Abstract
Excess soil moisture damage of wheat has a serious impact on wheat productivity in Kitakami city, in Iwate prefecture, Japan, where farmers in upland areas break furrows and unite some small fields to raise cultivation efficiency. To evaluate the effectiveness of open ditches and underdrains for wheat productivity at the field where have a risk of excess soil moisture damage, we conducted an on-site experiment. The four targeted fields were two with open ditches, one with underdrainage, and one with no treatment (control). Estimation of field yield using a yield monitoring combine harvester estimated the field yields, revealed greater than 25% higher yields with open ditches and underdrainage than that of the control field. Unattended Aerial Vehicle (UAV) images showed the wheat growth changes caused by soil moisture damage, with variations corresponding to the yields. The results showed that open ditch and underdrain systems improved the drainage and crop growth proving the benefit for crops threatened by excess soil moisture damage. The targeted fields had some gentle slopes caused by the breaking of furrows, leading to low soil fertility and depressions with insufficient drainage. The wheat planted in these fields showed poor growth by the Digital Surface Model (DSM). The yield monitoring combine harvester and UAV remote sensing provided labor-saving means for evaluating on-site experiments. Local constraints on farmer fields such as soil heterogeneity need to be removed. Further verification is required to determine the usefulness of open ditches and underdrainage for application in this and other regions.
