THE EFFECT OF NITROGEN FERTILIZATION ON NUTRIENT UPTAKE OF CUCUMBERS GROWN IN GROWING MEDIA WITH WOOD FIBER

Abstract

Greenhouse plants are usually grown in containers filled with growing media. Peat is the main component of the growing media used in greenhouses. However, peat substrate is made from peat from drained peatlands, which is a limited resource. Wood fiber can be an alternative to use as a growing media for controlled-climate crops. The chemical properties of the growing media interact and change continuously due to the small volume of the growing media, which is limited by the vegetative container. Therefore, this study aims to gain new knowledge on the impact of nutrient changes in the microbial degradation of carbon compounds in wood fiber and mixtures with peat substrate on the content and uptake of nutrients required by plants. Cucumbers (Cucumis sativus L.) were cultivated in growing media of peat substrate and wood fiber: 1) peat substrate (PS); 2) wood fiber (WF); 3) WF and PS 50/50 v/v; 4) WF and PS 25/75 v/v. The rates of fertilization were the following: 1) conventional fertilization; 2) N₁₃; 3) N₂₃; 4) N₃₀. Fertilization of cucumbers with different rates of nitrogen influenced the nutrient uptake. Plants grown in 50/50 and 25/75 growing media had the best Cu uptake when fertilized with N₂₃. When the plants grown in the wood fiber and in the 50/50 media were fertilized with N₁₃, N_23, and N₃₀, the Mn content in the growing media at the end of the growing season was significantly lower than the Mn content in the media with conventional fertilization. Thus, nitrogen improved the uptake of Mn by plants grown not only in the wood fiber but also in combinations with peat substrate. Growing plants in wood fiber and fertilizing them with N₂₃ can result in optimum uptake of micronutrients.