Kajian Struktur Tanah Lapis Olah: I. Pengaruh Pembasahan dan Pelarutan Selektif terhadap Agihan Ukuran Agregat dan Dispersitas Agregat = A Study of Surface Soil Structure: I. The Effect of Prewetting and Selective Dissol

The objective of this research was to study the aggregate size distribution and aggregate dispersion of top soil as affected by prewetting and selective dissolution. Soil samples were pretreatment with rapid, slow, and alcohol wettingand pyrophosphate, oxalate, and dithionitecitrate dissolution. After treatment, soil sample was determined the aggregate size distribution by wet sieving methods and aggregate dispersion by sedimentation methods. The results showed that aggregate size distribution was affected by prewetting and selective dissolution. Rapid wetting produced small aggregate more than slow wetting and alcohol wetting. Soil aggregate were destroyed by selective dissolution and produced about 80-90% particle less than 100 mm. Vertisols had highest aggregate size distribution, followed by Inceptisols and Alfisols. The aggregate size distribution up to 2.0 mm of Vertisols were 73.36%, Inceptisols were 71.47% and Alfisols were 55.84%. The natural dispersion of aggregate less than 100 mm by slow wetting and alcohol wetting of Vertisols were 14.67% and 14.60%, AlfisolS were 12.76% and 10.86% and Inceptisols were 11.66% and 10.38%, respectively. Keywords: aggregate dispersion â aggregate size distribution, âpre-wetting â selective dissolutio