The presence of mulch on the soil surface after the mechanical harvesting of sugarcane (Saccharum officinarum L.) enhances the cycling of nutrients, especially K, which can decrease K fertilizer recommendations for the crop. The aim of this study was to evaluate the effect of K addition to an Oxisol, with an initial concentration 0.07 cmol(c) K kg(-1), in first and second ratoon (no-till) sugarcane cultures by a conservationist system, i.e. rational use of fertilizers, use of alternative inputs and especially the maintenance of residues in soil that was previously burned to facilitate cutting. The following K doses were tested: 0, 32.5, 65, 130, and 195 kg K2O ha(-1), arranged in a randomized block design with five replicates. Potassium content in the soil and in the plant, as well as the yield and the quality of stalks were evaluated. Soil K application increased K concentration in soil and plant, and was reflected in the prodUction of stalks, with higher production (87.5 and 107.5 t ha(-1)) with the use of 120 and 123 kg K2O ha(-1) in first and second ratoon sugarcane, respectively. At the first 2 yr it was not possible to reduce the K fertilization in ratoon. Therefore, with the introduction of the conservationist system there was an increase (20 t ha(-1)) at the second ratoon regarding the first one with the same applied rate.
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机译：机械收获甘蔗（Saccharum officinarum L.）后，土壤表层覆盖物的存在增强了养分尤其是钾的循环，从而降低了作物对钾的施用量。这项研究的目的是通过保守派系统评估在第一和第二宿根（免耕）甘蔗文化中，将钾添加到初始浓度为0.07 cmol（c）K kg（-1）的Oxisol中的效果，即合理使用肥料，使用替代性投入物，尤其是保持先前燃烧以利于切割的土壤中的残留物。测试了以下K剂量：0、32.5、65、130和195 kg K2O ha（-1），以随机区组设计排列，重复五次。评价土壤和植物中钾的含量，以及茎的产量和质量。施用土壤钾增加了土壤和植物中的钾含量，并反映在秸秆的生产中，产量更高（分别为87.5和107.5 t ha（-1）），首先使用120和123 kg K2O ha（-1）和第二个再生区甘蔗。在最初的2年中，不可能减少再生区的钾肥。因此，随着保护主义制度的引入，与相同施用量的第一个再生草相比，第二个再生草增加了（20 t ha（-1））。
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