Fertility characteristics of kiwifruit

The kiwifruit is adapted to warm, moist, slightly acidic soils and is most afraid of clayey, strongly acidic or alkaline, poorly drained, excessively dry, infertile soils. Therefore, measures can be taken to improve the physical and chemical properties of the soil to create an optimal ecological environment for its growth.

Nitrogen nutrition and fertilisation: the distribution of nitrogen in the roots, stems, leaves, fruit and cortex and xylem of kiwifruit trees is as follows: roots, leaves, fruit > stems; cortex > xylem; the storage site for nitrogen in winter is the cortex of roots and stems, and mainly in the cortex of stems. In a kiwifruit orchard with a yield of 2000 kg/acre, the total nitrogen uptake by kiwifruit trees during the annual cycle was 14.45 kg/acre, with a total of 2.25 kg/acre taken up after the fruit harvest and before fruiting, and 12.2 kg/acre taken up throughout the fruit growing period, accounting for 15.57% and 84.43% of the total nitrogen uptake, respectively. The amount of nitrogen absorbed accounted for 53.13% and 31.30% of the total nitrogen uptake, respectively. Nitrogen deficiency occurs mostly in poorly managed orchards. It is therefore essential to apply sufficient nitrogen fertiliser at planting time in combination with the planting hole.

Phosphorus nutrition and fertilisation: the distribution of phosphorus in the roots, stems, leaves, fruit and cortex and xylem of kiwifruit trees is as follows: roots, leaves and fruit > stems; cortex of roots and stems > xylem. From the budding stage (28 March) to the beginning of fruit growth (18 May), 78.89% of the phosphorus required for kiwifruit leaf growth came from external uptake, 4.44% from the previous year's storage of phosphorus in the roots and 16.67% from the previous year's storage of phosphorus in the stems. From the beginning of fruit growth (18 May) to the end of rapid fruit expansion (9 July) kiwifruit trees absorb 55.40% of the total phosphorus for the year, the period of maximum efficiency in phosphorus nutrition. The total amount of phosphorus absorbed by kiwifruit trees in the annual cycle is 2.64 kg/mu (kiwifruit yield 2600 kg/mu). The recommended annual application of pure phosphorus is 6.16 kg/mu, calculated according to the formula (fertiliser uptake - natural soil supply) / fertiliser utilisation rate (%). A total of 0.73kg/mu was absorbed after the fruit harvesting period (8 September) and before fruiting (18 May), and 1.74kg/mu was absorbed throughout the fruit growing period, accounting for 29.55% and 70.45% of the total absorption respectively.