Potassium fertilization and its impact on production and mineral composition of peach trees

Abstract This study aimed at evaluating production parameters of peach trees subject to different doses of potassium fertilization and at establishing the critical level of this nutrient in the soil and in peach tree leaves. The experiment was conducted in the 2016, 2017 and 2018 seasons in a commercial orchard located in Morro Redondo, Rio Grande do Sul state, Brazil. Peach trees of the cultivar Sensação were fertilized at the following doses: 0, 40, 80, 120 and 160 kg ha-1 K2O as potassium chloride applied to the surface of the soil. In the 3-year study, production per plant, number of fruit, fruit mass and fruit diameter were evaluated while soil and leaf samples were collected to undergo chemical analyses. Potassium fertilization in peach orchards increases levels of this nutrient in the 0-20 cm soil layer. Potassium fertilization via soil increased potassium contents in peach tree leaves. Productivity of peach trees responds to superficial potassium application via soil but it does not affect mean fruit mass. The critical level between relative productivity and potassium content in the soil could not be established while the one between production and potassium content of leaves of peach trees was 2.84%.

摘要 本研究旨在评估不同钾肥施用量下桃树的生产参数，并明确该养分在土壤及桃树叶片中的临界含量。试验于2016、2017和2018种植季，在巴西里奥格兰德州（Rio Grande do Sul）莫罗雷东杜（Morro Redondo）的一处商业果园内开展。供试品种为"Sensação"的桃树，以氯化钾（potassium chloride）为钾肥源，按0、40、80、120及160 kg·ha⁻¹ K₂O（氧化钾）的用量进行地表土施。在为期三年的试验周期内，研究人员测定了单株产量、果实数量、单果质量及果实直径，并采集土壤与叶片样品开展化学分析。结果表明，桃园施用钾肥可提升0-20 cm土层的钾素含量；土壤施钾可提高桃树叶片的钾素水平。桃树产量对地表土施钾存在响应，但对平均单果质量无显著影响。本研究未能确定相对产量与土壤钾素含量间的临界值，而桃树叶片钾素含量与产量间的临界值为2.84%。