Nutrient Release Dynamics in Soils Amended With Municipal Solid Waste Compost in Laboratory Incubations

Two municipal solid waste composts were added to three agricultural soils developed over different parent material (schist, gabbro and granite) and incubated in two laboratory studies, in order to assess the effect of compost addition in the dynamics of soil Ca, Mg, K and P. Soils and mixtures of soil and compost (2.5% dry weight, roughly equivalent to 60 t ha^?1) were incubated at 25°C for three months in a first experiment, and for five months in a second experiment. The concentrations of available Ca, Mg, K and P were determined throughout both experiments. The soils amended with compost always had higher available Ca, Mg and K concentrations than the soils without amendment. The increases were approximately 800 mg kg^?1 for Ca, 30 mg kg^?1 for Mg, and 150 mg kg^?1 for K. Nevertheless, the concentrations of these elements did not increase with time. The available P concentrations were not increased by the addition of compost, an effect which is attributed both to microbial immobilization and to the P-fixation capacity of the soils. Therefore, the expected release of these elements in parallel to compost mineralization was not observed during the experiments, and the only fertilizing effect of the compost was that of their initial input in available forms.     

Evaluation of Pine Bark or Pine Bark with Goat Manure or Sewage Sludge Cocomposts As Growing Media for Vegetable Seedlings

The suitability as growing media of composts made from pine bark or pine bark cocomposted with goat manure or sewage sludge and either inoculated or not inoculated with effective microorganisms, was evaluated under greenhouse conditions with and without fertilization using cabbage as the test crop. The treatments were replicated three times and arranged in a randomized complete block design in a fibre glass covered greenhouse. Cabbage seedlings were grown in cavity trays for five weeks, after which plants were harvested and fresh and dry weights determined. Samples were also analyzed for N, P, K and selected heavy metal concentrations. Results revealed that pine bark-goat manure cocomposts supported good seedling growth and could thus be good substitutes for pine bark alone as a growing medium where goat manure or similar manures are available. The results also showed that despite the superior nutritional value of these alternative growing media, nutrient supplementation may still be necessary where seedlings are kept in the nursery for extended periods due to nutrient exhaustion through plant uptake and leaching. Pine bark-sewage sludge compost also had positive effects on seedling growth but could only be recommended as a growing medium for nonfood plants because its composting did not reach the thermophillic temperatures necessary for adequate pathogen kill. Inoculation with effective microorganisms improved seedling growth in sewage sludge and goat manure based composts but the mechanisms involved remain to be established.     

Effects of Cu, Ni and Zn on Lettuce Grown in Metal-Enriched Vermicompost Amended Soil

A study has been conducted in a salt marsh, located in the coast of the Mar Menor lagoon (SE Spain), in which three watercourses overflow. Water samples were regularly collected over a one-year period from two transects established through the salt marsh towards the lagoon. All the samples were analysed for electrical conductivity, pH, sulphides, chlorides, nitrate, ammonium and dissolved phosphorus. The quality of the water flowing from the watercourses to the salt marsh showed a seasonal pattern, with higher contents of nitrates (> 200 mg NO^? ₃ L^?1) in periods of maximum agricultural activities in the nearby areas, as well as a higher content of ammonium (> 30 mg NH⁺ ₄ L^?1) and phosphorus (> 10 mg PO^3? ₄?P L^?1) when the human population increased in the zone as a result of tourism. The general spatial pattern of nutrient retention in the salt marsh, indicated by a reduction in the nutrient concentrations in the water closer to the lagoon, was modulated depending on the season. In the driest months, the marsh was 100% effective in reducing nutrient concentrations, but in the rainy periods the effectiveness was reduced. This reduction was more evident for phosphorus in autumn, whose concentration increased in the lower part of the salt marsh closer to the lagoon until it reached that of the inflow. This could mainly be explained by the accumulation of water in some sites near the lagoon, which can act as sinks of pollutants. Our data support the existence of polluted water in the surface watercourses of the area, and the associated risk can include soil salinization and the eutrophication of aquatic systems. Based on our data, the Mar Menor coastal marshes have an important role as filters to reduce pollution in this lagoon.     

Efficient Purification of Heavy-Metal-Contaminated Water by Microalgae-Activated Pine Bark

Batch experiments were performed to study metal sorption by pine bark and algae-treated bark. The biosorption of copper (Cu), lead (Pb), zinc (Zn), cadmium (Cd), cobalt (Co), and nickel (Ni) in synthetic multimetal aqueous solutions was studied as a function of metal content in solution, and amount and size of bark particles used for sorption. Influence of water hardness (Ca²⁺ only was tested) on the metal sorption process was also evaluated. Metal uptake from solutions with high heavy metal content (i.e. 10× the limit for leachate from landfills) was found to be independent of Ca²⁺ concentration. At low metal content in solution (i.e. 1× the limit for leachate from landfills), uptake of Cu, Zn, Ni, and Cd decreased with increasing Ca²⁺ content in water. Microalgae-treated bark was found to increase the metal sorption efficiency. Air-drying of bark-entrapped algae was shown to be the best method for sorbent drying. In general, the green algae, Chlorella sp. and Pseudokirchneriella subcapitata showed the best results in metal uptake. Sorption of Co, Zn, Ni, and Cd from solution with high levels of both heavy metals and calcium increased by almost 50% with algae treatment of bark was applied. At low levels of metals and calcium content, 100% uptake of Cu and Pb in water was observed. Uptake of other metals from solution with low metal and Ca content was relatively high (50–60%). Low pH (pH 3.0) had no influence on metal sorption from solutions with high metal content. For solutions with low metal content a decrease of metal uptake by 10–15% was observed for all the metals but Pb. Thus, the treatment of bark with microalgae was successful and influenced positively the uptake capacity of the bark.     

Growth of Loblolly Pine and White Pine after Enrichment by Nutrient Loading

Low nutrient availability often constrains the growth of young trees following planting to fields or forests. Nutrient loading of young tree seedlings increases their growth in outplanting. Loblolly pine (Pinus taeda L.) and white pine (Pinus strobus L.) were grown for one year on nutrient-loading regimes that varied from 13 to 410 mg N L^?1 in sand culture. Other nutrients varied in proportion to the nitrogen (N) concentrations. Resulting plant growth showed that an array of nutritional regimes from deficient to excessive was applied. The young plants were transplanted into containers of sandy loam and were grown for one year without fertilization. Growth of each species increased with enhanced nutrient loading. The optimum concentration of N for nutrient loading was about 1.5 to 1.8% leaf dry weight for either species. Nutrient loading during nursery culture imparts transplants with nutrient levels that will enable growth for at least a year after outplanting.     

Suitability of Fly Ash Vermicompost as a Component of Pine Bark Growing Media: Effects on Media Physicochemical Properties and Ornamental Marigold (Tagetes spp.) Growth and Flowering

This study evaluated the possibility of mixing fly ash vermicompost (FA) with pine bark (PB) compost to produce a horticultural growing medium for ornamental plants using ornamental marigolds (Tagetes spp.) as the test crop. Fly ash vermicompost was mixed with pine bark compost at 0, 25, 50, 75, and 100% and marigold seeds were sown with or without fertilizer in the resultant media to test their suitability as seedling growing media. FA substitution up to 50% significantly improved water-holding capacity, total porosity, and air-filled porosity. It also raised pH from 4.52 to a maximum of 8.33 when incorporated up to 75%. Incorporation of FA up to 75% resulted in significantly high germination percentages above 90% compared to only 22.5% for the 100% PB medium. However, after 4 weeks of growth, seedlings in the 25 and 50% FA substituted media had higher plant height and leaf area. The 25% FA treatment resulted in significantly higher number of flowers and buds compared to the 50 and 75%. For effective marigold seedling germination and growth, a 50% FA:50% PB growing medium is recommended while for maturity and flower production, the 25% FA:75% PB combination is preferred.     

Plant Nitrogen Status of Southern Highbush Blueberry (Vaccinium corymbosum L. Interspecific Hybrid) Grown in Pine Bark Amended Soils with Varying Rates of Nitrates

An experiment evaluating three fertilizer types (granular, liquid, and controlled released fertilizer) with nitrate ranging from 0% to 44% was conducted over two seasons on southern highbush blueberry ‘Star’ at the University of Georgia’s blueberry farm in Alapaha, GA. The objective was to identify the effect on fruit quality, plant growth, and plant tissue nitrogen status. This work demonstrated that the applications of fertilizer had similar effects on fruit quality and growth for ‘Star’ grown in sandy organic soils. In addition, fertilizers with 36.5% or 44% nitrate did not appear to have significant accumulation of nitrate in the leaves. Soil analysis revealed that none of the fertilized soils significantly increased cation exchange capacity; however, soil pH increased in soils with 36.5% and 44% nitrate applications. This suggests these nitrate levels will require continued soil monitoring and possible soil acidification to maintain appropriate soil pH for blueberry production (4.0–5.5 pH).     

Nutrient Uptake and Leaching from Soil Amended with Cattle Manure and Nitrapyrin

We investigated whether nitrification inhibitor nitrapyrin can reduce nutrient leaching and increase nutrient uptake by corn (Zea mays L.) in cattle manure amended soil. Amendments included non-amended check (CK), urea (Urea), REG (manure from cattle fed barley grain), and DDGS (manure from cattle fed 60% dried distillers grains with solubles), co-applied with or without nitrapyrin and leached or unleached with water. Nitrapyrin reduced (P < 0.01) leaching of nitrate by 56, 32, and 24% from DDGS, REG, and Urea treatments, respectively, and also reduced (P < 0.05) leaching of phosphate (58%), potassium (39%), calcium (39%), and magnesium (39%) from DDGS treatment. While nitrapyrin reduces the rate of ammonium conversion to nitrate, higher magnesium and phosphate levels in DDGS-amended soil favor struvite formation and reduce their leaching. Corn biomass and nutrient uptake were higher (P < 0.01) in DDGS and Urea than CK and REG treatments, but remained unaffected by nitrapyrin. The benefits of nitrapyrin should be further investigated under field conditions.

Abbreviations: DCD, dicyandiamide; DDGS, dried distillers grains with solubles; NI, nitrification inhibitor; TP, total P; TN, total N.     

Boron Fixation and Its Release in Soils and Bark Compost

Batch studies were conducted to investigate the fixing and release behavior of boron (B) in the soils from Haruo-cho, Kochi, and a bark compost (BC). Boron fixation on river sand (RS) was extremely low. The amount of B fixed was 6.3 mg kg⁻¹ for the greenhouse soil (GS). However, BC showed a 10-fold higher fixation of B (64.1 mg kg⁻¹) compared to GS, indicating that BC here displayed a significant capacity for B trapping. In GS, only around 9% of the adsorbed B was released during a 1-month period of incubation. Bark compost showed the highest amount of release during the incubation period, accounting for 64% of the adsorbed B. Moreover, the ratio of B release increased to 77% in the case of the soil mixed with BC. These results, suggest that different kinds of fixation-releasing mechanisms operate in the soil and BC. The B fixation on soil is considered as specific adsorption on minerals. A possible mechanism for B fixation on BC is ligand exchange. B-diol complexes might be formed with BC, and then after decomposition by microorganisms, they may release B during the incubation period.     

蚯蚓粪对鹅掌楸容器苗生长及养分吸收的影响

在容器育苗基质中添加体积比为5％～20％的蚯蚓粪,通过无纺布容器育苗试验,研究了不同育苗基质对鹅掌楸根际环境中的微生物数量、根系建造和活力、养分吸收及育苗效果的影响.结果表明,育苗基质中添加蚯蚓粪可不同程度地提高鹅掌楸根际环境中细菌数量和微生物总量,真菌数量有所降低,但对放线菌数量影响差异不显著.蚯蚓粪有利于鹅掌楸根系的生长,尤其是增加了毛细根的重量和在根系体系中的比例,根系活力也有显著提高.此外,育苗基质中加入蚯蚓粪还提高了鹅掌楸根、茎和叶干物质的积累量,虽然对植物体内氮和磷的含量影响较小,但蚯蚓粪的添加显著提高了植物体内钾的含量.同普通育苗基质相比,加入15％体积比例的蚯蚓粪使氮、磷和钾的养分吸收量分别提高了22.23％,15.58％和26.66％.综合分析认为,育苗基质中加入一定比例的蚯蚓粪可显著改善鹅掌楸的根际环境,促进育苗植物对养分的吸收和利用,提高无纺布容器育苗效果.在试验蚯蚓粪添加比例中,育苗基质中添加体积比例为15％的蚯蚓粪效果最为显著.     

Effects of Carbofuran on Availability of Macronutrients and Growth of Tomato Plants in Natural Soils and Soils Amended with Inorganic Fertilizers and Vermicompost

The effects of lower field rate (LFR), field rate (FR), and higher field rate (HFR) applications of carbofuran on ammonium (NH₄)-nitrogen (N), nitrate (NO₃)-N, available phosphorus (P), and available potassium (K) contents in natural soils and those amended with inorganic fertilizers and vermicompost on the growth of tomato plants were studied. The NH₄-N, NO₃-N, available P, and available K contents increased up to FR but the most significant increase in was observed at LFR of carbofuran application. At HFR there was a significant reduction in nutrient availability. With passage of time all these parameters increase up to 30 days; thereafter, a decrease was observed up to the end of the experiment in both unamended and amended soils. The greater plant growth was observed at LFR of carbofuran application and at HFR the plants exhibited phytotoxicity in the form of marginal leaf scorching in both systems. The morphological growth parameters of tomato plants were positively correlated with nutrients availability.     

Foliar Accumulation of Zinc in Tree Species Grown in Hardwood Bark Media Amended with Crumb Rubber

Abstract

Artificial nursery medium sources of uniformity and quality are becoming more difficult to locate. Alternative components such as recycled crumb rubber (CR) may have potential to be incorporated into bark or other growing media. Recycled CR is a waste product from automobile tires. Mixtures of CR and hardwood bark were evaluated in production of container‐grown trees. Leaf tissue analysis revealed that linear or nonlinear increases in zinc (Zn) levels exceeded normal levels. Stem caliper, height, and quality of river birch (Betula nigra L.), pecan [Carya illinoinensis (Wangenh.) C. Koch], and lacebark elm (Ulmus parvifolia Jacq.) decreased with increasing percentages of CR.     

Nutrient Availability in a Calcareous Soil Amended with Different Types of Biomass Ash

An incubation experiment was conducted to evaluate the effects that three types of biomass ash, each applied at two doses, exert on the nutrient availability in a calcareous soil. The application of the ash from dry olive cake or greenhouse vegetable wastes significantly increased soil ammonium bicarbonate-diethylenetriaminepentaacetic acid (AB-DTPA)-extractable phosphorus (P), potassium (K), sodium (Na), copper (Cu) and zinc (Zn) as well as exchangeable and non-exchangeable K and Na. Wood ash was effective only for increasing soil ABDTPA-extractable Zn and Cu. By contrast, the three types of biomass ash hardly increased soil ABDTPA-extractable Fe or Mn. The high content in carbonate of the soil appears to minimize the potential of the ash to increase the micronutrients availability, which shortened with longer incubation time. Soil ABDTPA-extractable heavy metals were not detected in the different treatments tested. Other parameters of the soil, as pH and organic carbon, were scarcely affected by the ash, while conductivity and dehydrogenase activity increased.     

烟杆腐解速率及养分释放规律研究

利用安徽省池州市东至县典型烟田土壤,采用尼龙网袋法研究了烟杆还田后的腐解速率及养分释放规律。结果表明,烟杆还田后,腐解速率表现为前期快、后期慢。试验期间(120 d),常规还田、添加白云石粉和生石灰还田烟杆的累计腐解率分别为56%、53%和49%。各处理烟杆还田的养分释放率均为钾磷氮。烟杆还田前15 d内,钾的释放达到88%,磷的释放率为76%,而氮的释放率仅为53%。烟杆还田对土壤pH有显著影响,在整个腐解过程中生石灰和白云石粉处理土壤pH均显著高于常规还田和不还田处理。烟杆还田显著增加土壤速效钾的含量,较不还田提高47%。由烟杆腐解特点和养分释放的规律可见,烟杆中的钾是水浸提的速效钾,水稻推荐施肥量中可考虑减去(或部分减去)所用烟杆的钾含量。     

几种缓控尿素的养分释放特性研究

以简单的工艺对普通尿素进行处理,制备缓控型尿素(HU),并以2种包膜尿素YU、NU作对比,采用"土柱淋溶法"和"静态吸收法"研究其在土壤中的缓释性能和减少氨挥发作用。结果表明,等氮量条件下,HU、YU、NU全氮淋出量总和显著小于普通尿素处理,铵态氮的淋溶损失量也呈现相同的规律,而硝态氮和尿素态氮淋失量则表现为普通尿素大于HU、YU、NU处理;随时间增加,各处理淋洗液的pH呈先上升后下降趋势,pH值变化范围在5.89~8.68之间;EC值大体上呈下降趋势,变化范围是0.16~3.70mS/cm,在第五次淋洗后其值变化很小,并趋于稳定;培养试验结果表明,HU、YU、NU施入土壤后氨挥发损失显著小于普通尿素处理,氨挥发速率大小为UrYUHUNU,其中以HU和NU处理效果较好,这表明自制缓控尿素延缓了氮素释放的时间,具有较好的缓释效果。     

Accumulation of Mn in Leaves of Rosmarinus officinalis Cultivated in Substrates of Pine Bark

Rosmarinus officinalis is an important aromatic shrub cultivated for medicinal, culinary, and ornamental uses. To assess growth, the contents of trace metals cadmium (Cd), copper (Cu), iron (Fe), manganese (Mn), lead (Pb), and zinc (Zn) and macronutrients calcium (Ca), magnesium (Mg), potassium (K), nitrogen (N), and phosphorus (P) were measured in these plants cultivated on two substrates: pine bark (PB, pH 4.0, 80.5% organic matter) and pruning wastes–biosolids (BS, pH 6.9, 47.5% organic matter). These plants, initially of 3.5 ± 0.5 g dry weight and 31.1 ± 6.9 cm, were maintained under greenhouse conditions for 7 months. Nutrient solution samples were taken from each substrate in situ by rhizon probes, indicating that the concentrations of soluble Mn and Zn in PB were significantly greater than in the nutritive solution BS. At the end of the assay, the dry weight of leaves and height was significantly greater in plants cultivated in BS (40.0 ± 2.2 g and 75.9 ± 14.3 cm) than in PB (27.5 ± 4.0 g and 62.4 ± 10.2 cm). Plants cultivated in PB showed slight chlorosis, attributed to the high concentration of Mn in leaves (106.6 ± 7.8 mg kg^?1), which was much greater than in plants cultivated in BS (8.2 ± 0.9 mg kg^?1). The concentration of toxic metals Cd and Pb in plants cultivated on both substrates did not exceed the recommended levels for consumption of the leaves as condiment. If R. officinalis is cultivated on the substrate of pine bark to acid pH for food or medicinal use, the accumulation of Mn must be considered.     

Mass and Nutrient Losses During the Composting Of Dairy Manure Amended with Sawdust or Straw

Composting has become an increasingly popular manure management method for dairy farmers. However, the design of composting systems for farmers has been hindered by the limited amount of information on the quantities and volumes of compost produced relative to farm size and manure generated, and the impact of amendments on water, dry matter, volume and nitrogen losses during the composting process. Amendment type can affect the free air space, decomposition rate, temperature, C:N ratio and oxygen levels during composting. Amendments also initially increase the amount of material that must be handled. A better understanding of amendment effects should help farmers optimize, and potentially reduce costs associated with composting. In this study, freestall dairy manure (83% moisture) was amended with either hardwood sawdust or straw and composted for 110-155 days in turned windrows in four replicated trials that began on different dates. Initial C:N ratios of the windrows ranged from 25:1 to 50:1 due to variations in the source and N-content of the manure. Results showed that starting windrow volume for straw amended composts was 2.1 to 2.6 times greater than for sawdust amendment. Straw amended composts had low initial bulk densities with high free air space values of 75-93%. This led to lower temperatures and near ambient interstitial oxygen concentrations during composting. While all sawdust-amended composts self-heated to temperatures >55°C within 10 days, maintained these levels for more than 60 days and met EPA and USDA pathogen reduction guidelines, only two of the four straw amended windrows reached 55°C and none met the guidelines. In addition, sawdust amendment resulted in much lower windrow oxygen concentrations (< 5%) during the first 60 days. Both types of compost were stable after 100 days as indicated by CO₂ evolution rates <0.5 mg CO₂-C/g VS/d. Both types of amendments also led to extensive manure volume and weight reductions even after the weight of the added amendments were considered. However, moisture management proved critical in attaining reductions in manure weight during composting. Straw amendment resulted in greater volume decreases than sawdust amendment due to greater changes in bulk density and free air space. Through composting, farmers can reduce the volume and weights of material to be hauled by 50 to 80% based on equivalent nitrogen values of the stabilized compost as compared to unamended, uncomposted dairy manure. The initial total manure nitrogen lost during composting ranged from 7% to 38%. P and K losses were from 14 to 39% and from 1 to 38%, respectively. There was a significant negative correlation between C:N ratio and nitrogen loss (R₂=0.78) and carbon loss (R₂=0.86) during composting. An initial C:N ratio of greater than 40 is recommended to minimize nitrogen loss during dairy manure composting with sawdust or straw amendments.     

Sulphur and Heavy Metal Concentrations in Scots Pine Bark in Northern Finland and the Kola Peninsula

Sulphur and heavy metal deposition in northern Finland (= in Lapland) and the Kola Peninsula were surveyed using Scots pine bark samples. Sulphur concentrations in bark close to the Kola smelters were on an average twice as high as on the Finnish side of the border. The Cu and Ni concentrations near the smelters were almost 100-fold the mean values in northern Finland. There was a marked decrease in the sulphur and heavy metal concentrations with increasing distance from the emission sources. The effects of emission from the Kola Peninsula were evident in Finland only close to the border, especially in the eastern parts of Inari (NE corner of Lapland) where the Cu and Ni concentrations were 2- to 6-fold those in western Lapland. The sulphur and heavy metal concentrations in most of northern Finland were low. However were the concentrations of Cr in bark in the SW corner of Lapland considerably high, due to the emissions from the Tornio refined steel plants.     

Effect of Mixing Pine Needles Litters on Soil Biological Properties and Phosphorus Availability in Soil Amended with Fertilizers and Manures

Effect of different manures and pine needles application on soil biological properties and phosphorus availability was evaluated in sandy loam soils. Fertilizers nitrogen, phosphorus, and potassium (NPK); Sesbania aculeata green manure (GM); farm yard manure (FYM); and vermicompost (VC) were applied alone or in combination with pine needles. Microbial biomass carbon, dehydrogenase, and alkaline phosphatase activity increased significantly due to manures and NPK. Pine needles reduced the microbial biomass carbon (MBC) and dehydrogenase activity in FYM and VC but increased in NPK and GM. Acid phosphatase activities were found to be significantly increased by pine needles application in NPK, FYM, VC, and GM as compared to without pine needles counterparts. No significant differences were found in soil solution phosphorus in manure treated soil due to pine needle application, but phosphorus uptake was reduced significantly in these treatments. Pine needles application clearly influenced the soil biological properties without any perceptible effect on nutrient release from the manures.     

Decomposition and Nutrient Release from Intra-specific Mixtures of Legume Plant Materials

Abstract

Because farmers use mixtures of leaves and stems as a soil amendment, data of leaves, stems, and a leaf/stem mixture of Indigofera constricta and Mucuna pruriens from a 20‐week litterbag study were analyzed to assess their decomposition, nutrient release, and possible interactions within mixtures. Decomposition and nitrogen (N)–release patterns were leaves≥mixtures≥stems, whereas phosphorus (P)–release patterns were the opposite (P<0.05). Leaves released 110–130 Kg N ha^?1, and mixtures released 30% less. A similar ratio was obtained for P release. This suggests that nutrient release from leaf/stem mixtures is overestimated when only leaves are considered. Decomposition and nutrient‐release patterns of mixtures occasionally differed from estimated patterns by 2–5% (P<0.05), indicating that minor interactions took place. However, estimations based on the amount of released nutrients generally showed non significant interactions. This suggests that the impact of low‐magnitude interactions within mixtures during its decomposition on soil fertility are negligible when considering total nutrient release.