Drip irrigation has been the latest and most effective development in plant growth in the last century. Water and fertilizer use has made it possible to extend the land area that can be utilized for food production and more recently for bio fuels.

I now describe a major improvement in this type of irrigation- which I call the “Water and Nutrient on Demand (WANOD) Irrigation System. With this system, both water and land use is optimized by (a): delivering water and/or nutrients to the plants’ root zone only when requested by the plant and (b): in amounts required by the plant. Thus both under or over watering does not occur and wasteful fertilizer is avoided. With increased demand for bio fuels extra farmlands have become essential forcing the use of less favorable land for farming.

In January 1981 a friend from the University of Manitoba’s Plant Science Department suggested that I attend one of their seminars to be given by a chemist from at 3M in St. Paul MN. It was an amazing talk in which Dr. L. Errede described how he grew plants in soil with a minimum amount of water. I wrote to Dr. Errede to obtain a small sample of the membrane material he used in order to try and test his method. He didn’t have any material to spare but referred me to his source from which I purchased a small roll for some experiments in the Chemistry Department’s coffee room. I was able to grow some flowers in a pot for a couple of years by using two membranes, one for water and the other for nutrients.

I left this topic to devote more time to my other research interest. This included a boat coating that reduces friction as the boat moves through water. This hydrophilic coating that does not dissolve in water was patented and is now available commercially as HySpeedKote.
I returned to the plant growth system in 2002 after I retired in 1997.  It seemed  to me that the potted planter was not an efficient way of growing crops for human use.  It took a year of constant search to find a suitable material with which to work.  This was a Canadian made irrigation tube with micro pores composed of polyethylene and made by Dupont.  By treating this membrane with the boat coating it was possible to obtain long lengths of tubing (2 cm diameter) which could be made hydrophilic by treatment with my boat coating and therefore responsive to the plants’ water requirements.  The system was tested in my home basement and my back yard garden.  A patent for the system was filed in USA in May 2002 and issued in April 2007.  I call this patented process a “Water And Nutrient On Demand (WANOD)”  Irrigation system.

The initial work on this system was developed by L. Errede at 3M in the 1970’s for potted flower plants and included one US Patent and six published articles.  He tested the system for over 1000 flower plants during about 10 years of study.  My second US Patent is under consideration and includes data that clearly shows that the plants can selectively chose between water and nutrient solution as its needs change.  Errede had shown that when the ratio of nutrient to water is doubled the uptake of the nutrient solution is decreased by almost ½.

How does the WANOD system work?  It is postulated that organic impurities in water become adsorbed onto the exit ends of the subsurface of the micro porous channels in the polymeric hydrophilic tubular membrane.  This reduces the flow rate of water through the membrane to significant extents depending on the pressure and level of the organic components in the water.  I have shown that the addition of paraffin wax to distilled water will be effective in reducing the flow rate of water through the membrane to a significant extent depending on the pressure. Distilled water does not stop flowing through the membrane since there is no change in the surface composition of the pores.  When the plant is in need of water and/or nutrients, the plants’ roots emit, among it many exudates, a substance, which has yet to be identified, that acts as a surfactant and removes the adsorbed organic contaminants and flow through the membrane is resumed.  The periodic flow has been verified by Errede for single plants.  However in a long row planter such fluctuations are not observed because of the differing needs of the multiple plants that are seldom synchronized.  I have grown vegetables in potted soil, sand, and other synthetic media such as vermiculite, perlite, rochwool, peatmoss and Fleximate.  Vegetables/Fruit that have been successfully grown with my new method include: tomatoes, cherry tomatoes, carrots, eggplants, zucchini, radishes,  potatoes, sweet potatoes, corn, cucumbers, lettuce, spinach, beans,  beets,  parsley, celery, onions,  parsnip,  Swiss chard,  rice,  grape vines, wheat,  canola, barley, melons, grape vines, strawberries, pineapple and more.

Rice grown in Dr. Guesser’s basement.

A search of the WEB identified two Desert Research Institutes—one in Nevada and the other in Sede Boker, Israel.  Neither showed any great interest in my  work although I eventually found some NATO funds to visit Israel.  In November 2004 I met with the people at the Blaustein Institute for Desert Research as well as with two manufacturers of drip irrigation tubing. However no great interest developed. 

The patents have been licensed to a Florida company that has extended its applications and is in the process of selling the system to an appropriate buyer.

In the meantime, our paper on the system has just been published in Journal of Applied Irrigation Science. Vol. 44,  (2009) pp 31 -37.