FIELD CHANNELS

1. Introduction

Field channels are concrete walled channels 102’ long, with varying widths up to 4’, that are permanent irrigation channels in the field.  They are large hydroponic channels that grow crops without the use of soil. The irrigation water is recirculated within the channels.
 The channels are intended to be used year round for the cropping of different crops in open fields.  In some cases, modified greenhouses called hoop houses can be used for protection although environmental controls are not as concise as in greenhouses.  Some examples are:

1. Starch crops and grains: taro, potatoes, and yams; and grains such as rice
2. Trees and bush crops: Blackberries, blueberries, raspberries, pineapples,
    apples, citrus, palm, grapes, tea, cocoa, olives, coffee and artemisia (antimalarial) 
3. Vine: grapes, tomatoes, cucumbers, eggplant            
4. Melons and squash
5. Forage crops: alfalfa

2.  Channel Description

           Materials                                   Concrete walls, metal mesh 

           Construction                              Cast in sections, near, or on site using local

                                                            sand, gravel, and local labour   

           Length                                      102’  / 31m for each field channel

           Channel Widths                         1’ /.3 m, 2’ / .6 m, 4’ / 1.2 m; width depends

                                                            on crop grown

            Rows between Channels            Varies with crop grown; 2’ / .6 m to

                                                            8’ / 2.43 m

3.  The main advantages of field channels are:

·         High quality food crops due to consistent nutrition and water

·         Faster growing and bigger crops due to consistent nutrients and water 

·         With this system we can grow any plant – size doesn’t matter – possibilities are 

      unlimited

·         Roots of crops can be harvested for animal or human consumption – a bonus crop ·         Better sales and more income due to higher quality of crops 

·         Longer storage life of some crops over traditional field crops

·         No weeding or herbicides, pesticides, algaecides

·         We can install this system over any type of flat land – fertility or arability is not an

      issue

·         Non arable industrial land can be “capped” with sand or gravel as a base for the

      channels

·         10% of the water used for field agriculture in arid conditions; water conservation

·         Water and nutrients are recirculated

·         Precise water management: none of the problems associated with major flooding 

·         Water handling with pumps

·         Drought proof (to a point) 

·         Not prone to rain or flood damage

·         Closer planting of crops

·         No soil infection problems such as bacteria, pollution, nematodes

·         Fast crop rotation times

·         No: tractors, oxen, ploughing, hoeing, land preparation

·         Sustainable: does not use up soil resources at each cropping

·         Retention of nutrients – a saving because they are recirculated; they are not going

      into the ground

·         No back breaking labour

·         Higher incomes compared to soil based operations

·         Minimal skill levels for crop tending

·         Pollution is zero; no nitrate pollution of water tables; all water is used by plants 

·         Adaptable to machine seeding and harvesting

Rice example:

Time from direct seeding to maturity allotment                     100 days

Crop yields considered normal                     India                 4 tonnes / hectare

                                                                Korea                7          “

                                                                 Phillipines         5.5       “

                                                                 Italy                  6          “

Crop height                                                3' - 6' / 1 – 1.8 m

Crops per year with field channels                3 and possibly 4

Yields with field channels                             2-3 times normal with because of more

                                                                  harvests and nutrient control 

                                                                                        
4.  The main disadvantages of field channels are:

·         Initial cost of installation

·         Best operated in warm climates where multiple cropping year round is possible

·         Flat land

·         Skill level required for irrigation and nutrient management – but learned quickly 

 The following pictures are successful tests of small field channels.

 Field channel test - squash

 Field channel test - zucchini