Fenomena Toksisitas Besi pada Tanaman Padi Sawah yang Ditanam pada Tanah Masam

Abstract

A desk research was conducted to study the phenoenon of iron toxicity in rice planted in acid wetland soils. Dry lands with high level of weathering that be converted to paddy land shows many problems; one of them is the iron toxicity that restrict the yield of rice. The iron toxicity in wetland rice emergences when rice is planted on soils with low pH, CEC and base saturation, high organic matter and bad drainage. Soil waterlogging will decrease the soil redox potential, and increase soil pH and ferrous form of iron. The most important chemical change happened while soil is waterlogged are the iron reduction (Fe3+ to Fe2+) and the increasing iron solubility accompanying it. The intermittence drainage can reduce the unwanted factors of waterlogged acid soils to rice growth and yield. The improving growth and yield of rice gets along with the ferrous iron decreasing accompanying the intermittence drainage. The drainage also improves the soil physical properties, such as the bulk density ang the O2 content, and soil biological and chemical properties, such as the decomposition of organic matter. When done properly, the intermittence drainage can increase the rice yield as much as 2 – 27 %, mostly 10 – 20 %.