EFEK MULSA ALANG-ALANG, PUPUK P DAN PENGOLAHAN TANAH PADA TANAMAN KEDELAI DAN GULMA

Abstract

An experiment to study the effect on of spear-grass mulch, P fertilizer and soil tillage on soybean plant and weeds was conducted at Experimental Farm in Tanjung Seteko Indralaya of Ogan Ilir in South Sumatera from Januari to May 2005. It was arranged in a split-split plot (2×3×3) design. Main plot was soil tillage, consisted of without-, in row and conventional tillage. Subplot was P fertilizer, consisted of 0, 100 and 200 kg P2O5 ha-1. Sub-subplot was spear-grass mulch application, consisted of 0 and 10 t ha-1. Results showed that highest dry weights were on 4 and 6th week. Highest pod number and yield were reached by combination of in-row tillage, 200 kg P2O5 ha-1 and 10t mulch ha-1, namely 1.20 t ha-1. Highest root-nodule number was reached by combination of in-row tillage, P2O5 ha-1 and no-mulch, namely 5.75 stem-1. On combination of 200 kg P205 ha-1, 10t mulch ha-1 and conventional tillage shifted weed composition before and after experiment. Highest SDR value was on no-tillage Digitaria sanguinalis (11.10%), in-row tillage in Ageratum conyzoides (16.05%), and conventional tillage in Ageratum conyzoides (25.90%).