关键词: 甜橙, 品种, 变异系数, 营养诊断, 叶片元素适宜含量

Abstract: The present study was carried oat in Changtai, Piaghe and Nanjing counties of south Fujian during 1990-1991 in order to find out the optimum range of the mineral element content in the leaves of Yinzigan, Gailiang and Valencia orange, which were major cultivars of sweet orange (Citrus sinensis) in south Fujian. The main results are as follows. The amount of macro-and micro-elements in the leaves within the same cultivars was affected by different locations and years of sampling. The difference of the contents of nutrient elements among the three cul-tivars was not steady. The authors therefore suggested that it was pertinent to establish the common criteria of plant nutrient diagnosis for the three sweet orange cultivars. The statistical analysis indicated that the variation coefficients of N and P contents in the leaves were lower, while those of Mg,K and Ca contents were higher; the variation coefficients were higher for most micro-element contents (especially B, Mn and Cu) in the leaves than those for macro-element contents. The preliminary study suggested that the values of optimum range of leaf mineral elements in spring shoot of productive sweet orange were s N 2.50-3.30%, P 0.12-0.18%, K 1.00-2.00%, Ca 2.00-5.00%, Mg 0.22-0.40%, Cu 4.0-18.0 ppm, Zn 25.0-70.0 ppm, Mn 20.0-100.0 ppm, Fe 90.0-160.0 ppm, B 25.0-300.0 ppm, and the optimum ratio between the amount of macro-elements in leaves was N:P:K:Ca:Mg=1:0.05:0.52:0.95:0.11. These diagnostic criteria may provide the parameters of fertilizer guide.

Key words: Sweet orange, Cultivar, Coefficient of variation, Nutrient diagonsis, Optimum range of leaf element content