Determination of Planting Patterns Based on Land Suitability Test in the Tanjung Baik Budi Swamp Irrigation Area, Ketapang Regency

Abstract

Tidal lowlands offer considerable potential for rice cultivation; however, soil acidity, shallow pyritic layers, drainage constraints, and seasonal water-level fluctuations present significant challenges to sustainable agricultural management. This study aimed to determine suitable rice cropping patterns for the Tanjung Baik Budi Swamp Irrigation Area in Ketapang Regency, West Kalimantan, Indonesia. A descriptive-evaluative approach was employed, integrating spatial, quantitative, and qualitative analyses across a study area of 935.04 hectares. Land suitability was assessed based on soil texture, soil pH, depth to pyritic layers, hydrotopographic conditions, and drainage characteristics using field observations and geographic information system (GIS) overlay analysis. The assessment was integrated with water management zoning, irrigation and drainage network evaluation, and monthly water availability and crop water requirement calculations. The results indicated that 825.00 hectares (88.23%) were classified as moderately suitable (S2), while 110.04 hectares (11.77%) were classified as marginally suitable (S3) for rice cultivation. Soil acidity and shallow pyritic layers were identified as major limiting factors, highlighting the importance of controlled drainage and groundwater-level management to minimize pyrite oxidation and associated acidification. Water management zone III encompassed the largest proportion of the study area and was considered suitable for rice cultivation under appropriate water management conditions, whereas transitional and more constrained zones required additional management interventions. Seasonal water balance analysis identified potential water deficits between April and September, with the greatest deficit occurring in August. Based on the combined land suitability and water availability assessments, two rice-growing seasons were proposed, extending from October to January and February to May, followed by a fallow period from June to September for irrigation and drainage system maintenance. The findings demonstrated that integrating spatial land suitability assessment with seasonal water balance analysis provided a practical basis for developing adaptive rice cropping schedules and improving the sustainable management of tidal lowland agricultural systems.