Impact of Controlled Release NPK (16:16:16) Fertilizer on Soil Total Nitrogen Content, Nitrogen Uptake, and Growth of Sweet Corn (Zea mays saccharata L.) in Jatinangor Inceptisols

The potential for sweet corn in Indonesia is very high, however, its cultivation often experiences problems, one of which is that the planting land has a low fertility level. Optimizing the use of fertilizer is one way to increase soil fertility and increase the growth of sweet corn. Using controlled-release NPK fertilizer is the best way to ensure that nutrient availability meets plant nutrient needs. This experiment aims to obtain the best effect and treatment of coating and time on total soil N content and N uptake of sweet corn plants. The experiment was carried out from June to September 2021 at the Experimental Garden and Laboratory of Soil Chemistry and Plant Nutrition, Department of Soil Science and Land Resources, Faculty of Agriculture, Padjadjaran University, Jatinangor. This experiment used a Split Plot Repeated Observation Design experiment over time with 12 treatment combinations and 3 replications consisting of 3 levels of coating treatment, namely without coating (C0), 5-6% coating (C1) and 11-12% coating (C2); and 4 treatment time levels, namely 15 days after planting (W1), 30 days after planting (W2), 45 days after planting (W3), and 60 days after planting (W4). The research results show that; (1) there is no interaction between the coating factor and the time factor on total soil N content and plant N uptake; (2) There is an independent influence of the coating factor on soil N-total and plant N uptake. Coating treatments of 5-6% (C1) and 11-12% (C2) produced lower total soil N content and plant N uptake compared to the treatment without coating (C0); and (3) There is an independent influence of the time factor on the total N content of the soil, but it has no significant effect on plant N uptake. The longer the application time is followed the higher the total N content of the soil and plant N uptake.