Biomass yield willows ten years

Abstract

High-density willow plantations are used for biomass production in several countries, but in Argentina, information about the adequate management for such plantations is scarce. This fact hinders the development of commercial plantations that could reduce the country dependence on fossil energy. The aim of this work was to analyse the productivity of a willow Short Rotation Coppice (SRC) plantation in an agricultural soil, in order to identify potential and actual biomass yields under local conditions during several years. We hypothesise that water availability will be a major limitation for biomass yield in the area. A short-rotation coppice willow system was planted in an agricultural soil in the Pampa Ondulada region of Central Argentina, and its yield was measured for a period of 10 years. The factors analysed were: irrigation (drip irrigation and rainfed), planting density (13,300 and 20,000 plants ha-1) and two genotypes: Salix alba and a S. matsudana × S. alba hybrid. The trial was disposed in a split-split plot design, and the rotation length was one year. The irrigated treatment consistently yielded more than the rainfed one. Yield correlated with water availability during the summer months (r=0.79; p˂0.001). Biomass production was high in the first four years, but afterwards, yield steadily declined, both in irrigated and rainfed treatments. To develop commercial biomass plantations with willows in Central Argentina, it will be necessary to irrigate during the summer months. A possible option could be to combine the willow biomass plantation with wastewater treatment, providing irrigation and an environmental service simultaneously.