Effect of fertilization methods on nutrients and fruit economic characteristics of Camellia oleifera

To clarify the impact of fertilization methods on the nutrients and economic characteristics of Camellia oleifera, explore the relationship between nutrients and fruit economic characteristics, and to identify suitable fertilization methods for Camellia oleifera forests.

Using ‘Ganxing 48’@@@ Camellia oleifera as the material, three fertilization treatments were set up: hole fertilization (D), furrow fertilization (G), and no fertilization (CK). The nutrient content and fruit economic characteristics of Camellia oleifera leaves, fruits, roots, and flower buds were investigated, and a partial least squares path model was constructed to analyze the relationship between tree nutrients and fruit economic characteristics as well as the influence of fertilization methods on tree nutrients and fruit economic characteristics.

Compared with CK, the fruit shape index of the hole application treatment is closer to 1, and the quality of fresh fruits increased by 21.51% and 9.00%, respectively. The oil yield of fresh fruits increased by 22.21% and 24.67% respectively, and the oil production per plant increased by 33.12% and 41.23% respectively; With the extension of growth time, N and K nutrients gradually accumulate as a whole; P nutrients gradually transfer from leaves, fruits, and roots to flower buds. The soluble sugars in roots and flower buds gradually transfer to the fruit; The overall trend of soluble starch content is decreasing and increasing. Fertilization can promote the accumulation of N, K and soluble starch in various organs, increase P content in roots, leaves, and fruits during the growth period of spring shoots, promote the accumulation of soluble sugars in leaves and fruits, and alleviate the consumption of soluble sugars in roots and flower buds. The results of the PLS-PM show that G mainly increases fruit nutrients and reduces leaf nutrients during the oil conversion period, while D mainly reduces leaf nutrients during the rapid growth period of spring shoots and increases root nutrients during the peak fruit growth period, thereby improving fruit economic traits. The results of PCA showed that 5 fruit quality indicators, 2 moisture content indicators, fruit shape index, fresh fruit oil content, dry seed oil content, and oil production were the main indicators for evaluating the fertilization effect, with a cumulative contribution rate of 88.79%. The comprehensive score from high to low was D>G>CK.

Hole fertilization is a more suitable fertilization method for Camellia oleifera forests, as it improves fruit economic characteristics by affecting the nutrients of Camellia oleifera at different stages.