Find in Library

Due to long-term excessive fertilization, the fruit quality of the <i>Guanxi</i> pomelo (Citrus grandis) has been declining. The classification of fruit quality and its relationship with nutrients in soils and trees were studied to declaim the characteristics of nutrients in <i>Guanxi</i> pomelo orchards, ultimately guiding the fertilization for high-quality fruit production. By cluster analysis, 281 samples were grouped into four clusters. High-quality fruit (HF) showed a gourd shape with moderate weight size, high sweetness, edible rate (ER) up to 73%, and vitamin C content over 40 mg/100 g. Compared to sub-quality fruit (SF), common fruit (CF), and inferior fruit (IF), the content of magnesium (Mg) in the leaves of HF was 11.76, 11.76, and 18.75% higher, while the content of iron (Fe) was 6.45, 5.76 and 10.97% higher, respectively. Meanwhile, the contents of Zinc (Zn, 8.51, 6.44, and 11.22% higher than SF, CF, and IF, respectively) and Boron (B, 13.47, 13.83, and 25.40% higher than SF, CF, and IF, respectively) were also found to increase. However, the contents of Mn (35.34, 27.51, and 25.53% higher) and Cu (31.90, 31.99, and 5.64% higher) in IF were significantly higher than in HF, SF, and CF. Acid soils (4.24–4.40) with low OM content (23.00–26.71 g kg⁻¹) led to an imbalance uptake of nutrients of citrus, ultimately resulting in poor quality. These results indicated that farmers should reduce the application of nitrogen (N), phosphorus (P), and K fertilizer and pesticides and increase micronutrient and organic fertilizer, which provides a theoretical basis for scientific fertilization to improve the fruit quality of <i>Guanxi</i> pomelo <i>(Citrus grandis)</i> of Pinghe County.