Effect of meatworks effluent irrigation on soil, tree biomass production and nutrient uptake in Eucalyptus globulus seedlings in growth cabinets

Abstract

The effects were examined of five different irrigation rates of water or meatworks effluent on the soil, tree biomass production and nutrient uptake of Eucalyptus globulus seedlings grown in three growth cabinets at various temperatures (5°C, 15°C and 25°C), representing seasons (winter, spring/autumn and summer). Effluent irrigation influenced soil properties, reducing soil pH and increasing soil nutrient concentrations. At the same time, it enhanced tree leaf area, biomass production, nutrient uptake and shoot:root ratio. However, the temperature and irrigation rates significantly influenced the effects of effluent irrigation. At 5°C, the seedlings showed no response to effluent irrigation rates, but the soil pH increased. How much of the nutrients originating from the effluent were recovered by the seedlings was not dependent on nutrient input via effluent irrigation, but highly dependent on the temperature. The most successful nutrient recovery occurred at 15°C, but with more nitrogen recovered (average about 60%) than phosphorus (average about 30%). Hence, all these factors should be considered when managing forest systems linked with effluent land-treatment systems.