Fertilizer Requirements and Scientific Fertilization Methods for Kiwifruit

    The four best fertilization schemes for kiwifruit are formulated according to the annual growth and fertilizer requirements of kiwifruit, for fruit growers' reference.

Kiwifruit Fertilization

    Topdressing bud-promoting fertilizer in early spring: After the soil thaws in spring and the sap begins to flow, the tree starts its activity. Fertilizing at this stage promotes budbreak, flowering and new shoot growth. The bud-promoting fertilizer should be applied before budbreak, mainly with quick-acting nitrogen fertilizer (nitrogen fertilizer accounting for 1/2-1/3 of the annual nitrogen fertilizer amount), supplemented with a small amount of phosphorus and potassium fertilizer. For a 4-year-old kiwifruit tree, apply generally 8-10 kg of pure nitrogen, 4 kg of pure phosphorus and 4 kg of pure potassium per mu. Broadcast over the whole orchard or apply per plant, then irrigate with 1-2 spring waterings.

    Topdressing fruit-promoting fertilizer after flowering: 30-40 days after petal fall is the rapid swelling period of kiwifruit. At this stage kiwifruit grows rapidly and its volume increases quickly; a fertilizer deficiency will hinder the swelling. The fruit-promoting fertilizer should be applied 20-30 days after petal fall, mainly with quick-acting compound fertilizer. For a 4-year-old kiwifruit tree, apply 0.25-0.3 kg of diammonium phosphate per plant. After application, irrigate the whole orchard once.

    Topdressing fruit-strengthening fertilizer in midsummer: To make the interior of kiwifruit firm, increase single fruit weight and improve quality, apply phosphorus and potassium fertilizer once in June-July. To make up for the insufficient nutrition for late shoot growth, quick-acting nitrogen fertilizer can also be sprayed on the leaves 1-2 times. Spraying calcium fertilizer on the leaves at this stage can also enhance the storage tolerance of kiwifruit. This fertilization is mainly foliar spraying, and the fertilizers can be 0.5% monopotassium phosphate, 0.3%-0.5% urea solution and 0.5% calcium nitrate.

    Applying overwintering fertilizer as base fertilizer after harvest: After fruit harvest, the leaves lose a large amount of nutrients, so supplementing nutrients to the tree at this time is particularly important. Before leaf fall, spray 0.5% urea solution on the leaves once to increase leaf photosynthesis, promote the return flow of nutrients to the roots and stems, and increase nutrient reserves. In autumn, basal application should be done early, mainly with organic fertilizers such as pen manure, composted manure, compost, barnyard manure and cake fertilizer, mixed with an appropriate amount of quick-acting fertilizers such as superphosphate and ammonium nitrate. Generally, for a 4-year-old kiwifruit tree, apply 20-30 kg of organic fertilizer per plant, plus 0.25 kg of superphosphate and ammonium nitrate. It can be broadcast over the whole orchard or applied in furrows. Irrigate once promptly after application.