Orchard Fertilization Management Methods in Pineapple Cultivation

Mineral nutrients in the soil are the material basis for the vegetative growth and reproductive growth of pineapple plants. Soil fertility, the amount of fertilizer applied, fertilizer quality and fertilization techniques are among the important factors that directly affect the normal growth of pineapple plants and the achievement of high and stable yields. Pineapple is a perennial herbaceous fruit tree that is planted once and harvested for 2-3 crops. It has the characteristics of large fruit, high yield per unit area and rapid vegetative growth, so it requires relatively more fertilizer. If the soil lacks various mineral nutrients, it directly affects the vegetative growth of the plant, causing slow growth, weak and premature aging, and reproductive growth is thereby also affected, resulting in small flower buds, small fruit and low yield. In order to make the plant grow vigorously, come into production on schedule, produce large fruit and high yield, and maintain sustained high and stable yields, fertilization should be carried out reasonably according to the biological characteristics and site conditions of pineapple.

1. Fertilization of non-producing orchards. From planting to fruiting is the vegetative growth stage. Fertilization should be mainly nitrogen fertilizer, supplemented by phosphorus and potassium fertilizer. The purpose is to promote the emergence of pineapple leaves, increase leaf number and leaf area, and lay the foundation for reproductive growth. From flower bud emergence to fruit maturity is the reproductive growth stage, and fertilization should be mainly potassium fertilizer, supplemented by nitrogen and phosphorus fertilizer. In pineapple fertilization, the application ratio of nitrogen, phosphorus and potassium is roughly 3:1:2, that is, 1 part phosphorus fertilizer (phosphorus pentoxide), 2 parts potassium fertilizer (potassium oxide), and 3 parts nitrogen fertilizer (nitrogen). The application amount of the three elements nitrogen, phosphorus and potassium per mu (calculated as pure nutrients): nitrogen 35-60 kg, phosphorus pentoxide 14-40 kg, potassium oxide 13-50 kg, with a yield per mu of 1000-2800 kg.

Fertilizer application methods: one is as base fertilizer, and one is as topdressing. Base fertilizer is applied before planting and before overwintering after each fruit harvest. The amount of base fertilizer before planting is generally 0.5 kg of farmyard manure per plant, and about 20-100 kg per mu of cake fertilizer and compound fertilizer. For newly reclaimed land and fertile soil, use less; for old reclaimed land and poor soil, use more. The amount of base fertilizer after fruit harvest and before overwintering is generally 0.5 kg of farmyard manure per plant, plus an additional 10 kg per mu of cake fertilizer or compound fertilizer. The specific amount depends on the size and growth vigor of the seedlings. Base fertilizer before overwintering is commonly applied in holes combined with earthing up.

Topdressing is divided into rhizosphere topdressing and foliar topdressing (that is, leaf surface topdressing). Rhizosphere topdressing is carried out at least twice a year. The first time is from December to February of the following year (that is, before flower bud emergence), with the purpose of promoting flower bud development; the second time is after fruit harvest in July, with the purpose of promoting sucker growth. Each time, 10 kg of urea and 10 kg of potassium sulfate are mixed per mu and applied in holes around the rhizosphere, or 1000-1500 kg of decomposed dilute human and livestock manure urine is poured into the leaf axils at the base of the plants. Foliar topdressing is aimed at promoting plant growth and fruit development, and is mainly carried out in the vigorous growth season of pineapple, roughly once each in April, June, July and September, and twice each in May and August. Each time, use a 1% urea aqueous solution (with 0.5% potassium sulfate added), or dilute (1:10) decomposed human and livestock manure urine, and spray or splash it on the pineapple leaf surface. For foliar topdressing in May and August, an additional 1 kg of potassium sulfate should be applied per 667 sq m each time.

2. Fertilization of producing orchards. Pineapple orchards that are about to come into production or have already come into production should continue to be fertilized; for semi-producing plants and plants that have already emerged flower buds, fertilization is still mainly potassium fertilizer, supplemented by nitrogen and phosphorus fertilizer, because at this time the suckers have begun to emerge and the slips are gradually growing larger. Therefore, this kind of fertilization not only satisfies the process of fruit transition from development to nutrient transformation, but also meets the needs of vegetative growth and development. To improve fruit quality, foliar topdressing is adopted when the fruit turns green, spraying 0.1% potassium dihydrogen phosphate. After fruit harvest, if the daily average temperature is above 18°C, quick-acting chemical fertilizer or decomposed human and livestock manure urine should be applied as topdressing. For chemical fertilizer, apply 15 kg of urea, 10 kg of potassium fertilizer and 10 kg of compound fertilizer per mu around the rhizosphere; or splash-apply 1000 kg of decomposed diluted human and livestock manure urine. After fruit harvest, if the temperature has already dropped and root growth has slowed down, cut off the old leaves extending into the furrow and press them into the rows, then apply organic fertilizer (such as compost, bran fertilizer, barnyard manure, etc.), and then earth up heavily. This fertilization is both a bud-promoting fertilizer and an overwintering fertilizer. Apply 2000 kg of compost and garbage fertilizer, 30 kg of phosphorus fertilizer and 40 kg of tung bran fertilizer per mu.

After weeding and leaf cutting, if it is from April to October, apply heavy quick-acting fertilizer, mixing 15 kg of urea, 10 kg of potassium fertilizer and 10 kg of compound fertilizer per mu and applying it between rows or between plants, or splash-apply 1000 kg of decomposed diluted human and livestock manure urine. This fertilization is mainly to promote sucker growth so as to bear fruit the following year. The Cayenne variety adopts one fruit crop as one growth cycle, and should also be fertilized to promote buds, so that the buds grow robustly. In addition to rhizosphere fertilization, because the temperature is high, foliar fertilizer can also be applied twice a month. After fruit harvest, if it is from November to February of the following year, it should be changed to heavy application of organic fertilizer. Apply 2000 kg of compost and barnyard manure, 30 kg of phosphorus fertilizer and 40 kg of tung bran per 667 sq m, then earth up heavily, both to promote buds and to protect against cold and overwinter.