Key Techniques for Intercropping Sweet Potato with Sesame

Sweet potato is a vining crop with a low light-receiving position. When intercropped with sesame, which has a high light-receiving position, it forms a well-layered crop community, thereby improving light energy utilization. Generally, without reducing sweet potato yield, it increases sesame seed income by 30-40 kg per mu. This planting method is suitable for all sesame-producing regions.

1. Planting methods (1) Sweet potato is cultivated with plastic film mulching. When preparing the land, form ridges with a height of 10-12 cm, a top width of 60 cm, a bottom width of 80 cm, and a ridge spacing of 40 cm. Sweet potato seedlings are raised 7-10 days earlier than usual according to conventional practice. Around late April, when the soil temperature at a depth of 5 cm under the film reaches above 15°C and no major weather changes are expected in the coming days, seize the time to quickly transplant the sweet potato, with a density generally of 3500-4000 plants. Around late May, dibble 2 rows of sesame in the ridge spacing at a plant spacing of 15-20 cm, with a sowing rate of 150-200 g per mu. (2) For open-field cultivation of sweet potato, the row spacing is 72-78 cm and the plant spacing is 23-26 cm. Sweet potato is transplanted early at the appropriate time according to local climatic conditions. Around late May, plant 1 row of sesame between the sweet potato rows, with a plant spacing of about 20 cm, leaving 2 seedlings per hole.

2. Key cultivation techniques (1) For sweet potato, it is advisable to choose short-vine varieties that form tubers early. For plastic film mulching, it is advisable to choose Liaoshu No. 40, Shandong Fengshoubai, 131, etc. For sesame, choose varieties with high yield potential, early maturity, and strong stress resistance, such as Zhongzhi No. 7, etc. (2) Fertilization should be mainly farmyard manure, supplemented by chemical fertilizers; mainly base fertilizer, supplemented by topdressing. Therefore, before land preparation for sweet potato, apply 3000-4000 kg of high-quality farmyard manure per mu, about 15 kg of diammonium phosphate, and 50-75 kg of plant ash to meet the growth and development needs of sweet potato and sesame. (3) Before sowing sesame, use methods such as winnowing to carefully clean the seeds, and use plump, healthy grains with a high germination rate as seed. Also pay attention to improving sowing quality, keeping sowing depth consistent (generally 1.5-2 cm deep), pressing the soil after sowing, and strengthening seedling-stage management, so as to create conditions for strong sesame seedlings to emerge early and prevent sesame from forming weak seedlings or leggy seedlings due to the influence of sweet potato. The mid-to-late stage management of sesame is the same as that of ordinary fields. (4) Other management of sweet potato can refer to plastic film mulching cultivation or open-field cultivation management.