The Application of Liquid Organic Fertilizer and Inorganic Fertilizer on Exchangable K, K-Uptake, and Sweet Corn (Zea mays saccharata Sturt) Yield in Inceptisols

Inceptisols are widely distributed in Indonesia and are often characterized by low fertility, particularly in essential nutrients such as potassium (K), which is crucial for crop growth, including sweet corn. This study investigates the effects of liquid organic fertilizer (LOF) combined with NPK fertilizers on exchangeable potassium levels, potassium uptake, and the yield of sweet corn grown in Inceptisols. The experimental design used randomize block design with six treatments: 1 control treatment, 1 treatment with the recommended dose of NPK fertilizer, and four treatments of liquid organic fertilizer and NPK combination. Each treatment was repeated four times. The results showed that the combination of LOF and NPK improved both exchangeable K and K-uptake compared to NPK alone. Specifically, treatment E (¾ NPK + 1 ½ LOF) yielded the highest exchangeable K (0.76 cmol kg-1) and K uptake (1.64%), resulting in the highest cob weight per plant (0.52 kg) and per plot (12.48 kg). Additionally, treatment E achieved the highest fresh cob weight per hectare (22,187 kg ha⁻¹).