Characterization of vermicompost of coconut husk mixed with cattle dung: physicochemical properties, SEM, and FT-IR analysis

Assessment of microbial flora and pesticidal effect of vermicast generated from Azadirachta indica (neem) for developing a biofertilizer-cum-pesticide as a single package

The soil comprising organic matter, nutrients, serve as substrate for plant growth and various organisms. In areas where there are large plantations, there is a huge leaf litter fall. The leaf litter upon decomposition releases nutrients and helps in nutrient recycling, for which the soil engineers such as earthworms, ants and termites are important key players. In this context, the present study was conducted to assess the characteristics of the vermicast obtained by vermicomposting neem leaf litter in terms of microbial flora, plant growth promoting properties and antagonistic activities of the vermicast against phytopathogens. Vermicomposting of neem leaf litter was done using two epigeic earthworm species Eisenia fetida and Eudrilus eugeniae. The vermicast exhibited antagonistic potential against plant pathogens. Out of the four vermiwash infusions studied, the 75 % formulation reduced the disease incidence against mealybug by 82 % in the tree Neolamarkia cadamba. The result of the study suggests that vermicast made from neem leaf litter may be a potent combination of a biofertilizer and a pesticide.

Vermicompost and millicompost as a resource in sustainable agriculture in semiarid: decomposition, nutrient release, and microstructure under the action of nitrogen and organic-mineral fertilizers

With the expansion of organic agriculture, research is needed to indicate economically and ecologically viable fertilizer options, especially in semiarid regions, with low soil organic matter and nitrogen content. In the Brazilian semiarid region, vermicomposts are widely used by farmers and are scientifically investigated; however, there is no information for millicompost, a new type of organic compound that has shown very promising results in other regions. Thus, this study aimed to analyze the decomposition rate, nutrient release, and microstructure evaluation of vermicomposts from different sources and of millicompost produced from plant residues, with the application of mineral nitrogen-urea and organo-mineral fertilizer in the Brazilian semiarid region. The experimental design was a randomized block in a 4 × 3 factorial scheme, with four replicates; four organic composts (millicompost, commercial vermicompost, vermicompost from bovine manure, vermicompost from goat manure); and three types of fertilization (without fertilizer, with mineral-urea and organo-mineral fertilizer). The organic composts were decomposed using litterbags at the soil surface. The variable's decomposition rate and the nutrient release were evaluated at six-time intervals (0, 30, 60, 90, 120, and 150 days), and microstructure was evaluated at the beginning and the end of the experiment, with scanning electron microscopy (SEM). The highest decomposition was verified for commercial vermicompost rich in macro and micronutrients and with lower P contents. The lignin:N ratio and the initial P content were more important in the permanence of the organic compost in the field than the C:N ratio. Regardless of the organic composts, the use of urea as a mineral fertilizer stimulated decomposition more than the organo-mineral fertilizer. The initial composition of the nutrients was decisive in the dynamics of nutrient release, mass loss, and decomposition of C. There was no pattern in the release order of macronutrients. However, for the micronutrients, the release order was Cu > Fe > Mn, in all treatments. Microstructure analysis is a visual analysis where differences are detected through microphotographs and the biggest difference occurred with millicompost, which showed elongated fibers and fiber bundles, forming a relatively open structure characteristic of the presence of fulvic acid. However, the addition of organo-mineral fertilizer formed agglomerates in compacted micro-portions, helping the mineralization of C and N.

Effect and its mechanism of potassium persulfate on aerobic composting process of vegetable wastes

Vegetable waste (VW) is a potential organic fertilizer resource. As an important way to utilize vegetable wastes, aerobic composting of VW generally has the problems of long fermentation cycle and incomplete decomposition of materials. In this study, 0.3-1.2% of potassium persulfate (KPS) was added to promote the maturity of compost. The results showed that the addition of KPS promoted the degradation of materials, accelerated the temperature rise of compost. KPS also promoted the formation of humic substances (HS). Compared with the control, HS contents of treatments with KPS addition increased by 7.81 ~ 17.52%. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscope (SEM) analysis reveal the mechanism of KPS affecting the composting process: KPS stimulated the degradation of various organic substances such as lignin at high temperature stage, and the degradation of lignin could accelerate the release and decomposition of other components; KPS made the structure of the material looser, with more voids and pores, and more specific surface area of the material, which was more suitable for microbial degradation activities. Therefore, the addition of KPS can promote the decomposition of organic matter in the early stage of composting, accelerate the process of thermophilic phase, and shorten the composting process and improve product maturity.

Physiological and behavioral assessment of Metaphire posthuma in response to clothianidin insecticide: Insights from molecular and biochemical analysis

In the present study, Clothianidin [(E) - 1-(2 - chloro-1,3 - thiazol - 5-ylmethyl) - 3-methyl - 2- nitroguanidine] (CLO) was selected as a soil pollutant and earthworm was employed as a test organism. The various responses like biochemical and detoxification process of earthworm Metaphire posthuma towards Clothianidin at lethal and sublethal doses were studied using OECD-standardized toxicological guidelines. The present study examined the toxicity of CLO to earthworms after 28 days of exposure at conc. 0, 1.5, 3, 6, 12 and 24 mg kg-1 in a soil mixture. Biochemical markers including Guaiacol peroxidase (POD), Superoxide dismutase (SOD), Catalase (CAT), Glutathione S-transferase (GST) and content of Malondialdehyde (MDA) in earthworms were measured. Acute toxicity tests revealed that CLO caused a concentration-dependent increase in mortality with LC50 (Lethal concentration) values of 10.960 and 8.201 mg kg-1 for 7th and 14th day respectively. The earthworms were exposed to CLO contaminated soil for 56 days and reflecting the significant decrease in earthworm growth, cocoon and hatchling production. Moreover, enzyme activities such as CAT, SOD, POD and MDA content were significantly enhanced with the increased concentration and exposure period of CLO. Molecular docking studies indicated that CLO primarily interacts to the junction site of SOD and in active centres of CAT, POD and GST. As a result, the current findings imply that the sub chronic CLO exposure can induce variations in physiology and avoidance behaviour of earthworms, oxidative stress as well as alterations in enzyme activities.

Application of neem waste vermicompost in compensating nematode induced stress and upregulating physiological markers of tomato plants under glass house conditions after 10 days of exposure

Farming, food processing, animal husbandry and other agro-based activities contribute to global environmental degradation by producing millions of tons of organic and inorganic solid waste. In terms of sustainable agriculture, agricultural waste management and conversion into useful products are essential. In addition, plants are facing various kinds of biotic stress, which ultimately affects their defense system. Altered defense systems in plants ultimately lead to the death of plants and a reduction in crop production. The present study is designed to keep the abovementioned fact in mind, which mainly focuses on the reuse of agricultural waste and its application to the antioxidant potential and structural components of tomato plants during nematode stress. In the present study, neem leaves were collected and mixed with cattle dung for the preparation of vermicompost. Then, tomato seeds were pre-treated with vermicompost extract before being germinated in earthen pots. After germination, they were transplanted to separate pots and inoculated with freshly hatched juveniles of Meloidogyne incognita. The experiments were conducted for 10 days under glass house conditions, and after that, plants were harvested and various physiological (antioxidant capacity, percent electrolyte leakage) and structural markers (carbohydrate content, Fourier transform infrared spectroscopy) were analyzed. Results revealed that all physico-chemical properties make vermicompost superior as compared to soil and pre-compost material. Further, nematode stress leads to altered physiological and structural markers as compared to uninfected seedlings. However, treatment with vermicompost significantly increases carbohydrate content and antioxidative capacity in a concentration dependent manner. In addition, electrolyte leakage was found to be decrease with an increase in the concentration of vermicompost. All these findings conclude that vermicompost has strong potential to limit the damage caused by nematodes and boost the antioxidant potential of the host plants. Further, this study provides strong evidence for using vermicompost as an eco-friendly alternative to chemical nematicides and a potential strategy for agricultural waste management. This is the first study in which the tomato plant's structural and physiological markers were assessed during nematode stress after being supplemented with vermicompost under glass house conditions for an initial 10 days of nematode exposure.

Physiological, biochemical and structural changes in tomato plants by vermicompost application in different exposure periods under glass house conditions

In modern era, various inorganic fertilizers and pesticides are used as plant growth supplements in a variety of crop in order to gain maximum output and also reported as hazardous to mankind as well as environment. In addition, some of the plants died in initial phase of the growth after germination due to poor nutrient content of the soil or exposure to biotic stresses. In the beginning of sustainable agriculture, these chemical fertilizers were replaced with some alternative growth boosters such as organic fertilizers. In the present study, vermicompost was prepared using garden waste and cattle dung followed by analysis of various physico-chemical properties. Then tomato seeds were allowed to germinate in soil and supplemented with different doses of vermicompost (0-100%). The plants were harvested after 10 and 45 days of their germination and tissues were subjected to analysis of various morphological and biochemical parameters. Morphological parameters included root length, shoot length, root fresh weight, shoot fresh weight and number of leaves. Whereas biochemical parameters such as protein content, antioxidative enzymes (catalase, superoxide dismutase, ascorbate peroxidase, polyphenol oxidase), non-enzymatic antioxidants (ascorbic acid, glutathione, tocopherol), osmolytes (proline, carbohydrate), photosynthetic pigments (chlorophyll, carotenoid) and secondary metabolites (phenol, flavonoid, anthocyanin) were estimated on UV-visible spectrophotometer using standard protocols. Further, structural analysis of plant tissue was done using fourier transform infrared spectroscopy spectra (FTIR) and carbon hydrogen nitrogen (CHN) elemental analyzer. Results obtained from the present study revealed significant difference in all morphological and biochemical markers at both 10 and 45 days intervals of time. Further, growth of all plants was found to be directly proportional to the concentration of vermicompost and exposure duration. FTIR spectra and CHN analyses reveal the breakdown of various complex compounds and their transformation from Vcom amended soil to roots of plants. This is the first study in which significant changes were observed in growth, physiology and structural composition of tomato plants at two different exposure periods (10 and 45 days) under glass house conditions which further concluded that vermicompost has a significant potential for increasing plant growth.

Production and characterization of enriched vermicompost from banana leaf biomass waste activated by biochar integration

Vermicomposting uses less energy and requires fewer infrastructures, and it is capable of restoring soil nutrition and carbon. Banana cultivation produces lots of trash in a single crop season, with 30 tonnes of waste generated per acre. The biodegradable fraction of banana leaf waste is thrown out in large quantities from temples, markets place wedding halls, hotels, and residential areas. Vermicomposting can be used for recovering lignin, cellulose, pectin, and hemicellulose from banana leaves. Earthworm digests organic materials with the enzymes produced in gut microflora. Biochar adds bulk to vermicomposting, increases its value as fertilizer. The goal of this study was to amend biochar (0, 2, 4 and 6%) with banana leaf waste (BLW) + cow dung (CD) in three different combinations (1:1, 2:1 and 3:1) using Eisenia fetida to produce enriched vermicompost. In the vermicompost with biochar groups, there were higher levels of physicochemical parameters, as well as macro- and micronutrient contents. The growth and reproduction of earthworms were higher in groups with biochar. A maximum of 1.82, 1.18 and 1.67% of total nitrogen, total phosphorus and total potassium was found in the final vermicompost recovered from BLW + CD (1:1) amended with 4% biochar; while the other treatments showed lower levels of nutrients. A lower C/N ratio of 18.14 was observed in BLW + CD (1:1) + 4% biochar followed by BLW + CD (1:1) + 2% biochar amendment (19.92). The FTIR and humification index studies show that degradation of organic matter has occurred in the final vermicompost and the substrates with 4% biochar in 1:1 combination showed better degradation and this combination can be used for nutrient rich vermicompost production.