The Influence of Tidal on Fe Distribution at Tidal Swamp Rice-Farming in Barito River Area, South Kalimantan, Indonesia

Iron (Fe) poisoning can cause problems on growth, the formation of saplings, and the filling of grains. These problems lead to and plant death or decrease in productivity. The inhibition of growth and production is increasingly higher in susceptible varieties. The distribution of iron concentration varies in different regions and locations of swamp rice farming. Various adverse effects of iron poisoning on rice have been widely reported, but the spatial distribution of iron in tidal fields is still rare. Iron distribution in various soil profile depths has not been widely investigated and data availability to avoid Fe poisoning in tidal swamps has not been widely reported. Spatial distribution of Fe concentrations is needed as a reference for rice cultivation in tidal swamps. This study has been conducted in November 2015 until August 2017 using the survey method in the Barito River area, South Kalimantan, Indonesia. The use of thematic maps such as tidal height difference (Δ), tidal flood type, and thickness of mud map. The results showed that the spatial concentration of Fe is highest in the zone I which has the highest difference (Δ) of high tide maximum and low tide maximum. While on the soil profile, the highest of Fe concentration is in layer 1 and the lowest concentration is in layer 3. Based on the overflow type, the highest Fe concentration is typed A and type B especially close to the estuary. To prevent iron poisoning, rice seedlings should reach layer 2 (> 10 cm) and choose the safe zone that is zone II, III, or IV to produce optimal rice production.