The effect of cultivation technologies on the mineral nutrition status of organically grown garlic

Garlic (Allium sativum L.) is among the main bulbous vegetable known worldwide for both economic and health value. The research was conducted in the framework of the project on the modernization of winter garlic cultivation to ensure guaranteed yield in the organic production system. The new technology is designed to prevent the effects of unfavourable soil and climatic conditions on the rooting and wintering ability of garlic – factors that significantly affect the garlic production in Latvia. Field studies were carried out at the experimental field of the organic farm, located at the Koknese’s district, Latvia, during the season of 2018/2019, on sandy loam using hardneck garlic cultivars and local clones. The aim of the study was to find out the nutrient status of winter garlic grown in traditional (planted in late autumn) and innovative growing technologies (wintering in a controlled condition, planted in spring as container plants) to reveal possible differences and nutrient imbalances. Soil and leaf testing were used as diagnostics methods for nutrient (N, P, K, Ca, Mg, S, Fe, Mn, Zn, Cu, Mo, B) assessment. A low concentration of N, Zn, Cu, and B was found for most soil samples. The sub-optimal soil conditions were partly reflected by the foliar chemistry. The results suggested that different cultivation technologies with respect to the wintering stage had a slight effect on the nutrient status of organic garlic. Several nutrient imbalances, regardless of the technology used, were identified. In general, deficiency of K, Mn, Zn, Cu and B in garlic leaves was found throughout the season. While no significant differences were found for foliar uptake of K, Mg, S, Zn, Cu, Mo and B throughout the crop cycle, the content of N, P, Fe and Mn was higher for garlic planted as container plants. Ca was the only nutrient that had a higher level in the leaves of traditionally grown garlic. Although further research is needed, innovative technology for preventing overwintering damages tended to provide the same or even better nutrient accumulation and is, therefore, a prerequisite for a high garlic yield. As nutrient imbalances adversely affect the yield and quality of garlic, measures must be taken to improve the supply of macronutrient K and micronutrients.