First reported quantitative microbiota in different livestock manures used as organic fertilizers in the Northeast of Thailand

Lampet Wongsaroj,Naraporn Somboonna,Ratmanee Chanabun,Pinidphon Prombutara,Somsak Panha,Naruemon Tunsakul

doi:10.1038/s41598-020-80543-3

Lampet Wongsaroj, Naraporn Somboonna + Show 4 more

Open Access

https://doi.org/10.1038/s41598-020-80543-3

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Abstract

Northeastern Thailand relies on agriculture as a major economic activity, and has used high levels of agrochemicals due to low facility, and salty sandy soil. To support soil recovery and sustainable agriculture, local farmers have used organic fertilizers from farmed animal feces. However, knowledge about these animal fecal manures remains minimal restricting their optimal use. Specifically, while bacteria are important for soil and plant growth, an abundance and a diversity of bacterial composition in these animal fecal manures have not been reported to allow selection and adjustment for a more effective organic fertilizer. This study thereby utilized metagenomics combined with 16S rRNA gene quantitative PCR (qPCR) and sequencing to analyze quantitative microbiota profiles in association with nutrients (N, P, K), organic matters, and the other physiochemical properties, of the commonly used earthworm manure and other manures from livestock animals (including breed and feeding diet variations) in the region. Unlike the other manures, the earthworm manure demonstrated more favorable nutrient profiles and physiochemical properties for forming fertile soil. Despite low total microbial biomass, the microbiota were enriched with maximal OTUs and Chao richness, and no plant pathogenic bacteria were found based on the VFDB database. The microbial metabolic potentials supported functions to promote crop growth, such as C, N and P cyclings, xenobiotic degradation, and synthesis of bioactive compounds. Pearson’s correlation analyses indicated that the quantitative microbiota of the earthworm manure were clustered in the same direction as N, and conductivity, salinity, and water content were essential to control the microbiota of animal manures.

Highlights

Sustainable agriculture requires healthy soils, provided that soil microorganisms play significant functions in soil nutrient cycling, decomposition of toxic and complex organic molecules, and an increased crop fertility and health[1,2,3,4,5]
Proteobacteria, Bacteroidetes, and Gemmatimonadetes became abundant in organic farm lands, and the presence of these bacteria were reported to correlate with an increased level of soil organic carbon (C) and nitrogen (N), and the total microbial b iomass[17]
The water content of the manure was lowest in G2, goats fed with P. purpureum (23.75 ± 3.07%), but increased two-fold in G1 goats fed with D. eriantha (49.35 ± 6.08%), suggesting a different type of grass feed might confer different fecal liquid and dry contents, or the chemical composition influenced the water activity in the goat’s gut

Summary

Introduction

Sustainable agriculture requires healthy soils, provided that soil microorganisms play significant functions in soil nutrient cycling, decomposition of toxic and complex organic molecules, and an increased crop fertility and health[1,2,3,4,5]. The assorted livestock species manures include Perionyx excavatus (earthworm, abbreviated as E), three breeds of Gallus gallus (Phuparn black-bone chickens) including black feather and bones breed (PC1), white feather but black skin and bones breed (PC2) and yellow feather but black skin and bones breed (PC3), three subspecies of Bos taurus (beef black cattles) including Phuparn cow (PCO), Charole cow (CC) and dairy cattle (DC), Bubalus bubalis (dairy Murrah buffalo, MB), Capra aegagrus hircus (goats) that were fed on (1) Pangola grass Digitaria eriantha (the highest quality of grasses for grazing with a high metabolizable energy, nutrients and protein level)[14] (G1) or (2) Napier grass Pennisetum purpureum (the major livestock feed among ruminant animals in Thailand with a low nutrient digestibility and crude protein content)[15] (G2), Cervus timorensis (Lucy deer, D), Sus scrofa domesticus (pig, S), and Oryctolagus cuniculus (rabbit, R) These animals have been predominantly farmed in the Northeast and their feces are used as organic fertilizers[16,17,18]. Organic fertilization is presumed to be one key to acquire a plant-beneficial bacteria community in the soil that is required for sustainable agriculture

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