Nitrogen dynamics in a mature Miscanthus x giganteus crop fertilized with nitrogen over a five year period

peer-reviewedThe objective of this study was to investigate N dynamics and response to N fertilization in a mature crop of Miscanthus x giganteus. A crop of Miscanthus x giganteus sown in 1994 was fertilized with five N rates (0, 38, 63, 90 and 125 kg N/ha/year) over a five year period (2008–2012) in Carlow, Ireland. Foliar chlorophyll concentrations were directly related to N fertilization level throughout the study and rose after N applications until July before falling with the onset of N remobilisation. Shoot numbers were unaffected by N fertilization until the final years of the study when they increased with N level. Crop height was unaffected by fertilization in the early years of the study but in the final years of the study, it increased with N level until July after which the effect diminished. There was a small but significant stimulation of harvested biomass yields in autumn (average 15 t/ha) with increasing N fertilization, but there was no effect on harvested yields in spring (average 10.5 t/ha). The N concentration in the rhizome network gradually built up during the course of the study and was proportional to N application. Aboveground biomass N content was also proportional to N application. Nitrogen remobilisation between the October and February harvests was small; abscissed leaves accounted for most of the N loss over this period. The deleterious environmental consequences of N fertilizer may outweigh any potential economic benefits if increases in biomass production are small or non-existent

Novel Approaches to Optimise Early Growth in Willow Crops

peer-reviewedWillow is a fast growing, high yielding biomass crop that can help reduce reliance on fossil fuels. However, long establishment times to get to profitability and sustainable yield may deter interest in planting the crop. A number of different approaches were investigated to optimise and accelerate early growth. These approaches were water immersion, plastic application, altering stem orientation at planting, altering coppicing timings and applying growth hormone. Glasshouse and field trials were used to test the different approaches. In this work, planting material was soaked for a varying number of days and plastic was applied or not applied in field trials. In the planting orientation approach, stems were planted diagonally or vertically with half of the planting material above the ground level or horizontally below ground level. Additionally, willow crops were coppiced at different times throughout their first growing season and a growth hormone trial was also incorporated in this work. Water soaking, plastic application, coppicing during the growing season or hormone application did not improve early growth or yield. However, early growth and yield were increased by manipulating the planting orientation of willow stems. Planting orientation treatments in which part of the stem was left above the ground increased early growth and yield significantly compared to the control without requiring extra inputs at planting. The beneficial effects of coppicing can be achieved by manipulating the planting procedure so that the first year’s growth is not disregarded

Bi-cropping of winter wheat and white clover.

End of Project ReportGrowing cereals in a leguminous living mulch (bi-cropping) could potentially reduce the need for synthetic inputs to cereal production while preventing losses of nutrients and increasing soil biological activity. The objective of this project was to investigate how bi-cropping (a low input production system for cereals) would compare with conventional winter wheat production systems in terms of total biomass, grain yield and biological diversity. This study has resulted in valuable information on bi-cropping being generated as well as identifying the potential benefits that can be expected under Irish conditions. While the results indicate that winter wheat can be successfully established in an understorey of white clover if sown early in good conditions, competition from grass weed species represents a serious impediment to successful bi-cropping in the longer term. Consequently further research is needed before such a system can be presented to the agricultural community.European Union Framework Programm

Cereal Grain Combustion in Domestic Boilers

This study compared the combustion characteristics and the combustion behaviour of oats, barley, triticale and wheat to that of wood pellets. Sustained grain combustion in domestic boilers was feasible but problematic, the main impediment being clinker formation with ash agglomeration. Clinker formation was lowest for oats which burned easily with fewer operational problems. Triticale displayed reasonably good combustion characteristics and also ignited easily. In contrast, barley and wheat proved difficult to ignite while barley combustion was prone to self-extinguish. Thermal and combustion efficiency and heat output were considerably higher at a grain moisture content of 15% compared to a moisture content of 20%. The efficiency of oat combustion was similar to that of wood pellets at a moisture content of 15%. Carbon monoxide (CO) emission from cereal grains increased with increasing moisture content, but was still below limit values. Oxides of nitrogen (NOx) emissions from cereal combustion were high and would require reduction by limiting the quantity of nitrogen applied to the crop and/or the use of air staging. Oats proved superior to the other grains as a combustion feedstock with similar efficiencies to those of wood pellets but low moisture content is a prerequisite for efficient grain combustion

The Effects of Elevated Concentrations of Carbon Dioxide and Ozone on Potatoe (Solanum tuberosum L.) Yield

End of Project ReportPotatoes (Solanum tuberosum L. cv. Bintje) were grown in open top chambers at Teagasc, Crops Research Centre, Oak Park, Carlow and exposed to ambient and elevated concentrations of CO2 in combination with ambient and elevated concentrations of O3 in the 1998 and 1999 growing seasons. Exposure to elevated concentrations of O3 caused visual damage to the leaves of the potato plants in both years of the study. In 1999, ozone damage to leaves was significantly reduced in the presence of elevated concentrations of CO2. Stomatal conductance was reduced by elevated CO2 and was reduced further by the elevated O3 treatment under elevated CO2. Exposure to elevated CO2 increased tuber fresh weight yield by 32% in both years of the study. The yield increase was attributable to larger tuber sizes and not to an increase in the number of tubers. Tuber yield was unaffected by elevated O3 at ambient concentrations of CO2 in both years of the study. In 1999, the yield increase induced by elevated CO2 was substantially reduced by the presence of elevated O3

Exploring the potential of grass feedstock from marginal land in Ireland: Does marginal mean lower yield?

peer-reviewedThe production of biomass feedstock from marginal land has attracted much attention as a means of avoiding conflict between the production of food and fuel. Yield potentials from marginal lands have generally not been quantified although it is generally assumed that lower biomass yields can be expected from marginal lands. A three year study was conducted in Ireland in order to determine if grass yields of perennial rhizomatous grasses (cocksfoot, tall fescue, reed canary grass, festulolium) for anaerobic digestion from three marginal land sites (very wet site, very dry site, site prone to flooding) could match yields from better soils. Randomised complete block designs were established on each site in 2012 with two varieties of each grass species as treatments. Three grass harvests were taken from each site in 2013 and in 2014. There was no significant difference between yields from the control site and those from the very dry site and the site prone to flooding. Biomass yields from the very wet site were 85% of those from the control site. Highest yields were obtained from festulolium which were significantly higher than yields from perennial ryegrass. An energy analysis showed that maximising the production of grass from low lying mineral marginal grassland in Ireland could provide enough energy to meet the energy requirements of both the private car fleet and the heavy goods vehicle fleet while avoiding conflict with food production which could be concentrated on conventional land

Effect of Harvest Timing and Soil Moisture Content on Compaction, Growth and Harvest Yield in a Miscanthus Cropping System

peer-reviewedHarvesting Miscanthus × giganteus (J.M. Greef & Deuter ex Hodkinson & Renvoize) after shoot emergence is known to reduce yields in subsequent seasons. This research was conducted in Miscanthus to assess the effects on crop response and soil compaction of annually repeated traffic, applied both before new growth in the rhizomes (early harvest) and after shoot emergence (late harvest), at two different soil moisture contents. While an annual early harvest, yields more than a late harvest, because damage to new shoots is avoided, soil compaction may be increased following repeated harvests. Five treatments were tested: (a) An untrafficked control, (b) early-traffic on soil with typical soil moisture content (SMC) (early-normal), (c) early-traffic on soil with elevated SMC (early-elevated), (d) late-traffic on soil with typical SMC (late-normal) and (e) late-traffic on soil with elevated SMC (late-wet). The experiment was conducted on a Gleysol in Co. Dublin, Ireland during 2010 and 2011. Crop response effects were assessed by measuring stem numbers, stem height, trafficked zone biomass yield (November) and overall stem yield (January). Compaction effects were assessed by measuring penetration resistance, bulk density and water infiltration rate. Trafficked zone biomass yield in the early-dry and early-wet treatments was, respectively, 18% and 23% lower than in the control, but was, respectively, 39% and 31% higher than in the late-dry treatment. Overall, stem yield was significantly lower in the late-normal and late-wet treatments (10.4 and 10.1 tdm ha−1 respectively) when compared with the control (12.4 tdm ha−1), but no significant difference was recorded in overall stem yield between both early-traffic treatments and the control. Penetration resistance values were significantly higher in all trafficked treatments when compared with the control at depths of 0.15 m (≥54–61%) and 0.30 m (≥27–57%) and were significantly higher in 2011 when compared with 2010 at depths of 0.15 and 0.30 m. Baler system traffic in Miscanthus significantly reduced yields and significantly increased compaction annually. Miscanthus harvested early, on a dry soil, yielded 1.1 tdm ha−1 more than when harvested late on a dry soil. The yield advantage increased to 1.3 tdm ha−1 when early harvesting on a soil with 40–43% moisture content was compared with late harvesting on a wetter soil (51–52% moisture content). In this study, the magnitude of yield losses from compaction or other causes in early harvests was substantially lower than the yield losses, which resulted from shoot damage in late harvests. It is likely in similar climates that the results of this study would also apply to other perennial crops growing in similar soil type

An Analysis of Abatement Potential of Greenhouse Gas Emissions in Irish Agriculture 2021-2030

Teagasc SubmissionThis report has been prepared by the Teagasc Working Group on GHG Emissions, which brings together and integrates the extensive and diverse range of organisational expertise on agricultural greenhouse gases. The previous Teagasc GHG MACC was published in 2012 in response to both the EU Climate and Energy Package and related Effort Sharing Decision and in the context of the establishment of the Food Harvest 2020 production targets

Physiological and transcriptional response to drought stress among bioenergy grass Miscanthus species

peer-reviewedBackground Miscanthus is a commercial lignocellulosic biomass crop owing to its high biomass productivity, resilience and photosynthetic capacity at low temperature. These qualities make Miscanthus a particularly good candidate for temperate marginal land, where yields can be limited by insufficient or excessive water supply. Differences in response to water stress have been observed among Miscanthus species, which correlated to origin. In this study, we compared the physiological and molecular responses among Miscanthus species under excessive (flooded) and insufficient (drought) water supply in glasshouse conditions. Results A significant biomass loss was observed under drought conditions in all genotypes. M. x giganteus showed a lower reduction in biomass yield under drought conditions compared to the control than the other species. Under flooded conditions, biomass yield was as good as or better than control conditions in all species. 4389 of the 67,789 genes (6.4%) in the reference genome were differentially expressed during drought among four Miscanthus genotypes from different species. We observed the same biological processes were regulated across Miscanthus species during drought stress despite the DEGs being not similar. Upregulated differentially expressed genes were significantly involved in sucrose and starch metabolism, redox, and water and glycerol homeostasis and channel activity. Multiple copies of the starch metabolic enzymes BAM and waxy GBSS-I were strongly up-regulated in drought stress in all Miscanthus genotypes, and 12 aquaporins (PIP1, PIP2 and NIP2) were also up-regulated in drought stress across genotypes. Conclusions Different phenotypic responses were observed during drought stress among Miscanthus genotypes from different species, supporting differences in genetic adaption. The low number of DEGs and higher biomass yield in flooded conditions supported Miscanthus use in flooded land. The molecular processes regulated during drought were shared among Miscanthus species and consistent with functional categories known to be critical during drought stress in model organisms. However, differences in the regulated genes, likely associated with ploidy and heterosis, highlighted the value of exploring its diversity for breeding

The challenge of sustainability for Irish Agriculture

ASA Dairy Masterclass Johnstown Castle 2019Presentation Overview • Introduction to Johnstown Castle • Ireland’s GHG/NH3 challenge • Scenarios for future emissions (without mitigation) • Mitigation pathways • GHG • NH3 • Water quality challenge • ACP highlights • New Ag. Sustainability Support & Advisory Prog