Rainfall Variability and Lowland Rice (Oryza sativa L.) Productivity in Tenggarong Seberang District

Abstract

Rice (Oryza sativa L.) is a primary food crop in Indonesia, playing a crucial role in meeting the population's food needs. Its productivity is heavily influenced by climatic conditions, particularly rainfall, which serves as the main water source for rain-fed paddy fields. Rainfall variability resulting from climate change can lead to irregular rainfall distribution, thereby affecting rice crop growth and yield. This study aims to determine the impact of rainfall variability on lowland rice productivity in Tenggarong Seberang. A descriptive-analytical method was employed using secondary data, including rainfall records from the Samarinda Meteorology, Climatology, and Geophysics Agency (BMKG) and lowland rice productivity data from the Tenggarong Seberang Agricultural Extension Center (BPP) and the Kutai Kartanegara Regency Agriculture and Livestock Office. Data analysis involved the Oldeman Classification method, rainfall classification based on threshold values, and an analysis of the relationship between rainfall variability and lowland rice productivity. The results indicate that the average annual rainfall (1999–2020) falls under the Oldeman Climate Classification B1, characterized by seven consecutive wet months and an average annual rainfall of 2,414 mm. In contrast, the average annual rainfall for the 2021–2024 period falls under the E1 climate classification, featuring one wet month and no dry months, with a total annual rainfall of 2,054 mm. Based on threshold value classification, the data showed three "normal" months, two "above-normal" months, and seven "below-normal" months.   Lowland rice productivity was 5.794 tons ha⁻¹ during the 2016–2020 period, whereas it was 3.991 tons ha⁻¹ during 2021–2024, representing a 31.112% decline in productivity.