Effect of Planting Work on Resistance to Slaking Collapse of Irrigation Facilities at Paddy Fields in Ghana

Abstract

In inland valleys of Ghana, it is necessary to develop low-cost irrigation facilities that can be constructed, maintained, and sustainably managed with the technological know-how of local farmers. For this purpose, we developed a reinforcement technology for irrigation facilities at paddy fields such as the levees and irrigation canals by implementation of planting works. The soil hardness greatly fluctuated within 7.3 - 27.8 mm in the facilities with no vegetation, and the soil water content varied widely from 4.3 to 37.1% regardless of the presence or absence of vegetation depending on the plant species. In addition, the irrigation facilities with implemented planting work showed significantly greater resistance to slaking collapse than those without vegetation in both cases of flooding and inundation. It was demonstrated that the vegetation would reinforce the irrigation facilities in the mechanical properties of the civil engineering structure to prevent slaking collapse. Moreover, in ascending order of the collapse grade, the root fresh weights of 4.71 g in Chrysopogon aciculatus, 2.07 g in Stenotaphrum secundatum and 2.05 g in Cynodon dactylon were included in test samples. The root weight was indicated the possibility to become quantitative estimation for resistance to slaking collapse.