Tutorial 3 : Fresh water is not that fresh

Question 1

livestock effluents

Answer 1

also known as wastewater

Question 2

aquifers

Answer 2

are underground water reservoirs

Question 3

agro-food sector

Answer 3

the entire chain of food production, from agriculture to food processing and distribution.
Important sector for ensuring food security and sustaining livelihoods globally

Question 4

plant water stress

Answer 4

occurs when plants do not receive enough water for optimal growth and development.
symptoms : wilting, leaf curling and reduced crop yield

Question 5

plant water status

Answer 5

hydration level of plants, affecting their physiological processes and overall health.
monitoring the plant status for optimization of irrigation management includes plant sensors and remote sensing technologies

Question 6

salination by sea level

Answer 6

sa;inity-tolerant crop varieties and soil management practices, such as drainage and leaching, help mitigate the effect of salination by sea level rise

Question 7

salination by irrigation

Answer 7

soil salinity buildup can be caused by an excessive irrigation and poor drainage.
- when fields are used to be irrigated with large amounts of water, the water evaporates in hot weather and salts would stay behind
- the minerals can accumulate on the nozzle of the drip irrigation systems

Question 8

irrigation methods (def)

Answer 8

various techniques and practices used efficiently to water crops, optimising water usage and maximise crop yield

Question 9

irrigation strategies (def)

Answer 9

approaches developed to manage the use of water for irrigation, considering water availability, crop requirements, climate conditions, resource sustainability

Question 10

drip irrigation

Answer 10

type of irrigation method that delivers water slowly and directly to the root zone of plants in small, controlled amounts through a network of tubes or pipes with emitters, minimising water wastage and maximising water efficiency

Question 11

rain-fed crop

Answer 11

crops that rely primarily on natural rainfall for their water supply, without the need for artificial irrigation

Question 12

irrigated crops

Answer 12

crops that receive supplemental water through artificial irrigation methods to meet their water requirements, in addition to any natural rainfall they may receive

Question 13

irrigation needs

Answer 13

the amount of water required by crops to sustain growth and development, which can vary depending on factors such as crop type, stage of growth, soil type, climate, environmental conditions
-> Irrigation water need (IN) equals the crop water need (ET crop), but some ET crop is provided from rainfall

Question 14

irrigation supplies

Answer 14

resources and infrastructures used to provide water for irrigation purposes
- > river, reservoirs, groundwater, pumps, pipes, distribution systems

Question 15

crop coefficient

Answer 15

a factor representing the ratio of actual crop evapotranspiration to reference evapotranspiration. It is used to estimate the water requirements of crops at different growth stages. It accounts for the crop’s characteristics and growth stage in relation to a reference crop under standard conditions

ETc = Kc * ET0

ETc -> crop evapotranspiration [mm d-1]
Kc -> crop coefficient [dimensionless]
ET0 -> reference crop evapotranspiration [mm d-1]

Question 16

soil sensors

Answer 16

device to measure soil parameters like moisture, temperature, PH and nutrients

Question 17

plant-based sensor

Answer 17

device that monitors the physiological responses of plants, such as leaf temperature, stomatal conductance, and chlorophyll fluorescence

Question 18

sensor controller

Answer 18

devices that manage and interpret data sensors. can automate tasks like irrigation, fertilisation, and climate control based on sensor reading

Question 19

vegetation indices

Answer 19

values that come from the data collected by sensors, that indicate the health, density, or type of vegetation cover in a given area

Question 20

normalised difference vegetation index

Answer 20

based on the difference between near-infrared and red light reflected by vegetation. the values range from -1 to 1, with higher values indicating healthier and denser vegetation

Question 21

crop evapotranspiration

Answer 21

process of water loss from a crop through evaporation from the soil and transpiration from the plants

Question 22

ET0

Answer 22

reference evapotranspiration is a rate from a well-watered, actively growing, uniform grass cover under standard weather conditions (obtained with the weather station)

Question 23

ETc

Answer 23

estimated crop growth requirements are the estimated crop evapotranspiration calculated based on the ET0 and a crop coefficient (Kc) that accounts for the specific water needs and growth stages of the crop

Question 24

sap flow (plant-based) sensor

Answer 24

measures the movement of fluid in the xylem via probes inserted directly into the plant’s sapwood

results are used to calculate the amount of water transpired by the plant each day

when the sap flow declines, indicates the plant is entering water stress
irrigation is triggered

Question 25

dendrometer (plant-based sensor)

Answer 25

measures the shrinkage/swelling of a plant diameter throughout a 24-hour period, indicating the amount of transpiration that has taken place

shrinks -> when transpiring
swallows -> when transpiration stops

Question 26

leaf turgor pressure (plant-based) sensor

Answer 26

turgor pressure is the pressure caused by hydrostatic forces created by the amount of water present in the cells of plants (turgor pressure in stomata regulates when they open and close)

It measures the pressure within the entire leaf tissue, rather than what is happening within an individual cell

Question 27

precision irrigation

Answer 27

irrigate each plant with the right amount of water at the right time, for optimal input use efficiency and minimum environmental impact.

relies on an optimal combination of the irrigation system, the irrigation strategy and the irrigation scheduling method

Question 28

regulated deficit irrigation

Answer 28

applying less water on the crop when the plant does not need much for its development at certain development stage

takes into account changes in the sensitivity of the crop to water stress at different developmental stages.

Challenging because it requires both a sound knowledge of the physiological response of the crop to water conditions and a precise assessment of plant water stress levels along the growing cycle

Question 29

scholander chamber

Answer 29

measure the approximate water potential of plant tissue

leaf and petiole or stem segment is placed inside a sealed chamber. Pressureiesd gas is slowly added to the chamber. As the pressure increases, at some point the liquid contents of the sample will be forced out of the xylem and will be visible at the cut end of the sample.

The pressure that is required to do so is equal and opposite to the water potential of the sample

Question 30

thermal sensing

Answer 30

uses thermal imagery or sensors to monitor temperature variations in plant and soil, aiding in crop management decisions for optimal yield and health

can be made at the plant level (ground-based imager) and from above the crop (airborne imagery)