PERTANIKA JOURNAL OF TROPICAL AGRICULTURAL SCIENCE

Rice productivity can be increased by improving land productivity with a ratoon crop of salibu system cultivated with the System of Rice Intensification (SRI) method. Rice cultivation using SRI is a method to increase the rice growth and development by managing the plants, soil, water and nutrients. Ratooning is the ability of the rice plant to regenerate new tillers after harvest. The beneficial aspects of ratoon are the increase of rice productivity and efficiency in terms of time, labour and cost. The local people of West Sumatra commonly re-cut the rice stalk at seven days after the main crop harvest. This method is called the salibu system, which is a modification of a ratooned crop that produces a higher yield than the non-salibu system (no cutting after first harvesting). The aims of this study are to analyse the physiological characteristics of ratooned rice and its agronomic performance under the salibu system using the SRI method. The Randomised Complete Block Design (RCBD) was used for the main crop to compare SRI and conventional methods, while RCBD with the factors of cutting technique and cultivation methods was used for the ratooned crop. The cultivation methods were SRI and the conventional methods, while the cutting technique was the salibu vs the usual (non-salibu) systems. The results indicate that the main crop under SRI was found to have a greater photosynthetic rate and higher vegetative and reproductive parameters than plants cultivated under the conventional method. The above trends were also observed in the ratooned crop for SRI using the salibu sytem compared with other combinations of cutting and cultivation methods. There was no interaction between cutting technique and cultivation method in the ratooned crop. The main crop yield using SRI was 24% higher than using the conventional method. Subsequently, the ratoon-crop yield under the salibu system using SRI was approximately 50% of the main crop. The ability of rice plants to produce a ratoon crop was highly influenced by their carbohydrate content and the phytohormones that remain in the intercalary meristem tissues of stubble after harvest. Furtheremore, better yield of the ratooned crop is possible by increasing fertilisers (especially nitrogen), as could be done in future research into ways of improving this innovation.