Nutritional demand of 'Grande Naine' and 'Prata Comum' banana bunches in two growing seasons

Abstract The quantification of nutrients accumulated and exported by banana bunches provides information on the crop nutritional requirements. Thus, the aim of this work was to determine the nutritional demand of 'Grande Naine' and 'Prata Comum' banana bunches in the region of Vale do Ribeira, state of São Paulo. Bunch sampling was carried out in six harvest seasons, summer, and winter. The results of dry matter production and nutrient accumulation in bunches were submitted to analysis of variance. Relative growth rates (TCR), organogenic net accumulation (TALON), export and order of nutrient accumulation in bunches were estimated. K and N were the nutrients most accumulated and exported by both cultivars. In har-vest period 5 (commercial harvest), more dry matter was produced in the summer and more nutrients were accumulated in the winter. The highest TCR values were observed between periods 2 and 3 in the summer and between 0 and 1 in the winter, but it did not always follow TALON. The results obtained are important to adapt the nutritional management of these cultivars to the study region, especially in relation to the growing season, due to the longer permanence of the bunch on the plant in the winter and greater demand for nutrients until commercial harvest.摘要 香蕉果穗累积与输出的养分定量研究，可为作物需肥规律提供参考依据。本研究旨在明确圣保罗州里贝拉谷地区‘格兰德内恩’(Grande Naine)与‘普拉塔库姆’(Prata Comum)两个香蕉品种的果穗养分需求。试验于夏季与冬季共设置6个收获季开展果穗采样。对果穗干物质生成量与养分累积数据进行方差分析，并估算相对生长速率(TCR)、器官建成净积累量(TALON)、养分输出量及果穗内养分累积顺序。结果显示，钾(K)与氮(N)是两个供试品种果穗累积与输出量最高的养分元素。在第5个收获季（商品采收期），夏季的果穗干物质生成量更高，而冬季的果穗养分累积量更多。夏季相对生长速率的最高值出现在第2与第3采收季之间，冬季则出现在第0与第1采收季之间，但该变化趋势并不始终与器官建成净积累量的趋势一致。本研究结果可为该地区上述两个香蕉品种的养分管理适配提供理论支撑，尤其需结合生育期因素考量：冬季果穗在植株上的留存时长更长，直至商品采收期的养分需求也更高。