IMPACT OF PERMANENT BED RENOVATION PRACTICE ON IRRIGATION PERFORMANCE AND PRODUCTIVITY

Renovating permanent raised beds (PRB) generally aims to restore shape and increase water infiltration. However, their impact on irrigation performance and productivity in clay soil are unknown. Therefore, no-tillage (NT), shallow cultivation (SC) and blade loosening (BL) renovation methods were evaluated on a corn crop in clay (Vertisol). Results showed optimal irrigation performance (irrigation efficiencies and uniformity >70%) for the NT treatment and significantly lower application efficiency (Ea) for the SC and BL treatments. However, the BL treatment significantly increased the lateral infiltration thus wetted the 2 m wide beds during the normal irrigation periods. Similarly, the 0-30cm bulk density profiles of the BL treatment were significantly less than that of the NT and SC treatments throughout the experimental period. However, BL treatment has shown the potential to increase water productivity (WP) up to 7% when compared with NT treatment. Modelling showed Ea for the SC and BL treatments could be improved to effectively equal that of the NT treatment by increasing (up to double) the inflow rate (Q) and reducing (up to half) time to cut-off (Tco). Thus, the BL treatment can quickly enhance lateral infiltration in subsided wide beds in Vertisol at no significant trade-off and has the potential to enhance productivity.