Yield and mineral composition of storage roots of carrots (Daucus carota L.) protected with biological methods

The aim of this study was to evaluate the yield and mineral composition of storage roots of carrots protected with biological methods, without the use of chemical control agents. The first experimental factor consisted of two carrot cultivars with different maturity periods. The second experimental factor comprised three methods of carrot fly biocontrol, compared in the following treatments: control – unprotected plants, carrots intercropped with dill (cultivar Szmaragd), carrots intercropped with Welsh onions (cv. Parade) and the application of Himal cubes containing paraffin-coated garlic pulp. The storage roots of carrots cv. Nantejska Polana and cv. Flakkese 2 were harvested in the first week of September and in the middle of October, respectively. After harvest, 100 carrot roots were collected from each replication to determine the percentage of roots infested by the carrot fly. In order to evaluate carrot yields in experimental treatments, the total and marketable yield of carrot storage roots were determined. Fifteen storage roots sampled from the marketable yield in each treatment were subjected to chemical analyses. The prepared material was analyzed to determine the content of: total- N, P, K, Mg, Ca and Cu. The organic crop protection methods based on the biological phenomenon of allelopathy as well as the biocontrol agent Himal significantly reduced the carrot fly population relative to the control treatment. An increase was noted in the total and marketable yield of carrots intercropped with Welsh onions, although the species competed for nutrients. Comparable yield was achieved when carrots were protected with Himal. The storage roots of carrots cv. Flakkese 2 intercropped with dill had the highest content of total N, K, Mg and Ca.