Fertilizer Requirements and High-Yield Fertilization Techniques and Timing for Sugar Beet in China

Fertilizer requirements and high-yield fertilization techniques and timing for sugar beet in China: Sugar beet is an important sugar crop. From spring sowing to autumn root harvest is the vegetative growth stage. During this period, the root system is well developed, the leaf canopy is lush, the yield per unit area is high, and nutrient requirements are large. In the second year, from spring planting of the mother plant to seed harvest is the reproductive growth stage, and nutrient uptake is relatively reduced. According to research, for every 1000 kg of roots produced by spring-sown sugar beet, it needs to absorb 3.9-5.5 kg of nitrogen, 1.3-2.2 kg of phosphorus, and 5.4-6.6 kg of potassium. For every 100 kg of seed produced by spring-planted mother plants, it needs 3.5 kg of nitrogen, 1.0 kg of phosphorus, and 4.6 kg of potassium. Obviously, sugar beet has a very large demand for nitrogen and potassium, especially potassium, whose demand exceeds that of nitrogen, and this should be considered when fertilizing.

The amount of nutrients absorbed by sugar beet differs among growth stages, and nutrient uptake also differs between the root production stage and the seed production stage. In the root production stage, nutrient uptake is relatively small at the seedling stage, accounting for only about 15% of the total. The vigorous leaf canopy stage and the root sugar increase stage are the key periods for forming aboveground vegetative organs and underground storage organs. During these periods, the uptake of nitrogen, phosphorus, and potassium increases rapidly. At the root sugar increase stage, the uptake of nitrogen, phosphorus, and potassium has already reached 71.9%, 49.5%, and 53.5% of the total uptake, respectively. Entering the sugar accumulation stage, although nutrient uptake declines, it still maintains a certain amount to provide nutrients for sugar synthesis and conversion. For the seed production stage, nutrients in the early period are provided by the mother plant, and the peak uptake period is mainly around bolting, which is the key period for fertilization.

Sugar beet fertilization differs between the root production stage and the seed production stage. In the root production stage, fertilization mainly includes base fertilizer, seed fertilizer, and topdressing. The amount of base fertilizer varies with yield level, soil conditions, and so on. Generally, for a root yield of 1,700 kg per 667 sq m, 1.7-2.7 tonnes of organic fertilizer should be applied and plowed into the soil before sowing. Seed fertilizer is applied at sowing, using about 0.7 kg of nitrogen, 1.0 kg of phosphorus, and about 0.7 kg of potassium per 667 sq m, avoiding direct contact with the seeds. For topdressing, apply 4-7 kg of nitrogen, 4 kg of phosphorus, and 5-7 kg of potassium per 667 sq m, preferably in two applications. The first is applied after thinning to a stand, and the second before ridge closing combined with intertillage. In the later period, foliar topdressing can be used to supplement nutrients.

In the sugar beet seed production stage, sufficient base fertilizer should also be applied. Per 667 sq m, 1-2 tonnes of organic fertilizer, 20-30 kg of superphosphate, and 10 kg of potassium chloride can be applied. For seed fertilizer, using 5-10 kg of superphosphate per 667 sq m mixed with 250 kg of decomposed organic fertilizer gives a better effect. Topdressing is applied before bolting, with 7-9 kg of nitrogen fertilizer (N) per 667 sq m. In the later period, urea and potassium dihydrogen phosphate can be used for foliar spraying. Spraying a 0.1%-0.2% borax solution from bolting to before flowering can increase yield and quality.