Effect of humic based soil conditioner, effective microbes and fertiliser on growth and flowering of sunflower (Helianthus annus L. ‘Dwarf Sunsation’)

Biological farming methods are becoming more widespread as many farmers move towards the application of composts, bio-fertilisers and other organic additives. To assess the impact of coal-based humus and effective microbes on plant growth, two trials were undertaken on sunflower (Helianthus annus L., 'Dwarf Sunsation'). Two-week-old seedlings were planted into 16-cm diameter pots containing a basic potting mix plus Ferbon^®, a lignite-based soil conditioner, at 0, 0.3 and 0.6 g pot^-1 (equivalent to 0, 150 and 300 kg ha^-1, respectively) in Trial 1, and 0 or 0.9 g Ferbon^® (equivalent to 450 kg ha^-1) in Trial 2. After planting, pots were placed on glasshouse benches arranged in a randomised block design with six replicates per treatment for both experiments. Activated effective microbes (EM-1, Vital Resource Management Pty Ltd.) were applied as a soil drench at 15 L ha^-1 to half the pots after planting in Trial 1, and 0, 15 or 30 L ha^-1 to pots in Trial 2. Pots were fertilised at weekly intervals with HoaglandRSQUOs solution at 0, 50 and 100% concentration in Trial 1, or 0 and 100% in Trial 2. The label rate of 15 L ha^-1 EM increased the number of nodes and stem height. Ferbon^® had no effect on node numbers, but did increase stem height (Trial 1). The full rate of fertiliser resulted in increased stem height during the first 6 weeks of growth, but by week 9, the 50% fertiliser rate produced the same results as the full rate. Plants treated with EM displayed reduced leaf chlorophyll content compared with untreated plants. This reduction may be a function of increased biomass, evidenced by increase in plant height and stem diameter, deploying nitrogen. Ferbon^® had no effect on chlorophyll content. Applications of both EM and Ferbon^® resulted in earlier flowering. These results demonstrate that with the availability of adequate accessible nutrients, both effective microbes and lignite-based humates such as Ferbon^® have the potential to increase plant productivity.