Cattle Manure Fermented with Biochar and Humic Substances Improve the Crop Biomass, Microbiological Properties and Nutrient Status of Soil

Jiri Holatko,Lucie Bielska,Oldrich Latal,Maja Radziemska,Martin Brtnicky,Antonin Kintl,Jiri Kucerik,Adnan Mustafa,Tivadar Baltazar,Tereza Hammerschmiedt

doi:10.3390/agronomy12020368

Abstract

Co-composting of raw manure with other organic sources has recently gained the attention of the scientific community. In the present study, raw manure and manures enriched with humic substances (Humac) or biochar were co-composted to improve their physico-chemical properties. We conducted an experiment including variants consisting of soil amended with manure (M), manure + Humac (M + H), manure + biochar (M + B), and unamended (control). Soil physico-chemical, biological, and plant properties were assessed altogether. All matured manures differed from each other physico-chemically (nutrient content) and in microbial composition, and hence their effects on the observed parameters. Compared to control, the soil respiration and enzyme activities related to N and P mineralization were enhanced due to the amendment of either manure or enriched manures. The M + H treatment resulted in higher pH of the manures as compared to other treatments, whereas the M + B and M treatments revealed the highest Corg contents of the final product, which was negatively correlated with HA:FA. In the same manner, M + H and M + B were the most prominent treatments, causing higher variations in basal soil respiration. The same treatments resulted in the highest percent increase values of soil enzymes related to C, N, and P, which further show the potential of manure modification as a viable option to boost soil fertility and health.

Highlights

The fermentation experiment was carried out using three variants according to mixed materials: (i) manure only, (ii) manure mixed with humic substances, i.e., Humac (H), and (iii) manure mixed with biochar (B)
With limited air access, organic matter is only partially degraded from manure, and more methane would have formed, which prevents the decomposition of organic matter into carbon dioxide, water, and ammonia [43]
The results suggested that all matured manures differed in their physico-chemical characteristics, microbial composition, and nutrient contents as compared to the control

Summary

Introduction

Decreased soil fertility and degradation of croplands are the key challenges faced by farmers in recent eras. Organic matter is a universal indicator of soil quality and is considered an important component of healthy soils [1]. Its loss or decrease can result in reduced soil fertility or complete degradation of agricultural soils [2]. One way to enhance soil fertility is the use of high-quality manure as the primary source of organic matter and nutrients. Manure application to soil has a positive effect on crop yields, soil chemical and physical properties, and soil microbial activities, resulting in the accelerated recycling of nutrients [3,4,5], with the exception of suboptimal nitrogen: the phosphorus ratio [6]

Methods

Discussion

Conclusion