Chemical attributes of an Oxisol with the addition of conilon coffee straw biochar

Abstract The objective of this work was to evaluate the effects of increasing rates of biochar produced with coffee straw, at two pyrolysis temperatures, on the chemical attributes of an Oxisol cultivated with conilon coffee (Coffea canephora) and on the nutrient content of coffee tree leaves. Treatments consisted of pyrolysis at two temperatures (350 and 600 °C) and of five biochar rates (0, 5, 10, 15, and 20 Mg ha-1). The following soil chemical attributes were evaluated: pH in water; P, K, Ca, Mg, Al, H+Al, Zn, Cu, Fe, and Mn contents; effective and potential cation exchange capacity (CEC); sum of bases (SB); base (V) and aluminium (m) saturation; and N, P, K, Ca, Mg, Zn, Cu, Fe, and Mn contents in the leaves. The biochar produced at 600°C, at rates of 10 and 15 Mg ha-1, promoted a greater K release into the soil. Regardless of temperature, coffee straw biochar increased K and P availability, sum of bases, base saturation, and CEC in the soil, but did not influence macro- and micronutrient contents in the leaves. The addition of increasing rates of coffee straw biochar in the soil increases P, K, Mg, SB, CEC, and V, regardless of pyrolysis temperature.

摘要 本研究旨在评估两种热解温度下制备的咖啡秸秆生物炭施用量梯度，对种植科尼隆咖啡（Coffea canephora）的氧化土（Oxisol）化学性质，以及咖啡叶片养分含量的影响。试验设置两种热解温度（350℃与600℃）与五个生物炭施用量梯度（0、5、10、15、20 Mg·ha⁻¹）。本试验测定的土壤化学性质包括：水土比pH值；土壤磷、钾、钙、镁、铝、氢铝（H+Al）、锌、铜、铁、锰含量；有效与潜在阳离子交换量（CEC）；盐基总量（SB）；盐基饱和度（V）与铝饱和度（m）；以及咖啡叶片中的氮、磷、钾、钙、镁、锌、铜、铁、锰含量。在10与15 Mg·ha⁻¹施用量下，600℃热解制备的生物炭可促进土壤钾素释放。无论热解温度如何，咖啡秸秆生物炭均可提升土壤中钾、磷的有效性，以及盐基总量、盐基饱和度与阳离子交换量，但对咖啡叶片的大量与微量营养元素含量无显著影响。无论热解温度如何，向土壤中施加梯度递增的咖啡秸秆生物炭，均可提升土壤磷、钾、镁含量，盐基总量、阳离子交换量与盐基饱和度。