60 % can cause water stress. A low-relative humidity may happen during ventilation in arid climates, or when plants are young with small leaves. On the other
hand, serious problems can occur if the relative humidity exceeds 95 % for long
periods because this favors the rapid development of fungus diseases.
Cooling and heating methods/systems to control greenhouses environment may
include natural ventilation, shading screens, whitewashing, force ventilation,
evaporative cooling (fogging, sprinklers, wet pads), piping hot, and hot air generation (Baille 2004). The option to be used for control of climate inside a
greenhouse depends on the investment grade, the margin between the increase in
crop value, and the cost.
Greenhouses provide many advantages as well as several disadvantages. The
former are related to the harvest of high-quality agricultural products, increases
in volume production, obtaining of off-seasonal products and pest and disease
attacks are reduced to a minimum. The latter include high initial cost, high cost
maintenance, and specialized operation to effectively control climate inside the
greenhouse.
Much research is currently performed in order that in future greenhouses,
control can be made by plant monitoring methods through image analysis which
simulates the action of the greenhouse grower in evaluating the physiological
processes and the plant growth stages. Also, relevant studies are carried out related
to establishing setting points for the greenhouse microclimate control taking into
account plant processes such as transpiration and photosynthesis that vary with the
day and vegetative state of the plant. Advantages and disadvantages of control
theories applied in greenhouse climate control systems are summarized by Galvan
et al. (2012).
Horticulture in a protected greenhouse environment is increasing rapidly and it
is consequently increasing in its economic and social importance. For this reason,
the development of better greenhouse cover material, crop substrates, accurate
ways to achieve appropriate climate conditions to ensure high-yield, and quality
crops reducing energy consumption will continue to be topics of research, since
they are closely related to the future of agriculture. They are related to the manner
in which food products are going to be produced in order to satisfy the food
requirements related to quantity and quality of an increasing population.
1.11.3 Strategies for Increasing Yield in Fresh Weight
and Phytochemicals
At this point, it is necessary to define some important concepts that many times are
misunderstood. To have this common frame of concepts will facilitate the
understanding of the subsequent paragraphs.
Phytochemicals a variety of compounds made by plants. Chemical compounds
from naturally occurring in plants. They are responsible for the odor, taste, and
30
L. Garcia-Mier et al.
hand, serious problems can occur if the relative humidity exceeds 95 % for long
periods because this favors the rapid development of fungus diseases.
Cooling and heating methods/systems to control greenhouses environment may
include natural ventilation, shading screens, whitewashing, force ventilation,
evaporative cooling (fogging, sprinklers, wet pads), piping hot, and hot air generation (Baille 2004). The option to be used for control of climate inside a
greenhouse depends on the investment grade, the margin between the increase in
crop value, and the cost.
Greenhouses provide many advantages as well as several disadvantages. The
former are related to the harvest of high-quality agricultural products, increases
in volume production, obtaining of off-seasonal products and pest and disease
attacks are reduced to a minimum. The latter include high initial cost, high cost
maintenance, and specialized operation to effectively control climate inside the
greenhouse.
Much research is currently performed in order that in future greenhouses,
control can be made by plant monitoring methods through image analysis which
simulates the action of the greenhouse grower in evaluating the physiological
processes and the plant growth stages. Also, relevant studies are carried out related
to establishing setting points for the greenhouse microclimate control taking into
account plant processes such as transpiration and photosynthesis that vary with the
day and vegetative state of the plant. Advantages and disadvantages of control
theories applied in greenhouse climate control systems are summarized by Galvan
et al. (2012).
Horticulture in a protected greenhouse environment is increasing rapidly and it
is consequently increasing in its economic and social importance. For this reason,
the development of better greenhouse cover material, crop substrates, accurate
ways to achieve appropriate climate conditions to ensure high-yield, and quality
crops reducing energy consumption will continue to be topics of research, since
they are closely related to the future of agriculture. They are related to the manner
in which food products are going to be produced in order to satisfy the food
requirements related to quantity and quality of an increasing population.
1.11.3 Strategies for Increasing Yield in Fresh Weight
and Phytochemicals
At this point, it is necessary to define some important concepts that many times are
misunderstood. To have this common frame of concepts will facilitate the
understanding of the subsequent paragraphs.
Phytochemicals a variety of compounds made by plants. Chemical compounds
from naturally occurring in plants. They are responsible for the odor, taste, and
30
L. Garcia-Mier et al.