Phosphorus correlation study for vegetables grown in the ultisol: Nanggung, Bogor, Indonesia
Phosphorus (P) correlation experiment has been done in Ultisol soil in Nanggung District, Bogor, Indonesia from 2006-2007 to find the best P extraction method which suitable for vegetables i.e Amaranth (Amaranthus sp), Kangkong (Ipomoea aquatica L), Eggplant (Solanum melongena L), Chili (Capsicum annuum L), Tomato (Lycopersicon esculentum Mill), Green Bean (Pahaseolus vulgaris L), and Yard Long Bean (Vigna unguilata L). Treatments were P rate : 0, 45, 90, 135 dan 180 kg P2O5ha-1 or equal to 0, 125, 250, 375 dan 500 kg SP36 (36% P2O5) ha-1. Treatments were arranged in Randomized Complete Block design with three replications. Soil samples were taken from every plot and analyzed with five extraction methods. The extraction methods are HCl 25%, Morgan vanema, Bray 1, Mehlich and Olsen. Soil analysis result were correlated with each vegetable relative yield. The best soil extraction method is the soil extraction method that showed highest correlation with vegetable relative yield. Olsen method showed highest correlation with amaranth, chili and tomato relative yield, while HCL 25% showed highest correlation with yard long bean and eggplant. Morgan Vanema showed highest correlation with kangkong reative yield and Bray I for green bean.