For the successful reclamation of disturbed land, the reduction of initial erosion risk must be balanced with later vegetation establishment. A combination of erosion control and revegetation practices was researched using commercial (full-sized) equipment on a semi-desert grassland site in southern Arizona, USA. Two soils with different parent materials were used to add a 30 cm cap on sites at two elevations: 1646 and 1403 m asl. There were two surface roughness treatments: smooth and rough. Three straw mulch treatments were applied: no mulch, mulch incorporated into the surface soil, and mulch tackified onto the surface. Plots were planted with a 10 species native mix dominated by perennial grasses. After two growing seasons, the incorporated mulch treatment resulted in significantly more seeded grass aboveground biomass than the no mulch treatment while the no mulch treatment had more forb and volunteer biomass than the surface mulch treatment. There was significantly higher erosion on the rough surface treatment compared to the smooth surface. Increasing perennial grass biomass was correlated with reduced erosion while forb and volunteer biomass showed no relationship with erosion. The smooth surface with surface mulch best established perennial grasses, minimized weeds, and reduced erosion. This combination of practices both minimized erosion as well as maximized vegetation establishment. (C) 2016 The Authors. Published by Elsevier B.V.

Biomass, tiller numbers, flowering, and genet survival were accessed for the rhizomatous Elymus lanceolatus ssp. lanceolatus and caespitose E. l. ssp. wawawaiensis growing in mixtures with a range of densities of each taxon. Models of aboveground biomass of each taxon as a function of mixed densities were used to calculate competition indices. Tiller numbers and biomass of ssp. lanceolatus were higher than those of the caespitose taxon in the first year, but declined in the second year, while biomass and tiller numbers of ssp. wawawaiensis changed little. All tillers of ssp. wawawaiensis emerged in autumn; tillers of ssp. lanceolatus emerged from autumn through late spring. The rhizomatous taxon better exploited open resources in the first year; ssp. wawawaiensishad slower growth, but its production of many tillers early in the season may allow it to quickly exploit seasonally variable conditions of semiarid environments. Decline in flowering at higher densities and in the second year was more pronounced than that of biomass and tiller numbers. Genet survival was high and similar for both taxa. Substitution rates indicated ssp. lanceolatus was the better competitor in both years. In the second year, the two taxa differed somewhat less in substitution rates. A greater overlap in resources used by the two taxa was indicated. Subspecies lanceolatus experienced greater intensity of competition. Substitution rates and relative efficiency index indicated ssp. lanceolatus was the greater competitor between early and late spring, when overlap in resource use was greater. Another experiment addressed advantages of clonal foraging of ssp. lanceolatus in exploiting soil nutrient patches. A foraging response was found in the rhizomatous taxon, with greater numbers of closely spaced tillers in high-nutrient patches adjacent to the main clone, but root biomass in these patches, and aboveground biomass of the clones, indicated that both taxa accessed nutrients in the patches, but ssp. wawawaiens is used only root growth. The taxa were similar in their tolerance of low levels of soil nutrients. No difference among genets in degree of foraging response, and no relationship between degree of foraging response and fitness when nutrients are patchy were found. Subspecies lanceolatus did not show such a foraging response to high neighbor densities in mixed-density plots. Instead, rhizome lengths were reduced by higher neighbor densities and in the second year, by reduced resources overall.

Master of Science / Department of Agronomy / Scott A. Staggenborg / Volatile energy prices, energy independency, and environmental concerns have increased the demand for renewable fuel production in the United States. The current renewable fuel industry in the United States has developed around the conversion of starch into ethanol fuel, supplied mainly by corn (Zea mays L.) grain. Future energy demands cannot be met by corn grain alone; therefore greater amounts of biomass from traditional and alternative crops must be utilized. Nutrient removal by selected biofuel crops is important in order to determine biomass quality, required fertilizer inputs, and economic viability of biofuel cropping systems. The objectives of this study were to evaluate grain, stover, total biomass, and estimated ethanol yields of annual and perennial C4 crops grown under the same soil and weather conditions; and fermentable carbohydrate (FC) yields from extracted sweet sorghum juice. In addition, nitrogen (N), phosphorus (P) and potassium (K) concentrations of biomass were evaluated to determine total nutrient removal for annual and perennial crops. Field trials, at two locations in northeast Kansas, included corn, sorghum [Sorghum bicolor (L.) Moench] and perennial warm-season grass cultivars. Yields and nutrient removal were greater for annual crops than perennial grasses. Annual crop yields varied among cultivars, but were similar between locations and years. Perennial grass yields improved significantly from the 2007 establishment year to 2008, however nutrient removal was not affected by the yield increase. The highest grain yield and grain nutrient removal amounts were observed for corn across both years and locations. Total biomass yields were greatest for sweet and photoperiod sensitive sorghum cultivars. Average extracted sweet sorghum FC yields were 4.8 Mg ha[superscript]1. Estimated ethanol yields of sweet sorghum were greater than all other crop cultivars. Overall, nutrient removal was most affected by biomass yield variation among crop cultivars; however P concentrations, and subsequent removal, were dependent upon soil P levels at individual locations. These results suggest that annual crops can achieve the greatest biomass yields for multiple renewable fuel conversion processes, but are associated with high nutrient removal levels which must be considered when evaluating biofuel energy cropping systems.

Research objective The study was designed to investigate biomass production of tall fescue, cocksfoot, and reed canary grass and the quality of raw material for biogas as influenced by sward fertilization with different rates of nitrogen and different number of cuts per season and to establish the effect of fertilization with digestate on cocksfoot biomass production and quality. Research tasks: • to estimate the productivity of tall fescue, cocksfoot and reed canary grass, fertilized with different nitrogen rates, for biogas; • to assess the effect of cutting frequency and fertilization rate of tall fescue, cocksfoot and reed canary grass on the quality composition of biomass for biogas and biogas potential; • to estimate agroecological value of perennial grasses; • to determine the energy potential of biomass of the tested perennial grasses used for biogas production and to identify the energy balance of raw material preparation for biogas. Research subject - tall fescue (Festuca arundinacea Schreb.), cocksfoot (Dactylis glomerata L.), reed canary grass (Phalaris arundinacea L.). Originality of the research work. One of the potential raw materials for biogas production is biomass of perennial grasses. Each grass species differs in growth rhythm and rate, demand for nutrients, and other characteristics, therefore the amount of biomass is highly dependent on specific growing conditions and cultivation technologies that have to ensure the quality of raw material best suited... [to full text] / Tyrimo tikslas – ištirti nendrinių eraičinų, paprastųjų šunažolių ir nendrinių dryžučių biomasės kiekį bei žaliavos biodujoms kokybę pagal skirtingas azoto normas tręštuose žolynuose, taikant nevienodą pjūčių skaičių per sezoną ir nustatyti tręšimo biosubstratu įtaką paprastųjų šunažolių biomasės kiekiui bei kokybei. Tyrimo uždaviniai: • įvertinti biodujoms auginamų nendrinių eraičinų, paprastųjų šunažolių ir nendrinių dryžučių produktyvumą, juos tręšiant skirtingomis azoto normomis; • nustatyti nendrinių eraičinų, paprastųjų šunažolių ir nendrinių dryžučių pjūčių dažnumo ir tręšimo azotu įtaką biomasės biodujoms kokybinei sudėčiai bei dujų potencialui; • nustatyti tirtų daugiamečių žolių auginimo agroekologinę vertę; • įvertinti biomasės naudojimo biodujų gamybai energinį potencialą ir žaliavos paruošimo biodujoms energijos balansą. Tyrimo objektas – nendrinis eraičinas (Festuca arundinacea Schreb.), paprastoji šunažolė (Dactylis glomerata L.), nendrinis dryžutis (Phalaris arundinacea L.) Mokslinis naujumas. Viena iš potencialių žaliavų biodujų gamybai yra daugiamečių žolių biomasė. Tačiau kiekviena žolių rūšis nuo kitų skiriasi savitu augimo ritmu, trukme, maisto medžiagų poreikiu ir kitomis savybėmis, todėl biomasės kiekis labai priklauso nuo konkrečių augimo sąlygų ir auginimo technologijų, o kokybė turėtų būti tokia, kad būtų tinkamiausia pagal numatomą žaliavos panaudojimo paskirtį. Šio tyrimo metu nustatyta, kad vidutinių platumų klimato zonos šiaurinėje dalyje... [toliau žr. visą tekstą]

The effects of varying concentrations of two chelators: EDTA, citric acid (CA), and phosphorus on the accumulation of arsenic in soil by two perennial grasses, Leersia oryzoides and (rice cut-grass) Festuca arundinacea (tall fescue). Each experiment was run for eight weeks, after which plants were harvested, oven-dried, digested in acid and analyzed using an ICP-OES. Phosphorus soil amendments were applied as 0, 15, 30, 60, 120 mg P/kg soil. For the first chelator experiment, CA and EDTA concentrations of 0, 2.5, and 5.0 mmol/kg soil were added in pulse form to the soil. In the second chelator experiment, concentrations of CA were added in 0, 2.0, 4.0 mmol/kg soil and EDTA was added as 0, 0.25, 0.50 mmol/kg soil. Both plant species accumulated enough arsenic in the root and shoot tissues to be considered at hyperaccumulator species. Citric acid produced comparable results with EDTA, and is considerable much safer for the environment than any synthetic chelator. Certain soil amendments (citric acid and phosphorus) and hyperaccumulator species used in this study warrant further research in the field.

Research subject Process of preparation and processing of perennial grass (cocksfoot, tall fescue and reed canary grass) biomass into biogas. Objectives 1. To analyse the possibility and identify the energy potential of processing of perennial grass (cocksfoot, tall fescue and reed canary grass) biomass silage into biogas. 2. To assess energy consumption during the process of preparation and processing of perennial grass biomass into biogas and draw up the energy balance. 3. To identify environmental impact of preparation and processing of perennial grasses into biogas. / Darbo tikslas Ištirti daugiamečių žolių (paprastųjų šunažolių, nendrinių eraičinų ir nendrinių dryžučių) biomasės naudojimo galimybes biodujų gamybai, įvertinant žaliavos gamybos energinį balansą ir įtaką aplinkos taršos mažinimui.   Darbo uždaviniai 1. Ištirti daugiamečių žolių (paprastųjų šunažolių, nendrinių eraičinų ir nendrinių dryžučių) biomasės siloso perdirbimo į biodujas galimybę ir nustatyti energinį potencialą. 2. Įvertinti daugiamečių žolių biomasės paruošimo ir perdirbimo į biodujas metu, patiriamas energijos sąnaudas ir sudaryti energijos balansą. 3. Nustatyti daugiamečių žolių paruošimo ir perdirbimo į biodujas įtaką aplinkai.