Evaluation of a vermicompost and leachates on <i>Solidago x hybrida</i> and organic carbon mineralization under aerobic incubations

In the floriculture region of Tenancingo in the State of Mexico, the application of stabilized organic matter, such as vermicompost and leachates, contributes to improve the quality of the soil and plant nutrition. However, it is important to know the chemical composition of a vermicompost and the mineralization process. This is because the amount and speed of nutrient release which will be available to the crop will depend on that knowledge. The objective of the study was to evaluate the effect of the application of a vermicompost and leachates on various quantitative variables of Solidago x hybrid, and the mineralization of organic carbon under aerobic incubations. Vermicompost (74 and 36 g/kg soil), leachates (5 and 10 L/kg soil), 0.33 g/kg soil of chemical fertilizer Ca (NO₃)₂, and not treated soil (control) were applied under greenhouse conditions to evaluate their effects on plant growth variables. Mixtures of 100 g of soil with vermicompost and leachates were made in the laboratory which were incubated during 9 weeks to obtain the potentially mineralizable organic carbon (Corg PM) and the rate of mineralization (k) after adjusting an exponential model. In the greenhouse experiment there were no statistical differences after applying vermicompost and leachates on the quantitative variables (number of stems per plant, diameter of the panicle, fresh weight, plant length and stem diameter) with respect to the control (p>0.05). The effect among the applied doses was evident only for variables such as fresh weight, panicle length and stem diameter with respect to the control. In incubated soils, k values ranged between 0.209-0.325 C mg/kg soil/week. Only with the application of leachates in high doses two pools of organic matter were shown: one soluble labile (102.9 mg/kg soil) and the other hydrolysable (819 mg/kg soil). The soluble, labile fraction favored nutrient availability immediately after its application to the soil. However, a single pool of hydrolysable organic C (987-1074 mg/kg soil) was found when vermicompost was applied. It was associated with a release of organic matter during crop development, and to a possible stimulation of microbial activity. High values of electrical conductivity in vermicompost and leachates (8.2-11.7 mS/m) suggest a moderate application of both products.     

Potential of Allolobophora parva (Oligochaeta) in vermicomposting

The aim of this study was to assess the potential of Allolobophora parva Eisen as a candidate for vermicomposting practices. Five organic waste mixtures: cow dung (CD), biogas plant slurry (BGS), cow dung + vegetable waste (CD + VW), BGS + VW and VW + Soil were vermicomposted using A. parva. Vermicomposting showed a decrease in pH, organic C and C:N ratio, but increase total N, available P and exchangeable K at the end. C:N ratio of end material (vermicompost) was within the agronomic acceptable limit (<20). The high level of NPK in worm-processed material indicates the candidature of this species for waste management operations. The earthworm also showed an excellent growth in different wastes. Results thus indicate that A. parva appeared a potential tool for conversion of organic wastes into value added products for sustainable land restoration practices.     

Transformation of buffalo manure by composting or vermicomposting to rehabilitate degraded tropical soils

The addition of composted buffalo manure may lead to qualitative and quantitative improvement of the organic matter content of degraded tropical agricultural soils in Northern Vietnam. The objectives of this study were to follow the biochemical changes occurring during composting of buffalo manure with and without earthworms during 3 months and to study the effect of the end products (compost and vermicompost) on soil biochemical parameters and plant growth after two months of incubation under controlled conditions in an open pot experiment. Our conceptual approach included characterisation of organic matter of the two composts before and after addition to soil by elemental, isotopic analysis and analytical pyrolysis and comparison with conventional fertilisation. We also analysed for lignin content and composition.Our results showed that composting in the presence of earthworms led to stronger transformation of buffalo manure than regular composting. Vermicompost was enriched in N-containing compounds and depleted in polysaccharides. It further contained stronger modified lignin compared to regular compost. In the bulk soil, the amendment of compost and vermicompost led to significant modification of the soil organic matter after 2 months of exposure to natural weather conditions. The lignin component of SOM was unaffected whatever the origin of the organic amendment. Compost and vermicompost amendments both enhanced aggregation and increased the amount of organic matter in water stable aggregates. However, vermicompost is preferable to compost due to its beneficial effect on plant growth, while having similar positive effects on quantity and quality of SOM.     

Chemical and biological properties of wheat soil in response to paddy straw incorporation and its biodegradation by fungal inoculants

A field experiment was conducted to evaluate the relative contribution of organic fertilizers (paddy straw, microbial inoculants and vermicompost) and inorganic fertilizers (urea and superphosphate) in improving pH, C, N, humus, microbial biomass, dehydrogenase, phosphatase, cellulase, β-glucosidase and xylanase activities of soil under wheat crop. Vermicompost fertilization resulted in highest microbial biomass, available phosphorus, and nitrogen content of wheat soil. It was also found effective in minimizing the alkalinity of soil compared to other treatments as indicated by pH change. However incorporation of paddy straw in conjunction with N₆₀P₆₀ and T. reesei inoculation resulted in maximum dehydrogenase, alkaline phosphatase and highest humus content of soil. Mixed inoculation of A. awamori and T. reesei did not prove effective in improving the soil biochemical properties in comparison to single inoculation of T. reesei. Results showed that in situ incorporation of paddy straw in combination with N₆₀P₆₀ and T. reesei inoculation can be used as an effective measure for valuable disposal of paddy straw and to improve the soil health by reducing mineral fertilization.     

Pilot-scale vermicomposting of pineapple wastes with earthworms native to Accra, Ghana

Pineapple wastes, an abundant organic waste in Accra, Ghana, were vermicomposted using native earthworms (Eudrilus eugeniae Kinberg) collected from the banks of streams and around bath houses of this city. Triplicate pilot-scale vermidigesters containing about 90 earthworms and three other control boxes with no earthworms were fed pineapple pulp or peels, and the loss of wet mass was monitored over 20 weeks. In a second experiment, a 1:1 mixture of pineapple peels and pulp (w/w) was fed to triplicate pilot-scale vermicomposters and control boxes during a 20 week period. One month after feeding ended, the vermicompost and composted (control) waste was air dried and analyzed. During the first experiment, the vermicomposted pineapple pulp and peels lost 99% and 87% of their wet mass, respectively, indicating the potential for vermicomposting. Fresh pineapple waste exhibited an initial pH of 4.4, but after 24 weeks, the vermicompost and compost had acquired a neutral to alkaline pH of 7.2–9.2. The vermicompost contained as much as 0.4% total N, 0.4% total P and 0.9% total K, and had a C:N ratio of 9–10. A reduction of 31–70% in the Escherichia coli plus Salmonella loads and 78–88% in the Aspergillus load was observed during vermicomposting. The rapid breakdown of pineapple wastes by E. eugeniae demonstrated the viability of vermicomposting as a simple and low cost technology recycling this waste into a soil amendment that could be used by the 2500 vegetable producers of Accra and its surrounding areas.     

蚯蚓养殖及蚓粪对植物土传病害抑制作用的研究进展

利用蚯蚓养殖对有机废弃物进行资源化处理是一项古老而新兴的生物技术,20世纪70年代又获得了新进展．本文从蚯蚓养殖方法、蚓粪的理化性质、蚓粪的综合利用等方面进行了综述,并着重分析了蚓粪对土传植物病害的抑制作用及其抑制机理．蚓粪对土传植物病害的抑制是蚓粪应用的另一个重要新途径,虽然只是初步研究,但已表现出明显的应用潜力。植物土传病害抑制作用与蚓粪中丰富的微生物区系有很大的关系,尤其大量拮抗微生物的存在是蚓粪具有抑病作用的重要机制．     

Municipal solid waste (MSW) vermicomposting with an epigeic earthworm, Perionyx ceylanensis Mich

Municipal solid waste (MSW) was vermicomposted in combination with cowdung (CD) using Perionyx ceylanensis for 50 days. The decomposition rate of 55-78% was observed in different vermibed substrates, the highest being CD followed by 10:1 ratio of CD + MSW. The C/N ratio was reduced from 41.8 to 17.6 and 38.8 to 15.4 in MSW + CD (10:1) and CD, respectively. The difference in the final C/N ratio between MSW + CD (10:1) and CD vermicompost was not significant (p < 0.05). The important nutrients, NPK showed significantly (p < 0.05) higher contents in vermicomposts than worm-unworked composts. The degradation rate of cellulose and lignin was 37% and 12%, respectively, in 10:1 vermibed mix with P. ceylanensis. The bacterial, fungal and actinomycetes population in vermicompost was significantly higher than in the compost. The biomass, number and cocoons of P. ceylanensis collected after 50 days showed increase with the increase of CD incorporation in MSW.     

Improving yield-related physiological characteristics of spring rapeseed by integrated fertilizer management under water deficit conditions

Two separate field experiments were conducted in 2018 and 2019 as split-plot based on randomized complete block design with three replications to evaluate physiological responses of rapeseed to fertilization treatments (control, chemical fertilizer, inoculation of seeds with PGPR, vermicompost and combined fertilizers) under different irrigation levels (irrigation after 70,100, 130, and 160 mm evaporation). Water stress increased the activities of catalase, polyphenol oxidase, peroxidase and superoxide dismutase and the contents of proline, soluble sugars and malondialdehyde and also leaf temperature, but decreased membrane stability index, chlorophyll content, leaf water content, stomatal conductance and grain yield. Application of fertilizers particularly combined fertilizers decreased proline content and leaf temperature, but increased the antioxidant enzymes activities, soluble sugars, chlorophyll content, leaf water content, membrane stability index, and stomatal conductance under different irrigation intervals. These superiorities of fertilization treatments were led to considerable improvement in grain yield. The results revealed that the combined fertilizer application improved most of the physiological parameters. It was deducted that the application of combined fertilizers reduced chemical fertilizer by about 67% and alleviated the deleterious effects of water limitation on field performance of rapeseed.     

Bioconversion of garden waste,kitchen waste and cow dung into value-added products using earthworm Eisenia fetida

Solid waste management is a worldwide problem and it is becoming more and more complicated day by day due to rise in population, industrialization and changes in our life style. Transformation of industrial sludges into vermicompost is of double interest: on the one hand, a waste is converted into value added product, and, on the other, it controls a pollutant that is a consequence of increasing industrialization. Garden waste, kitchen waste and cow dung were subjected to recycle through vermicomposting by using the epigeic earthworm Eisenia fetida under field conditions. The pH, moisture content, total organic carbon, humus, nitrogen, phosphorous and potassium in vermicompost was analysed. It was found that moisture content, total organic carbon, humus, nitrogen, phosphorous and potassium was high in cow dung, followed by kitchen waste and garden waste. This study clearly indicates that vermicomposting of garden waste, kitchen waste and cow dung can not only produce a value added produce (vermicomposting) but at the same time reduce the quantity of waste.     

Evaluation of the effect of different concentrations of organic amendments and botanical extracts on the mortality and hatching of Meloidogyne javanica

Organic amendments and botanical extracts are considered as some of the eco-friendly alternatives to chemical pesticide in suppressing plant pathogenic nematodes (PPN). Root-knot nematode (RKN) is the most important group of PPN distributed globally causing both qualitative and quantitative damage to many crops. Vermicompost and biogas digestate (BD) are two forms of organic amendments reported to have potential to limit RKN infestation. Likewise, marigold (Tagates spp.) and cabbage (Brassica oleracea) are two widely studied botanicals having shown their potential to control RKN. However, there was not much in vitro research related to organic amendments and botanicals targeting a particular species of RKN to observe their nematicidal effect. An in vitro experiment was undertaken to evaluate the effect of these organic amendments and botanical extracts at different concentrations (10.0%, 25.0%, 50.0% and 100.0%) on the hatching and mortality of Meloidogyne javanica at different time spans. Mortality of J₂ and inhibition of hatching of egg mass of M. javanica differed significantly (p < 0.0001) among the interaction effect of treatments and incubation time for both organic amendments and botanical extracts. Findings of this experiment indicated that potentiality for increasing mortality and inhibition of hatching was higher and steadier in botanical extracts than those of organic amendments.