Respon genotipe sorgum [Sorghum bicolor (L.) Moench] terhadap pemupukan P pada berbagai taraf kejenuhan aluminium di tanah masam

Abstract

Sorgum merupakan salah satu tanaman serelia unggul yang dapat dikembangkan sebagai bahan pangan dan sumber energi alternatif. Biji sorgum dapat dimanfaatkan untuk pangan dan bahan baku bioetanol untuk sumber energi alternatif. Batang dan daun tanaman sorgum dapat dimanfaatkan sebagai hijauan pakan ternak. Oleh karena itu, sorgum mampu mengatasi krisis pangan dan energi dalam satu waktu dan tempat.

Sorghum is one of high value commodity for food and energy security. Sorghum can solve food and energy crisis integratedly in one time and space. Sorghum also can increase productivity of marginal land because sorghum is a drought tolerant crop and suitable to be developed in Indonesia uplands. The major problem of uplands in Indonesia is predominance of acid soil with Al toxicity. The objective of this research was to obtain information about differential response of sorghum genotype tolerant and sensitive aluminum to phosphorus fertilizer in different aluminum saturation levels in acid soil. This research consisted of two stages, i.e: (1) evaluation of differential response of sorghum genotype tolerant and sensitive aluminum to phosphorus fertilizer in different aluminum saturation levels in acid soil, (2) evaluation of growth and development response of sorghum root to phosphorus fertilizer in different aluminum saturation levels in rhizotrone. Evaluation of differential response of sorghum genotype tolerant and sensitive aluminum to phosphorus fertilizer on different aluminum saturation levels in acid soil was conducted in split plot design in Tenjo, Jasinga. Rhizotrone research was conducted in split plot design in greenhouse at University Farm, IPB, Bogor. Aluminum saturation level as a main plot was 2 levels: high level of aluminum saturation (74.78%) and low level of aluminum saturation (25.51%). Four genotytpes were evaluated in this research as sub-plot: Numbu (tolerant), Kawali (tolerant), B-69 (sensitive), and B-75 (sensitive). Phosphorus fertilizer was given into 4 doses as main-plot : P-25%, P-50%, P- 75%, and P-100%. The results from stage one showed that there were different response of each genotype to phosphorus fertilizer in different aluminum saturation levels in acid soil. Numbu has highest value for each variable on this research. On high level of aluminum saturation, P fertilizer didn’t effect to almost variable on this research except sugar level of stem in B-69. On low level of aluminum saturation, P fertilizer effect penicle weight, grain per penicle weight, total weight, and stem weight in B-69. On rhizotrone research, P fertilizer effect root dry weight and root wet weight in B-69 on low level aluminum saturation.