The Effect of Mg(NO3)2 Compound Fertilizer and N, P, K Fertilizer on N-Soil, N-Plant Total Contents, and Yield of Tomatoes (Solanum lycopersicum L.) on Inceptisols of Jatinangor

The research aimed to determine the effect of applying compound fertilizer Mg(NO3)2 combined with N, P, and K fertilizer on N-total content in the soil, N-plant content, and tomato yield; and to obtain the best dosage for tomato yields from Inceptisols from Jatinangor. The research was carried out at the Soil Fertility and Plant Nutrition Laboratory Experiment Field and soil and plant analysis was carried out at the Soil Fertility and Plant Nutrition Laboratory, Department of Soil Science and Land Resources, Faculty of Agriculture, University of Padjadjaran, Jatinangor, Sumedang Regency, West Java during from October to December 2023. The research used a Completely Randomized Block Design (CRBD), which consisted of 6 treatments that were repeated four times, namely as follows: A = control; B = 1 dose of N, P, K recommended (200 kg ha-1 Urea, 250 kg ha-1 SP-36, and 100 kg ha-1 KCl); C = 1 dose of Mg(NO3)2 compound fertilizer; D = ¾ dose of Mg(NO3)2 compound fertilizer + ¾ recommended dose of N, P, K (150 kg ha-1 Urea, 187.5 kg ha-1 SP-36, and 75 kg ha-1 KCl); E = 1 dose of Mg (NO3)2 compound fertilizer + ¾ recommended dose of N, P, K (150 kg ha-1 Urea, 187.5 kg ha-1 SP-36, and 75 kg ha-1 KCl); and F = 1 ½ doses of Mg(NO3)2 compound fertilizer + ¾ recommended doses of N, P, K (150 kg ha-1 Urea, 187.5 kg ha-1 SP-36, and 75 kg ha-1 KCl). The research results showed that the application of Mg(NO3)2 compound fertilizer and N, P, K fertilizer had a significant effect on the N-total content of the soil, N-plant content, yield components, and fruit yield of tomato plants. Treatment of 1 dose of Mg(NO3)2 compound fertilizer + ¾ recommended dose of N, P, K fertilizer resulted in the highest N-total soil content, N-plant content, and fruit weight per plot, namely respectively 0,34%; 2.01%; and 6.13 kg plot-1 while the lowest was produced in treatment A (control), namely 0.13%; 0.99% and 1.40 kg plot-1.