Biochar Improves Maize Nutritional Status and Yield under Two Soil Tillage Modes

Our field trial in Cameroon assessed the effect of biochar on nutrient uptake and maize yield, following a single application of 15 t ha-1 of biochar to an oxisol under two soil tillage modes. Treatments were (T2) fertilizer + corncob biochar (CCB), (T3) fertilizer + eucalyptus biochar (EB), (T4) Straw + fertilizer + CCB, (T5) Straw + fertilizer + EB and the control treatment (T1) consisted of fertilizer + straw only. Maize leaf tissues were collected at tasselling during each production period and analysed for macro-elements. Biochar significantly increased maize yield by 55 % above control during the first production period and by 54 % during the second period. The CCB amendment positively interacted with the furrows and ridges (FR) tillage mode to improve yield during the first production period. By compositional nutritional diagnosis (CND), the most deficient nutrients were identified as P, Mg and K. Despite higher yield, maize plants in biochar-treated plots were more nutritionally unbalanced during the first production period compared to control plants, the inverse was observed during the second production period. Further studies are required to improve maize fertilisation recommendations and to refine application frequency of biochar for continuous maize production on oxisols.