Effect of Water Management Improvement on Soil Nutrient Content, Iron and Aluminum Solubility at Tidal Low Land Area

Reclamation of tidal lowland at South Sumatra had been conducted since 1961. Land productivity at this area so far had still varied. The success of rice production at level of 6 ton/ha at Delta Telang I area (A/B Type) was not followed by rice production at other areas. The field study was conducted at two land typologies consisting of wet land at Delta Telang I and dry land at Delta Saleh. Improvement of water management was done by drainage system for wet land type (Telang I) and water retention in combination with leaching for dry land type (Saleh). The results showed that land at Delta Telang I, was belong to potential land whereas land at Delta Saleh was belong to acid sulphate land with pyrite layer at 60 cm depth and water table level at dry season was located more than 90 cm below soil surface resulting in phyrite layer oxidation and soil became very acid as well as an increase of iron solubility. Improvement effort of water management at tertiary level was capable to decrease the iron solubility from 78.68 ppm to 41.31 ppm at Delta Saleh and from 78.59 ppm to 39.24 ppm at Delta Telang I. On the other hand, land leaching had no effect on soil nutrients content. Improvement of water management had increased the average level of rice crop production from 3 ton/ha into 5 ton/ha at Delta Saleh.