HALF THE WATER SAME YIELD !

[danoz]

Hi all i'm a very kean grower and have been for some time i'm also a scientist.

 

Today i would like to talk about a watering method known as Partial root drying (PRD)

 

While doing some research for a client i came across a paper that was released in the CSIRO australian journal of experimental agriculture about ten years ago. I think this paper has huge relevence to outdoor weed growers.

 

The paper explored an experimental method of watering grape vines.

 

Two drippers were fed to each vine one on each side of the vine so that approx half the root system could be watered at a time. l

The experiment aimed at watering half the root system at a time while leaving one half dry.

The hypothesis was that if half the root system was left dry then the dry half of the root system would release the hormone ABA (absicisic acid) a key function of this hormone is to cause the pores on the leaves (stomates) to close and thereby reduce transpiration. However the watered half of the root system would provide enough water for all of the plant.

Basically the plant would switch into water saving mode while recieving plenty of water.

 

The results were amazing. Water use was close to halved. leaf and shoot matter was reduced but yield grape was not reduced. Grapes were smaller but sweeter and more plentiful.

 

This research has since been used in practice with great results.

 

This same hormone > stomata pathway exists in weed plants and there is no reason why it wouldnt work on weed. I plan to try it this summer.

 

Something you need to know however.

 

The effect wears-off after two weeks at which time you have to swith the half of the root system that is watered and the half that is dry - then the effect is reestablished.

 

Also some potential effects i can see are.

If you reduce transpiration you may reduce nutrient uptake therefore if you try this make sure nutrient status of soil is high to reduce potential for induced deficiency. Calcium would be particulary susceptable to this because it can only be obtained through young root tips and relies on transpiration for plant uptake. therefore some lime or gypsum with ferts is recommended.

 

Another thing is stomata are needed to obtain CO2.

 

Basically this method of watering is amazing but... has some draw backs. if the biggest limitation to your grow is water then this is for you. If sunlight is yours then this is not for you becuase u want max photosyn and this may reduce it because less gas transfer from stomata result.

 

As i said im gunna try this on my plants out bush this summer ill post my results

 

If anyone would like the paper email me because it costs shit loads for the 8 page paper off the CSIRO WEBSITE

However you can read the abstract for free and it has everything you need to know.

[MongyMan]

Interesting post Danoz, I'm interested to see the results you get. Experimenting is addictive though remember

 

Peace MongyMan