Soilless tomato grown under nutritional stress increases green biomass but not yield or quality in presence of biochar as growing medium

Biochar has been reported to improve soil fertility and growing medium performance. However, the role that biochar plays in plant nutrition is not completely understood, especially in plants grown under nutritional stress. Recent research indicates that the addition of biochar increases produce yield of tomato grown under salinity stress and drought; however, little information is available about the effects of biochar on fruit quality parameters. The use of biochar as a growth substrate in an intensive greenhouse cropping system may have the capacity of replacing non-renewable and less sustainable growing media like peat and in addition being a strategy to optimize chemical fertilisation. This work aimed to investigate the effects of biochar, as a potential candidate to replace peat, on tomato growing in soilless conditions under nutritional stress. Plant biomass accumulation, leaf fluorescence and chlorophyll, fruit yield and fruit quality parameters were measured as performance indicators. Biochar increased the green biomass, but it did not significantly affect yield or most quality parameters, apart from potassium content in ripe fruits. These results suggest that biochar has great potential as a peat alternative material and plant growth promoter, but no ability to improve tomato yield, under nutritional stress.