XÂY DỰNG HỆ THỐNG CHẨN ĐOÁN VÀ KHUYẾN CÁO TÍCH HỢP ĐỐI VỚI DINH DƯỠNG N, P, K CHO CÂY QUÝT HỒNG (Citrus reticulate Blanco.) TẠI HUYỆN LAI VUNG, TỈNH ĐỒNG THÁP

Abstract

The objective of this study was to establish the diagnosis and recommendation integrated system (DRIS) norms for mandarin based on foliar nutrient contents. The 10 healthy leaves per plant from non-fruiting terminals for each 10 plants per field were collected to analyze N, P, K concentrations and their respective yields in 25 mandarin fields in Lai Vung district, Dong Thap province. The results showed that higher foliar N, K concentrations were recorded in former group than latter group, foliar P concentration was not statistical difference between low-and high-yielding groups. Three nutrient ratios selected (P/N, K/N and P/K) as DRIS norms showed significant differences either the mean values or S²_l/S²_h ratio of the low-and high-yielding groups.