Maize straw- and rice husk-derived biochars were produced in a simple metal kiln without automated control. Their characteristics and effects on crop productivity were investigated in three fields in Nepal. The maximum temperature inside the kiln reached ~ 450 °C; the charring reaction was maintained for 90 min and 10 h for maize straw- and rice husk-derived biochars, respectively, until 30 °C was reached. The physicochemical properties of the biochars were similar to those of biochars manufactured previously in electric furnaces with automated control. Compared with control soil, incorporation of maize straw- and/or rice husk-derived biochars into soil significantly (p < 0.05) increased spinach biomass, onion bulb, millet and maize yields. The increase in crop productivity varied from 12.8% (millet yield at 10 t ha⁻¹ maize straw-derived biochar addition) to 220% (spinach biomass production at 10 t ha⁻¹ rice husk-derived biochar addition). Further research is needed to standardize the operating conditions of biochar manufacturing in a kiln to optimize crop productivity.

玉米秸秆和稻壳衍生的生物炭是在没有自动控制的简单金属窑中生产的。在尼泊尔的三个田间调查了它们的特征和对作物生产力的影响。窑内最高温度达到~450℃；对于玉米秸秆和稻壳衍生的生物炭，炭化反应分别保持 90 分钟和 10 小时，直到达到 30 °C。生物炭的理化性质与以前在具有自动控制的电炉中制造的生物炭相似。与对照土壤相比，玉米秸秆和/或稻壳来源的生物炭在土壤中的掺入显着（p < 0.05) 增加菠菜生物量、洋葱球茎、小米和玉米的产量。作物生产力的增加从 12.8%（添加 10 t ha ^-1玉米秸秆衍生生物炭时的小米产量）到 220%（添加 10 t ha ^-1稻壳衍生生物碳时的菠菜生物质产量）不等。需要进一步研究以标准化窑中生物炭制造的操作条件，以优化作物生产力。