Invention of “Double Depth Seeding” Technology for Improving Plant Emergence and Evaluation of Practicality in Sesame

Abstract

Plant emergence isinhibited by factors such as drought and soil crust. These factors vary depending on weather conditions. Emergence rate and proper seeding depth are significantly affected by precipitation conditions before and after seeding.The method of sowing more seed and manually thinning as a countermeasure is labor-intensive and difficult for field crops. Sincesmall-seeded crops are particularly susceptible to emergence inhibition, setting proper seeding depth based on weather conditions is important. However,prediction of post-seeding weather conditions is difficult. Therefore, I inventedthe “double depth seeding method.” In this method, seeds are sownalternately in shallowand deep soil with half the space of the rows to be cultivated, and then the rows with poorer plantemergence are thinned out by intertillage.In this study,double depth seeding of sesame was conducted 38 times under various weather conditions in the field and emergence rateswere investigated.As a result, there were three different patterns depending on weather conditions:1) only the emergence rate in the shallow plot was high, 2) only the emergence rate in the deep plot was high, and 3) there was little if any difference.Based on the posterior distribution of emergence rate and the occurrence rate of weather pattern, the emergence ratein the test area was simulated. The results showed that the probability of achieving the target value (45% to 75%)was 59% for the shallow sowing only and 54% for the deep sowing only, while it was 81% for the doubledepth seeding, indicating the practicality of the method.