Abstract
The “Cut-soiler” is a low-cost and easy to adopt technology developed in Japan for improving poor drainage condition in farmland. It is attached to a tractor and is used to make shallow subsurface drainage into the soil with depths of 40-60 cm by filling with crop residues. Construction of the drainage by Cut-soiler may contribute in mitigating soil salinization through physical destruction of soil structure and improvement of drainage efficiency in farmland. The purpose of this study is to clarify the effect of the subsurface drainage constructed using Cut-soiler on mitigation of soil salinization in India. We investigated the crop yield after the construction and monitored the fluctuation of soil water and soil solutes using the dielectric moisture/salinity sensors in salt affected farmlands.
This study was conducted in experimental fields located in Hariyana State of India. We set four Cut-soiler treatments installed at 60 cm soil depth at intervals of 2.5, 5.0, 7.5 and 10 m for the subsurface drainage and one treatment without construction, with three replicates for each treatment. The Cut-soiler was operated in June 2018. Monitoring was conducted using GS3 Greenhouse Sensor (METER Inc.), a dielectric moisture/salinity sensor with digital data logger (Em50, METER Group, Inc.), in plots with subsurface drainage at 2.5 m and 7.5 m intervals and in plot without subsurface drainage. The experimental field was cultivated with pearl millet during the rainy season (July-October) and mustard during the dry season (October-April) from 2018 to 2020.
The yield of pearl millet was highest in non Cut-soiler treatment immediately after the construction but the yield for the following year under construction was higher than under non-implementation, and the highest yield was obtained under 2.5 m interval. There was no increase in the yield of mustard due to poor germination rate but the highest yield was obtained under 2.5 m interval among all treatments. Monitoring by the sensor during pearl millet cultivation showed that electrical conductivity of soil pore-water (ECp) in 2.5 m and 7.5 m intervals was lower than in non Cut-soiler treatment. In addition, the monitoring during mustard cultivation showed that increased ECp eventually dropped after rainfall and irrigation only in 2.5 m and 7.5 m intervals.
Therefore, the subsurface drainage constructed by Cut-soiler can contribute to decrease soil salinity level and increase crop yield in salt affected farmlands.
