有机无机改良剂对滨海盐渍化土壤酶活性和土壤微生物量的影响

[目的]为解决滨海地区土壤盐分高和生态环境恶劣的问题,研究发酵园林废弃物与膨润土不同比例配合施用对滨海盐渍土的改良效果。[方法]通过滨海地区田间试验,采用单独施用68 kg/m~3发酵园林废弃物(T_1)、单独施用15 kg/m~3膨润土(T_2)和二者混合施用(T_3)的方法,分析不同处理组土壤酶活性、微生物量碳、氮的变化及其与土壤理化性质的相关关系。[结果]有机无机改良剂混施(T_3)在提高土壤酶活性和微生物量碳、氮方面具有更显著的效果。脲酶、蔗糖酶和脱氢酶分别为对照的10.1,9.0和4.5倍;土壤微生物量碳、氮分别比对照提高了24.8%和78.1%。此外,混施也可以显著改善土壤理化性质,使土壤盐分降低了62.7%,养分各项指标增幅为57.2%～101.4%。同有机改良剂处理相比,无机改良剂对土壤酶活和土壤微生物量的影响较小。速效钾与速效氮是影响土壤酶活性与微生物量的主要因子,而含盐量、容重则与土壤酶和微生物量呈负相关,具有抑制作用。[结论]发酵园林废弃物的加入对土壤酶活性和微生物量的增加起到了决定性的作用。最佳施用处理组为原土混合掺拌68 kg/m~3发酵园林废弃物和15 kg/m~3膨润土。     

Effect of enriched municipal solid waste compost application on soil available macronutrients in the rice field

Abstract

A study was conducted in the Department of Environmental Sciences, Tamil Nadu Agricultural University, Coimbatore, India, to transform the normal compost into bioactive compost, which has multiple benefits to the crop system. The key players in this transformation process were Azotobacter sp., Pseudomonas sp., Phosphobacteria sp. and the waste materials like poultry litter and spent wash. This enrichment process increases both the quality and nutrient content of the municipal solid waste compost significantly. A study was carried out to evaluate the effect of application of different levels of enriched municipal solid waste compost on the availability of the macronutrient content to the rice field soil. The effect of enriched compost on soil available nutrients was significant. The soil ammonium nitrogen and soil nitrate nitrogen content was found to be high in the plots where the enriched compost was applied along with inorganic fertilizer with the values of 38.87 mg kg^?1 and 32.87 mg kg^?1, respectively. In addition, the availability decreased towards crop growth. The soil available P and K were also increased with enriched compost application to about 22.46 kg ha^?1 and 647 kg ha^?1 compared with control values of 19.44 kg ha^?1 and 518 kg ha^?1, respectively. Both phosphorus and potassium content decreased towards advancement of crop growth.     

Effect of solid waste compost on microbiological and physical properties of a burnt forest soil in field experiments

 The restoration of soil microbial activities is a basic step in the reclamation of burnt soils. For this reason, the ability of municipal solid waste compost to accelerate the re-establishment of bacterial and fungal populations, as well as to re-establish physical properties in a burnt soil, was evaluated in a field experiment. Four treatments were performed by adding different doses of compost (0, 0.5, 1 and 2 kg compost m^–2 soil) to a burnt Calcic Rodoxeralf soil, and the changes in microbial populations, salt content, aggregate stability and bulk density were evaluated for 1 year. Initially, the addition of compost had a negative effect on soil microbial populations, but 3 months after compost addition, the number of viable fungal propagules increased in all the amended soils. This positive effect lasted until the end of the experiment. From 30 days onwards, all the amended soils showed a greater total number of bacterial cell forming units than the unamended burnt soil. Organic amendment increased the percentage of 2- to 4-mm aggregates, although the effect on the stability of the 0.2- to 2-mm aggregates and on bulk density was less noticeable. Received: 24 November 1999     

Determining Optimal Maturity of Compost Used for Land Application

A stable compost is needed in plant growth media. However, when compost is land applied, its effect is through the initiation and acceleration of microbial processes leading to the production of soil stabilizing agents.

It was proposed that there is an optimum degree of maturity of compost used for land application, a degree characterized by the reduction of the labile organic matter to a point when the material is relatively stable yet is still active enough to support an increased microbial activity in the soil.

The effect of composting time on the efficiency of municipal solid waste compost (MSWC) to improve soil structural properties, evaluated through laboratory indexes, is presented in this work. MSWC was sampled immediately following 24 hours precomposting in a Dano drum. Samples were taken throughout 60 days of windrow composting. The compost samples were mixed with a structure-impaired loess soil and incubated aerobically for 21 days. Hydraulic conductivity and residual turbidity, a measure of microaggregate stability, were measured in solutions of two SAR levels, five and 20. Compost application had a positive effect on these soil structural properties. The optimal activity was obtained for the compost sampled following seven to 14 days of windrow composting. Polysaccharide concentrations also followed a similar optimum curve. The peak concentration was found following 14 to 30 days old compost application.

The determination of the optimal maturity of composted municipal solid wastes is essential toward an efficient utilization of the compost, toward satisfaction of environmental constraints and for a cost-efficient operation of composting plants. The present preliminary study calls for more research in this field.     

菌、热及菌热联合对垃圾堆肥腐熟的比较分析

为研究菌剂、余热及其联合作用对堆肥腐熟度的影响,采用强制通风静态堆肥系统,以现有堆肥工艺为对照（CK）,比较研究了添加菌剂（T1）、余热利用（T2）、添加菌剂并利用余热（T3）3种工艺垃圾对堆肥过程中腐熟度的影响。结果表明：从温度、pH、电导率（EC）、腐植酸光学特性（E4/E6）、水溶性碳（WSC）、固相C/N和发芽率指数（GI）来看,4个处理均达到腐熟;添加菌剂（T1）对EC、E4/E6、WSC、C/N和GI有显著影响;除E4/E6、WSC和C/N外,循环热风（T2）对其余腐熟度指标有显著影响,菌剂和余热的联合作用可显著提高堆肥的腐熟度,且二者对堆肥腐熟度的影响是一种协同作用。     

Modifications to atrazine degradation pathways in a loamy soil after addition of organic amendments

The effects of two organic amendments, a municipal solid waste compost and a composted straw, on [U-ring- ]atrazine degradation pathways in a loamy soil (Grignon, Yvelines, France) were studied during laboratory incubations under controlled conditions. Three month conditionings were conducted under sterile or non-sterile conditions, with soil plus atrazine, organic amendment plus atrazine, or soil plus organic amendment. Then either an organic amendment or soil or atrazine was added, respectively, to these three treatments and incubated for an additional 3 months under non-sterile conditions. Both organic amendments modified the behaviour of atrazine in soil but via different processes. The addition of municipal compost increased atrazine sorption and decreased its availability for degradation by soil microorganisms. The effect of the composted straw was mainly related to its high enzymatic activity, which appeared to be responsible for the production of large amounts of hydroxyatrazine. This hydroxylation favoured the opening of the triazine ring and its subsequent mineralization in the soil. At the end of the incubations, less atrazine was mineralized in the presence of the two types of organic amendment, which both increased the formation of non-extractable residues of atrazine. The addition of municipal compost preserved larger amounts of extractable atrazine, while the addition of composted straw enhanced hydroxyatrazine production. In all cases, the greatest effects were found when atrazine was directly in contact with the organic amendment during conditioning.     

Changes in enzyme activities and microbial biomass after “in situ” remediation of a heavy metal-contaminated soil

Microbial properties such as microbial biomass carbon (MBC), arylsulfatase, β-glucosidase and dehydrogenase activities, and microbial heterotrophic potential, together with several chemical properties such as pH, CaCl₂ soluble heavy metal concentrations, total organic carbon and hydrosoluble carbon were measured to evaluate changes in soil quality, after “in situ” remediation of a heavy metal-contaminated soil from the Aznalcóllar mine accident (Southern Spain, 1998). The experiment was carried out using containers, filled with soil from the affected area. Four organic amendments (a municipal waste compost, a biosolid compost, a leonardite and a litter) and an inorganic amendment (sugarbeet lime) were mixed with the top soil at the rate of 100 Mg ha⁻¹. Unamended soil was used as control. Agrostis stolonifera L. was sown in the containers. The soil was sampled twice: one month and six months after amendment application. In general, these amendments improved the soil chemical properties: soil pH, total organic carbon and hydrosoluble carbon increased in the amended soils, while soluble heavy metal concentrations diminished. At the same time, higher MBC, enzyme activities and maximum rate of glucose mineralization values were found in the organically amended soils. Plant cover was also important in restoring the soil chemical and microbial properties in all the soils, but mainly in those that were not amended organically. As a rule, remediation measures improved soil quality in the contaminated soils.     

Impact of Organic Amendments on Groundwater Nitrogen Concentrations for Sandy and Calcareous Soils

Experiments were conducted on calcareous and sandy soils to investigate the effects of organic amendments for vegetable production on groundwater nitrogen (N) concentration in south Florida. The treatments consisted of applying yard and food residuals compost, biosolids compost, a cocompost of the municipal solid waste and biosolids, and inorganic fertilizer. Nitrate nitrogen (NO₃-N), ammonium nitrogen (NH₄-N), and total N concentrations were collected for a period of two years for both soils. Statistical analysis results revealed that for the three species tested, there were no significant differences among treatments. NO₃-N concentrations for all treatments remained less than the maximum contamination level (10 mg/L). NO₃-N transport to groundwater was higher in calcareous soil (mean=5.3 mg/L) than in sandy soil (mean=0.6 mg/L). NH₄-N concentrations ranged from 0 to 13.6 mg/L throughout the experiment. Calcareous soil had lower NH₄-N concentrations (mean=0.1 mg/L) than sandy soils (mean=0.7 mg/L). Total N ranged from 0.4 to 21.7 mg/L for all treatments for both soils reflecting high adsorption of dissolved organic N in both soils. Overall, results indicated that all the compost treatments were comparable to inorganic fertilizer with regard to N leaching and N concentrations in the groundwater while producing similar or higher yields.     

Effect of A Waste Stream Component on the Agronomic Properties of Municipal Solid Waste Compost

Managing municipal solid waste (MSW) compost for agricultural use requires an understanding of waste stream components and how they affect the value of the finished product. We evaluated the influence of disposable diaper content in MSW compost because of the recent concern of the environmental impact of this product. To determine the potential effect of disposable diapers on MSW compost, the ‘normal’ concentration of soiled, disposable diapers in a waste stream was raised from 2 percent to 8 percent. Previous observations indicated that the diapers disassociated during in-vessel digestion and most of the components could not be distinguished from the primary compost. The objective of this study was to examine the effect of additional diapers on the agricultural value of mature MSW compost. Loamy sand and silt loam soils were amended with MSW compost at a rate of 20 percent. Comparisons between the two composts and their interactions with soil type were made on the basis of water retention characteristics; germination and emergence of corn, soybean, radish and lettuce; and yield and element uptake by corn and lettuce at two moisture regimes. Differences between the compost amended soils suggested that the primary benefits of additional diapers were increased nutrient availability and soil water retention, and the foremost concerns were excess total soluble salts and boron.     

Compost of municipal organic waste: Effects of different management practices on degradability and nutrient release capacity

We studied the degradability and nutrient release capacity of municipal organic waste (MOW) composts obtained with different management practices: shredding and/or mixing with wood shavings, cocomposting with biosolids, and vermicomposting. As indicators of degradability and nutrient release capacity, we measured net N and C mineralization, extractable-P release, N retained in microbial biomass, and dehydrogenase activity in 16-week laboratory incubations, using soil amended at a rate of 40 g kg⁻¹. We also determined the extent to which these indicators were predicted from the chemical characteristics of the amendments. All products increased soil N and P availability, and the size and activity of soil microbial populations. Carbon and N mineralization, and extractable-P release were influenced by amendment chemical characteristics, especially organic matter, total N, total P, C to N ratio, extractable-P and water soluble C. Cocomposting MOW and biosolids is an important alternative for MOW management, because it was the most effective strategy at increasing product degradability and nutrient release capacity (highest net N and C mineralization, extractable-P release, and microbial biomass-N). Shredding MOW increased C mineralization, while the addition of wood shavings decreased net N mineralization, but generally did not affect C mineralization. Thus, these two practices should be used when these specific product characteristics wish to be achieved. Vermicomposting did not prove to be an efficient strategy when MOW was mixed with biosolids.     

Short-term effects of municipal solid waste compost amendments on soil carbon and nitrogen content, some enzyme activities and genetic diversity

Municipal solid waste (MSW) composts have been frequently used as N and C amendments to improve soil quality and to support plant growth, with the additional benefit of reducing waste disposal costs. However, attention has been paid to the risks of MSW use for the soil environment. The presence of heavy metals in MSW composts can affect some microbiological characteristics of soil such as the structure of the soil microbiota, which are responsible for the transformations making nutrients available to plants. The effects of MSW compost and mineral-N amendments in a 2-year field trial on some physical-chemical properties, some enzyme activities and the genetic diversity of cropped plots (sugar beet-wheat rotation) and uncropped plots were investigated. Variations of pH were not statistically related to MSW compost and mineral-N amendments, or to the presence of the crop. Amendment with MSW compost increased the organic C and total N contents, and dehydrogenase and nitrate reductase activities of soil. In cropped plots amended with MSW compost, dehydrogenase activity was positively correlated with #-glucosidase activity, and both enzyme activities with organic C content. No MSW compost dosage effect was detected. No effects were observed on denaturing gradient gel electrophoresis and amplified rDNA restriction analysis patterns, indicating that no significant change in the bacterial community occurred as a consequence of MSW amendment.     

Nutrient dynamics from surface-applied organic matter amendments on no-till orchard soil

Advancing conservation agriculture depends on understanding nutrient dynamics of organic matter amendments (OMA) on no-till soil. This field incubation study compared surface-applied composted dairy manure (CM), green waste compost (GWC) and an unamended control from March to September in 2015 and 2016 using a RCBD in a California almond (Prunus dulcis) orchard. Measurements included OMA nutrient release rates, changes in soil organic carbon (SOC), total N (TN) and inorganic N, P and K availability using in-season soil sampling and collection of ion exchange resin (IER) membranes from 0 to 10 cm depth, and cumulative N and P availability using soil IER cores from 0 to 50 cm depth. We hypothesized OMA sources with a lower initial C:N increase soil N availability, greater soluble phosphorus (P) and potassium (K) concentrations increase P and K availability, and all OMA sources increase SOC with the greatest N recovery in the TN pool. No differences were observed in C, N and P release rates, while the K release rate was the greatest. In-season N availability showed no effect but P and K availability differed as evidenced by greater IER adsorption and soil extractable P and K. Both OMA sources significantly increased in SOC and TN. Net N mineralization from OMA sources ranged from 0.7% to 8.0% of applied N and total N recovery in TN and inorganic N pools increased based on the initial C:N. These results advance our understanding of nutrient dynamics while conserving the soil due to the no-till practice of surface-applied OMA.     

Soil organic matter evolution after the application of high doses of organic amendments in a Mediterranean calcareous soil

Purpose

We investigate the coevolution of soil organic matter (SOM) and soil properties in a semiarid Mediterranean agroecosystem, as well as the 1-year evolution of the different pools of soil organic and inorganic carbon and their influence on soil respiration after the application of a single high dose of three different organic amendments.

Material and methods

We applied a single high dose (160?Mg?ha^?1 in dry weight (DW)) of three types of organic amendments: aerobically digested sewage sludge (AE), anaerobically digested sewage sludge (AN), and municipal solid waste compost (MSWC), in a calcareous Mediterranean soil. The study area is located in the southeast of Madrid (Spain), characterized by a Mediterranean climate with a marked seasonal and daily contrast. We analyzed different forms of soil organic and inorganic carbon and soil respiration rates. The measurements have been performed quarterly for 1?year.

Results and discussion

The results showed that the coevolution of SOM and soil largely depends on the origin and composition of the organic amendments used. The AN sludge affected the soil chemistry more. The organic matter (OM) provided by AE treatments underwent more intense mineralization processes than AN, with the OM from MSWC being more stable. This behavior could be explained by the different pools of carbon involved in each case. The treatments contributed differently to soil respiration rates following the sequence: AE > AN > MSWC. The application of organic amendments in calcareous Mediterranean soils also modified the inorganic carbon pools.

Conclusions

SOM and soil coevolution after organic amendments application depends on the origin and chemical composition of the inputs. The decision-making process of urban organic waste application with regard to agricultural policy must take into account the different behavior in soil of the different types of amendments.     

The Use of Compost for the Reclamation of Saline and Alkaline Soils

? The results of a two year field experiment verified hypotheses concerning use of compost to improve saline and alkaline soils. The addition of compost to such soils was expected to release acids which would ultimately lead to the replacement of exchangeable sodium by calcium. The addition of compost would also stabilize soil structure and enhance plant growth. It was shown that the addition of municipal solid waste compost is equivalent, or even superior to the addition of gypsum, the common amendment used to reclaim alkaline soils. The overall effect of treatments on soil fertility was evident from yields of crops. The combined application of compost and gypsum raised yields to levels expected in good commercial fields.     

Heavy metal levels in apple orchards after the application of two composts

Abstract

Two composts were tested in eleven different Malus domestica orchards: one was a sewage sludge and bark compost with a low heavy metal content, the other was a municipal solid waste compost with a higher concentration of metals. For six years the zinc (Zn), copper (Cu), nickel (Ni), lead (Pb), cadmium (Cd), and chromium (Cr) content were monitored in the soil, both in ‘total’ and EDTA extractable form, and in leaves and fruits. The resulting data demonstrate clearly that the sewage sludge and bark compost did not cause any significant increase of heavy metal levels in soil and plants; this compost can thus be used to fertilize the soil with no danger either to the environment or to crops. In contrast, the municipal solid waste compost led to a notable accumulation of all the metals examined in the soil and, above all in the case of Pb and Cd, also in the vegetation and the fruits.     

Changes in the microbial activity of an arid soil amended with urban organic wastes

Changes produced in the biological characteristics of an arid soil by the addition of various urban wastes (municipal solid waste, sewage sludge and compost) at different doses, were evaluated during a 360-day incubation experiment. The addition of organic materials to the soil increased the values of biomass carbon, basal respiration, biomass C/total organic C ratio and metabolic quotient (qCO₂), indicating the activation of soil microorganisms. These biological parameters showed a decreasing tendency with time. Nevertheless, their values in amended soils were higher than in control soil, which clearly indicates the improvement of soil biological quality brought about by the organic amendment. This favorable effect on soil biological activity was more noticeable with the addition of fresh wastes (municipal solid waste or sewage sludge) than with compost. In turn, this effect was more permanent when the soil was amended with municipal solid waste than when it was amended with sewage sludge. Received: 28 May 1996     

Short-term effects of organic municipal wastes on wheat yield,microbial biomass,microbial activity,and chemical properties of soil

The objectives of this work were to (a) investigate the short-term effects of applications of mineral fertilizer, municipal solid waste (MSW) compost, and two sewage sludges (SSs) subjected to different treatments (composting and thermal drying) on microbial biomass and activity of soil by measuring microbial biomass C, adenosine 5′-triphosphate content, basal respiration, and dehydrogenase, catalase, urease, phosphatase, β-glucosidase, and N-α-benzoyl-l-argininamide-hydrolyzing activities and (b) explore the relationships between soil microbiological, biochemical, and chemical properties and wheat yields under semiarid field conditions by principal component analysis. The additions of MSW compost, SS compost, and thermally dried SS did not affect significantly soil microbial biomass, as compared to mineral fertilization and no amendment. However, microbial activity increased in organically amended soils, probably due to the stimulating effect of the added decomposing organic matter. Changes in soil microbiological and biochemical properties showed no significant relationships with wheat yields, probably because plant growth was primarily water-limited, as typically occurs in semiarid regions.     

Organic amendments differ in their effect on microbial biomass and activity and on P pools in alkaline soils

Organic amendments could be used as alternative to inorganic P fertilisers, but a clear understanding of the relationship among type of P amendment, microbial activity and changes in soil P fractions is required to optimise their use. Two P-deficient soils were amended with farmyard manure (FYM), poultry litter (PL) and biogenic waste compost (BWC) at 10 g?dw?kg^?1 soil and incubated for 72 days. Soil samples were collected at days 0, 14, 28, 56 and 72 and analysed for microbial biomass C, N and P, 0.5 M NaHCO₃ extractable P and activity of dehydrogenase and alkaline phosphomonoesterase. Soil P fractions were sequentially extracted in soil samples collected at days 0 and 72. All three amendments increased cumulative CO₂ release, microbial biomass C, N and P and activity of dehydrogenase and alkaline phosphomonoesterase compared to unamended soils. The increase in microbial biomass C and N was highest with PL, whereas the greatest increase in microbial biomass P was induced with FYM. All three biomass indices showed the same temporal pattern, with the highest values on day 14 and the lowest on day 72. All amendments increased 0.5 M NaHCO₃ extractable P concentrations with the smallest increase with BWC and the greatest with FYM, although more P was added with PL than with FYM. Available P concentrations decreased over time in the amended soils. Organic amendments increased the concentration of the labile P pools (resin and NaHCO₃-P) and of NaOH-P, but had little effect on the concentrations of acid-soluble P pools and residual P except for increasing the concentration of organic P in the concentrated HCl pool. Resin P and NaHCO₃-P_i pools decreased over time whereas NaOH-P_i and all organic P pools increased. It is concluded that organic amendments can provide P to plants and can stimulate the build-up of organic P forms in soils which may provide a long-term slow-release P source for plants and soil organisms.     

Effects of Application of Organic and Inorganic Wastes for Restoration of Sulphur-Mine Soil

In situ remediation with waste material is an inexpensive method to reduce contaminant availability in polluted soil. The experiments were done to investigate the effects of possible in situ application of two different amendments: inorganic material (marble sludge) and organic material (horticultural waste compost) on chemical and biological properties of abandoned metalliferous mine wastes. The results show that the application of inorganic material raises the pH above neutrality and the combination of inorganic and organic material would produce the highest ratio of biological activity. The reductions of available Zn, Pb and As in lime, organic and lime/organic amendments were favoured by incubation time. However, available Cd content increased after 275?days of incubation, except the treatment with inorganic amendment. This work denoted that the application of lime with organic amendments has a better effect than the lime alone because the addition of both amendments improves both soil chemical and biological properties.