2022 年 32 巻 S 号 p. 221-226
In drylands, salt accumulation due to excessive irrigation and poor drainage negatively affects agricultural production. Water saving and drainage system improvement can effectively prevent salt accumulation. However, drip irrigation and subsurface drainage require initial and maintenance costs, making them difficult for farmers in developing countries.
As a low-cost and simple technique to improve drainage function, a new subsoil breaker called cut-soiler, which fills channels at 40-60 cm depth in soil with crop residues and functions as a filter, was developed in Japan. In a previous study, cut-soiler contributed to the improvement of fields with poor drainage in Japan. However, its salinity control benefits for drylands are unknown. Therefore, this study aimed to experimentally demonstrate cut-soiler on salt-affected soil in India.
A lysimeter experiment (2 m squares) was conducted to evaluate the saline soil remediation with and without cut-soiler plots during the dry and rainy seasons from October 2018 to August 2019. The calculated saturated EC (EC(c)) was continuously monitored by dielectric soil moisture sensors (5TE) to investigate its dynamics. The results showed that the EC(c) peak with cut-soiler at 12 cm depth, after irrigation during the dry season, was 18.7% lower than that without cut-soiler. In the rainy season, the EC(c) with cut-soiler at 50 cm depth decreased in response to rainfall and was 38.2% lower than that without cut-soiler. These results indicate that salts were dissolved by irrigation or rainfall and the infiltration water containing dissolved salts flowed through the outlet pipe of the cut-soiler.
