PENGARUH JARAK TANAM DAN DOSIS PUPUK NPK TERHADAP PERTUMBUHAN DAN PRODUKSI AKAR WANGI (Vetiveria zizaniodes) PADA SISTEM BUDIDAYA POLIKULTUR DI BAWAH TEGAKAN TANAMAN KARET (Havea brasiliensis)

Get the best combination of plant spacing and fertilizer dosage for vetiver growth under rubber tree stands. This research was carried out at the Sungei Putih Research Unit, Rubber Research Center located in Galang District, Deli Serdang Regency, North Sumatra. This research used a factorial Randomized Block Design (RAK), which consisted of two factors, namely fertilizer dose and planting distance. The first factor given is the effect of fertilizer dose symbolized "U" which consists of four levels, namely: U0 = without NPK fertilizer (Control), U1 = 10 gr/plant, U2 = 20 gr/plant, U3 = 40 gr/plant . The second factor used is planting distance (J) which consists of three levels, namely: J1 = 20 cm x 40 cm, J2 = 20 cm x 60 cm, J3 = 20 cm x 80 cm. Each treatment level was repeated 3 times, so that there were 36 plots/experimental units and the total sample of plots was 12, the placement of each sample was carried out randomly. Planting distance 20 x 40 cm = 16 x 12 plots = 192 plants. Planting distance 20 x 60 cm = 16 x 12 plots = 192 plants. Planting distance 20 x 80 cm = 16 x 12 plots = 192 plants. So the total number of plants is 576 plants. The results of this research are that planting distance has a real influence on root wet weight and root dry weight, where a planting distance of 20x60 cm gives the best results. NPK fertilizer does not have an effect on all parameters.