Humic Acid and Water Management to Decrease Ferro (Fe2+) Solution and Increase Productivity of Established New Rice Field

Herviyanti Herviyanti,Amrizal Saidi,Teguh Budi Prasetyo,Fachri Ahmad

doi:10.5400/jts.2012.v17i1.9-17

Abstract

The purpose of this research was to gain a technological breakthrough in controlling Fe toxicity (Fe2+) on Ultisol in a new established rice field by using humic acid from rice straw compost and water management, so that optimal production of rice plants could be achieved. The experiment was designed using a 2 × 4 factorials with 3 replications in a split plot design. The main plot was water management consists of 2 levels: continuous and intermittent irrigation (2 weeks flooded and 2 weeks field capacity). Small plot was humic acid which was extracted from rice straw compost by NaOH 0.5 N which consists of 4 levels: 0, 200, 400, and 600 mg kg-1. The results showed that applications of humic acid from 0 to 600 mg kg-1 that was followed by 2 weeks of intermittent irrigation decreased Fe2+ concentration. It was approaching levels that were not toxic to plants, with soil Fe2+ between 180-250 mg kg-1. The best treatment was found at the application of 600 mg kg-1 humic acid extracted from rice straw compost combined with 2 week flooded – 2 weeks field capacity of water management. Those treatment decreased Fe2+ concentration from 1,614 to 180 mg kg-1 and increased the dry weight of grain from 5.15 to 16.73 g pot-1 compared to continuous flooding and without humic acid application.

Highlights

Ultisols is one of the marginal soils in Indonesia that it has great potential to be developed as a new established rice field
The purpose of this research was to gain a technological breakthrough in controlling Fe toxicity by using humic acid from compost of rice straw and water management in new established rice fields of Ultisol, so that optimal production of rice plants could be achieved
The continuous and intermittent irrigation treatments reduced soil Eh value, but decreasing Eh value with intermittent irrigation was relatively smaller than the continuous irrigation treatment

Summary

Introduction

Ultisols is one of the marginal soils in Indonesia that it has great potential to be developed as a new established rice field. The very high Fe avaibility does not cause problems for rice plant growth, because Fe is reacted with other elements and that are generally not soluble. The symptoms of Fe toxicity in the plant are visually marked with reddish brown spots along the edge strands of the leaf starting from the lower leaves or the oldest (Satari et al 1990; Sahrawat 2000). Another consequence is the formation of plaque on root tips of plants that can inhibit the absorption of both macro and micro nutrients (Hagnesten 2006)

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Conclusion