Weed emergence is among the most important problems in system of rice intensification (SRI) due to extensive planting geometry of at least 25 × 25 cm and moist environment, thereby leading to water loss by means of evaporation from the broad space as a result of the extensive planting geometry, and transpiration by the weeds. This reduces the additional water saving which affect the potential of SRI water productivity. It also reduces rice crop yields up to 70% if there is no weed control attempted. Nowadays, weed is being controlled by manual weeder which is labour demanding, while motorized weeders overcome the problem but still, it able to remove the weeds before rice canopy closure or 30 days after transplanting (DAT). This research was designed to evaluate the performance of UMAR-SRImat on soil moisture conservation and weed control. UMAR-SRImat was made using flaked rice straw and biodegradable adhesive. The design was laid out using randomized complete block design (RCBD) with three treatments [without soil cover (T1), SRImat (T2), UMAR-SRImat (T3)] and three replications. The analysis was conducted using analysis of variance (ANOVA). Volumetric moisture content (VMC) was determined at 18 and 25 DAT. Weeds were observed and recorded to determine the weed dry weight and weed control efficiency at 20, 40 and 60 DAT. Plant height per hill was measured at 30 and 50 DAT, likewise, the number of tillers were counted at 30 and 50 DAT. The result of VMC showed that UMAR-SRImat significantly conserved water higher than the control treatment at 18 and 25 DAT of 3100.0a and 2680.0a m3/ha, respectively. The effectiveness of UMAR-SRImat mulched was 100% at 20 DAT 99.64% at 40 DAT and 97.99% at 60 DAT. This research revealed that UMAR-SRImat mulch could retain soil moisture and suppressed weeds up to 60 DAT.
Planting Geometry and Herbicides for Weed Control in Rice: Implications and Challenges