Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous, recalcitrant, and potentially carcinogenic pollutants. Plants and their associated rhizosphere microbes can promote PAH dissipation, offering an economic and ecologically attractive remediation technique. This study focused on the effects of different types of vegetation on PAH removal and on the interaction between the plants and their as...

Ryegrass is a highly nutritious grass that can be utilized for grazing or production of baleage, haylage, or hay. In contrast to many regions of the world that are suitable for production of perennial ryegrass, annual ryegrass varieties are best suited for use in the Southeast US. When properly managed, annual ryegrass provides moderate concentrations of degradable protein. Annual ryegrass is h...

Sulphate leaching losses may reduce the long-term possibility of maintaining the S supply of crops in low input farming systems. Sulphate leaching and S balances were investigated in an organic dairy/crop rotation (barley [Hordeum vulgare] → grass-clover [Lolium perenne/Trifolium repens] → grass-clover → barley/pea [Pisum arvénse] → winter wheat [Tritucum aestivum] → fodder beet [Beta vulgaris]...

In a feeding trial with sheep, four animals each were fed one of the three roughages (perennial ryegrass (PR), meadow fescue (MF) and red clover (RC)) or one of the four different mixtures (g/day 250 : 250 : 250, 375 : 75 : 300, 525 : 187.5 : 37.5 and 75 : 525 : 150, respectively) of those three roughages, both with and without the inclusion of 100 g of beeswax-labelled barley. Further, four sh...

The effect of nitrogen (N) stress on the pool system supplying currently assimilated and (re)mobilized N for leaf growth of a grass was explored by dynamic ¹⁵N labeling, assessment of total and labeled N import into leaf growth zones, and compartmental analysis of the label import data. Perennial ryegrass (Lolium perenne) plants, grown with low or high levels of N fertilization, were labeled wi...

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 ...

Alternative stable states have long been thought to exist in natural communities, but direct evidence for their presence and for the environmental switches that cause them has been scarce. Using a combination of greenhouse and field experiments, we investigated the environmental drivers associated with two distinctive herbaceous communities in coastal ecosystems in New Zealand. In a mosaic unre...

The effects of soil water deficit and interspecific plant interaction were studied on the dry matter (DM ) yield of white clover and ryegrass and on the morphogenesis of white clover. Plants were grown either: (1) individually (no interaction); or in a mixture of equal plant numbers with either (2) just shoot interaction, or (3) both shoot+root interaction. Plants were subjected to soil water d...

STEMRUST_G, a simulation model for epidemics of stem rust in perennial ryegrass grown to maturity as a seed crop, was validated for use as a heuristic tool and as a decision aid for disease management with fungicides. Multistage validation had been used in model creation by incorporating previously validated submodels for infection, latent period duration, sporulation, fungicide effects, and pl...

Perennial ryegrass is the most abundant grass species in temperate climates. An increased herbage intake of dairy cows by breeding new cultivars could have a large potential impact on agriculture. The effects of cultivars on sward structure, nutritive value, physical characteristics and disease resistance of perennial ryegrass are discussed. Cultivar differences were found in several studies fo...