Combined biochar and nitrogen application stimulates enzyme activity and root plasticity

verfasst von
Xiaona Song, Bahar S. Razavi, Bernard Ludwig, Kazem Zamanian, Huadong Zang, Yakov Kuzyakov, Michaela A. Dippold, Anna Gunina
Abstract

Biochar (BC) and nitrogen (N) fertilizers are frequently applied to improve soil properties and increase crop productivity. Nonetheless, our mechanistic understanding of plant-soil interactions under single or combined application of BC and N remains incomplete. For the first time, we applied a split-root system to evaluate how BC or N contributes to the changes in soil enzyme activities, N and phosphorus (P) cycling as well as root plasticity. Left and right parts of rhizoboxes were filled with silty-clay loamy soil amended with BC (15 g kg−1 soil, from wheat straw, 300 °C), N (0.05 g KNO3-N kg−1 soil) or a control (no amendments), resulting in the following combinations: BC/Control, N/Control, BC/N. Soil enzyme activities, available N and P, root morphology and plant biomass were analyzed after plant harvest. Plant biomass (shoot + root) ranged from 0.56 g pot−1 (BC/Control) to 0.91 g pot−1(BC/N). The decreased soil bulk density and increased P availability in the BC compartment (BC/Control and BC/N) stimulated root length by 1.4–1.8 times – an effect that was independent of N availability in the same rhizobox. Biochar stimulated activities of β-glucosidase and leucine aminopeptidase (by 33–39%) compared to N due to the coupling of C, N and P cycles in BC/N treated soil. Nitrogen fertilization also increased β-glucosidase activity compared to the unfertilized control, whereas root elongation remained unaffected. Thus, the combined application of BC/N had more efficient benefits for plant growth than BC or N alone. This is linked with i) the stimulation of enzyme activities at the BC locations to reduce N limitation for both microorganisms and plants, and ii) an increase of fine root production to improve N uptake efficiency. Thus, combined BC/N application is potentially especially sustainable to overcome nutrient limitation as well as to maintain crop productivity because it accelerates root-microbial interactions.

Externe Organisation(en)
Georg-August-Universität Göttingen
Universität Kassel
China Agricultural University
Christian-Albrechts-Universität zu Kiel (CAU)
Peoples' Friendship University of Russia (RUDN)
Typ
Artikel
Journal
Science of the Total Environment
Band
735
ISSN
0048-9697
Publikationsdatum
15.09.2020
Publikationsstatus
Veröffentlicht
Peer-reviewed
Ja
ASJC Scopus Sachgebiete
Environmental engineering, Umweltchemie, Abfallwirtschaft und -entsorgung, Umweltverschmutzung
Ziele für nachhaltige Entwicklung
SDG 2 – Kein Hunger
Elektronische Version(en)
https://doi.org/10.1016/j.scitotenv.2020.139393 (Zugang: Geschlossen)