Compost Rates Research Articles

Evaluation of compost from seaweed and fish waste as a fertilizer for horticultural use

Composting may be an effective process for treating fish waste and drift seaweed to recover organic matter and nutrient resources and to produce fertilizers for organic agriculture. The aim of this study was to evaluate the use of this type of compost as a fertilizer in a horticultural crop rotation. A greenhouse trial was carried out to test the effects of the compost on a tomato crop and its residual effects on the succeeding lettuce crop. Different compost rates (C1, C2 and C3: 40tha−1, 50tha−1 and 66tha−1) were compared to single rates of a mineral fertilizer (M) and of a certified organic fertilizer made from dehydrated broiler litter (BL) as well as to the control treatment, which lacked fertilization (C). Tomato yield increased significantly (5.56kgplant−1) with the highest rate of compost compared to the mineral and control treatments (4.54 and 4.58kgplant−1, respectively). This increased yield was associated with an increase in the diameter and weight of the fruits. Moreover, the lettuce yield improved with compost rates C2 (395glettuce−1) and C3 (367g lettuce−1), showing a strong residual effect of the compost. This compost is suitable as organic soil fertilizer and may be recommended for improving horticultural crop yields.

Amaranthus Plant Nutrients and Soil Nutrient Dynamics with Cassava Peel Compost

ABSTRACTComposted cassava (Manihot esculenta. Crantz) peels may serve as a nutrient source in Amaranthus spp. cultivation. A screenhouse experiment was conducted to determine the rate of cassava peel compost needed to support optimum Amaranthus plant and residual soil nutrient content. A compost of cassava peel and poultry manure was applied at 0, 2.5, 5.0, 7.5, or 10 Mt.ha−1 2 weeks before sowing Amaranthus seed in plastic containers. Plants were harvested 5 weeks after emergence by ratooning and plant regrowth harvested after an additional 5 weeks. Plant shoot N was highest due to application of 5 Mt.ha−1 of compost; P was generally reduced, with the highest reduction due to application of 5 Mt.ha−1 of compost. Shoot K content was increased, with the highest occurring due to application of 2.5 Mt.ha−1 of compost. Root nutrient N and K contents were highest due to application of 10 Mt.ha−1 of compost; P was highest due to application of 7.5 Mt.ha−1 of compost. Soil pH was most reduced due to application of 2.5 Mt.ha−1 of compost. Organic matter content, organic carbon content, and total N were most increased due to application of 10 Mt.ha−1 of compost; soil exchangeable K was lowest due to application of 5 Mt.ha−1 of compost. Application of 7.5 Mt.ha−1 cassava peel compost produced the optimum Amaranthus shoot nutrient content with optimum residual soil nutrient content.

The Effect of Water Hyacinth (<i>Eichhornia crassipes</i>) Compost on Tomato (<i>Lycopersicon esculentum</i>) Growth Attributes, Yield Potential and Heavy Metal Levels

The potential of different water hyacinth compost application rates in influencing growth attributes, yield and heavy metal accumulation of lead (Pb), copper (Cu), nickel (Ni) and zinc (Zn) in tomato fruit was studied in Masvingo. Four treatments of water hyacinth compost rates of 0, 37, 55.6 and 74.1 t·ha-1 were each replicated three times and applied in a randomized complete block design set up. Results showed that water hyacinth compost application rates significantly affected plant height, days to maturity and yield but had no influence on the number of tomato fruits per plant. The plant height at application rate of 74.1 t·ha-1 was 25%, 56% and 63% higher than the control at week 6, 9 and 12, respectively. At application rates of 56.6 t·ha-1, plant heights were 11%, 13% and 12% higher than the control whilst marginal plant height differences of -4%, 6% and 4% were recorded between application rate of 34.7 t·ha-1 and the control at week 6, 9 and 12, respectively. Tomato plants under compost rates of 34.7, 56.6 and 74.1 t·ha-1 in comparison to the control delayed maturity by 10, 17 and 20 days, respectively. Yields of 52, 55, 60 and 68 t·ha-1 were realized from hyacinth compost rates of 0, 34.7, 56.6 and 74.1 t·ha-1, respectively. Heavy metal concentrations increased with increase in the water hyacinth compost rate but at all application rates, the average concentrations were 85%, 93% and 86% lower than the Codex Alimentarious Commission permissible levels for Pb, Cu and Zn. Water hyacinth compost at a rate of 74 t·ha-1 therefore can be used for increased tomato yield without exposing consumers to heavy metal toxicity.

Comparison of Two High-Yielding Rice Varieties, Kita-aoba and Tachijobu, for Hokkaido, Northern Japan, and Effects of Swine Compost Application on the Growth and Grain Yield of Tachijobu

The grain yield of two high-yielding rice varieties, Kita-aoba and Tachijobu, was examined in a field experiment by using swine compost at a rate of 0, 1 and 2 kg m–2 and chemical fertilizer at a rate of 5.25, 7.35, and 10.5 g N m–2 in 2010, and 5.25 and 10.5 g N m–2 in 2011 (Exp. 1). The grain yield of Tachijobu was also evaluated by applying compost at a rate of 0 or 2 kg m–2 and chemical fertilizer at a rate of 5.25, 10.5, and 15.75 g N m–2 from 2011 to 2013 (Exp. 2). Tachijobu had a lower grain yield than Kita-aoba under the same fertilizer management in Exp. 1 due to its lower sink production efficiency, but it showed the highest grain yield of 1085 g m–2 at the highest fertilizer level in Exp. 2. A significant interaction between compost application and nitrogen fertilizer level was observed in grain yield and nitrogen uptake in Tachijobu in Exp. 2, and the nitrogen uptake in Tachijobu reached its maximum at around 15 g m–2 at maturity. In addition, the apparent nitrogen use efficiency of compost (NUEcompost) was higher at a lower nitrogen fertilizer level. From the nitrogen uptake and NUEcompost at each fertilizer level, the optimum rates of compost and fertilizer were discussed. The compost also increased the concentration of protein in Tachijobu (significantly in 2013).

Composted Amendment Affects Soil Quality and Hedges Performance in the Mediterranean Urban Landscape

ABSTRACTThe influence of increasing rates (0, 15, 30, and 45%) of composted sewage sludge (CSS) in the plantation hole on both urban soil properties and three native Mediterranean woody hedge growth was monitored over a two-year period after establishment. The results indicate that the urban soil physical characteristics were positively influenced by the compost: the highest CSS rate showed an increase in both moisture and infiltration values. The chemical properties of the amended soils were also directly affected by the CSS rate, but the compost effect on organic matter, N and K contents decreased over time. At the end of the trial, the hedge grown on the 30% CSS rate showed significantly higher dry weight values compared to the 45% CSS. The growth response to the compost rates of the three species was not similar: mock privet presented hedges with higher dry weight value than the Mediterranean buckthorn mean value, whereas the lowest ones were found in Tarentum myrtle. Phillyrea, in our experimental conditions, developed regularly not being stressed by the presence of high pH values (45% compost rate); it encourages, in the the Mediterranea basin, sustainable landscaping and xerogardening. The results proved that, compared to urban non amended soils, the amended ones are more suitable to the hedge growth; therefore, a plan of hedge establishment based on the use of composted sludge as amendment for sclerophyllous could be feasible and, what is more, helpful to mitigate the environmental impact of organic waste disposal.

Effect of organic fertilization on nutrient concentration and accumulation in nectarine (Prunus persica var. nucipersica) trees: The effect of rate of application

The aim of the present investigation was to evaluate the effects of annual application of three rates of compost on nutrient concentration and accumulation in tree organs, after 11 years of continuous application of a municipal solid waste (MSW) compost in a commercial nectarine orchard. Trees were subjected, since their plantation (2001), to the following MSW compost rate: 0, 5 and 10tdwha−1yr−1, split in May (60%) and September (40%). In 2011/2012 biomass of pruned wood, thinned fruits, fruit pulp and stones at harvest, and abscised leaves were weighted and analyzed for macro (N, P, K, Ca, Mg) and micro (Fe, Mn, Cu, and Zn) nutrients concentration. In addition, leaves and fruit pulp at harvest were analyzed for heavy metal (Cd, Cr, Hg and Pb) concentration. Plant part biomass (with the exception of thinned fruits) was linearly related to compost application rate. The highest rate of compost increased N and decreased Ca and Mg concentration in leaves sampled in summer, whereas no differences among treatments were observed for the other nutrients. At the end of the season leaf N, K and Zn were remobilized to storage plant part, while P, Ca, Mg, Fe and Mn reached the highest values in abscised leaves. Nitrogen, K, Mg, Cu, Mn and Zn accumulation in the plant part analyzed increased as a consequence of the application of compost at 10tha−1 when compared with compost at 5tha−1 and control. Phosphorous accumulation was increased by compost at the highest rate compared with control; no differences were observed for Ca and Fe accumulation. Nitrogen and P were mainly accumulated in fruit, abscised leaves and pruned wood; K was allocated mainly into fruits, while Ca and Mg were found highest in abscised leaves. Concentration of heavy metals in leaves and fruits were not affected by treatments.

USING NATURAL ALTERNATIVE FERTILIZERS FOR POTATO PRODUCTION UNDER SANDY SOIL CONDITIONS IN EGYPT

Two field experiments were carried out during the two successive seasons of 2010/2011 and 2011/2012 in the Farm of Agric. Res. Station, Wady El-Natrown Area, Fac. Agric. Cairo University, Egypt under saline water and sandy soil conditions. This investigation aimed to study the effect of compost, natural alternative fertilizers (rock phosphate and feldspar) combined with bacterial inoculation (Azotobacter spp and Azospirillum perna + B. megaterium + B. circulans) on yield, tubers quality and its component of (dry matter, NPK, carbohydrate and nitrate) of potato tubers Diamant cultivar. Azotobacter spp and Azospirillum perna were used as nitrogen fixing bacteria from compost, B. megaterium was used as phosphate dissolving bacteria from rock phosphate and B. circulans was used as potassium dissolving bacteria from feldspar. The experiment included 13 treatments as follows three compost levels source of (N) (5.9, 8.8, 11.8 ton/fed.), three rock phosphate levels source of (P) (204.4, 140.7, 77.04 kg/fed.) and five feldspar levels source of (K) (888.8, 592.6, 580.7, 333.3, 251.9 kg/fed.) compared with control (mineral NPK at rate of 120 N -75 P2O5 - 96 K2O kg/fed.) were applied in a (RCBD) randomized complete blocks design with three replicates. Results at harvest showed that significant increases in yield characteristics as (yield/plant, total yield, number of tubers and weight of tubers/plant) and tubers quality (dry matter, carbohydrate, nitrate) were treated with high rate of compost (11.8 ton/fed.) combined with potassium at the highest rate in the presence of bacterial inoculation mixture and showed significantly increasing compared with control. Therefore, compost, rock phosphate, feldspar and biofertilizers could be an alternative to mineral fertilizer for potato production.

Enzymatic Activities in Soil Cultivated with Coffee (Coffea arabica L. cv. ‘Bourbon’) and Amended with Organic Material

The objective of this study was to investigate the growth of coffee (Coffea arabica L. cv. ‘Bourbon’) in soil amended with compost, vermicompost, and bokashi at 25%, 50%, and 66% while mycorrhizal colonization and activity of acid and alkaline phosphatases and urease in soil were monitored. Treatments with 25% compost as well as higher application rates of compost and bokashi (50% or 66%) increased coffee growth. Shoot fresh weight increased 5 times when 25% bokashi or compost was applied, 8 times when 50% was applied and 10 times when 66% was applied compared to the control plants without organic fertilizer. Acid and alkaline phosphatase and urease activity increased when organic fertilizer was applied to soil. Application of organic fertilizers increased the growth and fresh weight of root and shoot of coffee plants and improved the root mycorrizal colonization and enzymatic activity of the soil.

Impact of Compost on Metals Phytostabilization Potential of Two Halophytes Species

Phytostabilization of heavy metals in contaminated soils should be subject to two conditions, the first is the choice plant must be able to stabilize heavy metals in soil, the second is the plant material which produced from the phytostabilization process must be safe and useful to avoid overload on environmental system. A field experiment was conducted out to evaluate the phytostabilization potential of two halophytes species (Atriplex lentiformis and Atriplex undulata). Compost at rates of 0, 15 and 30 ton ha−1 was used to examine its role in plant growth and heavy metals uptake. The high rate of compost (30 ton ha−1) decreased zinc (Zn) concentrations in the leaves of A. lentiformis and A. undulata by 15.8 and 13.0%, while lead (Pb) in the leaves decreased by 37.6 and 35.2% respectively. Despite the extremely high total heavy metals concentrations in the studied soil, plants of Atriplex were able to grow and maintain shoots metals content below the toxic level and the produced plant materials had a high nutritive value compared to the conventional forage crops. Phosphorus (P) and chloride (Cl) in the roots of Atriplex plants play important function in heavy metals phytostabilization mechanism by the two halophytes plants.

Changes in a Rhodic Hapludox under no-tillage and urban waste compost in the northwest of Rio Grande do Sul, Brazil

The use of urban waste compost as nutrient source in agriculture has been a subject of investigation in Brazil and elsewhere, although the effects on soil physical and chemical properties and processes are still poorly known. The aim of this study was to evaluate the effect of application of urban waste compost and mineral fertilizer on soil aggregate stability and organic carbon and total nitrogen content of a Rhodic Hapludox under no-tillage in the northwestern region of Rio Grande do Sul, Brazil, in the 2009/2010 and 2010/2011 growing seasons. The experiment was arranged in a 2 × 6 (seasons and fertilization) factorial in a randomized complete block design with four replications. The factor time consisted of two growing seasons (sunflower in 2009/10 and maize in 2010/11) and the factor fertilization of five rates of urban waste compost (0, 25, 50, 75 and 100 m³ ha-1), and mineral fertilizer. Soil samples were collected from the 0.0-0.10 m layer to determine aggregate stability (mean weight and geometric diameter), soil organic carbon (SOC) and total nitrogen (TN). Rates of up to 75 m³ ha-1 of urban waste compost, after two years of application to no-tillage maize and sunflower, improved aggregation compared to mineral fertilization in a Rhodic Hapludox. After the second crop, the SOC and TN contents increased linearly with the levels of urban waste compost.

Wine-distillery waste compost addition to a drip-irrigated horticultural crop of central Spain: Risk assessment

The assessment of environmental effects is important before agricultural use of organic wastes, especially in irrigated agricultural areas vulnerable to nitrate pollution. A field study with melon crop was conducted during 2011 and 2012 in central Spain, using different rates of wine-distillery waste compost to quantify nitrogen (N) leaching under two regimes of irrigation. To evaluate the groundwater pollution risk associated with these practices, some environmental indices were used to determine the variation in the quality of drinking water (Impact Index (II)) and in the nitrate concentration of the groundwater (Environmental Impact Index (EII)). To combine environmental together with yield parameters, the Management Efficiency (ME) was calculated. Considering II and EII, compost addition together with adjusted irrigation (90–100% ETc) do not represent a risk to increase groundwater contamination, and, in high doses, may contribute to remove nitrate from drainage water and improve the quality of the drinking water. In contrast, applying large amounts of compost together with an excess of water (120% ETc) increased N leaching significantly and poses a higher risk of groundwater contamination. The rate corresponding to 13 t ha−1 of compost together with an efficient irrigation is sufficient to achieve the highest yield, does not exceed the maximum allowable limits established by II and EII and has an adequate ME.

USE OF COMPOST FROM DIFFERENT ORIGINS TO CONTROL SOILBORNE PATHOGENS IN POTTED VEGETABLES

USE OF COMPOST FROM DIFFERENT ORIGINS TO CONTROL SOILBORNE PATHOGENS IN POTTED VEGETABLES

Response of Wheat Productivity to Different Rates of Compost and Ni-trogen Fertilizer Under New Valley Conditions

Response of Wheat Productivity to Different Rates of Compost and Ni-trogen Fertilizer Under New Valley Conditions

Seasonal nitrous oxide emissions from field soils under reduced tillage, compost application or organic farming

Soil management practices shown to increase carbon sequestration include reduced tillage, amendments of carbon and mixed rotations. As a means to mitigate greenhouse gases, however, the success of these practices will be strongly influenced by nitrous oxide (N2O) emissions that vary with soil wetness. Few seasonal data are available on N2O under different soil managements so we measured seasonal N2O emission in three field experiments between 2006 and 2009 in eastern Scotland. The experimental treatments at the three sites were (1) tillage: no-tillage, minimum tillage, ploughing to 20cm with or without compaction and deep ploughing to 40cm, (2) organic residue amendment: application of municipal green-waste compost or cattle slurry and (3) rotations: stocked and stockless (without manure) organic arable farming rotations. Most seasons were wetter than average with 2009 the wettest, receiving 20–40% more rainfall than average. Nitrous oxide emissions were measured using static closed chambers. There was no statistical evidence, albeit with low statistical power, that reduced tillage affected N2O emissions compared to normal depth ploughing. With organic residue amendments, only in the wet season in 2008 were emissions significantly increased by high rates of green-waste compost (4.5kgN2O-Nha−1) and cattle slurry (5.2kgN2O-Nha−1) compared to the control (1.9kgN2O-Nha−1). In the organic rotations, N2O emissions were greatest after incorporation of the grass/clover treatments, especially during conversion of a stocked rotation to stockless. Emissions from the organic arable crops (1.9kgN2O-Nha−1 in 2006, 3.0kgN2O-Nha−1 in 2007) generally exceeded those from the organic grass/clover (0.8kgN2O-Nha−1 in 2006, 1.1kgN2O-Nha−1 in 2007) except in 2008 when the wet weather delayed manure applications and increased emissions from the grass/clover (2.8kgN2O-Nha−1). Nevertheless, organic grassland was the land use providing the most effective overall mitigation. Although the magnitude of fluxes did not relate particularly well to rainfall differences between seasons, greater rainfall received during some growing seasons increased the differences between tillage, organic residue and crop rotation phase treatments, negating any possible mitigation by timing management operations in dry periods. This was partly attributed to applying tillage and manures late and/or in wet conditions. Of benefit would be different sampling strategies including closed chambers or eddy covariance with standardised methodology. Controlled soil management experiments with a wide geographic spread to specify land management for mitigation also important.

Water Retention and Repellency of a Sandy Soil Amended with Municipal Compost

ABSTRACTThe aim of this study was to investigate the influence of a drying process on sandy soil amended with different rates of compost on physical properties and with a special focus on soil water retention characteristics. The mixtures of compost and sandy soil with different compost rates were prepared, namely, 100% compost, 20% compost, 10% compost, and soil without compost. The samples were dried in the following temperatures: 20, 40, and 80°C. The compost addition to the sandy soil led to an increase in soil porosity. Three pore fractions, bonding space, residual, and storage pores reached their highest values in the samples with higher compost rates. A reduction of residual and storage pores volume resulted in a decrease in available and productive water content. Lower compost content reduced the amount of stored water. The drying of the sandy soil amended with compost at rates of 100 and 20% triggered the water repellency effect.

EFFECT OF INORGANIC, ORGANIC AND BIO FERTILIZERS ON YIELD AND YIELD COMPONENTS OF SUNFLOWER Under Newly Reclaimed Soils

Tow field trials were carried out in 2010 and 2011 summer seasons to study the effect of mineral, organic, natural rocks and biofertilizers on yield and yield components of Sahka 53 and Giza 102 sunflower varieties in newly reclaimed soils. The field experiments were layout at the AgriculturalExperimentalDesert station, Faculty of Agriculture, CairoUniversity at Wadi El-Natroon, El-Beheira Governorate, Egypt. The results showed that the applying of organic fertilizers, natural mineral rocks and biofertilizers had positive effect on yield and yield components of two sunflower varieties under sandy soil condition as compared to NPKmineral fertilizers. Fertilizing with various rates of compost, natural mineral rocksandbiofertilizersincreased head diameter, seed yield /plant, seed yield /faddan and 100-seed weight by 4%, 5%,13% and 5% as compared to plants received recommend NPK mineral fertilizer dose,respectively at the first season and the corresponding values at the second one were 4%,8%,19% and 3% in the same order. The obtained results showed that, there were no significant effect of the interaction between the varieties and various form of fertilization (organic, bio and mineral) application in most of the studied traits except in seed oil content and seed protein content in both seasons. On the other hand, applying of compost, bio fertilizers and natural mineral rocks had support Rhizosphere microorganism (RMO) and gave higher values of total bacteria counts, nitrogenase and dehydrogenase activity as compared to untreated treatments.

EFFECT OF MOLE DRAINS AND COMPOST APPLICATION ON SOME SOIL PROPERTIES, WATER RELATIONS AND ITS PRODUCTIVITY AT NORTH DELTA.

A field experiment was conducted at Sakha Agricultural Research station, Kafr El-Sheikh Governorate, Egypt to evaluate the effect of mole drain types, mole spacing and compost application on improving some soil physio-chemical properties, some water relations and yields of wheat and sunflower. The experiments were conducted in split-split plots with four replicates. The most important findings can be summarized as follows: Sandy mole and narrow mole spacing effects were superior to without sandy mole and wider mole spacing on reducing soil salinity and sodicity. The reductions of salinity were 24.70, 20.16 and 10.30%, respectively, after two seasons from experiment installation under mole distance of 2-m, 4-m and 6-m. While, the corresponding values of SARe were 13.41, 10.62 and 19.40%, respectively. The higher reduction of soil salinity and sodcity, were noticed with increasing rates of compost in both growing seasons. The construction of mole drain is more effective in reducing soil bulk density and increasing basic infiltration rate. The reducing soil bulk density and increasing basic infiltration rate were higher under sandy mole than mole without sand. The effect of mole spacing on reducing soil bulk density and increasing basic infiltration rate can be arranged according to the following descending order 2m > 4 m > 6 m > compared to data obtained before treatments. The construction of mole with narrow distances between the ploughed lines seemed to be effective in increasing availability of N, P and K especially with high rates of compost. Sandy mole and narrow mole spacing were superior to without sandy mole and wider mole spacing on improving water application efficiency, field and crop water use efficiencies. The highest values of field and crop water use efficiencies for wheat and sunflower were achieved from the interaction between sandy mole at 6 m spacing combined with application of 20 ton compost fed-1. Mole types, mole spacing and compost rates have highly significant effect on yields and yield components of wheat and sunflower. Sandy mole caused increasing of grain and straw yield of wheat than without sandy mole by 74.30 and 116.1%, respectively. Also, sandy mole caused increasing of seed yield and seed oil content of sunflower than without sandy mole by 48.41 kg fed-1 and 0.26%, respectively. The effect of mole spacing on wheat and sunflower yields and its components can be arranged according to the following descending order 2m > 4 m > 6 m. Compost application caused high increases in wheat and sunflower yields and its components especially with the high rates. The construction of sandy moles at 2 m spacing combined with addition of 20 ton compost fed-1gave the highest production of wheat grain yield(3886.7 kg fed-1).

Soil Properties and Nutrient Export of a Duplex Hard-Setting Soil Amended with Compost

ABSTRACT Soils managed for field vegetable production often receive high nutrient inputs and are frequently cultivated. This can result in agronomically excessive soil P and soil structural degradation. In combination, these can lead to large losses of nutrients in runoff that can impact on aquatic environments. We investigated the effect of compost application at 62.5 and 125 t ha−1 in both 2005 and 2008 on soil nutrient and physical properties and runoff and nutrient export using simulated rainfall/runoff. The use of compost reduced (p < 0.01) the accumulation of available P in soils compared to conventional fertilizers but still resulted in excessively high soil P levels. The application of compost increased water stable aggregates, increased infiltration rates, and reduced the volume of runoff (all p < 0.01). Compost at either rate reduced runoff volumes by ∼50% compared to conventionally managed soils. As a consequence of reduced nutrient inputs/accumulation and improved soil physical properties, the use of compost at 62.5 t ha−1 resulted in a ∼50% reduction in N and P export in surface runoff, with no added benefit of using the higher compost rate. The rainfall simulations we reported only represent a ‘snap-shot’ of compost effects on runoff properties, and longer term monitoring of runoff would add further understanding of treatment effects. Nevertheless, we suggest that the use of compost may have environmental benefits although nutrient supply and status in the soil needs to be managed carefully to ensure adequate crop nutrition without unnecessarily increasing soil nutrients above the agronomic optimum.

INTERPRETING RESULTS FOR PLANT GROWTH PROMOTION AND DISEASE SUPPRESSION BIOASSAYS USING COMPOST

Applying high rates of humified, thermophilic compost and vermicompost to a soil depleted in organic carbon has the potential to improve soil structure and soil fertility, and also to suppress soilborne disease. In this paper, published bioassay methods were used to assess the disease-suppressing properties of cured, thermophilic cotton trash Applying high rates of thermophilic compost and vermicompost to a soil depleted in organic carbon has the potential to improve soil structure and fertility, and to suppress soilborne disease. Published bioassay methods were used to assess the disease-suppressing properties of three cured cotton trash composts, and the plant growth promoting properties of filtrate produced from pig manure vermicompost. The chemical properties of the composts and the Fusarium wilt infested receiving soil were analysed, to assess other soil health parameters likely to affect plant growth. Results were not as expected. Cotton seedling survival in the compost treatments was only marginally better than the control, with all seedlings showing disease symptoms. In the plant growth promotion assay, seed germination was highest in the water-only controls, with the vermi- and mesophilic (no worm) compost filtrates inhibiting root growth. The common factor responsible for the unexpected results was excessive salinity. To realize the soil health benefits of organic amendments, application rates must account for the concentration of plantavailable nutrients and soluble salts that they contain.

Combustion Characteristics of Combustion Chamber Using Compost as a Fuel

The aim of the present study is to develop the biomass furnace combustor which can effectively use the compost as a fuel. Here, the compost which is made from pig's waste and has the calorific value of 2000kcal/kg, is employed here. Emphasis is placed on the optimum conditions of fuel and air flow rates, moisture content of the compost and the corresponding combustion gas components and combustion gas temperature in the combustor. It is found from the study that (i) the self-combustion takes place less than 40% of the compost's moisture content, (ii) the effective combustion is induced using the fine particles of compost, i.e., the pulverized compost, and (iii) the steady-state combustion is maintained by the relationship of air and compost rate.