| Soils are an important component of the global carbon (C) cycle. It is estimated that there are 673,300 ha of turfgrass covered land in Ohio. Various management practices including grass species selection, grass establishment, rate and kinds of fertilizers and pesticides, mowing, and irrigation are used to manage turfgrass systems. As not much is known about C storage and dynamics in turfgrass systems, research will provide greater understanding of the turfgrass management practices that can promote C sequestration in these systems. For this dissertation field studies on experimental plots, and residential lawns at a residential neighborhood block, and regional scale were conducted to assess the impact of the above listed management practices on soil organic carbon (SOC) pools, and assess the variability of SOC pools at a neighborhood block and regional level.; The first study evaluated the effects of long term (15-yrs) applications of nine lawn management programs varying in the rate, type and amount of nitrogen (N) fertilizer and pesticide inputs on SOC and total soil nitrogen (TSN) pools, and turfgrass quality, and biomass in Kentucky bluegrass (Poa pratensis L.). The results show that the SOC and TSN pools in turfgrass systems can be influenced by the amount of N applied and weeds with their N fixing ability and broad leaf cover can reduce turfgrass aesthetic quality but play an important role in the amount of biomass returned to the soil and therefore contribute to C sequestration.; Our next study quantified the C emissions associated with management practices (fossil fuels required for the production, transport, storage, and application of fertilizers, pesticides, irrigation and mowing), and measure the sustainability of turfgrass systems to offset C emissions from, (1) the use of nine different long term turfgrass management programs used for urban lawns, and (2) the turfgrass management programs in which N is applied and clippings are either removed or returned. The sustainability indices (SI) were calculated as the gain of C sequestered in turfgrass soil for environment benefit as compared to the loss of C which results in environmental degradation. We concluded that greater sustainability of turfgrass systems for C can be achieved by reducing or replacing the use of mineral with organic fertilizers, replacing the use of chemical pesticides with biological pesticides, mowing less often, and returning clippings.; Our third study evaluated the effect of grass species selection on C dynamics and litter decomposition. Turf type tall fescue (Festuca arundinacea Schreb.) (TF) and perennial ryegrass (Lolium perenne L.) (PR) are commonly used for lawns and golf courses in the Northeast and Midwestern United States. We hypothesized that both the grass species and the endophyte infection influence C dynamics and litter decomposition in lawns. We conclude that carbon sequestration was not influenced by either the grass species or endophyte level during the 7 year period after plot establishment.; To gain further understanding in C dynamics in turfgrass systems, we collected data on the baseline soil C pools in newly constructed lawns, SOC spatial variability across a heterogeneous neighborhood block in a city, and variability at a regional scale by measuring SOC pools in urban lawns in Wayne and Holmes Counties in Ohio. Considering the average SOC pool of 25 Mg ha -1 in the 0--12 cm depth and the total turf area for Ohio at 673,300 ha, the total Ohio SOC pool is at 16.8 tera gram (Tg) which is 0.03 percent of the estimated 59.4 petagram (Pg) SOC pool in the conterminous 48 states. (Abstract shortened by UMI.)... |
