Impact of Excess Irrigation on Nitrogen Balance and Growth Traits in Local Kale Genotypes

Kale is a globally consumed vegetable of considerable economic importance. In countries with a long history of cultivation, open-field production is still practiced using traditional methods, often relying on local varieties. Nitrogen fertilization is essential for ensuring proper development. Production failures, caused by mistakes in application and meteorological events, lead to nitrate accumulation in the plant or soil, or to be leaching, causing environmental pollution. This study assessed the growth and nitrogen uptake responses of three local kale genotypes from Rize, Trabzon, and Giresun under varying irrigation levels simulating leaching conditions. Five irrigation treatments, ranging from field capacity to 100% excess water, were applied to induce nitrogen stress. Genotypes were compared using 14 parameters, including shoot and root development and some morphological attributes. Nitrogen analyses in leaves and soils were performed in all treatments of all genotypes. As a result, it was determined that the tested genotypes' growth, development and stress responses were different, and these differences were statistically meaningful. The T1 application contributed to the development of green parts of the plants in all genotypes. However, similar results were not found for the plant's dry weights. Depending on the increasing overwatering quantity, nitrogen levels in both plants and soil decreased. In conclusion, important scientific knowledge and practical applications were provided regarding increasing productivity and sustainable soil management in kale production.