Dynamics of pH, Ferrum and Mangan, and Phosphorus on Newly Opened Paddy Soil having High Soil Organic Matter on Rice Growth

Ladiyani Retno Widowati,Sukristyonubowo Sukristyonubowo

doi:10.5400/jts.2012.v17i1.1-8

Ladiyani Retno Widowati, Sukristyonubowo Sukristyonubowo

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https://doi.org/10.5400/jts.2012.v17i1.1-8

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Abstract

Research had been carried out at the Research and Soil Testing Laboratory and Greenhouse of Soil Research Institute, Bogor using newly opened paddy soil from Pesisir Selatan districts, West Sumatra (one year old). Total treatments tested were 12 which were combination of farmer rate, NPK recommendation (½×; ¾×; 1½×), straw compost (½×; ¾×; 1½×), and dolomite. The trial was conducted using a completely randomized design with three replications. This research had been prepared in two units, one unit for observing plant response to nutrient management and another unit for incubation trial with the same treatment placed in the greenhouse. Rice cultivar used was IR-42 in accordance to the preferred varieties of local farmers. The sampling method for measuring the solubility of Fe2+ and Mn2+, as well as the availability of PO43- was by centrifuge 50 g mud samples from the incubation pots then separated clear extract using filter paper. The observation results on dynamics of pH, Fe2+, Mn2+ and PO4-3 mainly occured in 1 to 14 days after submerging (incubation). After 14 days soil reaction had reached thermodynamic sequence of oxidation-reduction processes, the PO43- more available and pH of the soil reached the peak. The optimum dose of NPK fertilizer obtained 0.875 NPK or equal to 175 kg of urea, 87.5 kg of SP-36 and 87.5 kg KCl ha-1. The highest number of hills achieved from straw compost treatment 1½ organic matter (OM) or 3 tons with an increase of 20%. Application of ameliorant dolomite increased the number of tillers about 2-3%, but insignificantly different with no dolomite treatment.

Highlights

Rice places a strategic position in Indonesia as staple food as well as a source of income and employment
More than 90% of the total rice is produced through irrigated rice system and the rest is produced from non-irrigated rice systems (BPS 2006)
LR Widowati and Sukristyonubowo: Dynamics of pH, Fe, Mn, and P on Newly Opened Paddy Soil to plants when the Fe content exceeds 2,000 mgkg-1 (CSAR 1993) or when the concentration of iron in the plant is more than 300 mg kg-1 which is the critical limit of iron toxicity to rice plant (Joseph et al 1996; Lokossou 2006), and Sulaeman et al (1997) found 260 mg kg-1 is critical limit in the soil

Summary

Introduction

Rice places a strategic position in Indonesia as staple food as well as a source of income and employment. Ponnamperuma (1978) concluded that the submerging will reduce Eh, increases and decreases pH, and increases availability of phosphorus This P element derived from the liberation of an inert AlPO4 (KSP = 10-23) to form Al(OH) which is more difficult to dissolve (KSP = 10-33) (Dixon et al 1977) and it can be derived from the solubility of mineral strengit (FePO4.2H2O). LR Widowati and Sukristyonubowo: Dynamics of pH, Fe, Mn, and P on Newly Opened Paddy Soil to plants when the Fe content exceeds 2,000 mgkg-1 (CSAR 1993) or when the concentration of iron in the plant is more than 300 mg kg-1 which is the critical limit of iron toxicity to rice plant (Joseph et al 1996; Lokossou 2006), and Sulaeman et al (1997) found 260 mg kg-1 is critical limit in the soil. Soil rich in active Mn and organic matter will produce high Mn2+ dissolved in 1 to 2 weeks after submerging but it will decrease and stable at 10 mg kg-1 (Randhawa et al 1978) the critical limit of soil Mn is 15-60 mg kg-1 (Black 1968)

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