Abstract
Farm dairy effluents (FDE) from washing the milking parlor contain manure, urine, and chemicals and constitute a large amount of wastewater. Applying FDE as soil fertilizers to pastures can enhance forage yield and improve soil nutrient status. Since the dairy industry is increasingly attempting to maximize returns through better utilization of forage with lesser inputs, there is demand for a supply of FDE as fertilizers. Nevertheless, the impact of this practice on soil microbiota remains largely unexplored. It must be studied before large-scale soil disposal to avoid diminishing microbial diversity or enhancing pathogen abundance. This study evaluated the effects of applying lagoon-stored (Lagoon) and raw dairy effluents (Raw) at a rate of 50 kg N ha−1 in four equal doses, in comparison to urea fertilization, on soil fertility and the activity, abundance, and community structure of soil microbiota. Raw was obtained after solid separation, and Lagoon corresponds to the Raw stationed in a two-lagoon system. Microbial activity was assessed as basal respiration, potentially mineralizable N, potential nitrification activity, and enzymatic activities. The catabolic activity of the microbial community was evaluated using Biolog Ecoplates™. Bacterial and fungal community composition and diversity were analyzed through amplicon sequencing of 16S rRNA and ITS2. The application of FDE benefited soil fertility and microbial activity. Lagoon had the most potent effects on soil available P and extractable K+, Na+, Mg2+ and Ca2+. Soil treated with Raw displayed higher microbial activities, such as dehydrogenase, basal respiration, urease, and potentially mineralizable N, than the other treatments. FDE did not significantly alter the microbial composition, abundance, or functional diversity. In conclusion, in this short-term trial, despite changes in soil chemical properties and microbial activity, the composition and diversity of the bacterial and fungal communities remained unaffected by FDE irrigation.
| Original language | English |
|---|---|
| Article number | 103648 |
| Number of pages | 12 |
| Journal | European Journal of Soil Biology |
| Volume | 122 |
| Early online date | 25 Jul 2024 |
| DOIs | |
| Publication status | Published - Sept 2024 |
Bibliographical note
Publisher Copyright:© 2024 Elsevier Masson SAS
Funding
We thank Dana Montedonico, Yolanda Fernandez, Rebeca Gonnet, Ana Laura Rivero, and Gimena Arrarte for assistance in sampling and processing throughout the field experiment; and Ana Bianco for insight into common practices of management of dairy effluents as fertilizer. We thank Jose Pedro Dieste and the staff at Centro Regional Sur for logistical support in the collection of dairy effluents from the dairy farm and pasture sowing. We thank Marcio Leite and Kesia Lourenco for their assistance in performing the statistical analysis. This research was supported by the CSIC-Udelar project (Comision Sectorial de Investigacion Cientifica, Universidad de la Republica) "Irrigation with dairy farm effluents: a microbiological perspective on soil fertility and environmental impact". G.Illarze was recipient of a Ph.D. fellowship from CAP (Comision Academica de Posgrado-Udelar) . GI received a grant for a stay at NIOO to learn about GJAM.
| Funders | Funder number |
|---|---|
| CSIC-Udelar project (Comision Sectorial de Investigacion Cientifica, Universidad de la Republica) | |
| CAP (Comision Academica de Posgrado-Udelar) | |
| NIOO |
Keywords
- Community-level physiological profiles
- Dairy farm
- Lagoon-stored dairy effluents
- Microbial communities
- Organic fertilizer
- Raw dairy effluents
- Soil enzyme activities
