Biochar for sustaining productivity of cassava based cropping systems in the degraded lands of East Java, Indonesia

摘要

Field experiments were carried out to explore the beneficial effects of biochar on the productivity of cassava ( Manihot esculenta Crantz) based cropping system in the degraded uplands of East Java, Indonesia from September 2009 to May 2011. Two cropping systems namely cassava + maize ( Zea mays L.) and cassava + peanuts ( Arachis hypogaea L.) and five organic amendments, namely farm yard manure (FYM) applied once at the start of the experiment, FYM applied every year, biochar from FYM, biochar from cassava stem, and no FYM as control were evaluated. With no FYM addition, yield of cassava and maize during the succeeding year declined from 17.1 to 13.7 Mg ha–1 and from 3.6 to 2.7 Mg ha–1 respectively. Organic amendments improved soil fertility and crop yields. For cassava + maize intercropping, the beneficial effects of FYM (20 Mg ha–1), however, lasted for only one year; nonetheless for cassava + peanut intercropping it persisted for two years. Increases in cassava and maize yield following biochar application (15 Mg ha–1), however, continued for two years after planting, implying its potential for sustaining crop production over longer periods. Soil organic matter content in the FYM treatment also was high for a year, whereas in the biochar treatment it remained high well after the harvest of the second year cassava crop (20.3 to 25.8 g kg–1 soil C as against 10.3 to 11.2 g kg–1 for treatments without organic amendments), implying the profound potential of biochar for soil carbon sequestration owing to its recalcitrant nature.