Karakterisasi Pelepasan Nitrat pada Andisols di Jawa Barat dan Jawa Tengah

Abstract

Andisols occupies large area in Indonesia. The area is about 5.4 million hectares. This soil is used extensively by farmers for horticulture, tea plantation and small portion for livestock. The characteristics of nitrate release is very spesific location so that it is necessary to reveal soil properties affecting to the pattern of nitrate release on Andisols in West and Central Java. The experiment of nitrate release was conducted by incubation experiment. The objectives of the research were to (1) characterization of chemical properties of Andisols in West and Central Java, (2) characterization of the pattern of nitrate release on Andisols in West and Central Java, and (3) obtaining correlation between chemical properties and the pattern of nitrate release on Andisols in West and Central Java. Based on soil analyses, the chemical properties of Andisols in West and central Java were different. The release of nitrate on Andisols in Lembang, Pangalengan, Sukamantri and Dieng decreased as the depth of soil samples in the soil profile was deeper and increased as the periode of incubation was longer. Simple correlation test showed that the potential nitrate release (N0) positively correlated with total carbon (r=0.08), total nitrogen (r=0.14), oxalate-extractable iron (Feo) (r=0.05), dithionite-citrate-bicarbonate-extractable aluminum (Ald) (r=0.07) and dithionite-citrate-bicarbonate-extractable iron (Fed) (r=0.39). The N0 negatively correlated with oxalate-extractable aluminum (Alo) (r=-0.08) and Alo + ½ Feo (r=-0.07). As for the rate constant (k), k only positively correlated with Fed (r=0.04).