Detailed Explanation of Key Points for High-Yield Cultivation Techniques of Summer Sesame

Sesame belongs to the Pedaliaceae family, genus Sesamum, an annual herbaceous plant that prefers warmth, and its varieties include both black and white types. Besides being used for food, sesame oil is also a high-quality raw material for several daily-use industrial products and a lubricant and protective agent for the machinery industry, and its by-products are all good feed and fertilizer. In short, growing sesame well is of great significance for improving people's lives, developing industry and agriculture, supporting the country's socialist construction, and increasing the collective economy. In China, sesame cultivation is divided by sowing season into spring sowing, summer sowing, and autumn sowing, with summer sowing being the most common. The main growing areas are Zhumadian City in Henan Province, Anhui, Hubei, Shanxi, and others. The cultivation techniques for summer sesame are summarized below.

1 Fine land preparation

First, soil that is loose and fertile should be selected. Before planting, stubble should be cleared and the land prepared, with fine plowing and careful harrowing to ensure the field soil is fine, crumbly, level, and clean. Then beds should be made; the width of the beds and the depth of the ditches should be determined according to the terrain and soil quality. The length of the beds and the width and depth of the ditches should be determined by the size of the sesame planting area and the terrain, so as to achieve the goal of "irrigating when dry, draining when waterlogged." Ditches should be interconnected so that drainage is unimpeded, thus maintaining soil moisture.

2 Applying sufficient base fertilizer

Sesame has a short growth period, and its fertilizer demand period is relatively concentrated. Applying more base fertilizer is one of the fundamental measures for laying the foundation for a high sesame yield. The ratio of pure nitrogen fertilizer, phosphorus pentoxide, and potassium oxide required by sesame is 1:0.6-1:1. However, base fertilizer should mainly be farmyard manure, because farmyard manure has relatively comprehensive nutrients, and its fertilizer effect is released slowly and lasts long, while also promoting the activity of soil microorganisms. If decomposed calcium superphosphate, phosphate rock powder, bone meal, and an appropriate amount of ammonium sulfate and other fertilizers are also applied, the effect will be even better.

3 Timely sowing

Sesame is a warmth-loving crop, and the growth period of summer sesame is 90-105 d. If the temperature drops in the later stage, it will directly affect the sesame yield. Summer sesame is highly seasonal, and the key to increasing yield lies in seizing the time to sow as early as possible. In order to sow early, emphasis should be placed on harvesting, plowing and harrowing, sowing, and compacting to preserve soil moisture all in immediate succession. Strive to ensure that "the stubble does not stay overnight, and the field is not sown past noon." Therefore, sowing summer sesame from Xiaoman to Mangzhong is relatively suitable. Strive for early sowing, and at the latest it should not be later than Xiazhi, just as the farming proverb says: "Sow sesame at Xiaoman, and you can harvest 1 dan 8 per mu; sow sesame at Xiazhi, and you will have only a handful of flowers on top."

4 Sowing rate

There are 3 sowing methods for sesame: drilling, broadcasting, and dibbling. Generally speaking, drilling and broadcasting require a larger sowing rate than dibbling. However, each sowing method has its advantages and disadvantages. The sowing method should be adapted to local conditions and not followed rigidly; it should be determined according to the size of one's own sowing area and the terrain conditions. The sowing rate per mu is generally kept at 0.25-0.75 kg. Clay soil makes seedling emergence difficult, so the seed rate should be somewhat higher than for sandy loam; under conditions such as poor seed quality and low germination rate, the sowing rate should be appropriately increased.

5 Thinning and final singling of seedlings

Farming proverb: "If you want to eat sesame oil, first break the cross-shaped head." 3-5 d after sesame emerges, when the first pair of opposite true leaves grows, the people call it the "cross." At this time, the 1st thinning is carried out; when the second and third pairs of true leaves appear on the sesame, the 2nd thinning is carried out, at which time weak seedlings should be removed and strong seedlings retained, and preliminary final singling should be given. In order to prevent pests, diseases, and mechanical damage during thinning and final singling, it is advisable to carry out thinning and final singling in 3 operations, that is, first thinning, second thinning, and third final singling. The method is: "where sparse, keep dense; where dense, keep sparse; where neither sparse nor dense, keep strong seedlings." Make sure to keep them evenly spaced, keep them dense enough, and do not keep double-plant seedlings.

6 Intertillage and earthing up

Farming proverb: "Three scratchings at the sesame flowering stage." When the first and second pairs of true leaves appear on sesame, carry out the first intertillage, but hoeing the surface soil is suitable as the first scratching; when the third pair of true leaves appears, carry out the second intertillage, and this time deep cultivation of 3-6 cm can be done as the second scratching; when the fourth to fifth pairs of true leaves appear, carry out the third intertillage and earthing up, and at this time the intertillage depth can reach about 8 cm as the third scratching. During the second and third intertillage and earthing up, the functions of weed removal and covering the roots should be achieved, which is beneficial to root growth, beneficial to draining accumulated water from the field and preventing waterlogging damage, beneficial to reducing the occurrence of diseases, and also beneficial to inhibiting the growth of weeds around the roots and preventing lodging, and so on.

7 Scientific water use

During its growth period, sesame is extremely sensitive in its response to water demand; it cannot endure prolonged drought or waterlogging. The water requirement of sesame at the seedling stage is relatively small. If soil moisture at sowing is good, it can already meet the water requirement, so watering may not be necessary. However, upon entering the flowering and capsule-setting stage, it is extremely sensitive to water requirements. At this time, it fears both waterlogging and drought, so attention must be paid to timely watering when drought occurs and timely drainage when waterlogging occurs. By the topping stage, the water requirement gradually decreases. If moisture is maintained relatively well during the flowering and capsule-setting stage, then irrigation is generally not needed at this time.

8 Foliar topdressing

From the early flowering stage to the full flowering stage, sesame has a relatively large fertilizer requirement. To prevent fertilizer deficiency at this time, it is most suitable to apply quick-acting nitrogen fertilizer before the early flowering stage. During the budding and flowering stage, sesame's demand for phosphorus and potassium nutrients increases noticeably, but at this time field topdressing cannot be carried out, so spray topdressing is more suitable. For example, use 0.25 kg of potassium dihydrogen phosphate, mix with 100 kg of water, and spray. After that, spray once every 3-5 d, for 3-5 consecutive times.

9 Pest and disease control

Common sesame diseases include stem spot blight, bacterial wilt, fusarium wilt, damping-off, fungal angular leaf spot, and so on.

Control methods:

① Drain waterlogging and prevent waterlogging damage;

② Reasonable crop rotation and stubble reversal;

③ Select disease-resistant varieties;

④ Chemical control: for example, use 50% thiophanate-methyl 2000-fold solution or 1:1:300 Bordeaux mixture for root spraying treatment, and other methods. Pests include cutworms, aphids, sesame hawk moths, mirids, mole crickets, and so on. For every 667 sq m, use 100 ml of 80% dichlorvos emulsion mixed with 75 kg of water for spraying, or use 40% omethoate emulsifiable concentrate 2000-fold solution for spray control.

10 Timely harvest

Sesame matures 15-25 d after the final flowering stage. Its characteristics are that the stems, leaves, and fruits change from green to yellow, and leaf drop reaches 70%-80%, while a small number of capsules also show dehiscence. At this time, it can be harvested. Then it is sun-dried, threshed, processed, and finally stored.