Early season weed control in maize, new insights for a known phenomenon

Abstract

The studies demonstrate the effect of early weed control on maize yields compared to late weed control with corresponding herbicide control strategies. Maize yield with a late weed control strategy was 10 % lower compared to a strategy controlling weeds early based on ten field trials. Interestingly the thousand-grainweight (TGW) seems not to be affected significantly but the number of grains per cob were identified as major responsible factor for yield decrease. To explain these field effects, glasshouse test were undertaken to simulate the competitive weed effects. Specific methods allowed to grow maize plants to the yield stage even in the glasshouse under representative conditions. The field observations were confirmed clearly. The early yield parameters like number of grains per cob were mainly affected by the timing of weed control treatments (early vs. late), while the parameter grain rows per cob was more sensible than the number of grains per row. The TGW remained basically consistent. As a follow-up experiment, maize plants were grown under glasshouse conditions and as well grown to the yield stage. This time, subsamples were taken and the cob formation at very early stages was investigated destructively to follow the development of the cob formation. Ovules and rows were counted on 'mini cobs' (cobs with a size of 4 mm were harvested) under the binocular. Clearly, weed competition had an impact on the induction of the number of ovules early on and at the end impacted on the yield in ripe cobs.

Keywords

• Ertrag
• Ertragsparameter
• Herbizid
• Zea mays L.
• herbicide
• yield
• yield parameter