Biomass production in a high-density willow plantation through ten one-year rotation cycles in Central Argentina

Abstract

High-density willows 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 and to identify potential and actual biomass yields under local conditions. Our hypothesis was that water availability was major limitation for biomass yield in the area, so this factor was included in the trial design. The trial was planted in an agricultural soil in the Rolling Pampas 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 produced more than the rainfed one, the yield of irrigated treatment ranged between 10.4-22.6 MG ha-1, and between 2.9-17.6 MG ha-1 for rainfed plots. Yield correlated with water supply during the summer months (rs = 0.79). Biomass production was high in the first four years, but afterwards, yield steadily declined, both in irrigated and rainfed treatments. According to our results, to develop biomass SRC plantations with willows in Central Argentina, irrigation would be necessary during the summer months.