Potential Use of Uniola paniculata Rhizome Fragments for Dune Restoration

Abstract Uniola paniculata (sea oats) rhizomes uprooted by hurricanes and deposited as wrack could be salvaged and replanted in dune restoration. To test this unexplored technique, percent tiller emergence was observed for 4 years from U. paniculata rhizomes replanted after submersion in seawater; air exposure of 0, 1, 3, 5, 7, and 11 days; freshwater rinse; and reburial in pots (watered) or on the beach (with or without supplemental water). In addition, U. paniculata rhizomes uprooted by Hurricane Georges were experimentally planted, and effects of soil salinity and moisture on emergence were tested in the greenhouse. Tiller emergence declined with increasing length of air exposure and decreasing size of rhizome. Tiller survival was enhanced by rainfall, rinsing with salt or fresh water during exposure and immediately after planting or supplemental beach watering. Although emergence was not reduced by soil salinity of 1,800 μS/cm, emergence was reduced by soil salinity of 5,800 μS/cm. Across the 4 years of the study tiller emergence from treated rhizomes varied considerably. U. paniculata rhizomes lost bud viability after 3–5 days of beach exposure, unless fresh water from rainfall, wet burlap storage, or watering was applied within 3 days. Bud viability was extended through 11 days when supplied with water. Thus, reburial within 3–11 days after a storm is a viable restoration technique.     

Differential response of barrier island dune grasses to species interactions and burial

Barrier islands are at the forefront of storms and sea-level rise. High disturbance regimes and sediment mobility make these systems sensitive and dynamic. Island foredunes are protective structures against storm-induced overwash that are integrally tied to dune grasses via biogeomorphic feedbacks. Shifts in dune grass dominance could influence dune morphology and susceptibility to overwash, altering island stability. In a glasshouse study, two dune grasses, Ammophila breviligulata and Uniola paniculata, were planted together and subjected to a 20 cm burial to quantify morphological and physiological responses. Burial had positive effects on both plants as indicated by increased electron transport rate and total biomass. Ammophila breviligulata performance declined when planted with U. paniculata. Uniola paniculata was not affected when planted with A. breviligulata but did have higher water use efficiency and nitrogen use efficiency. Planted in mixture, differential reallocation of biomass occurred between species potentially altering resource acquisition further. As U. paniculata migrates into A. breviligulata dominated habitat and A. breviligulata performance diminishes, biotic interactions between these and other species may affect dune formation and community structure. Our study emphasizes the importance of studying biotic interactions alongside naturally occurring abiotic drivers.     

Aboveground and Belowground Impacts Following Removal of the Invasive Species Baby's Breath (Gypsophila paniculata) on Lake Michigan Sand Dunes

The removal of invasive species is often one of the first steps in restoring degraded habitats. However, studies evaluating effectiveness of invasive species removal are often limited in spatial and temporal scale, and lack evaluation of both aboveground and belowground effects on diversity and key processes. In this study, we present results of a large 3‐year removal effort of the invasive species, Gypsophila paniculata, on sand dunes in northwest Michigan (USA). We measured G. paniculata abundance, plant species richness, plant community diversity, non‐native plant cover, abundance of Cirsium pitcheri (a federally threatened species endemic to this habitat), sand movement, arbuscular mycorrhizal spore abundance, and soil nutrients in fifteen 1000 m² plots yearly from 2007 to 2010 in order to evaluate the effectiveness of manual removal of this species on dune restoration. Gypsophila paniculata cover was greatly reduced by management, but was not entirely eliminated from the area. Removal of G. paniculata shifted plant community composition to more closely resemble target reference plant communities but had no effect on total plant diversity, C. pitcheri abundance, or other non‐native plant cover. Soil properties were generally unaffected by G. paniculata invasion or removal. The outlook is good for this restoration, as other non‐native species do not appear to be staging a “secondary” invasion of this habitat. However, the successional nature of sand dunes means that they are already highly invasible, stressing the need for regular monitoring to ensure that restoration progresses.     

Uptake,accumulation and phytoextraction efficiency of cesium in Gypsophila paniculata

Abstract

To evaluate the phytoextraction efficiency of Gypsophila paniculata from Cs-contaminated soils and analyze the mechanism of Cs accumulation in G. paniculata, we analyzed the characteristics of Cs bioaccumulation and subcellular distribution, in addition to its chemical forms in the plant under hydroponic conditions. The results showed that total Cs content in the aboveground parts and the entire plant were as high as 6137.32?mg·kg^?1?dry weight and 7338.49?mg·kg^?1?dry weight, respectively, after 17?days in the 50?mg·L^?1 Cs treatment. The BCF was between 2.35 and 3.38. The TF was between 1.00 and 2.46 in G. paniculata. Subcellular distribution of Cs in the plant was as follows: soluble fraction?>?cell wall?>?organelles. Inorganic Cs (F-ethanol) and water-soluble Cs (F-dH2O) were the main types of Cs in G. paniculata. Further studies show that the phytoextraction efficiency can reach 10.30–11.91% planting a season of G. paniculata under potted conditions. The results suggested that G. paniculata, a perennial, drought-tolerant herb, was a high-accumulator of Cs, which may have potential uses in phytoremediation of Cs-contaminated soil.     

Spatiotemporal pattern of seed bank in the annual psammophyte Agriophyllum squarrosum Moq. (Chenopodiaceae) on the active sand dunes of northeastern Inner Mongolia, China

The seed banks of active sand dunes are critical for the adaptation of psammophytes to unstable habitats. However, existing reports have failed to effectively elucidate the spatiotemporal structure of these seed banks and the factors regulating them. The seed bank pattern of the annual psammophyte Agriophyllum squarrosum Moq. in active sand dunes was studied by taking into consideration the time, the depth of the soil profile, dune positions, and seed bank type (released seed bank, belowground and aboveground canopy seed banks). Most canopy-stored seeds were unburied before the following March of the maturation year; however, they were buried from March to May. The seed bank mainly comprised the aboveground canopy-stored seeds from September of the year of seed maturation to the following March. The seed bank was concentrated in the surface soil layers (0–10 cm) from March of the year following seed maturation to June and was concentrated in the deep soil layers (10–50 cm) after June. The seed bank in the lower leeward slope tended to be larger than those in the other dune positions. The canopy-stored seed:released seed ratio differed between dune positions. The findings of this study are: (1) sand burial and wind erosion play key roles in shaping the spatiotemporal pattern of the seed banks of active sand dunes, and (2) delayed seed release may be a major factor regulating the spatiotemporal pattern of the seed banks of certain psammophytes.     

Effectiveness of sand-fixing measures on desert land restoration in Kerqin Sandy Land,northern China

In the semi-arid Kerqin Sandy Land of north China, land desertification and frequent sand storms in the spring strongly affect the growth of grassland vegetation and crops, and give rise to large reductions in yield as a result of wind erosion and sand dune movement. To bring desertification under control and reduce its influence on grassland and farmlands, many measures have been developed and implemented for stabilizing mobile sand dunes and restoring desertified grasslands. This study was conducted from 1996 to 2003 to evaluate the effectiveness of desert land restoration after implementation of sand-fixing measures. The results showed that construction of straw checkerboards and planting of shrub seedlings significantly enhances topsoil development on the dune surface, increasing silt and clay content and facilitating accumulation of soil carbon and total N, as well as accelerating an increase in plant diversity, vegetation cover and plant density. These findings suggest that using straw checkerboards and planting shrubs are successful methods for mobile sand dune stabilization and desertified grassland restoration in semiarid regions. The mechanism creating these changes is a reduction in wind erosion and improvement of the soil environment for plants. In addition, our results showed that construction of straw checkerboards was slightly more effective in vegetation and soil restoration in comparison with planting shrub seedlings, especially at the primary stage.     

Establishment of Vesicular-Arbuscular Mycorrhizal Fungi and Other Microorganisms on a Beach Replenishment Site in Florida

Beach replenishment is a widely used method of controlling coastal erosion. To reduce erosional losses from wind, beach grasses are often planted on the replenishment sands. However, there is little information on the microbial populations in this material that may affect plant establishment and growth. The objectives of this research were to document changes in the populations of vesicular-arbuscular mycorrhizal (VAM) fungi and other soil microorganisms in replenishment materials and to determine whether roots of transplanted beach grasses become colonized by beneficial microbes. The study was conducted over a 2-year period on a replenishment project in northeastern Florida. Three sampling locations were established at 1-km intervals along the beach. Each location consisted of three plots: an established dune, replenishment sand planted with Uniola paniculata and Panicum sp., and replenishment sand left unplanted. Fungal and bacterial populations increased rapidly in the rhizosphere of beach grasses in the planted plots. However, no bacteria were recovered that could fix significant amounts of N₂. The VAM fungi established slowly on the transplanted grasses. Even after two growing seasons, levels of root colonization and sporulation were significantly below those found in the established dune. There was a shift in the dominant VAM fungi found in the planted zone with respect to those in the established dunes. The most abundant species recovered from the established dunes were Glomus deserticola, followed by Acaulospora scrobiculata and Scutellospora weresubiae. The VAM fungi that colonized the planted zone most rapidly were Glomus globiferum, followed by G. deserticola and Glomus aggregatum.     

Mycorrhizae and succession in plantings of beachgrass in sand dunes

A survey of arbuscular mycorrhizal fungi (AMF), arbuscular mycorrhizae (AM), and hyphal networks of AMF was carried out in sand dune sites of different successional stages in the Province Lands Area of Cape Cod National Seashore, Massachusetts. The study focused on large-scale plantings (each of 12–20 ha) of American beachgrass (Ammophila breviligulata) aged 0–7 yr and five adjacent natural dune areas. Sample sites ranged in vegetative cover from barren to forested. Spores of 17 species of AMF were recovered from the dunes. Over the successional sequence, there were increases in the richness and spore populations of the AMF community, the extent of colonization of A. breviligulata roots, and the mycorrhizal inoculum potential of the soil. Unvegetated sites lacked propagules of AMF, but roots of planted culms of A. breviligulata (which carried propagules of AMF) became mycorrhizal in <1 yr after planting. Spores were recovered from previously AMF-free sites that had been planted with beachgrass for 47 wk, and five species of AMF sporulated in sites <6 yr old. Significant hyphal networks were not present in any of the planted areas (<6 yr old at the time of sampling), but did occur in natural areas. The rate of invasion of areas planted to A. breviligulata by later successional plant species may in part depend upon the establishment of a vigorous network of hyphae of AMF in a site.     

Effects of different planting methods on the early establishment of two introduced tree species in the Mu Us Sandy Land of China

We investigated the effects of planting density and relative ground height (distance from the water table) on the early establishment of two introduced tree species [Mongolian pine (Pinus sylvestris var. mongolica) and white poplar (Populus alba var. pyramidalis)] in the Mu Us Sandy Land of China; we used GLMM to analyze experimental effects. In total, 14 afforestation plots (seven plots per species) with variable relative ground heights were established on a shifting sand dune. Trees were planted at intervals of 3, 5, and 7 m, and the distances between neighboring trees were fixed within plots. Planting intervals and numbers of neighboring trees were treated as measures of planting density, and relative ground height was treated as an indicator of water supply stability. For both species, tree survival rates decreased with increasing planting interval; the number of neighboring trees had a positive effect on survival. The effect of relative ground height differed between species. Pine tree survival rates decreased with increased relative ground height, while the survival rates of poplar trees were unaffected. We recommend that pine trees be planted at high density on lower sectors of sand dunes to prevent wind erosion in early spring. Poplar trees should be planted at high density without reference to relative ground height for the provision of fuelwood.     

Notes on Lejeuneaceae: I. Microlejeunea diversiloba (Spr.) K.M.

Abstract

Previous work on the bryophytic component of dune communities has demonstrated changes in the representation of species with the progress of succession. The ability of some to act as pioneers and the restriction of others to later stages may be associated with their reactions to recurrent burial by wind-blown sand.

Eighteen species were selected for experimental investigation of the effects of sand burial, along the following lines:

(a) Transplants. Samples of eight species were transplanted to four sites representing different stages of the dune succession. Where the sand increment over 11 months exceeded about 4 cm. none survived but species found naturally in mobile dune areas emerged from about 3 cm. Those belonging to fixed dune communities survived only in the absence of burial, although on excavation all species showed some upward growth through the covering sand.

(b) Experimental burial, Method I: samples of the same eight species, grown in pots standing in water but not watered from above, were buried in sand to depths of 1, 2, 4, 5 and 6 cm. The maximum depth through which emergence took place was 4 cm., from which Ceratodon purpureus, Bryum pendulum and Brachythecium albicans reappeared. From shallower layers, however, a greater rate of emergence was shown by Tortula ruraliformis. Pseudoscleropodiun purum and Climacium dendroides did not survive depths greater than 2 cm., and 1cm. was the maximum for Hylocomium splendns and Rhytidiadelphus squarrosus.

Method II. Sample strips of fourteen species were placed in aquarium tanks and, apart from a small portion len exposed, were buried under a sand slope grading up to 7 cm. in depth. Watering was from above and the humidity was kept high by glass lids. The time taken for the appearance of shoots from increasing depths was recorded, also the periods required for reestablishment from increasing depths of 50% and 100% of the original shoot density. For species tested by both methods the results were in most cases similar. Marked powen of recolonization were also shown by Polytrichum piliferum, P. juniperinum and Pohlia annotina.

In P. annotina, Ceratodon purpureus and Dicramum scoparium re-establishment by means of vertically extending rhizoids producing protonemata at the surface is described.

The maximum depth from which the various species can emerge, the depths from which effective recolonization of the surface is achieved within a fairly short time, the ability to produce rhizoids in the overlying sand and the growth-form of the shoots on emergence are regarded as the most significant aspects of reaction to burial, in relation to the role of the species in their natural habitats.     

Response of irrigated wheat to residual and fertilizer nitrogen

Summary A cotton and a wheat experiment were conducted in sequence to evaluate the effect of residual and fertilizer N on wheat with a water table fluctuating between 65 and 125 cm. Cotton treatments, replicated four times, consisted of 3 irrigation treatments as main plots and 6 N levels as subplots (0, 25, 50, 75, 100, 125 kg N/ha). After cotton the plots were planted to wheat and each subplot was divided into two equal sub-subplots. One received N at a rate similar to that previously applied to cotton and the other sub-subplot was left without N application for evaluating the residual effect. Determination of N forms in the soil before wheat indicated that NO₃-N content of the top 25 cm increased from 4.4 to 16.3 ppm as N applied to cotton increased from 0 to 125 kg/ha. On the other hand, mineralizable-N was greater in the control than in the fertilized treatments, suggesting a priming effect on the mineralization of soil N. The residual effect on wheat was related to mineralizable-N rather than to NO₃-N as grain yield was higher for the control than for the residual fertilizer N treatments. The yield was also higher for the more frequent than for the less frequent irrigation treatments, which may be attributed to increase in mineralization with soil water content. Wheat response to N application was significant. But high N levels accompanied by frequent irrigation enhanced lodging with subsequent reduction in yield. Measuring N uptake by grain and straw indicated 37% recovery of fertilizer N. It was concluded that under the prevailing conditions of high water table wheat response was largely dependent on the applied fertilizer due to insignificant residual N availability.     

Belowground mutualists and the invasive ability of Acacia longifolia in coastal dunes of Portugal

The ability to form symbiotic associations with soil microorganisms and the consequences for plant growth were studied for three woody legumes grown in five different soils of a Portuguese coastal dune system. Seedlings of the invasive Acacia longifolia and the natives Ulex europaeus and Cytisus grandiflorus were planted in the five soil types in which at least one of these species appear in the studied coastal dune system. We found significant differences between the three woody legumes in the number of nodules produced, final plant biomass and shoot ¹⁵N content. The number of nodules produced by A. longifolia was more than five times higher than the number of nodules produced by the native legumes. The obtained ¹⁵N values suggest that both A. longifolia and U. europaeus incorporated more biologically-fixed nitrogen than C. grandiflorus which is also the species with the smallest distribution. Finally, differences were also found between the three species in the allocation of biomass in the different studied soils. Acacia longifolia displayed a lower phenotypic plasticity than the two native legumes which resulted in a greater allocation to aboveground biomass in the soils with lower nutrient content. We conclude that the invasive success of A. longifolia in the studied coastal sand dune system is correlated to its capacity to nodulate profusely and to use the biologically-fixed nitrogen to enhance aboveground growth in soils with low N content.     

Effect of sand cover on the survival and vigor ofRosa rugosa Thunb.

Rugosa rose,Rosa rugosa Thunb., is adapted to the northeast coast of the United States. It can be used to trap blowing sand or planted for beautification. Unpredictable weather conditions during the year of establishment have caused survival to be generally poor. Field observations have indicated that rugosa rose spruted from old plants when covered with 30 to 60 cm of sand. To test this observation, rugosa rose was planted at three depths: 0, 15 and 30 cm deeper than the normal planting depth. Roses planted 30 cm deeper than normal developed expanded leaves sooner than did those planted at the normal depth. Peat moss mixed in the planting hole tended to delay leaf formation for the 0 cm treatment but had no effect on survival at any depth. Survival during the first year was 100% for the 30 cm depth and 93% for 0- and 15-cm treatments. The deeper planted roses were more vigorous at the end of the season than were those set at the normal depth. Rose hips developed on plants set at the two deeper treatments. No hips were produced on those plants for the normal depth. New roots grew on the buried stems. These new roots were near the sand surface rather than uniformly distributed along the buried stems.Presented at the Seventh International Biometeorological Congress, 17–23 August 1975, College Park, Maryland, USA.     

Hurricane wrack generates landscape‐level heterogeneity in coastal pine savanna

Wrack (vegetation debris) deposited by storm surges of major hurricanes along the northern Gulf of Mexico produces depressant effects that vary from partial to complete mortality of groundcover vegetation in coastal savannas. As wrack decomposes or is relocated by a subsequent hurricane, patches are opened to colonization. We postulated that patterns of wrack deposition and removal, coupled with differential responses by savanna plant species should produce alternate states of groundcover vegetation. We explored extreme effects of wrack deposited by Hurricane Katrina (2005) in savannas dominated by slash pine Pinus elliottii and cordgrass Spartina patens and located above mean high tide at the Grand Bay National Estuarine Research Reserve, Mississippi, USA. In 2008, we established plots in adjacent areas with and without wrack deposits. Almost no groundcover plant species occurred in wrack deposits compared to adjacent groundcover without wrack. We simulated redistribution of wrack during a new storm surge by removing wrack from replicated plots and depositing it in plots without wrack, recording plant species in treatment and control plots before, then one month and one year after manipulations. One year later, about half the species present before wrack addition (especially dominant graminoids) grew back through redistributed wrack, suggesting that some species were resistant to burial of limited amounts of wrack. Wrack removal resulted in germination and establishment of numerous herbaceous plant species not in undisturbed groundcover, doubling total aboveground numbers of species in the pine savanna and shifting groundcover communities to alternate states not present prior to Katrina. Removal of wrack opens space colonized by resilient species, including those transported in wrack and those surviving intervals between disturbances belowground. Wrack dynamics (deposition and removal) generated alternate states that resulted from resistance‐ and resilience‐driven changes in different patches of groundcover in coastal savannas.     

Effects of method of straw disposal and depth of cultivation on populations of Fusarium spp. in soil and on brown foot rot in continuous winter wheat

Soil samples (0–10 cm depth) taken from plots of continuous winter wheat at intervals between January 1993 and July 1996 were dilution-plated on PCNB agar to identify and enumerate colony-forming units (cfus) of Fusarium spp. Cfus of the main wheat pathogen, F. culmorum, were more numerous in soil from plots that were shallow-cultivated to 10 cm after each harvest than in those that were ploughed. They were also usually more numerous in plots in which straw had been chopped and incorporated (by shallow cultivation or ploughing) than in those in which straw had been burnt. Increasing amounts of straw tended to increase the number of cfus. Deeper sampling (15–25 cm) showed that ploughing resulted in a more even, but diluted, distribution of cfus down the soil profile. Populations of some commonly found species that are not pathogenic on wheat {F. oxysporum, F. equiseti, F. flocciferum and F. merismoides) were sometimes also affected by straw disposal or cultivation treatments. Alternative methods of estimating population densities (baiting soil with wheat kernels or wheat seedlings, or plating-out straw fragments) showed generally similar effects of treatments on populations of F. culmorum; the relative merits of the methods are considered. Large differences in population densities of all species occurred within and between seasons. The smallest populations were found in January 1995 but, in the case of F. culmorum, they increased to relatively large numbers in July 1995. The summer of 1995 was warm and dry and especially favourable for development of fusarium foot rot. Severe disease occurred only in this year and was less frequent after ploughing than after tine-cultivation but more frequent after straw burning than after straw incorporation. The implications of these observations for understanding the role of propagules of F. culmorum in soil as inoculum for foot rot are discussed.     

Effect of species on dune grass growth

Observations of experimental dunes made over a period of nine years indicate differences in utilizing three different dune species along the North Carolina coast and in the type of dunes produced by them.Ammophila is superior in ease of establishment and rate of sand accumulation but is shortlived. It produces a gently sloping dune.Uniola is difficult to propagate but is an excellent dune builder and eventually dominates the foredune. Grown alone, it produces a steep dune front.Panicum is an excellent companion plant to bothAmmophila andUniola. It is easy to propagate, relatively free of pests and produces dunes intermediate in shape, betweenAmmophila andUniola. Plantings of mixtures of two or more of these species should greatly improve long-term dune stability compared with either planted alone.Presented at the Seventh International Biometeorological Congress, 17–23 August 1975, College Park, Maryland, USA     

Nitric oxide emissions from rice-wheat rotation fields in eastern China: effect of fertilization, soil water content, and crop residue

A better understanding of nitric oxide (NO) emission from a typical rice-wheat agroecosystem in eastern China is important for calculating the regional inventory and to propose effective NO mitigation options. Nitric oxide flux measurements by static chamber method were made from treatments of conventional nitrogen-fertilizer (NPK plus urea) application, no-nitrogen application, and nitrogen-fertilizer with incorporation of wheat straw residue for an entire rotation period (June 2002 to June 2003). During the wheat growing season two further treatments of fertilizer without crops planted and bare soil without nitrogen (N) fertilization were applied. Total annual NO emissions for the conventional fertilizer, no N fertilizer and fertilizer plus straw application were 0.44?±?0.01, 0.22?±?0.01, and 0.57?±?0.02 kg N ha^?1y^?1, respectively. On average 27% of this emission occurred during the rice season due to flooding/drainage cycle. The N fertilizer-induced emission factor for the conventional fertilizer treatment was 0.05% of the total N applied. Incorporation of wheat straw in the rice season showed no significant effect on NO flux due to the high C/N ratio of the straw incorporated. During the wheat growing season, NO emissions for all treatments had similar variation pattern controlled by soil moisture dynamics. Total NO emissions in the wheat season for fertilized bare soil (no wheat planted) were 0.389?±?0.01 and 0.21?±?0.01 kg N ha^?1 y^?1, respectively. The results indicate the importance of N fertilizer and soil moisture to nitrogen loss through the formation of NO.     

High Metabolic Rates in Beach Cast Communities

Metabolic hotspots at land–water interfaces are important in supporting biogeochemical processes. Here we confirm the generality of land–aquatic interfaces as biogeochemical hot spots by extending this concept to marine beach cast materials. In situ atmospheric pCO_2, from a respiration chamber (10 cm in diameter and 20 cm high) inserted into wrack deposits, was determined using a high-precision (±1 ppm) non-dispersive infrared gas analyzer (EGM-4, PP-systems) at 1 minute recording intervals. The wrack deposits supported high metabolic activities, with CO₂ fluxes averaging (±SE) 6.62 ± 0.88 μmol C m⁻² s⁻¹, compared to median value of 0.98 μmol C m⁻² s⁻¹ (mean 2.21 ± 1.25 μmol C m⁻² s⁻¹) for bare sand adjacent to deposits. Wrack metabolic rates ranged 40-fold across beaches, from a minimum of 0.57 ± 0.22 μmol C m⁻² s⁻¹ to a maximum of 20.8 ± 5.04 μmol C m⁻² s⁻¹, both derived from beaches with deposits dominated by Sargassum. Rates tended to increase significantly (F test, P < 0.05) from the shoreline to reach maximum rates at about 10 m from the shoreline, declining sharply further from the shoreline, and increased with increasing thickness of the deposits (maximum about 10 cm deep), declining for thicker deposits. Wrack differing in composition had similar metabolic rates, although deposits consisting of a mixture of seagrass and algae tended to show somewhat higher rates. Our results show a meter square of wrack deposit supports a metabolic rate equivalent to that supported by 3 m² of living seagrass or macroalgal habitat. In wrack, the marine environment provides organic material and moisture and the land environment provides oxygen to render wrack ecosystems an efficient metabolic reactor. Intense wrack metabolism should also be conducive to organismal growth by supporting the development of a cryptic, but diverse wrack-based food web.     

Vegetative control of inland sand dunes in the Pacific Northwest

Mammoth wildrye,Elymus giganteus Vahl. was found, after exhaustive tests using a large number of native and some exotic perennial herbaceous and woody plants, to be most effective for inland sand dune control. A superior strain selected for its vigor and rapid vegetative growth was named Volga, released, and registered in 1964. It is propagated vegetatively. Under irrigation and with fertiliter, culms increase from 1 to 20 in one growing season. Plants are both dug and planted mechanically but must be processed by hand. Individual culms 3 to 5 mm in diameter are stripped of dead growth. Top leaves are trimmed to leave a plant 40 cm long. Specifications call for one or two plants per hill placed 20 cm deep in the sand with an approximate 50 × 50 cm spacing. Both digging and planting must take place during the dormant season which in the Northwest is November through February. The Army Engineers, the Bureau of Reclamation, Soil Conservation Districts, and State Game Departments have all used Volga wildrye. There is currently only one commercial source of planting stock.Presented at the Seventh International Biometeorological Congress, 17–23 August 1975, College Park, Maryland, USA.     

Field performance of Solanum sisymbriifolium, a trap crop for potato cyst nematodes. I. Dry matter accumulation in relation to sowing time, location, season and plant density

Solanum sisymbriifolium is an interesting trap crop to control potato cyst nematodes. A series of field experiments was carried out in the Netherlands between 2001 and 2003 to test its performance under field conditions. Experimental factors included sowing time, sowing density and site. Rate of germination, plant establishment and change over time in light interception were monitored. Growth analysis was performed at 7 and 14 weeks after emergence, and dry weight of component plant parts was determined. Time to 50% emergence was 36–38 days for planting at early April and declined to minimum values of ca 8–11 days when planting took place in June, July or the first week of August. When planted later, time to 50% germination increased again. Time to 50% light interception showed a similar trend with sowing time; minimum time was 35–40 days for planting between June and half of July. Planting before May did not advance crop growth. Crop performance was very variable across years and sites when planted later than the end of July to beginning of August. Dry matter accumulation up to 400 g m^?2 was found at 7 weeks after emergence and up to 1040 g m^?2 after 14 weeks. At 7 weeks after emergence, dry matter production increased with planting density (range 50–400 m^?2), but no statistically significant differences were found after 14 weeks. A seed rate of 100 m^?2 seems generally sufficient. Radiation use efficiency was 1.69 g MJ^?1 PAR (SE = 0.0208). Dry matter accumulation (2002–2003) was somewhat higher in Wageningen (51°58’N) on light sandy soil than in Flevoland (52°31′N) on clay soil and in Drenthe (52°51′N) on reclaimed peat soil. It is concluded that above‐ground growth of S. sisymbriifolium in the Netherlands is adequate if planted between early May and the end of July.