Composition and properties of soil humus in a mixed forest of Cunninghamia lanceolata and Tsoongiodendron odorum

This study was conducted in Xinkou Experimental Forestry Farm of Fujian Agricultural and Forestry University, Sanming, Fujian Province in January 1999. Taking pure stand of Chinese fir as control, the authors measured and studied the content of organic carbon, content of humic acid (HA), ratio of HA to fulvic acid (FA), and the characteristics of infrared light spectrum and visible light spectrum of soil humus in the mixed forest of Chinese fir and Tsoong?tree. Compared to humus composition in the pure stand of Chinese fir, the content of soil organic C, HA content, and the E4 value of HA for different layers of soil, except for the ratio of HA to FA, showed a significant increase in the mixed forest, while the ratios of E4 to E6 had a little decrease. The infrared light spectrum of humic acid had an absorptive peak at 1650 cm-1. It is concluded that the levels of humification and aromaticity of soil humus are higher in the mixed forest, which is favorable for the improvement of soil structure and nutrient supply, thus improving the soil fertility to a certain degree.

Dissolution and Fractionatoon of Calcium-Bound and Iron-and Aluminum-Bound Humus in Soils

This paper deals with the development of a sequential extraction method to separate the Ca-bound and Fe-and Al-bound humus from soils.First,comparative analyses were carried out on dissolution of synthetic organo-mineral complexes by different extractants,i.e.0.1M Na4P2O7,0.1M NaOH+0.1M Na4P2O7 mixture,0.1M NaOH,0.5M (NaPO3)6 and 0.5M neutral Na2SO4.Among the five extractants,0.1M NaOH+0.1M Na4P2O7 mixture was the most efficient in extracting humus from various complexes.0.5M Na2SO4 had a better specificity to Ca than 0.5M (NaPO3)6,by only extracting Ca-bound humus without destorying Fe-and Al-bound organo-mineral complexes.Then sequential extractions first with 0.5M Na2SO4 and then with 0.1M NaOH+0.1M Na4P2O7 mixture were applied to a series of soil samples with different degrees of base saturation.The cations were dominated by Ca in the 0.5M Na2SO4 extract and by Al in the 0.1M NaOH+0.1M Na4P2O7 mixture.The sequential extraction method can efficiently separate or isolate Ca-bound and Fe-and Al-bound humus from each other.

Dicyandiamide Sorption-Desorption Behavior on Soils and Peat Humus

The sorption-desorption behavior of dicyandiamide (DCD) is an importantchemical process that affects DCD fate and mobility in soils. Therefore, this study quantified DCDsorption-desorption on a phaeozem (Mollisol), a burozem (Alfisol), a soil with organicmatter-removed and peat humus using the batch-equilibration procedure, and identified soilproperties that influenced DCD sorption. The sorption on peat humus was higher than that on thephaeozem and the burozem, with much lower sorption observed on the soil with organic matter-removed,indicating that soil organic matter was the main carrier of DCD sorption. Due to its amphipathicproperty the DCD molecule sorption on the phaeozem and the burozem decreased as pH increased fromabout 2 to 5, but a further increase in pH led to a rise in DCD sorption. The DCD desorptionhysteretic effect for peat humus was greater than that for the phaeozem and the burozem using 0.01mol L^(-1) CaCl_2 as the background electrolyte, suggesting that the hydrophobic domains of organicmatter may play an important role in DCD sorption.

Straw ^(14)C Decomposition and Distribution in Humus Fractions as Influenced by Soil Moisture Regimes

14C-tracer technique and closed incubation method were used to study straw 14C decomposition and distribution in different fractions of newly formed humus under different moisture regimes. Decomposition of straw 14C was faster during the initial days, and slower thereafter. Decay rate constants of straw 14C varied from 3.29x10-3 d-1 to 7.06x10-3 d-1. After 112 d incubation, the amount of straw 14C mineralized was 1.17～1.46 times greater in submerged soils than in upland soils. of the soil residual 14C, 9.08%～15.73%was present in humic acid (HA) and 31.01%～37.62% in fulvic acid (FA). Submerged condition favored the formation of HA, and HA/FA ratio of newly formed humus (labelled) was greater in submerged soils than in upland soils. Clay minerals affected the distribution of straw 14C in different humus fractions. Proportion of 14C present in HA to 14C remaining in soil was greater in Vertisol than in Ultisol.

Effect of crude oil pollution on organic carbon and humus content in grey-brown soils in Mangyshlak, Pre-Caspian Sea Region

The organic carbon and humus content in oil polluted brown and grey-brown soils in Mangyshlak,Pre-Caspian Sea Region,was analyzed from 2000 to 2008.The results indicated that bitumen substances from crude oil pollution deteriorated the soil property,however,the organic carbon content increased significantly.The products of oil pollution changed the composition of car-bonaceous substances which formed soil humus,and changed the ratios of the humus components.Residual insoluble carbon increased with the rise of oil organic carbon.The mobility of humus components was significantly increased because of the high oxidation-reduction process in the topsoil,and the humus content and microorganism activity increased.The organic carbon content increased significantly,while it decreased with the distance away from the oil well.The rearrangement of physical,physical-chemical and chemical properties of the polluted soils was significant.

Effect of Humus on Activity of Mineral-Bound Hg: III.Effect on Leachability and Transfer of Mineral-Bound Hg Under Acid Leaching Condition

Effects of humus fractions (fulvic acid, brown humic acid and grey humic acid) on the leachability and transferring activity of five types of mineral-bound Hg were investigated. Under the acid leaching condition: fulvic acid could promote leachability and vertical transference of all the mineral-bound Hg. Brown humic acid could retard the leaching and transferring processes of CaCO3-Hg, Fe2O3-Hg, MnO2-Hg and kaolinite Hg but not bentonite-Hg. Grey humic acid could greatly enhance residing ability of the mineral-bound Hg in the soil column and restrain them from vertical transferring. The effect of humus on leachability and transferring activity on the mineral-bound Hg was closely related to its ability to convert the mineral-bound Hg into organic-bound form and the transferability of the latter in the soil column. The characteristics of the mineral-bound Hg in speciation were the internal factors that determined the extent and rate of the influence of the humus.

Rice Crop Application for Humus Bioreactor by Rural Sewage System

In this paper, author will report on the process of rice cultivation in paddy fields using treated water which treated domestic sewage wastewater. Odor problems from sewage treatment plants have been solved by confinement and ventilation, but reducing the color and odor of treated water is economically difficult and is a subject of recycling of discharged water. Humus pellet bioreactors can be attached to existing sewage treatment plants to suppress the odor of the sewage treatment plants as a whole and to prevent sludge from deteriorating and to improve the quality of treated water. The odor and color of the treated water discharged from the sewage treatment plant was reduced. In addition, we were able to obtain performance of treated water with nitrogen 3 mg/L, phosphorus 1 mg/L or less throughout the year. On the other hand, there are many cases of results that cannot be used for paddy rice cultivation and vegetable production etc. by ignoring plant growth and physiology (fertilizer). For that reason, laws and guidance such as having to dilute more than 50 times in order to use processed water for agriculture are being conducted without learning. It is a case of using humus pellets in sewage treatment system and using deodorized wastewater of sewage by adjusting fertilizer when used in paddy field rice production.

Stability on the ^(109)Cd,^(65)Zn Complex with Humus Acids

The radioactive isotope tracer and ion exchange balanced method was used to study the stability of 109Cd, 65 Zn complexes with humus acids. In the 109Cd and 65 Zn single existing system with humic acids, the stability constants of the humic-109Cd(65Zn) complex compound was higher than the fulvic-109 Cd(65Zn) complex compound. The stability constant of the humic (fulvic) -65Zn was higher than that of the humic (ful-vic)-109Cd. In the 109Cd and 65 Zn coexisting system, the stability constant and the co-ordination number of the humic (fulvic)-65Zn complex obviously increased, but the stability constant and the co-ordination number of the humic (fulvic)-109Cd complex obviously decreased as compared with its respectively single existing system . The result showed that the humus matter with higher molecular weight could more effectively reduce plant availability of heavy metals than that with lower molecular weight in polluted soil by heavy metals. The humus matter could more effectively reduce plant availability of Zn than that of Cd. Application of humus-acid increased the harm of Cd and decreased the harm of Zn to plants in Cd-Zn coexisting system.

Composition and Structural Features of Calcium—Bound and Iron—and Aluminium—Bound Humus in Soils

Calcium-bound and iron-and aluminium-bound humus extracted from different soils collected from north to south of China were characterized by chemical and spectroscopic methods. Meaningful differences in the composition and structure between them were revealed by (13)C NMR, visible spectroscopy and elemental analysis. Results showed that the contents of carbon, hydrogen and nitrogen were higher in iron-and aluminium-bound humus than in calcium-bound humus while oxygen content in calcium-bound humus was shown to be higher. The calcium-bound humus had hasher C/N and O/C ratios than iron- and aluminumbound humus. The calcium-bound humic acid (HA1) showed higher E4/E6 ratios than iron- and aluminumbound humic acid (HA2) while iron- and aluminum-bound pulvic acid (FA2) showed higher E4/E6 ratios than calcium-bound fulvic acid (PA1). An inverse relationship between E4/E6 ratios and aromaticity as determined by (13)C NMR spectra was observed for HA and FA from black soil. The (13)C NMR spectroscopy revealed that HA2 was more aromatic than HA1. On the other hand, FA1 exhibited a higher aromaticitythan FA2.

ON THE DIVISION OF NORTH BOUNDARY OF SUBTROPICALZONE ACCORDING TO THE COMPOSITIONS AND PROPERTIES OF SOIL HUMUS

In this paper predecessors′achievements about the division between subtropical zone and warm temperate zone on the south slope of Funiu Mountain are firstly summarized, and the cause why these viewpoints about the division are different also has been presented. Seven soil profiles at different heights above sea level are dug along the south slope of Funiu Mountain. Many compositions and properties of soil humus have been analyzed in laboratory. A comprehensive study has been made about the division according to the compositions and properties of soil humus with mathematical method. During the analysis process eight indexes have been used, such as altitude, organic carbon, humic acid (HA), fulvic acid (FA), the ratio of humic acid and fulvic acid (HA/FA), two extinction coefficients (E4,E6), and their ratio (E4/E6).The result indicates that the boundary is at about 1000 meters above sea level.

Effects of Long-term Located Fertilization on the Physico-chemical Property of Soil Humus

A systematic study concerning the effects of a long-term stationary fertilization on content and property of soil humus in fluvo-aquic soil sampled from Malan Farm, Xinji City, Hebei, and arid red soil and paddy red soil sampled from the Institute of Red Soil, Jinxian County, Jiangxi was conducted. The results showed that long-term fertilization had effects not only on the content and composition of soil humus, but also on the physico-chemical property of humus. With applying organic manure or combined application of organic manure and chemical fertilizer, E4 and E6 values of humic acid decreased in fluvo-aquic soil and arid red soil, but increased in paddy red soil. In paddy red soil, E4 and E6 values of humic acid increased also with a single application of chemical fertilizer, but E4 and E6 values had less change of humic acid in fluvo-aquic soil and arid red soil. The effects on the visible spectroscopic property of f ulvic acid were different from that of humic acid. Long-term application of organic manure or combined application of organic manure and chemical fertilizer could increase E4 and E6 values of f ulvic acid in three types of soil. Single application of chemical fertilizer had less effect on the E4 and E6. Long-term fertilization could also influence the ultraviolet spectroscopic property of humus. With a single application of organic manure or combined application of organic manure and chemical fertilizer, the ultraviolet absorbance of humic acid and f ulvic acid increased in the three types of soil. But this effect was obvious only in short wave length, and the effect could decrease if the wave length increased. With a single application of chemical fertilizer the ultraviolet absorbance of fulvic acid could increase, but it of humic acid increased only in fluvo-aquic soil. Long-term application of organic manure or combined application of organic manure and chemical fertilizer could increase the content of total acidic groups, carboxy groups and phenolic hydroxy groups of humic acid and fuvic acid in the three types of soil. Single application of chemical fertilizer had less effect on the content of total acidic groups, carboxy groups and phenolic hydroxy groups of humic acid and fuvic acid in the three types of soil.

Effects of Humus Fertilizer from Fermented Branches on Microorganisms and Enzyme Activity in the Soil under Dracontomelon duperreranum Trees

[Objective] This study aimed to explore the effect of humus fertilizer from fermented branches on pH, total porosity, contents of organic matter, alkaline hy- drolysable nitrogen, available phosphorus, rapidly available potassium, the number of microorganisms and the activity of enzymes in the soil under Dracontomelon duper- reranum trees. [Method] Experiments were carried out to study the physical and chemical properties of soil under Dracontomelon duperreranum trees, and soil with- out any fertilizer treatment was used as control. [Result] The results showed that application of humus fertilizer from fermented branches raised the total porosity of soil, and improved the contents of soil organic matter, available phosphorus, rapidly available potassium, the number of soil microorganisms and the activity of soil en- zymes. In addition, the number of soil microorganisms was positively related to the activity of soil enzymes. [Conclusion] Application of humus fertilizer from fermented branches markedly raised the ratio of the number of bacteria to the number of fungi, and promoted the transformation of fungi-rich soil into bacteria-rich soil, which thus significantly enhanced the soil fertility and improved the soil environment under Dracontomelon duperreranum trees.

Thermal Characterization and Lifetime Estimation of the Humus Lombricospt

Through this study, the humus produced in the breeding place of Universidad Autonoma de Occidente was thermally characterized. The humus was submitted to a heating program controlled by the Differential Scanning Calorimetry (DSC) technique to characterize the type of transition, Thermogravimetry (TGA) to study the equilibrium of phasesand Mass Spectrometry (MS) coupled to TGA to identify detached elements in a temperature range. The temperature range used in this study was 30℃ ℃. The energy required for the water desorption in the humus has been found in this study. The humus showed a quick desorption between 30℃ ≤ TDesorption ≤ 110℃ at a heating rate of 10℃/min and presented decomposition around 250℃. Moreover, the kinetics of the desorption of the humus was studied to obtain the activation energy three TGA measures for three different heating rates. The average activation energy was about 26 kJ/Mol. This result was carried out to obtain an estimation of the desorption time of water in the range from room temperature to the decomposition temperature around 350℃.

Humus Content in Soil and Yield in the Permanent Cotton Cultivated Fields

The article presents the data of a long-term experience on the reproductive capacity of the soil during the permanent cultivation of cotton, which has been carried out for 96 years at the Institute of Breeding, Seed Production and Agrotechnology for Growing Cotton in the Kibray district of the Tashkent region. The article presents the results of analyses by determining the content of humus, from which it can be seen that the decrease in humus was more marked on the control variant without fertilizers, and the amount of humus decreased after 20 years compared to the initial indicator by 11.4 t/ha, after 40 years 16 46 t/ha, after 60 years by 19.05 t/ha, after 80 years by 26.29 t/ha and after 96 years by 29.17 t/ha. It was also determined by the decrease in humus content in option 2, where NPK 250:175:125 kg/ha was applied annually, respectively: 6.487 t/ha;9.225 t/ha;10.09 t/ha;16.95 t/ha;19.65 t/ha;with an annual application of 30 t/ha of manure + 25 kg/ha of P2O in option 1, respectively: 0.335 t/ha;3.683 t/ha;11.40 t/ha;22.44 t/ha;32.58 t/ha. In addition, the article also provides data on the yield of cotton by options for permanent cultivation. It was determined that in the control variant, the yield decreased from 16.8 centners per hectare to 9.9 centners per hectare;in the variant where NPK was applied every year 250:175:125 kg/ha was 31 - 34 c/ha, where 30 t/ha of manure + 25 kg/ha P2O 29 - 32 c/ha were used every year.

Co-adsorption and selective-adsorption of heavy metals and dyes from aqueous solution by bio-based humus/chitosan hydrogels

An eco-friendly adsorbent was prepared by reverse suspension crosslinking method to remove multiple pollutants from aqueous solution.Both raw materials,derived from humus(HS)and chitosan(CS),are biodegradable and low-cost natural biopolymers.After combining HS with CS,the adsorption capacity was significantly improved due to compensation effects between the two components.HS/CS exhibited the features of amphoteric adsorption through pH adjustment,enabling it to adsorb not only anionic pollutants(Methyl Orange(MO)and Cr(VI)),but also cationic ones(Methylene Blue(MB)and Pb(II)).The adsorption capacities were approximately 242 mg/g,69 mg/g,188 mg/g and 57 mg/g for MO,Cr(VI),MB and Pb(II),respectively.HS/CS showed a slight preference for MO in MO/Cr(VI)co-adsorption system,whereas strong selectivity for MB over Pb(II)in MB/Pb(II)system under acidic condition(pH<3.0).This selective behavior would allow for potential applications in separating MB/Pb(II)effluents and selectively recycling Pb(II)in acidic environment.The isothermal and kinetic adsorption behaviors followed Langmuir model and pseudo-second-order model,respectively.The density functional theory(DFT)confirmed that the interaction between metal ions and adsorbents was primarily attributed to chelation and electrostatic adsorption,owing to nitric and oxygenic functional groups.Whereas,the adsorption mechanisms for dyes were involved in electrostatic attraction,H-bond andπ-πbond,due to available hydrogen,oxygen,nitrogen atoms and aromatic groups on the surface of adsorbent and adsorbates.The adsorbent could be efficiently regenerated and retained over 90%of its adsorption capacity after five cycles,which has a potential for practical applications in water treatment.

Mobilities and leachabilities of heavy metals in sludge with humus soil

Chemical forms of Zn, Ni, Cu, and Pb in municipal sewage sludge were investigated by adding humus soil to sludge and by performing sequential extraction procedures. In the final sludge mixtures, Zn and Ni were mainly found in Fe/Mn oxide-bound （F3） and organic matter/sulfide-bound （F4） forms. For Zn, exchangeable （F1）, carbonate-bound （F2）, and F3 forms were transformed to F4 and residual forms （F5）. For Ni, F1 and F2 forms were transformed to F1, F2, and F3 forms. Both Cu and Pb were strongly associated with the stable forms F4 and F5. For Cu, F2 and F3 forms were major contributors, while for Pb, F3 and F4 forms were major contributors to F5. Humus soil dosage and pH conditions in the sludge were strongly correlated with the forms of heavy metals. Five forms were used to evaluate metal mobilities in the initial and final sludge mixtures. The mobilities of the four heavy metals studied decreased after 28 days. The metal mobilities in the final sludge mixtures were ranked in the following order： Ni 〉 Zn 〉 Cu = Pb. Leaching tests showed that the mobilities of Zn and Ni in lower pH conditions （pH 4） were higher than those in higher pH conditions （pH 8）.

Humus-Rich Compost Increases Lettuce Growth, Nutrient Uptake, Mycorrhizal Colonisation, and Soil Fertility

Sandy soils, typical of Australia's west, either have little or no habitat protection for microbes including arbuscular mycorrhizal(AM) fungi, which are essential for nutrient cycling. To minimize this problem, the application of organic matter, such as humus-rich composts, is necessary during vegetable crop production. This study aimed at determining the effects of humus-rich composts on either indigenous or inoculated AM fungal colonisation in roots, lettuce(Lactuca sativa L. var. Quechua) growth, and soil fertility improvement. Four different humus-rich composts with varying humus contents were applied at the same standard rate to lettuce grown under glasshouse conditions for 10 weeks after sowing and compared with two low-humus composts and non-amended soil(control). Humus-rich composts significantly increased lettuce shoot growth, root growth, and AM fungal colonisation in roots. Humus contents in the composts were also correlated with lettuce shoot and root growth. Soil dissolved organic carbon, microbial biomass carbon, and fertility were increased with the application of humus-rich composts. These humus-rich composts, especially the compost of higher humic acid with and without AM inoculation, might have a significant role in sustainable vegetable production, for example lettuce growth. Overall, the results indicate that supplementation with humus-rich compost is highly beneficial to enhance soil fertility and potentially maintain the sustainability of vegetable production.

Impact of black cherry on pedunculate oak vitality in mixed forests:Balancing benefits and concerns

The vitality of European forests continues to decline due to new pests and diseases,climate-change related disturbances and high loads of atmospheric nitrogen deposition.Deteriorating soil health is a major factor underpinning the low vitality of West-European forests.Selecting tree species with soil ameliorative traits is proposed as an avenue to counteract soil acidification and improve overall forest vitality.Here we evaluate the impact of black cherry(Prunus serotina Ehrh.),a known rich litter species,on the vitality of neighboring pedunculate oak(Quercus robur L.)in ten mixed forests on sand in Germany,Belgium and the Netherlands.We found that black cherry admixture increases foliar N and P to a surplus whereas it causes deficiencies in foliar Mg,thereby resulting in an overall negative effect on oak foliar nutrient concentrations.Contrary,defoliation of oak leaves by herbivory decreases with the proximity of black cherry.Using structural equation modelling(SEM),we tested the hypothesized‘improved soil health’pathway.Our analyses showed that black cherry admixture leads to lower accumulation in the humus layer,resulting in higher soil base saturation which has a positive effect on foliar Ca yet a negative effect on total chlorophyll.Moreover,the SEM illustrated that herbivory of oak leaves decreases when black cherry is admixed,both via dilution and improved soil health.Indirect effects of black cherry on oak vitality via“improved soil health”in our SEM are however small in comparison to direct relations.Hence,our study showed that the combined positive and negative impacts of black cherry on oak vitality are limited,which tempers the potential benefits of using the rich litter species to counteract oak decline via improved soil health–yet,the concern of black cherry as an invasive alien species negatively affecting the vitality of mature pedunculate oak trees may also be exaggerated.

A review on the chemical speciation and influencing factors of heavy metals in Municipal Solid Waste landfill humus

Heavy metal pollution in landfill humus can cause serious environmental problems and may endanger soil ecosystems and human health.The biological toxicity of heavy metals is not only related to their total amount but also influenced to a greater extent by the distribution of their chemical speciation.Exploring the different chemical speciation and proportions of heavy metals can provide a more comprehensive and accurate understanding of the pollution characteristics and biological toxic-ity of heavy metals in landfill soil.Based on a review of the relevant literature,this paper systematically summarizes the recent research status of typical heavy metal chemical speciation in landfill humus.This chemical speciation is diverse and complex.For instance,heavy metals in residual states and organically bound states have little impact on organisms,while heavy metals in exchangeable states and Fe-Mn oxide states can easily migrate and transform.The chemical speciation of heavy metals is affected by many factors,among which the soil pH and organic matter content are some of the most important factors.Finally,the existing gaps in the current research on the chemical speciation of heavy metals in landfills are described and future research directions are proposed.This work provides a theoretical reference for researching the restoration of heavy metal-contaminated humus soil and the resource utilization of humus soil.

Soil Fertility in Agroforestry System of Chinese Fir and Villous Amomum in Subtropical China

A trial of interplanting and non-interplanting villous amomum (Amomum villosum Lour.) under the canopy of Chinese fir (Cunninghamia lanceolata Hook.) at age 22 was established in Sanming, Fujian of China, and a survey on soil fertility was carried out 10 years after its establishment. Compared with the control (non-interplanting), the properties of soil humus in agroforestry system were ameliorated, with a higher level of humification and resynthesis of organic detritus. The soil microbial population and enzymatic activities were both higher under the influence of villous amomum. Both the nutrient supplying and nutrient conserving capacities of the soil were improved. This agroforestry system exhibited an advantage of improved soil fertility as well as an accelerated growth of Chinese fir, it was, therefore, a sustainable management system suited for Chinese fir in South China.