Study of the efficiency N, P, and K fertilizer application to increase yield of sweet corn on inceptisol

Inceptisols, Oxisols, Vertisols, and Andisols are the main agricultural soils in Indonesia because they have a very wide distribution, Inceptisols 70.52 million ha (37.5%), Oxisols 14.11 million ha (7.5%), Vertisol 2.12 million ha (1.1 %), and Andisol 5.40 million ha (2.9%) most of which are paddy fields. Sweet corn is planted in paddy fields at the second or third planting times after paddy. Farmers generally use inorganic fertilizers that only contain macro nutrients N, P, and K and often do not add Granulated Organic Fertilizers (GOF) which also contains micronutrients. The aim of the study was to determine the efficiency of N, P, and K fertilizers added with the right dose of GOF. The study was conducted in Malang at 2019 with 9 combination treatments of N, P, K fertilizer and GOF, repeated 3 times. The data obtained were analyzed for using a Randomized Complete Block Design (RCBD) and continued with DMRT at α= 5%. The results showed that GOF are effectively combined with inorganic fertilizers and can increase agronomic levels by up to 25%. The use of 350 kg/ha-1 Urea+ 125 kg/ha-1 SP-36 + 125 kg/ha-1 KCl combined with GOF 2.500 kg/ha-1 could produce the highest harvest weight reaching 15.48 ton/ha-1.