Rapid NPK diagnosis in tomato using petiole sap analysis with the DRIS method

ABSTRACT One of the factors determining success in tomato production is plant nutrition. The diagnosis and recommendation integrated system (DRIS) is a tool used to obtain fertilizer recommendations. The objective of this study was to determine DRIS indices using petiole sap analysis (PSA) and compare them with those obtained using leaf analysis in two tomato cultivars grown under greenhouse conditions. A complete randomized design with eight treatments and 60 plants per experimental unit was used. To determine whether employing PSA with the DRIS methodology can provide a reliable diagnosis of fertilization, doses of some elements, such as N, P, or K, were reduced by 30% and supplied to two tomato cultivars, namely, Cid and Moctezuma. The indices for PSA-DRIS and DRIS were estimated. R2 values greater than 0.84 were obtained for the relationships between the leaf concentrations and petiole extract (PE) concentrations of some elements in both tomato cultivars. The PSA-DRIS method detected 62.5% of the cases of deficiency identified via DRIS. The PSA-DRIS method is a low-cost way to rapidly fertilize recommendations in tomato.摘要：番茄生产成功的关键影响因素之一为植株营养状况。诊断与推荐综合系统（Diagnosis and Recommendation Integrated System, DRIS）是获取肥料施用建议的常用工具。本研究旨在通过叶柄汁液分析（Petiole Sap Analysis, PSA）计算DRIS指数，并对比温室种植的两个番茄品种分别采用该方法与叶片分析法得到的指数结果。本研究采用完全随机试验设计，设置8个处理，每个试验单元包含60株植株。为验证结合DRIS方法的PSA能否为施肥状况提供可靠诊断，本研究对两个番茄品种‘Cid’与‘Moctezuma’施加了氮、磷、钾等元素30%的减量施肥处理。研究分别估算了PSA-DRIS与传统DRIS的指数。两个番茄品种的叶片养分浓度与叶柄提取液（Petiole Extract, PE）浓度间的相关系数R²均大于0.84。PSA-DRIS方法可检出62.5%的DRIS法识别的养分缺乏案例。PSA-DRIS方法是一种可快速生成番茄施肥建议的低成本技术途径。