Efficiency of cow dung based vermi-compost on seed germination and plant growth parameters of Tagetes erectus (Marigold)

Dual-Purpose Vermicompost for the Growth Promotion and Suppression of Damping-Off Disease on Potted Vegetable Soybean

Vermicompost is applied as a soil amendment to promote plant growth and yield. It also helps to significantly reduce the incidence of soil-borne diseases. However, its efficiency depends on the type of earthworm from which it is formed. The current study aims to compare the effects of two vermicompost types derived from African nightcrawler (AF) and Tiger worm (TG) as a soil amendment to evaluate its potential for suppressing damping-off disease both in vitro and in vivo. It also aims to determine the effects of both vermicompost types on the growth and yield-related traits of potted Thai vegetable soybean [Glycine max (L.) Merrill] variety "Chiang Mai 84-2" grown under greenhouse conditions when amended to the soil at various application rates (1%, 2%, 3% w/w). AF vermicompost exhibited better suppression of damping-off disease than TG vermicompost in vitro and under greenhouse conditions. AF vermicompost performed significantly greater suppressive efficacy on the mycelial growth of Athelia rolfsii in vitro than TG vermicompost, indicated by 50% and 16% inhibition, respectively. Damping-off incidence on vegetable soybean seedlings grown in soil amended with AF vermicompost was significantly lower (21%) than in soil amended with TG vermicompost (32%) under greenhouse conditions. With an increased application rate of 1% to 2% or 3% for each vermicompost type, plant yields significantly enhanced, with no significant variations among the 2% and 3% rates. Applying vermicompost at 2% w/w through soil amendment was the appropriate rate for promoting the growth and yield of potted vegetable soybeans. The results can be used to guide the application of vermicompost to control soil-borne plant diseases, promote plant growth, and enhance yields, especially in terms of organic crop production. Further research is needed to evaluate its potential for other potted crops and protect against soil-borne diseases.

The effect of calcium hydroxide addition on enhancing ammonia recovery during thermophilic composting in a self-heated pilot-scale reactor

A modified outdoor large-scale nutrient recycling system was developed to compost organic sludge and aimed to recover clean nitrogen for the cultivation of high-value-added microalgae. This study investigated the effect of calcium hydroxide addition on enhancing NH₃ recovery in a pilot-scale reactor self-heated by metabolic heat of microorganisms during thermophilic composting of dewatered cow dung. 350 kg-ww of compost was prepared at the ratio of 5: 14: 1 (dewatered cowdung: rice husk: compost-seed) in a 4 m³ cylindrical rotary drum composting reactor for 14 days of aerated composting. High compost temperature up to 67 °C was observed from day 1 of composting, proving that thermophilic composting was achieved through the self-heating process. The temperature of compost increases as microbial activity increases and temperature decreases as organic matter decreases. The high CO₂ evolution rate on day 0-2 (0.02-0.08 mol/min) indicated that microorganisms are most active in degrading organic matter. The increasing conversion of carbon demonstrated that organic carbon was degraded by microbial activity and emitted as CO₂. The nitrogen mass balance revealed that adding calcium hydroxide to the compost and increasing the aeration rate on day 3 volatilized 9.83 % of the remaining ammonium ions in the compost, thereby improving the ammonia recovery. Moreover, Geobacillus was found to be the most dominant bacteria under elevated temperature that functions in the hydrolysis of non-dissolved nitrogen for better NH₃ recovery. The presented results show that by thermophilic composting 1 ton-ds of dewatered cowdung for NH₃ recovery, up to 11.54 kg-ds of microalgae can be produced.

Cow products: boon to human health and food security

The world population exceeded 7.8 billion people in 2020 and is predicted to reach 9.9 billion by 2050 as per the current increasing rate of 25%. In view of this, ensuring human health and food security has become an issue of key importance to countries with different degrees of economic development. At the same time, the livestock sector plays a strategic role in improving the economic, environmental, and sociocultural stewardship of any nation. The cow (Bos indicus) has held a distinctive role in human history ever since its domestication because of its valued harvests like dairy products (milk, clarified butter, yogurt, curd, and buttermilk) excreta like dung and urine. These products, except dung, provide all the necessary energy and nutrients to ensure the proper growth and development of the human. They are the source of many bioactive substances, which possess immense pharmacotherapeutic action against various physiological, metabolic and infectious disorders, including COVID-19. The use of urine and dung can be considered a low-cost agricultural practice for farmers and has been extensively used in modern agriculture practices to ensure food security via soil fertility, plant pathogens, and pests. Cow urine mediated synthesized nanomaterial also display distinctive characteristics and novel applications in various fields of science and technology. Thus, this paper aims to provide a comprehensive overview of cow products, describing their biochemical constituents, bioactivities, and their utilization in the area ranging from human welfare to agriculture sustainability. An attempt is also made to present possible applications in bioenergy production and pollution reduction.

Vermiwash: An agent of disease and pest control in soil, a review

Vermiwash is a liquid extract produced from vermicompost in a medium where earthworms are richly populated. It comprises a massive decomposer bacteria count, mucus, vitamins, different bioavailable minerals, hormones, enzymes, different antimicrobial peptides, etc. This paper aimed to assess how these natural products in vermiwash suppressed the pathogen and pests. Thus, we have reviewed the importance of vermiwash/vermicompost in disease control, the mechanism of disease suppression, the components of vermiwash applied in disease suppression, and pest control to use the scientific facts in agriculture to enhance the productivity of the crops. The bioactive macromolecules from the skin secretion of earthworm, coelomic fluid, and mucus directly able to defend pathogenic soil microbes against the worm and thereby freed the environment from the disease. Earthworms establish symbiotic relations with microbes, produce an essential product that supports the growth of plants, and suppress plant's root disease. It is recomended that earthworm should be inoculated in an agricultural field, or prepare and apply its vermiwash/vermicompost as a spray or as additive bio-fertilizer in the soil to enhance the productivities of the crops.