Potassium and Nitrogen Fertilization Effects on Jiggs Bermudagrass Herbage Accumulation, Roo Rhizome Mass, and Tissue Nutrient Concentration

Abstract

Adequate supply of potassium (K) is an important factor that can affect bermudagrass [Cynodon dactylon (L.) Pers.] production and persistence, particularly in soils with limited nutrient holding capacity. The objectives of this study were to (i) evaluate the effects of different nitrogen (N) and K fertilization strategies on Jiggs bermudagrass herbage accumulation (HA), root-rhizome mass, and K concentration and accumulation in above- and belowground tissue; and (ii) identify the critical minimum tissue K concentration below which bermudagrass HA is reduced. The experiment was conducted in a greenhouse at Ona, FL, from August to December, 2014 and 2015. Treatments were a factorial combination of three N (0,45, and 90 lb/acre) and four K2O fertilization levels (0, 18, 36, and 72 lb K2O/ acre, the equivalent of 0, 15, 30, and 60 lb K/acre) after every harvest, distributed in a completely randomized design with four replicates. Herbage was harvested every 6 weeks, and root and rhizome mass determined at the end of each year. There were no effects of K fertilization on HA and root-rhizome mass when no N was applied; however, Jiggs HA and root-rhizome biomass increased linearly with increasing K fertilization levels at 45 and 90 lb N/acre. For these N levels, HA increased with tissue K concentration up to 1.4%. Root and rhizome K concentrations decreased linearly with increasing levels of N. Conversely, root-rhizome K content increased with increasing levels of N fertilization. Potassium fertilization increased HA and root-rhizome mass of Jiggs bermudagrass; however, the responses were influenced by N fertilization levels.