Soil nitrogen and water management by winter-killed catch crops
<p>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 winte...
| Main Authors: | , , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2022-04-01
|
| Series: | SOIL |
| Online Access: | https://soil.copernicus.org/articles/8/269/2022/soil-8-269-2022.pdf |
| Summary: | <p>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 (<span class="inline-formula"><i>N</i><sub>min</sub></span>) 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 <span class="inline-formula"><i>N</i><sub>min</sub></span>
pools by between 40 % and 72 % 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 <span class="inline-formula"><i>N</i><sub>min</sub></span> values between 18 % and 92 % 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.</p> |
|---|---|
| ISSN: | 2199-3971 2199-398X |