Abstract
Agronomical Risks of Straw Mulch Covers in Reduced Soil Tillage Systems I. Influence of Chopping Intensity of Wheat Straw on the Liberation of Phytotoxins Phytotoxic effects of cereal straw are assumed to contribute to yield depressions of crops sown into mulch covers. Leaching of straw-derived phytotoxins and their inactivation in soil may be accelerated by cutting harvest residues into short pieces combined with destroying the tubular structure of cereal straw culms. In model trials, conventionally (mainly transversally) and intensively (transversally plus longitudinally) chopped winter wheat straw was leached before and after aerobic rotting processes had started, and the aqueous extracts were analysed for phytotoxicity in bioassays with curly cress (Lepidium sativum L.). The concentrations of four selected phenolic acids (para-hydroxy-benzoic-, vanillic-, t-ferulic- and t-para-coumaric-acid) were determined by HPLC-technique. High toxin concentrations were detected only in extracts of undecomposed straw. Toxin liberation decreased from very high rates at the beginning to low rates after 60 hours of extraction. Intensively chopped straw released more phytotoxins than conventionally chopped straw during the first 4,5 hours of extraction. Subsequently, no differences in toxin liberation rates were observed. These results were confirmed by the phenolic acid analysis. To conclude, intensive chopping of straw exhibited no advantages with respect to straw derived phytotoxicity. The absence of allelochemicals in extracts of aerobically rotted straw indicates that under normal field conditions at Gottingen toxic effects from winter wheat harvest residues are of low importance for subsequent crop growth.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
