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Tolerance of four cool-season turfgrass species sheep fescue (Festuca ovina), perennial ryegrass (Lolium perenne), colonial bentgrass (Agrostis tenuis) and rough bluegrass (Poa trivialis) to SO2 was studied by investigating their injury and physiological responses under SO2 stress for 14 days. Results showed that sheep fescue and perennial ryegrass had better SO2 tolerance than rough bluegrass and colonial bentgrass. Chlorophyll a and carotenoid contents were significantly higher in the SO2-tolerant turfgrass species (sheep fescue and perennial ryegrass) than in the SO2-sensitive turfgrass species (rough bluegrass and colonial bentgrass). Relatively lower levels of reactive oxygen species (ROS), malondialdehyde, and electrolyte leakage (EL) were observed in SO2-tolerant turfgrass species. Gradually increased antioxidant enzyme activities and proline content in SO2-tolerant turfgrass species could counteract such damages and harmful effects caused by ROS and EL, respectively. Sulfite reductase played an im...

This paper presents a survey of grass weeds in grass seed crops in Denmark. The survey is based on an analysis of data from a database containing monitoring of grass weeds in the period from 2004 to 2009 on an acreage of approximately 400,000 ha. The survey is based on weed monitoring carried out during a mandatory field inspection of grass seed crops. All fields grown with grasses for seed production are monitored shortly before harvest at a time when the weeds present are a result of a combination of the cropping history of the field, competition from the crop and the weed control carried out in the field. The survey showed that Poa annua, Elytrigia repens and Poa trivialis were the three most frequent grass weeds in grass seed crops. Furthermore, Bromus hordeaceus, Bromus sterilis, P. trivialis and Vulpia spp. showed an increasing frequency in the study period. The perennial weed, E. repens, and Dactylis glomerata were the only important grass weeds with a declining frequency during the six years. Vulpia spp. has recently become a significant problem in red fescue for seed production, and a significant increased frequency was seen during the study period. However, the study also showed that Vulpia spp. is primarily a problem in red fescue crops established in the autumn, whereas spring establishment of red fescue almost solves the problem with this primarily autumn-germinating grass weed. This paper presents a survey of grass weeds in grass seed crops in Denmark. The survey is based on an analysis of data from a database containing monitoring of grass weeds in the period from 2004 to 2009 on an acreage of approximately 400,000 ha. The survey is based on weed monitoring carried out during a mandatory field inspection of grass seed crops. All fields grown with grasses for seed production are monitored shortly before harvest at a time when the weeds present are a result of a combination of the cropping history of the field, competition from the crop and the weed control carried out in the field. The survey showed that Poa annua, Elytrigia repens and Poa trivialis were the three most frequent grass weeds in grass seed crops. Furthermore, Bromus hordeaceus, Bromus sterilis, P. trivialis and Vulpia spp. showed an increasing frequency in the study period. The perennial weed, E. repens, and Dactylis glomerata were the only important grass weeds with a declining frequency during the six years. Vulpia spp. has recently become a significant problem in red fescue for seed production, and a significant increased frequency was seen during the study period. However, the study also showed that Vulpia spp. is primarily a problem in red fescue crops established in the autumn, whereas spring establishment of red fescue almost solves the problem with this primarily autumn-germinating grass weed.

Calcium silicate has been used to supply silicon (Si) as a plant nutrient for enhancing crop production and the suppression of turf diseases. Research was initiated to determine the effect of calcium silicate on silicon uptake, turf quality, and its residual activity in providing plant available Si in two turfgrass systems. During 2005 and 2006, calcium silicate (CaSi, 12% Si) was applied as a topdressing at eight rates ranging from 0 to 342 kg m−2 to a ‘Tifdwarf’ (Cynodon dactylon × C. transvaalensis Burtt Davy) green in the spring and to the same plots overseeded with ‘Wintergreen’ rough bluegrass (Poa trivialis L.) in the fall. At initiation of the study, dolomitic limestone and magnesium sulfate (MgSO4) was applied to equilibrate calcium across all treatments based on the highest rate of CaSi. Every 28 days, treatments were rated for turf quality and then harvested to determine Si accumulation. One month after applying CaSi in 2005, Si concentration in the leaf tissue of Tifdwarf had increased linearl...

Ground covers and irrigation are important compo- nents of orchard floor management systems that affect fruit tree vigor and productivity. Three experiments were conducted in a greenhouse to determine the relative water use of candidate ground covers (rough- stalk bluegrass, RB, Poa trivialis), Chewing's fescue (CH, Festuca rubra subsp. commutata Gaudin), creeping red fescue (RF, Festuca rubra L. subsp. rubra), tall fescue (TF, Festuca arundinacea Schreber, Fawn), and perennial ryegrass (PR, Lolium perenne L., 'Saint') and the response of apple trees to those ground covers and to drip irrigation applied at two soilless substrate depths. Grass ground covers with large and deep root systems (TF and PR) used more water than a shallow- rooted grass (RB) and leaf water potential decreased more rapidly in apple trees grown with TF than RB when irrigation was withheld. Although apple tree shoot growth was greater with shallow- than deep- rooted grass, photosynthesis, transpiration, and root biomass distribu- tion were not differentially affected by grass type. When grown with RB or TF, irrigation depth affected apple tree growth. During the first season in the greenhouse, deep irrigation at 37 cm depth increased

The use of plants to remediate crude oil-contaminated soil has been a particular interest in environmental cleansing. Some plants such as grasses have been demonstrated to have better capacity in biodegradation of oil in the soil. In this study the effect of different concentrations (1–15%) of heavy crude oil on germination and growth of Poa trivialis (Rough meadow-grass) was studied. Our results showed that the planting occurred in all crude oil concentrations including 15% heavy crude oil. The heavy crude oil in the soil in both high and low concentrations, could delay germination and reduce the number of germinations, the length and the width of the leaves and also decrease the biomass in vegetated soil. The reduction of the crude oil in the vegetated soil was higher than the non-vegetated soil. The roots of the plants were well distributed in the soil in concentrations up to 3% while it was poorly distributed in 10% and 15% of the crude oil concentrations. The absolute reduction of the oil in 15% vege...

Alley cropping may promote greater sequestration of soil organic carbon. The objective of this study was to examine spatial variability of soil organic carbon (C) and nitrogen (N) fractions relative to tree rows in established alley cropping systems in north central Missouri. Soils were collected to a depth of 30 cm from two alley cropped sites, a 19-yr-old pecan (Carya illinoinensis)/bluegrass (Poa trivialis) intercrop (pecan site) and an 11-yr-old silver maple (Acer saccharinum)/soybean (Glycine max)-maize (Zea mays) rotation (maple site). Particulate organic matter (POM) C constituted 15-65% and 14-41% of total organic C (TOC) at the pecan and maple sites respectively, whereas POM N comprised 3 to 24% of total N (TKN). TOC and TKN were on average 13% and 18% higher at the tree row than at the middle of the alley for surface soils (0-10 cm) at the pecan site, respectively. Similarly, POM C was two to three times higher at the tree row than the alley for subsurface soils at the maple site. No differences in microbial biomass C and N between positions were observed. Observed results suggest the existence of spatially dependent patterns for POM C, TOC, and TKN, relative to tree rows in alley cropping.

Eight field experiments, which tested the effects of lime, phosphorus (P), and two rates of nitrogen (N) on a range of permanent grassland swards in Northern Ireland (NI), were re‐examined to investigate the influence of sward botanical composition on aerial dry matter (DM) productivity under ‘low’ and ‘high’ levels of ? input. The aim of the investigation was to verify results previously obtained using ‘pure’ single‐species swards, which suggested that secondary grasses are more productive than perennial ryegrass at low levels of ? input (i.e., < 100 kg ? ha‐1 a‐1)#lb The swards used in the investigation varied considerably in botanical composition, but were largely dominated by three main species: perennial ryegrass (Lolium perenne L.), creeping bent (Agrostis stolonifera L.), and rough stalked meadow grass (Poa trivialis L.), all of which were characteristic of fertile habitats. The results confirmed that under reduced ? input management, swards dominated by these secondary grasses are capable...

Summary The composition of Monks Wood, a 157 ha nature reserve in eastern England, in 1964–66 was compared with that in 1996 using data from 36 temporary sample plots distributed systematically across the wood and from a 70 × 35 m permanent sample plot. The overall composition of the wood changed little, but declines in the abundance of Betula pendula, and locally of other species such as Populus tremula had occurred. Both the density of tree stems and of shrub stools declined significantly between 1966 and 1996: for trees from 1469 to 611 stems per hectare, for shrubs from 235 to 177 stools per hectare. Stem basal area also increased. There were substantial changes in the ground flora: reductions in frequency of Mercurialis perennis, increases in Brachypodium sylvaticum, Carex pendula, Glechoma hederacea, Poa trivialis and Urtica dioica. The changes in the tree and shrub layer appear to be mainly a consequence of ‘internal’ factors, stand growth and self-thinning. The ground flora changes reflect a new ‘...

Herbage yields from Poa trivialis-white clover, perennial ryegrasswhite clover, and P. trivialis-perennial ryegrass-white clover swards were measured under two cutting managements. 17.8–l5.1 cm (“long”) and 7.6–2.5 cm (“short”). Ryegrass-c1over swards out yielded P. trivialis-c1over swards by 13% per annum (1335 kg/ha dry herbage) and P. trivialis-ryegrass-c1over swards by 11% per annum (1125 kg/ha dry herbage). P. trivialis-clover swards out yielded ryegrass-c1over swards only in winter under long cutting. In limiting periods for herbage production, such as in winter and in summer, differences between swards were less than 6% kg/ha dry herbage. Seasonal contribution of P. trivialis to total herbage yields from the P. trivialis-ryegrass-clover swards was up to %. Interspecific competition in P. trivialis-ryegrass-clover swards was more between P. trivialis and ryegrass than between P. trivialis and clover, because the seasonal growth patterns of the grasses were more coincident than those of P. t...

For swards of Poa trivialis L. and Lolium perenne L. ‘Grasslands Ruanui’, in which P. trivialis contributed about 20% to harvested herbage yield in autumn, neither variation in frequency (17.8 cm or 7.6 cm height of herbage at cutting) or in intensity (5.t cm or 2.5 cm stubble after cutting) of defoliation prevented dominance of P. trivialis in winter. Although variation in intensity of defoliation affected subsequent rate of regrowth of the species contributing most to herbage yield in autumn and winter, ryegrass and P. trivialis respectively, rate of regrowth of the other species was not affected. P. trivialis dominance of ryegrass continued into spring until affected by dry weather. Nitrogen fertiliser applied at regular intervals from autumn to spring interacted with phosphorus fertiliser applied in autumn, so that at the higher rates of nitrogen, dry herbage yield from P. trivialis in winter increased more than that from ryegrass.

Established plots of 10 different pasture species were trodden at different rates nine times between December 1958 and October 1959, with mature Romney sheep. Treading generally reduced measured herbage yield, the heaviest treading causing the greatest reduction. Reduction in tiller number appeared to be the main cause of the reductions in yield. Under heavy treading, plant tolerance order, from most to least, was: perennial ryegrass (Lolium perenne L.), Poa pratensis L., Poa trivialis L., short-rotation ryegrass (Lolium perenne L. × Lolium multiflorum Lam.), browntop (Agrostis tenuis), white clover (Trifolium repens L.), timothy (Phleum pratense L.), cocksfoot (Dactylis glomerata L.), red clover (Trifolium pratense L.), and Yorkshire fog (Holcus lanatus L.). Under moderate treading the order was P. trivialis, perennial ryegrass, P. pratensis, short-rotation ryegrass, white clover, timothy, browntop, cocksfoot, red clover, and Yorkshire fog.

Subanguina radicicola (Greeff, 1872) Paramanov, 1968 is recorded for the first time in New Zealand. It is widespread in Southland on Poa annua L. Experimental infections were achieved on P. annua, P. trivialis L., P. pratensis L., and wheat (Triticum aestivum L. ‘Rongotea’) but field infections were found only on P. annua.

An observational trial was carried out on sprinkler irrigated ryegrass (Lolium perenne L.)/white clover (Trifolium repens L.) pasture, which also contained some cocksfoot (Dactylis glomerata L.) and Poa trivialis L., to compare the response to P, K, and N under mowing with removal of herbage and under sheep grazing with little or no transfer of fertility.