Dear readers, as mentioned in a previous article, we implemented an experimental test related to worm farming and where the variable frequency of irrigation was manipulated in order to evaluate the effects they may have in relation to the biomass of the worms and the chemical characteristics of the vermicompost leachate, in this test (3) treatments were established in which the frequency of irrigation was varied as follows in 2,4 and 7 days, fed with vegetable residues.
In the following link you can consult the methodology established in the test:
After the evaluation, some important results were obtained and they will be shared below.
Let's start by mentioning the variable biomass of the worm, which is related to growth and that in the three treatments there was no statistically significant difference and the worms maintained an average weight of 0.42 live weight per 100 weighed annelids, for which a weight per individual of 420 mg/individual is estimated. In relation to this, some bibliographic references such as Durán and Henríquez, (2009) among other authors, have indicated that the worm weighs approximately 1 g as an adult, however, similar values were not observed in this research. However, the results are close to those obtained by Mammadov, Fatemi and Sedaghathoor (2016), who reported a weight between 621 and 490 mg/worm fed with beef manure and a mixture of beef manure and cane bagasse.
It is important to highlight, that according to the mentioned by Hernández, Pietrosemoli, Farias, Palma, Canelon and Martínez (2009), it is inferred that biomass is influenced by population density, the higher the density, the lower the biomass, therefore, it is possible that the observed results vary with increasing or decreasing density; these authors also indicate that the individual biomass curves, did not report weight increase in a research in which they offered a medium and high feeding frequency, compared to a zero frequency.
On the other hand, it is inferred that the particle size of the plant residues may have influenced the growth of the worms, since, according to Mamani, Mamani, Sainz and Villca (2012), immature worms may not have found an ideal particle size to feed on, a condition that beef manure can fulfill in the feeding of the annelid according to the mentioned authors; however, it was possible to maintain a viable population of worms.
Physical chemical variables such as temperature, humidity and pH of the substrate were also evaluated, which indicates the environment in which the worms developed. As for the temperature in each treatment, it was an average of 27.95 °C and the pH remained around 7.8 respectively; while the humidity variable was higher with a percentage of 87% in treatment 3 which was the one that was irrigated every 2 days.
In relation to the temperature, it can be evidenced that it was found above the values indicated by Somarraba and Guzmán (2004), which mention that the ideal temperature for the proper development of the worms ranges from 15 to 24 °C, since the body value of the annelids is 19 °C; data that allow inferring, that the environmental temperature of the area could affect the behavior of this variable in the earthworms, since the same authors affirm, that the practice of compotage may have better results in temperate climates.
On the other hand, the humidity of the treatments was maintained in the optimal allowed ranges, in this sense, Hernández, et al. (2006), describes that this variable exerts a direct influence on the consumption and development of the clitellum in worms, also points out that the optimal range should be from 80 to 90% and an acceptable limit range from 60 to 90%.
As for the chemical characteristics, the pH is one of the variables to keep in mind, since it is an indicator that influences the microbiological activity of the process, in relation to this, in the test a pH value was obtained that ranges from the ranges estimated in the Mexican humus regulations 5.5 to 8.5; therefore, the substrate can be characterized with a pH of strongly acidic to slightly alkaline, the results of the test could be favored by the frequency of irrigation, because a washing and dragging of alkaline elements of the material was caused, avoiding higher alkalinity, since according to Mamani, Mamani, Sainz and Villca (2012), household waste has alkalizing elements, such as salts and ammonium released during the fermentation of nitrogen-rich waste.
Finally, a chemical analysis was performed on the leachate obtained from the compost worm, which when interpreted, it can be observed that the frequency of irrigation increased the alkaline elements, which suggests that irrigation caused a washing of the substances found in the substrate.
When contrasting the results obtained with other investigations, it was found that Mamani, Mamani, et al., (2012), obtained similar values of electrical conductivity (8 dS/m) when they used kitchen scraps to feed the worms, so according to the authors, these organic residues by nature have high salinity components; in the present research the leachate showed a high electrical conductivity which allows inferring that it was caused by the washing of those compounds present in the substrate.
In the same vein, Morales, Fernández, Montiel and Peralta (2009) explain that the electrical conductivity can decrease significantly over time, that is, the salt content can increase as the decomposition of the materials progresses, presenting an increase in the salt concentration due to mass loss, together with the composition of the different organic sources used, a situation that improves as the maturity state of the decomposed material progresses. The author's proposal allows us to infer that the electrical conductivity of the test was high because the irrigations were carried out on a substrate in the middle of the decomposition process.
With regard to the pH variable, the product has carbonates and bicarbonates, which maintains the alkalinity levels, authors such as Bonanomi, De-Filippis, Zotti, Idbellaa, Cesaranoa, Al-Rowailyc, and ElGawadc, (2020), mention that high pH levels may be due to alkalizing elements present in vegetable waste for domestic use, such as salts and ammonium that are released during the decomposition of nitrogen-rich products, also, in relation to what was discussed by other researchers cited above, the alkalinity may have been affected by an insufficient fermentation process. Such behavior was also observed by Serrano (2004) during the vermi composting of urban organic waste.
Dear readers, it is important to mention that the product is appropriate to apply as a source of potassium and phosphorus, reaching 0.24% and 1.23% respectively; like other chemical variables, the amount of these macroelements in the leachate are strongly related to the organic source to be composted, for example, Nourbakhsh, (2007), states that potassium is found abundantly in kitchen scraps. On the other hand, phosphorus showed levels of P2O5, which according to Nourbakhsh, (2007), intervenes on many plant processes such as photosynthesis, cell division, among others.
Durán, L. and Henríquez, C. (2009). Growth and reproduction of the red worm (Eisenia foetida) on five organic substrates. Agronomía Costarricense, 33 (2): 275-281.
Mammadov, G. M., Fatemi Chokami, A., y Sedaghathoor (2016). Growth and reproductive performance of eisenia foetida in cow manure, cow manure + sugarcane bagasse, and cow manure + sawdust waste mahboub khomami. Applied ecology and environmental research 14(1): 237-247. ALÖKI Kft., Budapest, Hungary.
Hernández, J., Pietrosemoli, S., Faría, A., Canelón, R., Palma, R. and Martínez, J. (2009). Frequency of irrigation in the growth of the earthworm (Eisenia spp) and chemical characterization of vermicompost. UDO Agricultural Magazine. 6 (1): 20-26. 2006.
Mamani, G., Mamani, F., Sainz, H., and Villca, R. (2012). Behavior of the red worm (Eisenia spp.) in vermicompotation system of organic waste. Scielo magazine online version. Vol 3-1.
Somarraba, R. Y Guzmán, G. (2004). Análisis de la influencia de la cachaza de caña y estiércol bovino como sustrato en lombriz roja californiana para producción de humus. Trabajo de grado no publicado. Universidad Nacional Agraria. Managua, Nicaragua.
Morales, J., Fernández, M., Montiel, A., and Peralta. B. (2009). Evaluation of organic substrates in the production of vermicompost and the development of the vermicompost. Biotechnology Vol XI - 1.
Bonanomi, G., De-Filippis, F., Zotti M., Dibella, M., Cesarano a, G., Al-Rowaily c, S. y ElGawadc, A. (2020). Las aplicaciones repetidas de enmiendas orgánicas promueven la microbiota beneficiosa, mejoran la fertilidad del suelo y aumentan el rendimiento de los cultivos. Ecología Aplicada del Suelo. 156: 103714.
Nourbakhsh, F. (2007). Influence of vermicomposting on solid wastes decomposition kinetics in soils. Journal of Zhejiang University Science B, 8 (10): 725-730.
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