Effects of residual biochar amendment on soil chemical properties, nutrient uptake, crop yield and N2O emissions reduction in acidic upland rice of East Lampung

Previous studies have been recognized that biochar addition to poor soil may lead to improve soil and crop productivity, also reduce greenhouse gas (GHG) emissions. However, the results were varied and the mechanisms were not clear. Two rates of rice husk (RH) and cacao shell (CS) biochar namely 0 and 15 t ha(-1) were applied to soil, to investigate the effect of RH and CS biochar on soil chemical properties, nutrient uptake, crop yield, and N2O emissions reduction on upland rice at acidic soil of East Lampung. It was residual effect study; biochar was applied only in the first planting season of 2012. In addition, N2O emissions from the soil were monitored with close chamber method. The result showed that 15 t ha(-1) CS biochar treatment was the best treatment, resulted 1.21 t ha(-1)yield. Meanwhile on 15 t ha(-1) RH biochar treatment was only 0.22 t ha(-1). However, no significance difference on both nutrient uptake and N2O emissions among the treatments. N2O emissions from RH and CS biochar treatment were reduced 26% and 21% compare to control. Our result proposed that CS biochar may use as soil amendment, to improve crop productivity and also to combat climate change.