Land suitability study for sweet sorghum (Sorghum bicolor (L.) Moench) farming in Pleret Yogyakarta

Marginal land and geological disaster-prone in the Opak Fault zone area need to be studied for the basic potential for the development of multi-purpose crops for food, feed, and renewable energy. The study was aimed to determine the potential of the soil and evaluate the suitability of the land for sweet sorghum (Shorgum bicolor) crop in Gunung Kelir, Pleret District, Bantul, Yogyakarta as part of the Opak Fault line. A total of 20 sample points were collected based on geological data, land use, slope, and administrative maps. Analysis of soil physical and chemical properties was carried out to classify soil types and land suitability for sweet sorghum plants. The developing soils in the study area were originated from volcanic breccias, Young Merapi Volcano, and the alluvial of the Opak River, with included in orders of Entisols and Inceptisols. The cation exchange capacity of soils that develop from volcanic breccias is higher than those that develop from Merapi volcanic soils. Suitability of land for sweet sorghum plants includes S2 class with limiting factors for nutrient retention, temperature, and erosion hazard area of +/- 24,011 Ha (76.23%), S3 class with limiting factors for erosion hazard and surface stonies of +/- 3.85 Ha (12.22%), and N class with a root zone constraint of +/- 0.139 Ha (0.44%), and others are not agriculture. Based on the results of this study it is expected that sweet sorghum is able to be developed in the Opak Fault zone to enhance the use of marginal land.