Seasonal patterns in accumulation and partitioning of biomass and macronutrients in Typha spp.

Seasonal patterns of biomass and nutrient accumulation in Typha latifolia L., T. angustifolia L. and T. × glauca Godr. grown in cultivated stands in Minnesota, U.S.A. were monitored over the course of two growing seasons and two winters. Nitrogen, phosphorus and potassium were the nutrients studied, because of their implications for commercialization of bio-energy and waste-water treatment systems. Results indicate that biomass and nutrient accumulation are in a lag phase during the first 4–8 weeks of growth in the spring. The plants then enter a rapid growth phase in which 47–80% of the total seasonal biomass production and nutrient uptake occurs in a 4–8 week period. During this time, Typha leaves account for 60–70% of the biomass and represent the major nutrient sink. As the rate of biomass and nutrient accumulation diminishes, translocation of nutrients and photoassimilate from leaves to rhizomes occurs, with an estimated 40% of leaf nitrogen, 35–44% of leaf phosphorus and 4–38% of leaf potassium translocated to the rhizomes by 27 October. Over the winter, 75% or more of the rhizome biomass, nitrogen, phosphorus and potassium is preserved. The results are discussed with respect to the management of a bio-energy production system.