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.)

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.

Effect of Mussel Shells as Soil pH Amendment on the Growth and Productivity of Rosemary (Rosmarinus officinalis L.) Cultivation

“…The positive impact of mussel shells on rosemary growth and productivity observed in our study aligns with the potential described by Mwithiga et al [25], signifying mussel shells as a promising soil amendment. The variability in plant height observed in the second growing year underscores the multifaceted nature of the interactions, implicating both mussel shells and biological fertilizer.…”

“…The use of shells by-products (such as mussel shells) as an alternative practice management in decreasing soil acidity is an innovative, eco-friendly, and sustainable approach that offers several potential benefits. The mussel shell use is expected to replace the common soil amendments, including marl, chalk, industrial by-products, organic wastes, crop residues, and limestone, in order to obtain new sources of calcium carbonate [13,14,25]. The calcium carbonate content in mussel shells acts as a natural pH buffer, helping to neutralize acidic soils.…”

Initial Weed and Maize Response to Conservation Tillage and Liming in Different Agroecological Conditions

“…Liming application led to an increase in the average maize yield due to many positive effects on soil properties, which allowed more favorable conditions for crop growth [44][45][46]. The proven liming effect refers to improving the rooting systems, availability and uptake of nutrients, the water supply, and thus, better drought resistance, which were probably reflected by the increase of maize yield in this research.…”