Effect of high planting density and foliar fungicide applicationon the grain maize and silage and methane yield

摘要

The research investigated ways to enhance maize yield inintensive maize cropping system by evaluating the effect of highplanting densities combined with foliar fungicide treatments. Theconsidered assessments were fungal leaf disease, biomass andgrain yield and methane production through anaerobic fermentation.The experiment was conducted in the years 2012 and 2013.The treatments compared at each location were factorial combinationsof two plant densities and three fungicide applications. Astandard planting density (StD, 7.5 plants m–2 on a 0.75 m interrowspacing) was compared with the high density (HiD, 10 plantsm–2 on narrow 0.5 m inter-row spacing). Two fungicides, pyraclostrobinat 0.2 kg AI ha–1 and a mixture of pyraclostrobin andepoxiconazole at 0.2 and 0.075 kg AI ha–1 respectively, wereapplied at the tassel emergence stage and compared with anuntreated treatment. The HiD system positively increased thesilage maize yield (+16%), grain (+17%) and methane yield perhectare (+19%) in comparison to the StD. The fungicide applicationsignificantly restrained foliar disease symptoms only in 2012.Fungicide did not affect plant silage composition (protein, starchor fibre content) and methane yield, conversely it significantlyincreased grain yield for both planting density systems (+5%). Theoverall boost in yield obtained by combining both strategies in anintensive system, HiD combined with the fungicide, was +24% formethane and +21% for grain yield compared to StD without fungicideapplication. This work proved that an intensive high plantingsystem with up to 10 plants m–2, supported by leaf fungicide treatments,can lead to a real yield enhancement of both maize grainand silage.