Influence of different methods of cropping and weed control on the content of Cu and Zn in fodder maize (Zea mays L.) and on their uptake by maize

Strip intercropping is the practice of growing two or more species of plants in strips wide enough for independent mechanical cultivation, yet narrow enough to allow interaction between the species. This can affect not only crop yield but also competition in the uptake of nutrients and thus the chemical composition of the plants. The aim of this study was to assess the impact of strip intercropping and three methods of weed control on the content of zinc and copper in maize and on uptake of these components by maize. The study was conducted in 2004-2006 on a private farm located in the village of Frankamionka in the administrative district (powiat) of Zamoœæ. It was based on a field experiment conducted on clayey silt soil with grain-size distribution of clay and a moderate Zn and Cu content. The experiment design was a split-plot randomized complete block in four replications. The factors taken into account were two methods of cultivation: sole cropping and strip cropping (common bean, dent maize, and spring wheat in adjacent strips) and three methods of weed control: mechanical – weeding of interrows twice; mechanical-chemical – the herbicide Gesaprim 90 WG 1.5 kg ha–1 + weeding of interrows once; and chemical – the herbicides Gesaprim 90 WG 1.5 kg ha–1 + Milagro 040 SC 1.5 L ha–1. Fodder maize was grown for silage and harvested during milky-wax maturity. The content of copper and zinc in the dry matter of maize was determined by atomic absorption spectrophotometry (AAS) after digestion in HNO3 (extra pure) in accordance with PN-EN ISO 6869:2002. On average for the experiment, strip cropping of maize with common bean and spring wheat reduced zinc content in maize, but in successive years of the study, the impact of the cultivation methods was varied. Strip cropping significantly increased the copper content in the plants in comparison with sole cropping. Zn and Cu content varied depending on the location of a row in strip cropping.