What are the key factors to consider when assessing the sustainability of crop production under greenhouse conditions?5 answersWhen assessing the sustainability of crop production under greenhouse conditions, key factors to consider include the choice of covering materials impacting crop yields and environmental performance, evaluation indicators such as relative moisture efficiency and cooling effectiveness, the greenhouse system type and cultivation method affecting energy use and resource efficiency, the use of suitable soilless media for plant regeneration and agronomic performance under greenhouse conditions, and the impact of microclimate on plant growth and development within the greenhouse structure. These factors collectively influence the environmental, economic, and social sustainability of greenhouse crop production, highlighting the importance of integrated approaches and technology adoption to enhance overall sustainability in agricultural practices.
What is the significance of a farmer's age in terms of corn production?4 answersThe age of a farmer has a significant impact on corn production. Farmers of different ages operate with slightly different technologies and use various inputs at different efficiencies. Middle-aged farmers appear to be the most productive. Additionally, the productivity of farmers varies with age, with efficiency increasing by an average of 4.5 percent every ten years until the age interval of 35 to 44, after which it decreases at the same rate. Furthermore, a study found that the productivity of farmers over the age of 65 is 10% lower than the youngest farmers, indicating a decrease in productivity of older farmers due to technology. Therefore, the age of a farmer is a significant factor to consider when it comes to corn production.
High carbon dioxide and low oxygen MAP content in MAP accelerate fruit senescence?3 answersHigh carbon dioxide and low oxygen modified atmosphere packaging (MAP) content can accelerate fruit senescence, but the effects depend on the specific fruit and the duration of exposure. In some cases, low oxygen and high carbon dioxide levels can delay ripening and senescence, maintain quality, and prolong the commercial life of horticultural crops. However, if the levels of carbon dioxide and/or oxygen are not properly managed, it can lead to the production of ethanol and other fermentative metabolites that negatively affect the quality and general metabolism of the produce. Additionally, prolonged exposure to low oxygen or high carbon dioxide can result in skin injury, blotchy ripening, and increased disease incidence in some fruits. Therefore, it is important to carefully manage the levels of carbon dioxide and oxygen in MAP to avoid physiological disorders and maintain fruit quality.
In greenhouse farming what costs the most?5 answersIn greenhouse farming, the cost that varies the most is the marginal abatement cost of greenhouse gas (GHG) emissions. The study found that the average marginal abatement cost for a broadacre farming system in Western Australia was $29.3 per tonne CO2-e. Additionally, the integration of semitransparent organic photovoltaics (OPVs) into greenhouse designs can significantly reduce environmental impacts, particularly in regions with high solar insolation and electricity-intensive energy demands. However, in colder regions, the shading effect of OPV can increase heating demands and potentially increase life cycle environmental burdens. The initial cost of greenhouse technology is a major concern for farmers, but efforts have been made to reduce costs through the use of alternate construction materials and innovative environmental control technology. Desalination systems are also used in greenhouses, and the economic evaluation of desalination technologies for greenhouses shows that different technologies have varying costs and payback periods depending on factors such as location and water costs. The environmental efficiency of greenhouse tomato farms can be improved through awareness, training, and the adoption of green production practices.
What is Senescence in plants?5 answersSenescence in plants is a major developmental transition that involves a reprogramming of gene expression and is regulated by complex networks of transcription factors, epigenetic mechanisms, and small RNA-mediated regulators. It can be either age-dependent or stress-induced and is characterized by the degradation and remobilization of macromolecules and nutrients. Plants can carefully regulate the timing of senescence in response to environmental cues, and this timing can have significant effects on their fitness and reproductive success. Senescence can also impact the plant's response to pathogen attacks, with necrotrophic pathogens causing more severe symptoms on senescent plants and biotrophs preferring juvenile tissues. Protein kinases play a crucial role in the regulation of leaf senescence, perceiving and transducing signals to orchestrate the orderly degeneration process. Overall, senescence is a complex process that is essential for plant fitness and involves intricate interactions between genetic, epigenetic, and environmental factors.
Has it been proven that CO2 causes a greenhouse effect?5 answersSim, está provado que o CO2 causa um efeito estufa. O Projeto Europeu de Deteção de Gelo na Antártica analisou a temperatura e a concentração de CO2 ao longo de 800.000 anos e descobriu que a concentração de CO2 é maior durante a redução da temperatura, indicando um efeito estufa. Além disso, um estudo sobre o clima marciano mostrou que uma camada de nuvem de gelo de CO2 pode causar um forte efeito estufa, elevando a temperatura da superfície acima do ponto de fusão da água. Além disso, um cálculo da “sensibilidade climática” do CO2 no efeito estufa da Terra destacou o papel do espectro de absorção de CO2 no aumento da temperatura. Na Terra, o efeito estufa é resultado de certos gases na atmosfera absorvendo calor e causando aumento de temperatura. No entanto, há uma visão divergente que argumenta contra o efeito estufa atmosférico, alegando que é um mecanismo fictício.