The Effect of Anaerobic Digestate on the Soil Organic Carbon and Humified Carbon Fractions in Different Land-Use Systems in Lithuania

Alvyra Slepetiene,Mykola Kochiieru,Aida Skersiene,Linas Jurgutis,Olgirda Belova,Audrone Mankeviciene

doi:10.3390/land11010133

Alvyra Slepetiene, Mykola Kochiieru + Show 4 more

Open Access

https://doi.org/10.3390/land11010133

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Journal: Land	Publication Date: Jan 15, 2022
Citations: 20	License type: CC BY 4.0

Affiliation: Lithuanian Research Centre for Agriculture and Forestry

Abstract

The most important component of agricultural system are soils as the basis for the growth of plants, accumulation of water, plant nutrients and organic matter. The main task of our research was to ascertain changes in soil organic carbon (SOC) and mobile humified carbon fractions in digestate-treated soils. We have performed three field experiments using the same design on two soil types in 2019–2020. We studied the fertilization effects of different phases of digestate on Retisol and Fluvisol. Fertilization treatments: control; separated liquid digestate 85 kg ha−1 N; and 170 kg ha−1 170 N; separated solid digestate 85 kg ha−1 N; and 170 kg ha−1 N. We have found a greater positive effect on the increase in SOC because of the use of the maximum recommended fertilization rate of the solid digestate. The content of mobile humic substances (MHS) tended to increase in grassland and crop rotation field in digestate-treated soil. In our experiment, maximum concentration of SOC was found in 0–10 cm soil layer, while in the deeper layers the amount of SOC, MHS and mobile humic acids proportionally decreased. We concluded, that long-term factors as soil type and land use strongly affected the humification level expressed as HD (%) in the soil and the highest HD was determined in the grassland soil in Fluvisol.

Highlights

As the world is facing climate changes issues today, there is a strong demand for the alternative ways to manage our ecosystems
We summarize that regular soil incorporation of transformed organic matter as an anaerobic digestion residue, including relatively stable carbon compounds, contained in digestates used, even in the short term may be important for soil organic carbon (SOC), mobile humic substances (MHS) and mobile humic acids (MHA)
The use of digestates was associated with the plan to replace mineral fertilizers with bio-fertilizers, needed to produce agricultural crop production, and in the hope that the soil would be enriched with SOC and soil organic matter (SOM) composition would be improved

Summary

Introduction

As the world is facing climate changes issues today, there is a strong demand for the alternative ways to manage our ecosystems. Soils form a landscape, accumulate water, plant nutrients and organic matter, captures pollutants and exert climate control functions [3]. The soil and the multitude of organisms that live in it provide us with food, biomass and fibers, raw materials, regulate the water, carbon and nutrient cycles and make life on land possible [4]. Different cultivation and fertilization have an impact on its chemical properties. The improper use of agricultural land leads to the deterioration of the soil agricultural properties and the decrease of its fertility [5]. The excessive agricultural activity causes the destruction of soil organic matter (SOM) due to the depletion of the organic carbon (Corg )

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