Results Regarding Biomass Yield at Maize Under Different Plant Density and Row Spacing Conditions

Maize (Zea mays L.) is important for supplying biomass to be used as substrate for biogas production either as energy crop or as crop residues. As energy crop for producing biomass, maize is recognized as being one of the most used crops. Maize as energy crop need a specific crop technology, with specific technological features among which there are counting the using of the suitable plant density and row spacing. From this perspective, the aim of the present paper is to present the results we have obtained regarding the biomass yield at several maize hybrids studied under different plant density and row spacing conditions. In this respect, four maize hybrids (H1, H2, Cera 400, and Cera 430) were studied at different plant densities (70,000; 80,000; 90,000; 100,000; 110,000; 120,000 and 125,000 plants.ha⁻¹) and at two row spacing conditions (75 cm and 37.5 cm). Researches were performed in a field experiment in the year 2015, under rainfed conditions. The field experiment was located in South Romania, respectively at Fundulea, Calarasi County (44°28’ N latitude and 26°28’ E longitude). The biomass determinations were performed in the early dough - dough plant growth stages, with the purpose to calculate the yields of above-ground biomass (expressed in tons.ha⁻¹) in the growth stages of the maize plants when the biomass could be used as raw material for biogas production, but also as fodder (silo) for animals. In our field experiment, increasing in plant density was associated with an increase of above-ground biomass yield up to a threshold beyond which the biomass yield is decreasing, this threshold being different according to row spacing. Smaller plant densities favoured the biomass yields at wide rows (row spacing of 75 cm), while higher plant densities favoured the biomass yields at narrow rows (row spacing of 37.5 cm). The biomass yields registered higher values at row spacing of 37.5 cm than at row spacing of 75 cm.