Analysis of the Effect of Rainfall on Lowland Rice Productivity in Southeast Sulawesi, Indonesia

Abstract

Variability in precipitation may impact water supply and, in turn, alter the efficacy of lowland rice cultivation. This research examined long-term changes in precipitation and rice yield and evaluated their statistical correlation in Southeast Sulawesi from 1990 to 2025. We assessed yearly secondary data, including 36 observations, using descriptive analysis and basic linear regression. Precipitation varied from 618.50 to 3,273.50 mm, while rice production ranged between 2.699 and 4.684 tons per hectare. The regression analysis revealed a positive and statistically significant relationship between precipitation and rice yield (R = 0.475, R2 = 0.226, F = 9.904, α = 0.003). Precipitation explained 22.6% of the observed fluctuations in production, suggesting that most productivity variance was driven by factors outside this single predictive model. Residual diagnostics showed no substantial non-normality or heteroscedasticity. The Durbin–Watson score of 0.939 suggested possible positive serial correlation, necessitating careful interpretation of the regression findings. The results suggest that precipitation influences fluctuations in lowland rice yield; however, yearly rainfall alone does not sufficiently account for productivity changes. Rice cultivation strategies in Southeast Sulawesi must therefore incorporate rainfall variability, effective water management, and other production-related factors.