Data from: Biochar from "Kon Tiki" flame curtain and other kilns: effects of nutrient enrichment and kiln type on crop yield and soil chemistry

Biochar application to soils has been investigated as a means of improving soil fertility and mitigating climate change through soil carbon sequestration. In the present work, the invasive shrub "Eupatorium adenophorum" was utilized as a sustainable feedstock for making biochar under different pyrolysis conditions in Nepal. Biochar was produced using several different types of kilns; four sub types of flame curtain kilns (deep-cone metal kiln, steel shielded soil pit, conical soil pit and steel small cone), brick-made traditional kiln, traditional earth-mound kiln and top lift up draft (TLUD). The resultant biochars showed consistent pH (9.1 ± 0.3), cation exchange capacities (133 ± 37 cmolc kg-1), organic carbon contents (73.9 ± 6.4 %) and surface areas (35 to 215 m2/g) for all kiln types. A pot trial with maize was carried out to investigate the effect on maize biomass production of the biochars made with various kilns, applied at 1% and 4% dosages. Biochars were either pretreated with hot or cold mineral nutrient enrichment (mixing with a nutrient solution before or after cooling down, respectively), or added separately from the same nutrient dosages to the soil. Significantly higher CEC (P< 0.05), lower Al/Ca ratios (P< 0.05), and high OC% (P<0.001) were observed for both dosages of biochar as compared to non-amended control soils. Importantly, the study showed that biochar made by flame curtain kilns resulted in the same agronomic effect as biochar made by the other kilns (P > 0.05). At a dosage of 1% biochar, the hot nutrient-enriched biochar led to significant increases of 153% in above ground biomass production compared to cold nutrient-enriched biochar and 209% compared to biochar added separately from the nutrients. Liquid nutrient enhancement of biochar thus improved fertilizer effectiveness compared to separate application of biochar and fertilizer.

向土壤施加生物炭（biochar）作为提升土壤肥力、通过土壤碳固存缓解气候变化的手段，已得到广泛研究。本研究以入侵灌木紫茎泽兰（Eupatorium adenophorum）为可持续原料，在尼泊尔不同热解条件下制备生物炭。本研究采用多种类型的窑炉制备生物炭：包括4种焰幕式窑（flame curtain kilns）子类——深锥金属窑、钢护土坑窑、锥形土坑窑与小型钢锥窑，砖砌传统窑、传统土堆窑，以及顶升式通风窑（top lift up draft, TLUD）。所有窑炉制备的生物炭均表现出稳定的理化性质：pH值为9.1±0.3，阳离子交换量（cation exchange capacity, CEC）为133±37 cmolc kg⁻¹，有机碳含量为73.9±6.4%，比表面积为35~215 m²/g。本研究开展玉米盆栽试验，探究以1%和4%施用量施加不同窑炉制备的生物炭对玉米生物量产出的影响。试验中生物炭分别采用热态或冷态矿质养分富集处理——即分别在热解后冷却前或冷却后与营养液混合，或与等量养分分别施入土壤。与未施加改良剂的对照土壤相比，两种施用量的生物炭处理均表现出显著更高的CEC（P<0.05）、更低的铝钙比（Al/Ca，P<0.05）以及更高的有机碳占比（P<0.001）。值得注意的是，本研究表明焰幕式窑制备的生物炭与其他窑炉制备的生物炭具有相当的农艺效应（P>0.05）。当生物炭施用量为1%时，热态养分富集生物炭的地上部生物量产出较冷态养分富集生物炭提升153%，较养分分别施入组提升209%。由此可见，对生物炭进行液态养分富集处理，相较于生物炭与肥料分别施入的方式，可提升肥料利用效率。