14 research outputs found
Evaluation of Potato Cultivars for Resistance Against Water Deficit Stress Under In Vivo Conditions
Yield and phenology of yam as affected by the physiological rest period of seed-rhizomes
Environmental burdens of producing bread wheat, oilseed rape and potatoes in England and Wales using simulation and system modelling
Background, aims and scope Food production is essential to life. Modern farming
uses considerable resources to produce arable crops. Analysing the environmental
burdens of alternative crop production methods is a vital tool for policymakers.
The paper describes the production burdens (calculated by life cycle analysis)
of three key arable crops: bread wheat, oilseed rape and potatoes as grown in
England and Wales using organic and non-organic (contemporary conventional)
systems. Resource use (e.g. abiotic and energy) and burdens from emissions are
included (e.g. global warming potential on a 100-year basis, global warming
potential (GWP), and eutrophication and acidification potentials). Methods Crop
production was analysed, using systems models, so that the effects of factors
like changing N fertiliser application rates or irrigation could be examined.
Emissions of nitrate were derived from a simulation model in which soil organic
N was driven to steady state so that all long-term effects were properly
accounted for. Yield response curves to N were similarly derived from long-term
experiments. Crop nutrient inputs and plant protection applications were derived
from national survey data and the literature. All major inputs were accounted
for including fertiliser extraction, manufacture and delivery; pesticide
manufacture; field fuel use; machinery and building manufacture; crop drying,
cooling and storage. The current balance of production systems were found from
survey data. The weighted mean national production was calculated froma
combination of three rainfall levels and soil textures. The system boundary is
the farm gate.
The functional unit is 1 t marketable fresh weight of each product. Results and
discussion The primary energy needs for the producing the three main crops were
2.4, 4.9 and 1.4 GJ/t for bread wheat, oilseed rape and potatoes, respectively.
When expressed in terms of dry matter, protein or energy, wheat incurred smaller
burdens than oilseed rape, which incurred lower burdens than potatoes. The crops
do, of course, all play different roles. Organically produced bread wheat needed
about 80% of the energy of non-organic, while organic potatoes needed 13% more
energy than nonorganically produced ones. While pesticide use was always lower
in organic production, other burdens were generally inconsistently higher or
lower. Land occupation was always higher for organic production. Lower
fertiliser use (and hence energy use) in organic systems is offset by more
energy for fieldwork and lower yields. Main crop potato energy needs are
dominated by cold storage. Reducing the N application rate for bread wheat
production reduces energy use and GWP. The optimum for energy is with N at about
70% of the current level. It seems to be lower for GWP, but the sub-models used
are beyond their range of reliability. The results are generally of the same
order as those from other European studies. Conclusions Arable crop production
depends heavily on fossil fuel in current major production systems. The
emissions causing GWP are very dependent on nitrous oxide, more so than fuel
consumption. That, together with emissions of ammonia and nitrate, means that
agriculture has a C-N footprint rather than the C footprint that typifies most
industrial life. Recommendations and perspectives With the large influence of
nitrous oxide on GWP, evaluation of nitrous oxide emissions by another method,
e.g. crop-soil simulation modelling instead of the more rigid IPCC method would
improve the robustness of the analysis. The transition betweenfarming systems
was not included in this study, but there could be short to medium term benefits
of converting from nonorganic to organic methods that should be evaluated.
System modelling allows alternative production methods to be readily explored
and this greatly enhances LCA methodology
Efeito do CO2 e etileno no período de dormência de minitubérculos de batata cv. Macaca Effect of CO2 and ethylene on the dormancy period of potato cv. Macaca minitubers
Avaliou-se o efeito do CO2 e etileno no período de dormência de minitubérculos de batata da cultivar Macaca produzidos em telado durante duas safras. Imediatamente após a colheita, os minitubérculos foram submetidos aos tratamentos de abafamento com etileno (1000 mL L-1) por 72 h; CO2 (20%) por 72 h; carbureto de cálcio (200 g m-3) por 72 h; e 1-metilciclopropeno (1-MCP) (1mL L-1) por 24 h (apenas na safrinha); e imersão em solução de ethephon (840 mg L-1) por 5 s. A testemunha não recebeu nenhum tratamento. O delineamento experimental foi um fatorial (safras x tratamentos) no inteiramente casualizado, com quatro repetições de 15 minitubérculos. Em intervalos semanais foram avaliadas a respiração e a produção de etileno. A cada 15 dias avaliou-se o número de brotos e a percentagem de tubérculos brotados, calculando-se a área abaixo da curva de progressão. Os minitubérculos produzidos durante a safra, comparados com os da safrinha, apresentaram menor período de dormência e aumentaram a taxa respiratória durante o período de armazenamento, claramente relacionados com a brotação dos minitubérculos. O CO2 e etileno não promoveram o encurtamento, enquanto que o 1-MCP prolongou o período de dormência de minitubérculos de batata cv. Macaca.<br>The effect of CO2 and ethylene treatments were evaluated on the dormancy period of 'Macaca' minitubers produced in greenhouse during two growing seasons. Minitubers were treated soon after harvesting. The treatments were suffocation with ethylene (1000 mL L-1) during 72 h; CO2 (20 %) during 72 h; calcium carburet (200 g m-3) during 72 h; and 1-methylcyclopropene (1-MCP) (1 mL L-1) during 24 h (only for second season); and immersion with 2-cloroetil fosfonic acid (840 mg L-1) during 5 s. Control minitubers did not receive any treatment. The experiment was a factorial (seasons x treatments) in a randomized design, with four replications of 15 minitubers. Respiration and ethylene production were evaluated every week. Sprout number and percentage of sprouted tubers were evaluated every 15 days to obtain the area under progression curve. Minitubers produced during the first season presented shorter dormancy than those produced during the second season. First season minitubers presented an increase in respiration rate during storage that was clearly related to sprouting. CO2 and ethylene did not reduce, while 1-MCP enhanced dormancy period of potato cv. Macaca minitubers