Reduction of Irrigation and Pruning leaves for Solar Radiation Use Efficiency of Maize in Dryland

Abstract

In Indonesia, maize (Zea Mays L.) is cultivated mostly on the dry land, where water is the main limiting factor for production. Thus, it is necessary to develop the efficient cultivation techniques in terms of water use. The objective of this study was to evaluate the effect of the reduction of irrigation and pruning leaves below the cob on the ability of plants to intercept solar radiation for growth, and for radiation and water use efficiency (RUE and WUE) and maize productivity. Irrigation treatments for crop water requirement is conducted on 3 levels, namely 100% fulfilment of the total water requirement for one growing season (DI 100%), the reduction of 20 and 40% of the total crop water requirement (DI 80% and DI 60%). While pruning is conducted by the time plants have entered the generative phase with 3 level of treatments, i.e. without pruning (P0) as a control, and prunning of 3 and 6 leaves below cob (P3 and P6). Radiation use efficiency (RUE) treatments DI 80% (3.2 g MJ-1) was not significantly different from treatment DI 100% (3.1 g M-1), is greater than the RUE treatments DI 60% (2.6 g MJ-1). RUE P0 treatment (3.1 g MJ-1) was not significantly different from treatment RUE P1 (3.0 g MJ-1), both higher than the P6 RUE treatment (2.7 g MJ-1). These results indicate that the reduction of 40% of the total crop water requirement or trimming 6 below cob leaf can decrease the RUE. Plant productivity on DI 100% treatment (7.0 ton ha-1) was the highest. Plant productivity on DI 80% treatment (6.6 ton ha-1) was not significantly different from DI 60% and DI 100% (6.2 ton ha-1). WUE treatment DI 60% (0.74 kg m-3) significantly higher than WUE treatment DI 80% (0.59 kg m-3) and WUE treatment DI 100% (0.50 kg m-3). The results showed that the reduction of irrigation up to 40%, could reduce the crop productivity because of crop water requirements are not fulfilled optimally. Nonetheless, the reduction of irrigation can be applied as an efficient cultivation techniques in terms of water use so that the sustainable production and conservation of water resources can be achieved.