Gesunde Pflanzen (2020) 72, 245-256

Jens Wienberg, Rolf Bünte and Bärbel Gerowitt (2020)
Trockener Sommer, nasser Sommer – können Untersaaten Unkräuter im Maisanbau begrenzen?
[Dry summer, wet summer—can undersowing reduce weeds in maize cultivation?]
Gesunde Pflanzen 72 (3), 245-256
Abstract: In the years 2017 and 2018 in the district of Leer (northwest of Lower Saxony) nine experiments were conducted to investigate undersown crops and their effects on the weed vegetation in continuous maize cropping. In three treatments the maize was cultivated without an undersown crop or with two different undersown grasses (Lolium spp., Festuca rubra). Herbicides were applied according to the three cultivation systems and were thus different.
The weather conditions of the two years differed considerably. While the growing period of maize 2017 was characterized by high precipitation, this period had a long time of summer drought in 2018. This offered the opportunity to investigate the performance of the three cropping systems and their weed vegetation under different weather conditions.
The annual weather conditions had a significant impact on the undersown crops and the weeds. In 2018, the weed density was significant lower than in 2017 at all assessment dates. With Echinochloa crus-galli, however, a weed species benefited from the weather conditions in 2018: despite the drought the density of this species was higher.
In the rainy year 2017 the weed cover was reduced in the cropping systems with undersown crops for approximately 15%. In the dry year 2018, the treatment with the undersown Lolium spp. reduced the weed cover by 5% compared to treatment without cover crops. The undersown Festuca rubra grasses suffered more from the drought in 2018 than Lolium ssp.. While the Lolium spp. undersown crop had a relative cover of 48% at the end of the experimental period, at the same time the Festuca rubra undersown crop covered only 33%.
In the summer 2017 with high precipitation the average amount of dry matter was 20.88 t/ha and in the year 2018 with dry weather conditions 19.08 t/ha. In both years, the yields did not differ significantly. In 2018, in the treatments with undersown grass crops the maize was ready for harvesting earlier than in the treatment without undersown crops.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Bärbel Gerowitt

Research topic(s) for pests/diseases/weeds:
environment - cropping system/rotation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Echinochloa crus-galli (weed)	Maize/corn (Zea mays)	Germany