Comparison of iron application ways in coffee seedlings

Iron (Fe) is shown to be of great importance in some specific functions, and without it, the plant can experience a nutritional imbalance, thus affecting its development. The present study aimed to evaluate the effects of the application of Fe doses in coffee (Coffea arabica L.) ‘Obatã IAC 1669-20’ seedlings via foliar, previous fertilization of the substrate, and aqueous solution on the substrate and identify the best management. The experiment was carried out in a completely randomized design, with seven treatments and five replicates. The treatments were five Fe concentrations via foliar (0.30, 0.45, 0.60, 0.75, and 0.90 g of Fe L-1), previous fertilization on the substrate (0.372 g Fe m-3), and aqueous solution on the substrate (0.30 g Fe L-1), totaling seven treatments. Fertilization with Fe via foliar at 0.45 g Fe L-1 in the production of coffee seedlings showed significant influence on seedling height, stem diameter, and leaf area, in addition to having one of the highest values of Dickson quality index. Thus, coffee seedlings with the application of 0.45 g Fe L-1 via foliar had the best results, with 11.2 cm height, 4.1 mm diameter, 17.3 cm2 leaf area, and 0.32 Dickson quality index. It promoted seedlings with more significant gains in the foliar area (24.2%) and stem diameter (27.4%), allowing a shorter time in nursery. The treatment aqueous solution 0.30 g Fe L-1 on the substrate is a second option for the Fe application in coffee ‘Obatã IAC 1669-20’ seedlings. The treatment with the previous fertilization of the substrate with 0.372 g Fe m-3 is the less recommended.