Meningkatkan Efektifitas Pup Uk Majemuk Phonska Untuk Pertanaman Ba Yam (Amaranthus tricolor. L) Dengan Penambahan Bahan Organik Pada Latosol Darmaga
In general fertilizer application is needed to add nutrients for plant growth. However, fertilizer application may become inefficient due to leaching. Therefore ameliorant application is needed to reduce the level of leaching. The objective of this research was to study the efficacy of compound fertilizer PHONSKA on Latosol Darmaga as effected by various level of compost and irrigation water applications. The level of compost applied consisted of 0 tonlha (KO), 10 tonnes/ha (K 1) and 20 tonnes/ha (K2). The level of irrigation water applied consisted of 100 % Field Capacity (FC) (AI), 120 % Fe (A2), 140 % Fe (A3) and 160 % Fe (A4). All treatments were arranged using factorial completely randomized design with three replications. Therefore, there were 12 treatment combinations with three replications to make 36 experimental units. Statistical analysis showed that the application of compost reduced significantly the total leaching of Nand P but increased the total leaching of K and spinach production. On the other hand, the increasing of water application above field capacity increased significantly total N, P and K leaching, and reduced spinach production. Interaction between compost application and irrigation water application above field capacity showed that the efficacy of PHONSKA utilitation for spinach production will be increased with the increasing compost application up to 20 tonnes/ha, when water application did not exceed 100 % field capacity. The efficacy of PHONSKA fertilizer will be decreased, when the application of irrigation water exceeded 100 % field capacity on every level of compost applications.