2022 Volume 91 Issue 3 Pages 356-365
Vegetable soybean, cultivated in the Nakakawachi region in Osaka Prefecture, is highly regarded as a special vegetable soybean in Japan. Understanding yield variability, and environmental factors that influence yield, are important for stably producing high quality vegetable soybeans. The objective of this study was to determine the respective effects of soil properties, including physicochemical and biological parameters, on agronomic traits of vegetable soybean cultivated under greenhouse conditions in the Nakakawachi region targeting 18 fields in the 2017 to 2018 season. Substantial differences in vegetable soybean yield were observed among fields, and the yield ranged from 299 to 968 kg/10 a. Regarding agronomic traits, pod production was significantly correlated with total node number, the number of branches and pods, while cultivation duration was also positively correlated with the market base pod yield. Although the nodule dry weight (DW) had no significant correlations with any agronomic traits among farmer’s fields, correlation analysis within each field frequently showed nodule DW had a positive correlation with vegetable soybean production. Regarding soil physicochemical factors, the factors influencing yield included total carbon, total nitrogen (N), and available N. Bacterial diversity in soil was evaluated at harvest of vegetable soybean in 2017. Principal coordinates analysis with 16S rRNA gene amplicon sequencing data showed fields could be divided into three groups. We assessed the correlation between vegetable soybean yield and the relative abundance of each bacterial family, resulting in significant correlations of some bacterial families with pod production. This study provides information on soil chemical factors that led to stable production of vegetable soybean cultivated in the Nakakawachi region.
