When is the best time to fertilize the oilseed crop sesame? What fertilizer should be applied? Roughly how much fertilizer is needed per mu? (Including fertilization methods for each stage)

Sesame is the seed of flax, divided into black and white types, and each type has different effects. Because it can be pressed for oil and used as a seasoning, it is widely cultivated. But to achieve high sesame yields, in addition to basic management work, you also need to master the fertilization amount well. So when is the best time to fertilize sesame? What fertilizer should be applied? Roughly how much fertilizer is needed per mu?

During the growth process, sesame needs a lot of fertilizer, and it must be fertilized at almost every stage. When fertilizing, attention should be paid to combining nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer, organic fertilizer, inorganic fertilizer, etc., to promote rapid growth and high yields in sesame. The specific fertilization times are:

1. Topdressing at the seedling stage. For topdressing at the seedling stage, furrow application in bands is best. Under conditions of poor soil, insufficient base fertilizer, and weak seedling growth, a small amount of seedling-promoting fertilizer can be applied first, with diluted decomposed human manure and urine or urea giving better results. Seedling-stage topdressing should be carried out after thinning to a stand. For branching-type varieties, before branching; for single-stem-type varieties, before budding, 2.5 kg of urea or 1500-2000 kg of human and livestock manure and urine can be used per 667 sq m. If the soil is fertile, the base fertilizer is sufficient, and the seedlings grow vigorously, then no topdressing is needed at the seedling stage.

2. Topdressing at the budding and early flowering stage. Topdress 1-2 times during the flowering period. If the soil has good fertilizer retention and supply capacity, topdress once at the early flowering stage; otherwise, topdress twice at the budding and early flowering stage, and apply once more during the flowering and capsule-setting stage. The time should be early rather than late. Generally, apply 6-8 kg of urea, or 15-25 kg of ammonium sulfate, or 15-35 kg of ammonium bicarbonate, or 2000-2500 kg of human and livestock manure and urine per 667 sq m. In plots lacking boron in the soil, boron fertilizer should be added. In addition, at the initial flowering stage of sesame, about 100 kg of plant ash or about 10 kg of potassium chloride can be broadcast per 667 sq m.

3. Topdressing at the flowering and capsule-setting stage. Applying an appropriate amount of quick-acting nitrogen fertilizer and phosphorus fertilizer gives better results. Applying 7.5 kg each of ammonium sulfate and superphosphate per 667 sq m can increase yield by 30%. At this stage, topdressing should be early rather than late, and at the latest should not be later than the full flowering stage; if topdressing is too late, and if there is rainy weather, it is easy to cause excessive vegetative growth and delayed maturity, worsening disease. Therefore, in order to fully bring out the yield-increasing effect of fertilizer, sesame topdressing should be combined with field management such as intertillage, earthing up, and watering.

4. Foliar fertilization. Spraying boron, phosphorus, and potassium fertilizers on the leaves can significantly increase sesame yield. Spraying 1%-2% urea solution or 0.1%-0.5% monopotassium phosphate 1-2 times at the initial flowering stage and early full flowering stage has an obvious yield-increasing effect; spraying a mixed solution of 0.1% boron fertilizer and 0.3% monopotassium phosphate on the leaves during the flowering stage can increase grain weight; sesame is relatively sensitive to manganese fertilizer, and commonly used manganese fertilizers include manganese sulfate and EDTA chelated fertilizer, with foliar spraying 7-10 days before budding giving better results; iron fertilizer is mainly ferrous sulfate or chelated iron fertilizer, and iron fertilizer is best applied by foliar spraying, with a commonly used concentration of 0.1%-0.5%.

How should fertilization be done?

When drilling, open a furrow about 10 cm from the sesame plants and apply in bands or in spots, placing it into a 10 cm deep soil layer to facilitate root absorption, then cover with soil after application. According to experiments, when the same fertilizer is applied per mu, shallow application (10-13 cm) increases yield by about 11% compared with deep application (25 cm). In the case of broadcasting, decomposed cake fertilizer or granular urea can be mixed with soil and broadcast, followed immediately by intertillage and loosening the soil to cover the fertilizer. In dry weather, water should be sprayed after application to fully bring out the fertilizer effect.

Roughly how much fertilizer is needed per mu?

1. Fertilizer requirement pattern

Generally, for every 50 kg of sesame produced, it is necessary to absorb 4.5-5 kg of pure nitrogen, 1.25 kg of phosphorus pentoxide, and 5-5.2 kg of potassium oxide.

2. Base fertilizer

Fertilization plan for a target yield of 75 kg of sesame per mu: 1500 kg of farmyard manure, 15-20 kg of superphosphate, 3-4 kg of potassium sulfate or potassium chloride (potassium fertilizer may be omitted on lime concretion black soil, the same below), 2-3 kg of urea or 10-15 kg of ammonium bicarbonate.

Fertilization plan for a target yield of 100 kg per 667 sq m: 2000 kg of farmyard manure, 30-35 kg of superphosphate, 4-5 kg of potassium sulfate or potassium chloride, 4-5 kg of urea or about 15 kg of ammonium bicarbonate, 1 kg of zinc sulfate or 0.2 kg of borax.

Fertilization plan for a target yield of 125-150 kg per 667 sq m: 2000-2500 kg of farmyard manure, about 50 kg of superphosphate, 4-5 kg of potassium sulfate or potassium chloride, 5-10 kg of urea or 20 kg of ammonium bicarbonate, together with boron, zinc, and other trace element fertilizers.

Among these, boron fertilizer is usually borax, which can be applied as base fertilizer, topdressing, or seed fertilizer. As base fertilizer, generally apply 0.5-0.7 kg per mu; for seed dressing, the usual amount is 0.4%-0.6% of the seed weight; for seed soaking, the liquid fertilizer concentration is 5%, and the soaking time is 20-24 hours; for root-zone topdressing, it is best to spray 2-3 times from the initial flowering stage to before full flowering, at a concentration of 0.1%-0.2%.

Zinc fertilizer is commonly zinc sulfate, applied as a base application at 1-2 kg per mu, and for seed dressing at 4-6 grams per kg of seed. If sprayed on the leaves, the concentration is 0.1%-0.5%, and spraying at the bud stage gives better results, that is, spraying 25-30 days after emergence.

Manganese fertilizer is commonly manganese sulfate. Manganese fertilizer should be applied early. If manganese fertilizer is applied in the middle and late stages, it is very difficult to correct manganese deficiency. Generally, apply 0.5-0.75 kg per mu as a base application, and for seed dressing use 6-7 grams of manganese sulfate per kg of seed. Foliar spraying of liquid fertilizer gives better results 7-10 days before budding.

If the soil organic matter content is high, farmyard manure may also be omitted, and corresponding amounts of compound fertilizer or other chemical fertilizers may be used directly as base fertilizer. On acidic soil, applying an appropriate amount of quicklime, plant ash, etc. as base fertilizer can neutralize soil acidity and improve soil physical properties.

3. Seed fertilizer

Generally, apply 5-8 kg of well-decomposed cake fertilizer, 2 kg of bone meal, 2 kg of urea, and about 500 kg of miscellaneous soil manure per 667 sq m. Each kg of seed needs to be mixed with 1 gram each of ammonium molybdate or rare earth. When sowing, first dissolve ammonium molybdate in a small amount of water, or dissolve rare earth in acidic water, then wet-mix the seeds in a container or spray while mixing, and after mixing evenly and drying in the shade, they can be sown.