Soil nitrogen and water management by winter-killed catch crops

verfasst von

Norman Gentsch, Diana Heuermann, Jens Boy, Steffen Schierding, Nicolaus Von Wirén, Dörte Schweneker, Ulf Feuerstein, Robin Kümmerer, Bernhard Bauer, Georg Guggenberger

Abstract

Improving N cycling in agroecosystems is one of the key challenges in reducing the environmental footprint of agriculture. Further, uncertainty in precipitation makes crop water management relevant in regions where it has not been necessary thus far. Here, we focus on the potential of winter-killed catch crops (CCs) to reduce N leaching losses from N mineralization over the winter and from soil water management. We compared four single CCs (white mustard, phacelia, Egyptian clover and bristle oat) and two CC mixtures with 4 and 12 plant species (Mix4 and Mix12) with a fallow treatment. High-resolution soil mineral N (Nmin) monitoring in combination with the modelling of spatiotemporal dynamics served to assess N cycling under winter-killed CCs, while soil water was continuously monitored in the rooting zone. Catch crops depleted the residual Nmin pools by between 40g% and 72g% compared to the fallow. The amount of residual N uptake was lowest for clover and not significantly different among the other CCs. Catch crops that produce high N litter materials, such as clover and mustard leaves, showed an early N mineralization flush immediately after their termination and the highest leaching losses from litter mineralization over the winter. Except for clover, all CCs showed Nmin values between 18g% and 92g% higher on the sowing date of the following maize crop. However, only Mix12 was statistically significant. Catch crops depleted the soil water storage in the rooting zone during their growth in autumn and early winter, but preserved water later on when their residues covered the ground. The shallow incorporation of CC residues increased water storage capacity during the cropping season of the main crop even under reduced soil water availability. Hence, catch cropping is not just a simple plant cover for the winter but improves the growth conditions for the following crop with decreased N losses. Mixtures have been shown to compensate for the weaknesses of individual CC species in terms of nutrient capture, mineralization and transfer to the following main crop as well as for soil water management. Detailed knowledge about plant performance during growth and litter mineralization patterns is necessary to make optimal use of their potential.

Organisationseinheit(en)

Institut für Bodenkunde

Externe Organisation(en)

Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK)
Deutsche Saatveredelung AG (DSV)
Hochschule Weihenstephan-Triesdorf

Typ

Artikel

Journal

SOIL

Band

8

Seiten

269-281

Anzahl der Seiten

13

ISSN

2199-3971

Publikationsdatum

04.2022

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja

ASJC Scopus Sachgebiete

Bodenkunde

Ziele für nachhaltige Entwicklung

SDG 12 – Verantwortungsvoller Konsum und Produktion

Elektronische Version(en)

https://doi.org/10.5194/soil-8-269-2022 (Zugang: Offen)