抄録
Five series of experiment were conducted to determine a proper method of estimating the yield for a missing stand in sweet potato plot experiments of diffierent varieties under different cultivation methods and growing seasons. It was ascertained that there were no differences in the degree of increase in yield of the neighbouring plants of the vacant stand throughout the various conditions, so that the author considered of a method of estimating the yields of the missing plants as follows. As soon as vacant stands have been discovered, they should be replanted. But, regardless whether they were replanted or not, we may as well measure the average of the yields of the nighbouring two plants in the row and the average of ten plants taken at random from that plots excluding the two plants mentioned above and border plants. Compare the two average values thus obtained, x^-' for two plants and x^- for ten plants, and, when x^-' is larger than 1.5x^-, equal to(1.0∼1.5)x^-, or smaller than 1.0x^-, the missing value may be estimated as zero, (1.0∼1.5)x^- or 1.0x^- for the respective cases.
