Pengaruh Pemberian Abu Volkanik Gunung Kelud Letusan Tahun 2014 terhadap Produksi dan Efisiensi Pemupukan Kedelai.

Abstract

Indonesia has many volcanoes that their material eruption causing rejuvenation of soil forming process and renew long term soil fertility. One of volcanoes in Indonesia is Kelud Mountain*. This research is to investigate the effect of Kelud Mt. volcanic ash application on soybean growth and yield efficiency. The pot experiment was carried out in poor-very acid Inceptisol soil. The ash was dominated by fine size particles (<100 μm). Based on total chemical analysis, Kelud volcanic ash was intermediet material in composition that consisted of SiO2, Al2O3, CaO, Fe2O3, Na2O, MgO, K2O, TiO2, SO3, P2O5, MnO, SrO, ZrO2, Cr2O3, ZnO and CuO. The field experiment conducted in randomize factorial block design with combination of four doses of volcanic ash (0, 10, 20, and 30% of w/w), and three doses of fertilizers (0, 50, and 100% of NPK recommendation doses), in five replication. The result showed that fertilizer application was not significant effect to all variables. In other side, Kelud volcanic ash addition had significant effect to nutrients uptake of P, K, and Ca, and was very significant effect to upper bio mass, amount of pods, pods weight, yield, and nutrient uptake of N and Mg. The treatment that was the highest effect was of application 30% volcano ash of doses treatment. Higher volcanic ash rates higher P and K fertilizer efficiency.