The Effect of Steel Slag and Bokashi of Husk to Soil Bulk Density, Soil Aggregate Stability, Soil Porosity and Plant Biomass Broccoli in Andisol Lembang

Abstrak

ABSTRACT
Andisol soil has very good soil physical characteristic, however it has problem with the P
retention. Giving ameliorant to reduce the P retention is expected to maintain, moreover to
improve some soil physical characteristics. The objective of this research was to find out the
interaction between steel slag and bokashi of husk to bulk density, aggregate stability, soil porosity
and biomass of broccoli on Andisol Lembang. This study used a randomized block design factorial
with two factors. The first factor was steel slag and the second factor was bokashi of husk. Each of
them consisted of 4 levels: 0%, 2.5%, 5.0% and 7.5% with two replications. The result of this
research showed there was not interaction between steel slag and bokashi of husk to soil bulk
density, soil aggregate stability, soil porosity and biomass of broccoli. The statistical results showed
that bokashi of husk influence independently to decreasing soil bulk density until 0.53 g cm-3,
decreasing soil aggregate stability until 3.25 and increasing soil porosity until 80.22%, but the
provision of steel slag and bokashi of husk didn‟t influence to biomass of broccoli.
Keywords : organik matter, silicate, bulk density, agreggate stability, broccoli
ABSTRAK
Andisol mempunyai sifat fisika tanah yang baik, namun bermasalah dengan retensi P. Pemberian
amelioran untuk mengurangi retensi P, diharapkan dapat mempertahankan, bahkan meningkatkan
beberapa parameter fisika tanah tersebut. Penelitian bertujuan untuk mengetahui interaksi terak
baja dengan bokashi sekam padi terhadap bobot isi, kemantapan agregat, porositas tanah dan
biomassa tanaman brokoli pada Andisol Lembang. Penelitian menggunakan Rancangan Acak
Kelompok Pola Faktorial dengan dua faktor. Faktor pertama terak baja dan faktor kedua bokashi
sekam padi masing-masing 4 taraf: 0%, 2,5%, 5,0% dan 7,5%, diulang dua kali. Hasil penelitian
menunjukkan bahwa tidak terjadi interaksi antara terak baja dengan bokashi sekam padi terhadap
bobot isi, kemantapan agregat, porositas tanah dan biomassa tanaman brokoli. Hasil statistik
menunjukkan bahwa bokashi sekam padi berpengaruh mandiri untuk menurunkan bobot isi tanah
sampai 0.53 g cm-3, menurunkan kemantapan agregat tanah sampai 3,25 dan meningkatkan
porositas tanah sampai 80,22%, namun pemberian terak baja dan bokashi sekam padi tidak
berpengaruh terhadap biomassa tanaman brokoli.
Kata kunci : bahan organik, silikat, bobot isi, kemantapan agregat, brokoli