PENENTUAN PENAMBATAN N2UDARA DENGAN PERUNUT ISOTOP 15N PADA BEBERAPA JENIS TANAMAN PUPUK HIJAU Dl TANAH MASAM

Abstract

This research was conducted in Green House and Nutrition and Soil Laboratory BAT AN,Jakarta. The aim is study the effect of liming in acid soil to percentage and sum of N2 fixing ofgreen manure crops. The experimental with Completely Randomized Design for Factorial 7x2 wereused. The first factor was green manure crops, consists of seven levels (Caliandra tetragona,Flemingia congesta. Gliricidia sepium, Leucaena leucocephala, Leucaena glauca, Ses~aniarostrata, Sesbania sesban) and second factor was lime addition, consists of two levels (wfthoutliming and 1xAI-dd). The result of research for average of three tim~s cutting indicat~s that: (1) Thehighest N2 fixing without liming was Sesbania rostrata (61,68%) wfth sum of N2 ~xmg w~s 503,_60mglpot, and 71,89% (989, 54 mglpot) in acid soil that liming 1 x Al-dd; (2) The h1g~~~t ~ncrea~mgpercentages of N2 fixing with liming were Caliandra tetragona (154,66%), Glmc1d1a septum(118,38%), Sesbania rostrata (96,50%), Sesbania sesban (93, 15%), Leucaena leucocephala(76, 10%), Leucaena glauca (44,58%), dan Flemingia congesta (26,85%).

Key words: N2 Fixing, isotop 15N, acid soil, green manure, liming.