Effect of biochar blended organic fertilizers on soil fertility, radish productivity and farm income in Nepal

Abstract

Declining soil fertility and nutrient availability are one of the major threats to reducing crop productivity in Nepal. A field experiment was conducted to assess the potential of biochar (10 t ha-1) blended with organic and inorganic fertilizers on improving soil fertility and radish productivity in Morang district, Nepal. Biochar was prepared from locally available twigs, branches, and wood using the soil pit “Kon tiki” method. The experiment was laid out in Randomized Complete Block Design with 7 treatments having four replications viz., control (CK), biochar (BC), biochar + cattle manure (CM), biochar + poultry manure (PM), biochar + cattle urine (CU), biochar + commercial biofertilizers (BF) and biochar + inorganic fertilizers (urea-N). The nitrogen rate used in all the treatments was equivalent to 100 kg ha-1. The agronomic effect of biochar blended organic amendments was compared with control and inorganic urea-N treatments. Biochar amended plots showed significantly higher soil pH (6.5), organic matter (4%), total N% (0.8%), available P (80.1 kg ha-1), and K (203.6 kg ha-1) compared with control. CM increased marketable yield by 320% (63 t ha-1) and biomass yield by 198% (100 t ha-1) compared with control (15.0 t ha-1 and 34 t ha-1) of marketable and biomass yield, respectively. CM increased marketable yield by 44% compared with the urea-N treatment (44 t ha-1). Moreover, net return was observed highest with CM treatment among all the organic and urea-N treatments. The study suggests that the combination of biochar with locally produced cattle manure has the potential to increase radish productivity and could compete with mineral nitrogen fertilizers while producing similar or even higher crop yields and economic returns.