The Effect of Humalite on Improving Soil Nitrogen Availability and Plant Nutrient Uptake for Higher Yield and Oil...

Over the last half-century, the widespread use of synthetic chemical fertilizers has boosted crop yields but caused noticeable environmental damage. In recent years, the application of humic substances to increase plant growth and crop yield has gained considerable interest, largely due to their organic origin and their ability to reduce nutrient losses while enhancing plant nutrient use efficiency. Humalite, found exclusively in large deposits in southern Alberta, Canada, is rich in humic substances and has low levels of unwanted ash and heavy metals, which makes it particularly valuable for agricultural applications. However, its effects on canola, the largest oilseed crop in Canada and the second-largest in the world, have yet to be evaluated. This study investigated the effects of five Humalite rates (0, 200, 400, 800, and 1600 kg ha^-1) in combination with nitrogen, phosphorus, and potassium (NPK) applied at recommended levels, on canola growth, soil nitrogen availability, plant nutrient uptake, photosynthesis, seed yield, seed oil content, and nitrogen use efficiency under controlled environmental conditions. The results demonstrated that Humalite application significantly enhanced soil nitrogen availability, uptake of macro- and micronutrients (N, P, K, S, Mg, Mn, B, Fe and Zn), shoot and root biomass, net photosynthesis, and water use efficiency as compared to the NPK alone treatment. The application of Humalite also led to increased seed yield, seed oil content, and nitrogen use efficiency. Taken together, Humalite could serve as an effective organic soil amendment to enhance canola growth and yield while enhancing fertilizer use efficiency.