Bermuda grass sod production as related to nitrogen rates

O N é o nutriente que proporciona as maiores respostas no crescimento das gramas, e a adubação nitrogenada adequada pode proporcionar a formação do tapete com boa qualidade em menor tempo. Neste trabalho, objetivou-se avaliar a influência da adubação nitrogenada na produção e qualidade de tapetes de grama-bermuda. O experimento foi instalado e conduzido em área de produção comercial de grama, localizada na cidade de Capela do Alto, SP. A grama utilizada foi a Cynodon dactylon (Pers) L., conhecida como grama-bermuda. O delineamento experimental utilizado foi o de blocos casualizados, com cinco tratamentos e quatro repetições. Os tratamentos foram constituídos por cinco doses de N: 0, 150, 300, 450 e 600 kg ha-1. O aumento das doses de N aumentou a taxa de cobertura do solo pela gramabermuda, reduzindo o tempo para formação do tapete. O máximo acúmulo de matéria seca de rizomas + estolões + raízes foi proporcionado pela dose de 354 kg ha-1 de N, e a resistência dos tapetes, pela dose de 365 kg ha-1 de N. Doses de N entre 354 e 365 kg ha-1, aumentaram a resistência dos tapetes e, com isso, a capacidade deles serem manuseados após a colheita, podendo promover assim maior rendimento da área.

Uso de lodo de esgoto na produção de tapetes de grama esmeralda

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Nutrição, produção e qualidade de tapetes de grama bermuda e esmeralda influenciados pela adubação nitrogenada

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Características físicas do solo e produção de tapetes de grama esmeralda em função de manejos mecanizados

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Doses de lodo de esgoto compostado em produção de tapete de grama esmeralda imperial

The efficiency of nitrogen fertilization for sod production can be increased by using slow-release sources such as sewage sludge compost, which, due to its characteristics can be a substitute of part or all inorganic fertilization for grass. No results were found for the use of sludge compost in sod production in Brazil. This study evaluated the effect of rates of sewage sludge compost on the production of zoysiagrass. Treatments consisted of five rates of composted sewage sludge compost (0, 12, 24, 36 and 48 Mg ha-1, on a dry basis), plus a treatment of inorganic fertilization (300 kg ha-1 N, 80 kg ha-1 P2O5, and 200 kg ha-1 K2O). The results indicated different mineralization rates of the organic compounds present in the sludge; 120 days after sludge application, more Mg (100 %), K (90 %) and N (67 %) has been released than S (57 %), P (40 %) and Ca (31 %). The use of composted sewage sludge for zoysiagrass adequately supplied nutrients when applied to the soil surface at rates more than 36 Mg ha-1. After sod cutting, the rates of sewage sludge compost provided a linear increase in potential soil acidity, soil contents of OM, P, S, Fe, Cu, Mn, Zn, Cu and Ni, and linear decrease in pH, soil concentration of Ca and Mg and base saturation. Compost rates, increasing from 0 to 48 Mg ha-1, reduced the sod mass, reaching values of 4.0 kg/sod at the highest rate. High compost doses (36 and 48 Mg ha-1, respectively) also induced the highest resistance, with values in the order of 35 and 33 kgf.

Reguladores de crescimento no desenvolvimento de diferentes espécies de grama

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Cynodon dactylon, Green Couch Grass 'Oz-E-Green'

Spontaneous mutation or chance seedling: discovered in 2001 as a superior plant growing among “Common” green couch on the breeder’s turf farm at Berries Road, Childers. A selected piece of sod was removed and broken into vegetative sprigs to propagate a larger area of this variety elsewhere on the breeder’s property. The original plant has now been multiplied vegetatively three times without showing any discernible off types. Selection criteria: dense prostrate habit and limited inflorescence production (giving a low mowing requirement), high turf quality, dark green colour. Propagation: vegetative. Breeder: Robert William Morrow, Childers, QLD. PBR Certificate Number 2844, Application Number 2004/035, granted 22 August 2005.

Effect of beta-glucan on activity of antioxidant enzymes and Mx gene expression in virus infected grass carp

The effects of beta-glucan, an immunostimulatory agent, on the superoxide dismutase (SOD) and catalase (CAT) activities of erythrocytes and Mx gene expression were studied from grass carp that were challenged with grass carp hemorrhage virus (GCHV). The SOD and CAT activities in erythrocytes and Mx gene expression in spleen from the fish were detected by spectrophotometry and RT-PCR, respectively. Negative control fish were injected with PBS; positive control groups were injected with either P-glucan or GCHV only; and the experimental groups were pre-injected with beta-glucan 15 days prior to injection with GCHV. The results show that the SOD and CAT activities were higher in fish injected with beta-glucan for 15 days than the negative control group injected with PBS. The SOD and CATactivities significantly decreased when the fish were challenged with GCHV, but it was higher in the group pre-treated with beta-glucan than in infected fish not pre-treated, 15 days after GCHV infection. Mx gene expression levels increased during the early stages (at 12 h and 36 h) of GCHV infection, and it remained at higher levels from the 6th till the 10th day in the beta-glucan pre-treated group, but it was failing from the 6th day in the beta-glucan untreated group. The GCHV-infected group pre-treated with P-glucan had a higher survival rate (60%) than the group not pre-treated with P-glucan (20%), suggesting that beta-glucan possesses or enhances anti-viral responses. (C) 2009 Elsevier Ltd. All rights reserved.

Efficacy of sod removal in regenerating fen vegetation for the conservation of the marsh fritillary butterfly Euphydryas aurinia, Montiaghs Moss Nature Reserve, County Antrim, Northern Ireland.

The efficacy of ‘sod removal’ as a fenland restoration technique was tested using an experimental approach at Montiaghs Moss Nature Reserve, Northern Ireland, from 2006 to 2008. The site suffered from rank growth of purple moor-grass Molinia caerulea which was out-competing herbaceous species. Soil was removed up to a depth of 15 cm completely denuding vegetation in the experimental plot exposing bare peat. By July 2007, 15.2% of sod-removal areas were revegetated; by October 2008 cover had risen to 64.6%. Of this cover, purple moor-grass accounted for only 9-11% compared to 78- 79% on control plots. Cover of other rank-forming grass species was also significantly reduced. Sod removal significantly increased the cover of species characteristic of fenlands including sedges Carex spp., rushes Juncus spp., marsh pennywort Hydrocotyle vulgaris and lesser spearwort Ranunculus flammula. It seems likely that sod removal, which lowered the surface of the peat, restored minerotrophic conditions and exposed the historical seed bank stimulating regeneration of some fenland specialists and pioneer species; this resulted in significantly higher species richness on sod removal plots than control plots two years after treatment. There was no demonstrable effect of sod removal on abundance of devil’s-bit scabious Succisa pratensis, the larval food plant of the Annex II listed marsh fritillary butterfly Euphydryas aurinia. We recommend that consideration should be given to artificially seeding devil’s-bit scabious soon after sod removal treatment to promote early recolonisation and to increase plant abundance on the site.

Designing for participation in local social ridesharing networks : grass roots prototyping of IT systems

This abstract explores the possibility of a grass roots approach to engaging people in community change initiatives by designing simple interactive exploratory prototypes for use by communities over time that support shared action. The prototype is gradually evolved in response to community use, fragments of data gathered through the prototype, and participant feedback with the goal of building participation in community change initiatives. A case study of a system to support ridesharing is discussed. The approach is compared and contrasted to a traditional IT systems procurement approach.

Plastic traits of an exotic grass contribute to its abundance but are not always favourable

In herbaceous ecosystems worldwide, biodiversity has been negatively impacted by changed grazing regimes and nutrient enrichment. Altered disturbance regimes are thought to favour invasive species that have a high phenotypic plasticity, although most studies measure plasticity under controlled conditions in the greenhouse and then assume plasticity is an advantage in the field. Here, we compare trait plasticity between three co-occurring, C 4 perennial grass species, an invader Eragrostis curvula, and natives Eragrostis sororia and Aristida personata to grazing and fertilizer in a three-year field trial. We measured abundances and several leaf traits known to correlate with strategies used by plants to fix carbon and acquire resources, i.e. specific leaf area (SLA), leaf dry matter content (LDMC), leaf nutrient concentrations (N, C:N, P), assimilation rates (Amax) and photosynthetic nitrogen use efficiency (PNUE). In the control treatment (grazed only), trait values for SLA, leaf C:N ratios, Amax and PNUE differed significantly between the three grass species. When trait values were compared across treatments, E. curvula showed higher trait plasticity than the native grasses, and this correlated with an increase in abundance across all but the grazed/fertilized treatment. The native grasses showed little trait plasticity in response to the treatments. Aristida personata decreased significantly in the treatments where E. curvula increased, and E. sororia abundance increased possibly due to increased rainfall and not in response to treatments or invader abundance. Overall, we found that plasticity did not favour an increase in abundance of E. curvula under the grazed/fertilized treatment likely because leaf nutrient contents increased and subsequently its' palatability to consumers. E. curvula also displayed a higher resource use efficiency than the native grasses. These findings suggest resource conditions and disturbance regimes can be manipulated to disadvantage the success of even plastic exotic species.

An invasive grass shows colonization advantages over native grasses under conditions of low resource availability

Increased or fluctuating resources may facilitate opportunities for invasive exotic plants to dominate. This hypothesis does not, however, explain how invasive species succeed in regions characterized by low resource conditions or how these species persist in the lulls between high resource periods. We compare the growth of three co-occurring C4 perennial bunchgrasses under low resource conditions: an exotic grass, Eragrostis curvula (African lovegrass) and two native grasses, Themeda triandra and Eragrostis sororia. We grew each species over 12 weeks under low nutrients and three low water regimes differentiated by timing: continuous, pulsed, and mixed treatments (switched from continuous to pulsed and back to continuous). Over time, we measured germination rates, time to germination (first and second generations), height, root biomass, vegetative biomass, and reproductive biomass. Contrary to our expectations that the pulsed watering regime would favor the invader, water-supply treatments had little significant effect on plant growth. We did find inherent advantages in a suite of early colonization traits that likely favor African lovegrass over the natives including faster germination speed, earlier flowering times, faster growth rates and from 2 weeks onward it was taller. African lovegrass also showed similar growth allocation strategies to the native grasses in terms of biomass levels belowground, but produced more vegetative biomass than kangaroo grass. Overall our results suggest that even under low resource conditions invasive plant species like African lovegrass can grow similarly to native grasses, and for some key colonization traits, like germination rate, perform better than natives.

Unravelling the mechanisms behind the invasion of an introduced and now undesirable grass species

The introduction of Eragrostis curvula (African Lovegrass, herafter Lovegrass) for pasture improvement across Australia has not been successful. Instead Lovegrass, a C4 perennial grass originating from Southern African, has proven unpalatable to stock and to have low nutritional value if stocks do eat it. It has spread prolifically along roadsides, stream banks, conservation areas and pastures. Because control efforts have not been effective, our aim was to determine the putative mechanisms responsible for the dominance of Lovegrass, specifically disturbance (selective grazing) and competition.