Analysis of growth and nutrition of a young Castanea × coudercii plantation after application of wood-bark ash

Abstract

The aim of the present study was to evaluate the effects of the application of wood-bark ash (WBA) on the growth and nutritional status of a 5-year-old hybrid chestnut plantation in two consecutive periods of 3 and 4 years, i.e., from age 5 to 8 years and from age 8 to 12 years, respectively. A field experiment, which included 3 treatments and 4 replicate blocks, was established on an acidic, organic matter-rich mineral soil. The treatments were two different doses of ash (10 and 20 t ha−1) and an unfertilized control. Application of the ash (by spreading on the ground) produced mean increases of 16% in diameter and 11% in height growth of trees during the first 3 years, considering both doses together; the response was also significant for the subsequent period, particularly with the higher dose of ash (increases of 11% in diameter and 15% in height growth). The ash had a marked effect, although clearly short lived, on pH (H2O) levels (an increase of 0.6 units) and on exchangeable soil K, Ca and Mg. The nutritional status of the plantation was improved, mainly in terms of K, Ca and Mg, and the results of a vector analysis indicated that these elements, particularly K, were limiting forest production. Foliar or soil nutrient concentrations in the mineral soil were no longer affected by the ash at age 12 years. We recommend the application of two doses of 10 Mg ha−1 throughout the rotation for fertilizing acid mineral soils that are rich in organic matter.