Effects of ring-cutting time and arc on nutrient allocation and fruiting of <italic>Camellia oleifera</italic> trees in full-fruiting season

<bold>Objective</bold> This study aims to investigate the effects of ring-cutting time and arc on nutrient partitioning and fruit set in <italic>Camellia oleifera</italic> at the peak fruiting stage，thus elucidating the relationship between tree nutrients and fruit growth. <bold>Method</bold> The 7-year old <italic>Camellia oleifera</italic> was subjected to 180° and 360° ring-cutting treatments in November during the blooming period and in March of the following year before the spring tip sprouting，respectively.Nitrogen，phosphorus and potassium nutrients，soluble sugar，soluble protein and soluble starch contents of each organ，as well as the number of fruits per plant，the weight of fruits per plant and yield were determined and analyzed in different treatments before the ring cuts healed（May），and after the healing（July，August and October）. <bold>Result</bold> （1）Ring cutting under different conditions increased the inorganic nutrients in the root system before ring healing as well as the phosphorus，potassium and organic nutrient contents of the leaves during the fruit expansion stage；In addition，it decreased the leaf nitrogen as well as the soluble sugar and soluble starch contents of the leaves during the fruit ripening stage.（2）The effect of ring-cutting arc was more pronounced than ring-cutting time on the nutrient content of <italic>Camellia oleifera</italic> leaves and roots.（3）360° ring cutting before spring tip emergence reduced the initial fruit drop of <italic>Camellia oleifera</italic>，improved the fruiting rate，and increased the number of fruits hanging on a single plant and the fresh fruit yield of a single plant，but its fruits were smaller and lighter.（4）The correlation between <italic>Camellia oleifera</italic> fruit drop and leaf and root nutrition was not significant，but there was a significant synergistic and antagonistic relationship between fruit yield and some leaf and root nutrition.（5）Suitable ring-cutting treatments significantly increased fruit set and yield per plant by increasing total potassium，leaf total phosphorus，leaf soluble sugar content and decreasing root soluble starch content in <italic>Camellia oleifera</italic> roots. <bold>Conclusion</bold> 360° ring cutting of <italic>Camellia oleifera</italic> before spring sprout is conducive to the leaf accumlation of soluble sugar，soluble protein for fruit rapid growth period，as well as the accumulation of nitrogen，phosphorus，potassium nutrients in the root system.It can promote the hanging of the fruit，reduce the fruit drop，the best effect on the production of <italic>Camellia oleifera</italic>.