Nitrogen status of mixed clover and Kentucky bluegrass dicultures in a greenhouse setting

Abstract Incorporating clover into lawns may reduce fertilizer applications and improve pollinator forage; however, much of the recent research has focused on white clover ( Trifolium repens ), while other clovers have not been as widely researched. White, strawberry ( Trifolium fragiferum ), crimson ( Trifolium incarnatum ), and rose ( T. hirtum ) clover grown as dicultures with Kentucky bluegrass ( Poa pratensis ) were tested in a greenhouse study under nonfertilized and nitrogen (N) fertilized conditions to determine their influence on soil and aboveground turfgrass and clover tissue N status compared to nonfertilized and fertilized Kentucky bluegrass monocultures. Soil total N, nitrate, and ammonium were not impacted by clover species additions, though N fertilization did impact soil total N. Aboveground white clover tissue in nonfertilized pots had more total N than all other clover tissues in nonfertilized pots, while white clover and strawberry clover tissues in fertilized pots had more total N than crimson and rose clover tissues in fertilized pots. Total N of aboveground turfgrass tissue in fertilized pots was greater than that of aboveground turfgrass tissue in all nonfertilized clover dicultures and Kentucky bluegrass monocultures. Association with different clover species did not affect N content of tissue, while N fertilization impacted turfgrass N status more than association with clover species.