Growth and yield of the Indonesian local rice variety (Oryza sativa cv. Mentik

The research was aimed to obtain the role of cow manure (CM) and rice husk biochar (RHB) on the performance of one of Indonesian local varieties that was rice cv. Mentik Susu. A 3×3 split plot experiment with a completely randomized block design was used throughout the study. The main plot consisted of three levels of CM, CM-0 = no added-CM; CM-36 and CM-72 were added 36 and 72 ton CM/ha, respectively. The sub plot was three RHB levels, RHB-3, RHB-6 and RHB-9, respectively for 3, 6 and 9 ton RHB/ha. This research was conducted from June to September 2021, experimentally in the rice fields of Ketapang Village, Susukan Sub-District, Semarang District, Central Java Province, Indonesia. It is located at coordinates 7°24'22″S - 110°36'33″E at an altitude of 613 meters above sea level. The activity of observing destructive plant samples was carried out at the Ecology and Plant Production Laboratory, Faculty of Animal and Agricultural Sciences, Diponegoro University, Semarang, Indonesia, located at 6o50′-7o10′ S - 109o35′-110o50' E. The parameters observed were plant height, number of tillers, leaf greenness, leaf chlorophyll content, carotenoid content, plant growth rate, plant dry weight, percentage of productive tillers, rice yield per hectare, and weight of 1000 grains. The data obtained were analyzed using Analysis of Variance (ANOVA). Treatments that showed a significant effect on the observed parameters were further tested using the Honestly Significant Difference (Tukey HSD) with a confidence level of 95%. The results showed that the application of 36 tons of CM/ha and 9 tons of RHB/ha was a treatment combination that provides optimal results. However, because the rice yield between the 36 ton CM/ha and 9 ton RHB/ha treatments was not significantly different to the rice yield in the 36 ton CM/ha and 3 ton RHB/ha treatment.