Potential of Industrial By-Products as Liming Materials and Digestate as Organic Fertilizer and Their Effect on Soil Properties and Yield of Alfalfa (Medicago sativa L.)

Vladimir Ivezić,Tihana Teklić,Brigita Popović,Krunoslav Karalić,Vladimir Zebec,Meri Engler,Zdenko Lončarić

doi:10.3390/su131911016

Abstract

Acid soils with pH values below 5.5 have a negative effect on agricultural production. For this reason, liming is applied as a measure to raise the soil pH to the optimum (pH = 6–7). The aim of our research was to evaluate and compare the effectiveness of four liming materials (wood ash from biomass powerplant, filter dust from cement factory, blast furnace slag from iron factory, and carbocalk (limestone, a by-product from a sugar factory)) in combination with and without solid digestate (a by-product from biogas plant) as organic fertilizer. Two field trials were set up to determine the effect of the studied materials to neutralize the acidity, and the impact on soil fertility and nutrient status in the soil. The results showed that all four liming materials raised the pH of the soil. Out of these four, wood ash showed to be the best while blast furnace slag was the worst. The yield of alfalfa increased with the application of all four lime materials. Application of liming materials with solid digestate increased soil organic matter and had slightly higher yields compared to liming materials without solid digestate. The highest yields were achieved with the application of wood ash, probably due to somewhat higher concentrations of potassium and phosphorus in wood ash. Further research on the financial aspects of investigated by-products application is necessary to exploit their potential as a liming material.

Highlights

Soil pH is one of the key factors controlling the plant species distribution, composition, and yields
We observed a significant increase in potassium uptake in treatment with wood ash compared to carbocalk treatment (Figure 7)
All of the investigated liming materials significantly increased soil pH levels compared to the control and showed higher yields of alfalfa compared to the control

Summary

Introduction

Soil pH is one of the key factors controlling the plant species distribution, composition, and yields. Acidic soils with pH values below 5.5 create unfavorable conditions for plant growth which in agriculture results in lower crop yields on such fields [1,2]. Around 30% of the world’s ice-free land area is affected by acidity [3]. Soil acidification is caused by a combination of natural and anthropogenic processes. To increase crop yields in agriculture it is necessary to improve soil conditions, i.e., raise the soil pH level by applying liming materials. Increasing soil pH creates favorable conditions for micro-organisms growth and increased mineralization which results in loss of labile soil organic matter [4]

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