CORRELATIONS OF pH, Eh and EC TO NITROGEN DYNAMICS IN RICE TIDAL SWAMP AREAS

Abstract

The source of N in rice soil with no frtilizer input comes from N -organic mineralization. Nitrogen dynamics which include mineralized N, availability of N, N-uptake by plant and N-microbial biomass in an-aerob soil were control by development of pH, Eh and EC during plant growth. Information about correlation between dynamics of N with pH, Eh and EC on rice tidal swamp area with no fertilizer input was limited. This study was aimed to learn correlation between dynamics of N with pH, Eh and EC on the rice tidal swamp areas with no fertilizer input. The study was done at four tidal swamp areas in South Kalimantan (Malintang, Balandean, Tambak sirang baru, and Handil manarap). Rice varietiy, which was used on the experiment, was Siam Unus and planted on three experiment blocks respectively for each locations. Mineralized N, availability of N, N-uptake by plant, N-microbial biomass, pH, EH and EC were measured as the experiment parameters. Results of study demonstrated that dy namics of N from four rice tidal swamp areas planted with Sian Unus with no fertilizers input were very dynamics and showed similar pattern during the period of plant growth. The dynamics of N were not correlated to pH, Eh and EC values of the soil (r < 0 .35, not significant P>0.05). Values of pH (3.56 – 5.05), Eh (160 – 416 mV) and EC (35 – 382.9 Scm-1) observed during experiment did not influence of N mineralized, N available, N -uptake by plant and N-microbial biomass.