What are the key management techniques for increasing sesame yields?
In order to help farmers increase production and income, the sesame field management techniques are summarized below for reference.
1. Promptly break up soil crusting. After sesame is sown, heavy rain followed by sudden clearing often occurs, causing surface soil crusting, which suffocates the seeds and is unfavorable for seedling emergence, so it should be broken up promptly. The method is, on a clear day after rain, when the surface soil turns white and moisture is suitable, to shallowly hoe and loosen the soil, or use a spike-tooth harrow to lightly harrow perpendicular to the sowing rows to break the hard surface crust. The breaking should be done early, with good soil moisture, and the harrow should press lightly, so as to avoid causing artificial gaps in the seedlings.
2. Check seedlings and fill gaps. After sesame is sown, if emergence is incomplete, measures should be taken immediately. For severe gaps, re-sow early; for partial gaps, promptly pregerminate the same variety and replant, so that late-planted small seedlings are not shaded by larger ones and grow poorly; for a small number of gaps, when sesame has 4-5 pairs of true leaves, combine with thinning to transplant seedlings with a trowel, keeping soil around the roots.
3. Thin and fix seedlings in time. After sesame emerges, timely thinning and fixing of seedlings can save soil moisture and nutrients, allow seedlings to grow steadily, and prevent "seedling overcrowding" from causing yellow, thin, spindly seedlings that reduce yield. The first thinning should be early, when the 1st pair of true leaves appears, followed by 1-2 more thinnings, and fix the seedlings when 3-4 pairs of true leaves appear. If continuous rain makes it impossible to thin and weed with a hoe, carry out hand thinning and rush to fix the seedlings.
4. Intertillage weeding and earthing up. Sesame grows slowly in the seedling stage, with young and small roots, and weeds easily grow in the field. Intertillage weeding not only eliminates weeds but also loosens the soil, improves aeration, and preserves moisture. From emergence to before first flowering, 3-4 intertillage weedings are needed. Generally, carry out the first intertillage when the first pair of true leaves appears. When 2-3 pairs of true leaves appear, intertill again. The first intertillage should be shallow, generally just breaking the soil surface; the second should be deep; later intertillage should be shallow rather than deep, with special care not to damage the roots. Do not hoe before rain, always hoe after rain, and hoe whenever there are weeds. Frequently check and pull out weeds around the plants, and stop intertillage after the rows close. Combining intertillage with earthing up around the roots helps drainage and prevents waterlogging and lodging.
5. Scientific topdressing. According to the fertilization patterns of sesame, the topdressing principle is to apply seedling fertilizer early, apply heavily before flowering, and supplement during flowering. In the seedling stage, for fields with small or weak seedlings, generally after fixing the seedlings apply 2-3 kg of urea per mu; when drought is severe, first relieve the drought and then topdress, or apply diluted thin human manure as irrigation. From squaring to early flowering, combine with intertillage and earthing up to apply in concentrated bands or holes, applying 5-8 kg of urea per mu. During flowering, spray a mixture of 0.2% boron fertilizer and 0.3% potassium dihydrogen phosphate to increase yield. Spraying fertilizer should preferably be done on a clear afternoon, avoiding the effects of high temperature and dry wind as much as possible, reducing losses from evaporation, promoting absorption, and improving fertilizer efficiency.
6. Drought resistance and drainage. Sesame is very sensitive to water, fearing waterlogging yet also unable to lack water. Too much or too little water is unfavorable to sesame growth and development, and may even reduce yield or cause total crop failure. Ditches should be cleared in time to ensure smooth drainage and irrigation, so that after rain stops the furrow ditches dry.
7. Control diseases and pests. To ensure sound development of sesame throughout the growth period, generally spray once each in the seedling stage or flowering stage with 50% carbendazim (kejunjing) 800-fold solution to control sesame diseases.
8. Top at the right time. Timely topping can inhibit late-stage terminal growth, reduce nutrient consumption, allow nutrients in the plant to be redistributed, prolong the functional period of green leaves, and concentrate nutrients on filling grains and increasing weight, reducing empty tips. Topping is generally done in the middle of full flowering; for summer sesame, generally 10-20 days after first flowering. Method: pinch off the top 1-3 cm growing point by hand, lightly topping strong plants and heavily topping weak ones. Strictly prohibit removing leaves in the late stage.