Water use and Irrigation Flashcards
What are the different types of irrigation systems
furrow, drip, flood, dual drip, micro-sprinkler
How does water move in plant
from regions of higher to lower water potential 0-> -1.0
Osmotic potential
potential of water molecules to move from a hypotinic solution (more water, less solutes) to a hypertonic solution (less water, more solutes) across semipermeable membrane
Drought Stress symptoms
kernels shrivel, nut size reduction, wilting, defoliation, shoot growth inhibition
Excess Moisture symptoms
leaching of nitrogen, water logging, fungal diseases, water wastage, energy wastage
What determines the rate of infiltration into a soil
volume of air space (porosity) and size of pores
True or false there is a direct relationship between texture and pore size?
true
which irrigation system is the most efficient?
Drip, 90-95%
How do you determine water needs
soil based methods, visual touch method, soil moisture probe, plant-based methods, pressure chamber, weather-based methods
TDR
time domain reflectometry, based on travel time of a high frequency electromagnetic pulse through the soil
FDR
Frequency Domain reflectometry,
tensiometer
principle: directly measure soil matrix potential, porous ceramic cut at base in contact with soil
What causes low potential at the leaf stomata
photosynthesis, gas exchange, plant water loss
What does a pressure chamber do?
measures plant water tension by applying pressure to a severed leaf and stem enclosed in an airtight chamber
Evapotranspiration
the sum of water loss from leaves (transpiration) and water loss from soil (evaporation)
Reference evapotranspiration (ETo)
defined as the rate of evapotranspiration from a hypothetical reference crop with an extensive surface of green grass of uniform height, actively growing, well-watered, and completely shading the ground
Allowable depletion
safe amount of depletion as a percentage of total available water in the profile prior to growth reductions
what are the crop factors of evapotranspiration?
crop, cultivar, phenology stage of development, height, planting design, rooting depth and profile characteristics, ground cover
What are the management factors of evapotranspiration?
disease, insects, fertility, salinity, irrigation system, planting design, soil water content, ground cover, windbreaks, mulches
Cimis
repository of climatological data collected at more than 125 automated active weather locations throughout California
What soil texture has the higher water holding capacity
loamy, silt clay loam
What soil texture has the least amount of water holding capacity
very course
When can you reduce irrigation in almonds for drought
after mid june, likely result of modestly lower individual kernel weight
When should pistachios not be under-irrigated
from bloom to end of shell expansion, nut filling to hull split
When can you practice di in pistachios
50% reduction in irrigation during shell hardening, 70-75% reduction in irrigation during the postharvest period
