AKTIVITAS FISIOLOGI KELAPA SAWIT BELUM MENGHASILKAN MELAUI PEMBERIAN NITROGEN PADA DUA TINGKAT KETERSEDIAAN AIR TANAH

Abstract

One constraint in palm oil cultivation is inefficient fertilization. This inefficiency increased with lesser available soil water. This research aimed to analyze increasing plant physiological activities by nitrogen addition under different soil water availability. The experiment was carried out in young palm oil plantation of PTPN IV Kera-kera unit. It was arranged split-plot design. Main plot was soil water availability based on potential matrix, ψm, ranging from -5 to -10 kPa and from -20 to -200 kPa. Nitrogen dosage was set as sub-plot, namely no-nitrogen, 200 and 400 g N plant-1. These six treatment combinations were replicated three times. Higher level of soil water availability increased plant physiological activities (shown by decreasing stomata conductance and transpiration rate, increasing leaf water potential and photo-synthesis rate). Higher physiological activities were also caused by increasing nitrogen dosage (400 g plant-1). Under higher soil water availability (from -5 to -10 kPa) combined with higher nitrogen dosage of 400 g plant-1, photosynthesis rate increased from 14.25 to 16.67 μmol CO2 m-2 s-1.