Fertilizer Requirements of Sesame in China and High-Yield Fertilization Techniques and Timing

Fertilizer Requirements of Sesame in China and High-Yield Fertilization Techniques and Timing: Sesame is a crop with relatively high fertilizer requirements. According to measurements, producing every 100 kg of sesame seeds requires 6.2-8.2 kg of nitrogen, 2.0-2.7 kg of phosphorus, and 4.4-6.7 kg of potassium. Nutrient uptake varies considerably across different growth stages.

During the seedling stage, the amounts of nitrogen, phosphorus, and potassium absorbed account for 12.3%, 6.5%, and 11.2% of total uptake over the whole growth period respectively, mainly for the growth of leaves, stems, and roots. From budding to early flowering, sesame growth accelerates, but the increase in nutrient uptake is not large, with nitrogen, phosphorus, and potassium uptake accounting for 17.5%, 13.6%, and 17.0% of total uptake respectively. Entering the full flowering stage, stems and leaves grow fastest, and large numbers of buds, flowers, and capsules form, with nitrogen, phosphorus, and potassium uptake accounting for 43.9%, 34.0%, and 49.4% respectively; this stage is the period of maximum efficiency for nitrogen and potassium nutrition. After full flowering, sesame enters the maturity stage, the growth of vegetative organs such as stems and leaves slows down, seeds in the capsules form and tend toward maturity, and oil or protein accumulates in the seeds. During the maturity stage, nitrogen, phosphorus, and potassium uptake still accounts for 26.3%, 45.9%, and 22.4% respectively. Maintaining appropriate nutrients can sustain internal metabolism and prevent premature aging of the plants.

Given that sesame has high fertilizer requirements and a relatively short growth period, fertilization should focus on heavy application of base fertilizer. Generally, 1-1.5 tonnes of high-quality organic fertilizer is applied per 667 sq m, with 5-6 kg of nitrogen, 4-5 kg of phosphorus, and 5 kg of potassium applied according to soil conditions. Since sesame is a shallow-rooted crop, base fertilizer is best applied shallowly and in a concentrated manner. Topdressing of sesame should adhere to the principles of early application of seedling fertilizer, heavy application before flowering, and supplementary application during flowering. Seedling fertilizer is generally applied after thinning; otherwise, it should be applied early. Topdressing at the flowering stage is key and can be applied in two applications or one, depending on the soil's fertilizer retention capacity. If applied once, it should be applied at the early flowering stage; if applied twice, it can be applied at budding and early flowering (as the main application) and at flowering and capsule formation (as a supplementary application). The application rate is generally 5-8 kg of urea and 5 kg of potassium fertilizer per 667 sq m, applied in concentrated furrows or holes in combination with intertillage and earthing up. In the late growth stage of sesame, foliar spraying of a 0.2% potassium dihydrogen phosphate solution can increase the number of capsules and improve the seed-setting rate and oil content. Spray once every 5-7 days, for two consecutive applications.

Note: Sesame, also known as zhi ma or hu ma (scientific name: Sesamum indicum), is the seed of hu ma, an annual erect herbaceous plant, 60-150 cm tall. It is found throughout the world's tropical regions and some temperate regions. Sesame is one of China's major oil crops and has high application value. Its seeds have an oil content of up to 55%. Since ancient times, China has had many kinds of foods and delicious dishes made with sesame and sesame oil, which have long been renowned throughout the world.

Sesame is known as the champion of the eight grains. Sesame is an oil crop, and the oil extracted from it is called sesame oil, hu ma oil, or xiang you. It is characterized by a mellow aroma and can be used both raw and heated.