Effects of High Nutrient Supply on the Growth of Seven Bamboo Species

Abstract Over the last decade, bamboo has emerged as an interesting plant for the treatment of various polluted waters using plant-based wastewater treatment systems. In these systems, nitrogen and phosphorous concentrations in wastewater can exceed plant requirements and potentially limit plant growth. The effects of two nutrient rates on the growth of seven bamboo species were assessed in a one-year experiment: Dendrocalamus strictus, Thyrsostachys siamensis, Bambusa tuldoides, Gigantochloa wrayi, Bambusa oldhamii, Bambusa multiplex and Bambusa vulgaris. Nutrient rates were applied with a 20:20:20 NPK fertilizer as 2.6 and 13.2 t.ha.yr−1NPK to three-year-old bamboo planted in 70 L containers. Morphological characters, photosynthetic responses, and NPK content in bamboo tissues were investigated. Under high-nutrient supply rate, the main trend observed was an increase of culm production but the culms' diameters were reduced. For the seven species, the aboveground biomass yield tended to increase with high-nutrient rate. Increasing in nutrient rates also improved the photosynthetic activity which is consistent with the increase of nitrogen and phosphorus contents measured in plant tissues. All the bamboo species tested appears suitable for wastewater treatment purposes, but the species Bambusa oldhamii and Gigantochloa wrayi showed the higher biomass yield and nutrient removal. KEY WORDS: Bamboo speciesspecific leaf areachlorophyll a fluorescencehigh nutrient ratebamboo biomass ACKNOWLEDGMENTS The research was funded by the following French governmental funds: "Fonds unique interministeriel", as part of the "Run Innovation II" project, supported by Qualitropic, the Reunion Island competitive cluster. We would like to thank all the team at Phytorem SA for their support and Patrick Legier and Jocelyn Idmond at the CIRAD Laboratory (Saint Denis, Reunion Island) for their availability and useful advice. We also would like to thank Alexandre Perrusot (Bambouseraie du Guillaume, Reunion Island, France) who shared his bamboo knowledge with us, and allowed us to carry out the experiment at his bamboo nursery. Huge thanks go to Remi Hidouci, Stéphane Maillot, Laurent De Fondaumière, and Charles-Lee Hoareau for their help in collecting field data and for their technical support.