Dolichodorus marylandicus n. sp. is described and illustrated from grass (Zoysia japonica) in College Park, Maryland. Specimens have also been collected from perennial bluegrass (Poa pratensis) pasture at Beltsville, Maryland, and from pine (Pinus sp.) in North Carolina. This new species is related to D. heterocephalus Cobb, D. similis Golden, and D. aestuarius Chow &Taylor. Females are distinc...

Responses to elevated CO"2 have not been measured for natural grassland ecosystems. Global carbon budgets will likely be affected by changes in biomass production and allocation in the major terrestrial ecosystems. Whether ecosystems sequester or release excess carbon to the atmosphere will partly determine the extent and rate that atmospheric CO"2 concentration rises. Elevated CO"2 also may ch...

Elevated CO2 concentration may promote plant growth while high temperature is inhibitory for C3 plant species. The interactive effects of elevated CO2 and high temperatures on C3 perennial grass growth and carbon metabolism are not well documented. Kentucky bluegrass (Poa pratensis) plants were exposed to two CO2 levels (400 and 800 μmol mol-1) and five temperatures (15/12, 20/17, 25/22, 30/27,...

One hundred fifty Simmental-Hereford cows and calves were used in a 3-yr study to evaluate three creep grazing treatments and an early weaning treatment on cow and calf performance during midsummer (July to September). Calves were approximately 150 d of age and averaged 178.6 kg when treatments were initiated. Tifleaf pearl millet (Pennisetum Americanum L. Leeke) was used as the forage for two ...

Polymer coated urea (PCU) is a N fertilizer which, when added to moist soil, uses temperature-controlled diffusion to regulate N release in matching plant demand and mitigate environmental losses. Uncoated urea and PCU were compared for their effects on gaseous (N2O and NH3) and aqueous (NO3(-)) N environmental losses in cool season turfgrass over the entire PCU N-release period. Field studies ...

In grasses, food reserves in crowns and rhizomes support herbage production and allow regrowth in the spring. One important factor leading to the relative competitiveness of Kentucky bluegrass and smooth brome is that they initiate spring regrowth earlier than their native counterparts in the mixed-grass prairie. It still remains to be tested if there is a greater biomass investment to crowns o...

Tradi t ional weed control in agric u l t u r e ha s b e e n a c c o m p l i s h e d primarily through the use of chemical herbicides and cultivation. Cultivation practices are of little use for weed control in turfgrass management. Turf managers, therefore, tend to rely heavily on chemicals for weed control. Chemical herbicides tend to exhibit rather broad spectrum characteristics. Two common ...

Climate warming may drive invasions by exotic plants, thereby raising concerns over the risks of invasive plants. However, little is known about how climate warming influences the growth and competitive ability of exotic plants from their home and introduced ranges. We conducted a common garden experiment with an invasive plant Centaurea maculosa and a native plant Poa pratensis, in which a mix...

Bioassay techniques are often used to study the effects of allelochemicals on plant processes, and it is generally observed that the processes are stimulated at low allelochemical concentrations and inhibited as the concentrations increase. A simple empirical model is presented to analyze this type of response. The stimulation-inhibition properties of allelochemical-dose responses can be descri...

We examined the effect of fire on vegetation composition with the use of an experiment with four different fire frequencies (annual, 2-yr interval, 4-yr interval, and an intended control with no burning) over a 27-yr period in an infertile, old-field grassland at the Cedar Creek Ecosystem Science Reserve, located in Minnesota, United States. We measured the plant species’ aboveground biomass in...