Amelioration of actual acid sulfate soils to improve soil chemical properties and rice yields

Abstract

This study aim was to determine the effectiveness of various types of ameliorant in improving soil chemical properties and rice yields in actual acid sulfate soils. The study was conducted in Tamban Baru Tengah village, Tamban Catur Subdistrict, Kapuas, Central Kalimantan, from April-September 2019. The research design used a Randomized Block Design with treatment (A1) 5 t ha-1 of lime given once at the beginning, (A2) 3 t ha-1 lime + 2 t ha-1 lime given at the rice age of 1 month, (A3) 3 t ha-1 lime + 2 t ha-1 'Porre' organic fertilizer, (A4) 3 t ha-1 lime + 2 t ha-1 rice husk ask. Each treatment was replicated 4 times. Periodic soil observations included pH H2O, EC, SO42-, Fe2+ and Al3+, plant height, tillers number, and rice yields were observed. The results showed that the ameliorant treatment was able to reduce concentration of Fe2+ at planting from 6400 ppm to 1000-1500 ppm, SO42- from 8000 ppm to 2100 to 4300 ppm, Al3+ from 16.31 cmol(+) kg-1 to 5.2-6.7 cmol(+) kg-1. Lime combined with "Porre"organic fertilizer (A3) gave the highest rice yield (>17% higher than A1). The use of "Porre"organic fertilizer was able to reduce the use of lime in tidal swampland.