Scheduling irrigations for lettuce using climate data Ted






















- Slides: 22

Scheduling irrigations for lettuce using climate data Ted Sammis

The Water Budget Method • • The lelttuce root zone is a reservoir Water is added by irrigation or rainfall. Water is removed by evapotranspiration. Added water can be lost by deep percolation if the amount exceeds the field capacity of the soil.



Management Allowed Depletion • Management Allowed Depletion Is the percent of water that can be removed before soil moisture stress limits growth. • (For lettuce MAD is % 30. )




Evapotranspiration • Evapotranspiration is determined from climate data to calculate potential Evapotranspiration (water used by grass) and a scaling coefficient or crop coefficient for lettuce • The crop coefficient depends development of the crop or the land area covered by the crop. The crop coefficient changes throughout the growing season increasing to a maximum at maximum leaf cover.




Calculation of Evapotranspiration • • Potential Et= 0. 3 inches / day Et= K*PET K= 0. 8 Et= 0. 8* 0. 3 =. 24 inch/day


Calculated when to irrigate • Readily available water (RAW) = available water (AW) * management allowed depletion (MAD) • Example: • Aw = 2 inches/ft * 1. 5 ft root zone • Mad = 30% • RAW= 2 inches/ft*1 ft*0. 3 = 0. 9 inches

Irrigation Interval • Irrigation interval = RAW / Et / day • Irrigation interval = 0. 9 inches / 0. 24 inches /day = 4 days • Irrigation interval changes with changes in the Et or soil type. • Et changes with cover of lettuce and weather.

Source of Potential Evapotranspiration • New Mexico Climate Center Homepage • http: //weather. nmsu. edu


Temperature sensor and radiation shield

The Water Balance Spread Sheet • • • Inputs Climate data, paste into spread sheet Soil water holding capacity inch/ft Irrigation amount applied at each irrigation. Output – Date to irrigate on


Conclusion • The water balance-check book method can be used to schedule irrigations for lettuce. • The water use of lettuce can be calculated from climate data, and this is all that is needed to apply the correct amount of water at the correct time • The check book method can also determine the decrease in yield and amount of water stress when time between irrigation is to long.
Lettuce scheduling
Sjn scheduling
Climate change 2014 mitigation of climate change
Stages of lettuce growth
Amoebas
Burger king foot lettuce meaning
Nouns
Brocoli countable or uncountable
A student hypothesized that lettuce seeds
Crichex
Lettuce anyone
Lettuce počitatelné
Lettuce
Let’s get ______ lettuce
Lettuce
Romaine lettuce
A student notices that the lettuce in a salad
Jerry banks simulation
Big data on kubernetes
Hedera: dynamic flow scheduling for data center networks
Formuö
Novell typiska drag
Tack för att ni lyssnade bild