Emisi Gas Dinitrogen Oksida dari Tanah Sawah Tadah Hujan yang diberi Jerami Padi dan Bahan Penghambat Nitrifikasi

Abstract

ABSTRACT
Nitrous Oxide Emission from Rainfed Lowland Rice Soils through Applications of Rice Straw
and Nitrification Inhibitor Materials. Alternate wet-dry of soil condition under rainfed lowland
system influence on source and sink dynamics of green house gases. Lowland rice soil is one
of antropogenic sources of nitrous oxide (N2O) emission produced by microbiological
nitrification-denitrification mediated processes. Attempt to increase soil productivity in lowland
rice system by organic amendment is predicted to stimulate nitrous oxide production. The
increase of N2O production in lowland rice could be suppressed by using nitrification inhibitor
materials. A field experiment was conducted in rainfed lowland rice during 2009 dry season. The
objective was to study interaction of rice straw application and nitrification inhibitor materials
on nitrous oxide emission from rainfed lowland rice. Experiment was arranged using factorial
randomizes block design with three replicates and treatment of rice straw application (without
rice straw, fresh straw, composting straw) and inhibitor nitrification materials (without inhibitor
nitrification, neemcake, carbofuran). Interaction of rice straw and nitrification inhibitor materials
decreased significantly N2O emission from lowland rice soil. Nitrous oxide emission in plot
without rice straw was higher than in plot treated with neither fresh rice straw nor composting
straw. Application neemcake combined with composting straw emitted lowest nitrous oxide
with flux of 72 g N2O ha-1 season-1, whereas the highest N2O emission was found in plot without
nitrification inhibitor materials and rice straw with flux of 454 g N2O ha-1 season-1. Compared
with treatment of without nitrification inhibitor, application of neemcake and carbofuran could
suppress nitrous oxide emission of 48.6 and 41.3 %, respectively.
Key words : nitrous oxide emission, rainfed lowland, rice straw, nitrification inhibitors