposition, ash content, total nitrogen, and total carbon content of hydrolytic matter as well as content of major elements: Na, K, Mg, Ca. The results show that the botanical composition of peat deposits is no reliable indication of their trophic status. The common feature of investigated Holocene peatlands is their valley localisation on the flood terrace. The specific character of local geommorpho8ogicml and hydrological condition caused that the bottom layer of all investigated bog profiles was made of wood peats (Piceaeti, Pineti, Alneti, and Saliceti peat). The geochemical investigations of stratigraphical profiles confirm that the presented peat bogs showed specific morphological separateness comparing to other raised bogs situated in mountains or lowlands     

Optimal Acidity Indices for Soybean Production in Brazilian Oxisols

Soybean is an important crop for the Brazilian economy, and soil acidity is one of the main yield-limiting factors in Brazilian Oxisols. A field experiment was conducted during three consecutive years with the objective to determine soybean response to liming grown on Oxisols. Liming rates used were 0, 3, 6, 12, and 18 Mg ha^?1. Liming significantly increased grain yield in a quadratic trend. Ninety percent maximum economic grain yield (2900 kg ha^?1) was achieved with the application of about 6 Mg lime ha^?1. Shoot dry weight, number of pods per plant, and 100-grain weight were also increased significantly in a quadratic fashion with increasing liming rate from 0 to 18 Mg ha^?1. These growth and yield components had a significant positive association with grain yield. Maximum contribution in increasing grain yield was of number of pods per plant followed by grain harvest index and shoot dry weight. Uptake of nitrogen (N) was greatest and phosphorus (P) was least among macronutrients in soybean plant. Nutrient-use efficiency (kg grain per kg nutrient accumulation in grain) was maximum for magnesium (Mg) and lowest for N among macronutrients. Application of 3 Mg lime ha^?1 neutralized all aluminum ions in soil solution. Optimal acidity indices for 90% of maximum yield were pH 6.0, calcium (Ca) 1.6 cmol_c kg^?1, Mg 0.9 cmol_c kg^?1, base saturation 51%, cation exchange capacity (CEC) 4.8 cmol_c kg^?1, Ca/Mg ratio 1.9, Ca?/?potassium (K) ratio 5.6, and Mg/K ratio 3.0.     

Growth and nutritional disorders of coffee cultivated in nutrient solutions with suppressed macronutrients

The objective was to evaluate the effect of omitting macronutrients in the nutrients solution on growth characteristics and nutritional status of coffee. The treatments were complete nutrients solutions and solutions with nutrient omission: N (nitrogen), P (phosphorus), K (potassium), Ca (calcium), Mg (magnesium) and S (sulfur). The experiment was carried out under greenhouse conditions with 3 replicates in a completely random design. Plant height, number of leaves per plant, stem diameter, relative chlorophyll index, photosynthesis rate, stomatal conductance, transpiration, carbon dioxide (CO₂) concentration, dry matter, content levels of macronutrients in plant aerial part and root system, and nutritional disorders were evaluated. Macronutrients suppression affected nutrients concentration in many plant parts, inducing the appearance of symptoms characteristic of each nutrient. The most limiting nutrients for coffee plants development were nitrogen and calcium, reflected in the lower dry matter accumulation and nitrogen the most required.