Effect of Fortified Humic Acid on Total Uptake of Primary Nutrients (NPK) by Mangalore Cucumber and NPK Status in Postharvest Soil

Field experiment was conducted from December (2022) to March (2023) at College of Agriculture, V. C. Farm. Mandya to study the effect of minerals (Ca, Fe and Zn) fortified humic acid on totalmajor nutrient (N P K) uptake by Mangalore cucumber and NPK status of soil after harvest of Mangalore cucumber. The experiment was laid out in Randomized Complete Block Design (RCBD) with fifteen treatments, which involves foliar spray of humic acid (T3), fortified humic acid (T4 to T7) and inorganic salts (T8 to T11) at 30 and 45 DAS and soil application of fortified humic acid (T8 to T11) at the time of sowing. The data unveiled that foliar application of Ca, Fe and Zn (each @ 50 ppm) fortified humic acid @ 0.25 % (T7) at 30 and 45 DAS recorded significantly higher total uptake of nitrogen (53.89 kg ha-1), phosphorus (17.59 kg ha-1) and potassium (58.40 kg ha-1).Lowest available N, P2O5 and K2O status in soil after harvest of Mangalore cucumber has been noticed in absolute control 204.42 kg ha-1), 27.27 kg ha-1 and 204.65 kg ha-1, respectively and it was followed by treatment T7 which recorded available N, P2O5 and K2O status of 207.48, 49.87 and231.17 kg ha-1, respectively. The results suggested that two foliar spray of Ca + Fe + Zn fortified HA at 30 and 45 DAS along with PoP resulted in higher NPK uptake by Mangalore cucumber.