Irrigation Dreams

Last week, we tackled what is to me a challenging topic: farm irrigation. I am not a puzzle person, so for me, looking at a lot of hose, tape, sprinkler heads and random pieces that make it all fit together is extremely daunting. There are two main types of irrigation used at the farm: drip and overhead. Each has it’s benefits and challenges, and the trick is to try to maximise the former, and minimise the latter. Many different things come into play, including water pressure, type of crop, distance from water source, topography, animals, etc.

Drip

Miles of plastic drip tape

Miles of plastic drip tape

Drip irrigation is done by drip tape, thin hoses with holes built into it at certain intervals. As the name indicates, you spread it along the ground beside the crops, and when turned on at the right pressure, it will deliver water in small amounts directly at the base of the plant.

Drip irrigation is great for water conservation, because it uses much less water, and water is applied directly to where it is needed, instead of being wasted on land not planted. This also reduced weed pressure, since theoretically, weeds are not accessing the water. Drip is also essential for plants like tomatoes, that don’t like having water on their leaves.

For me, the biggest disadvantage of the drip tape is just the vast amounts of plastic being used, a resource I am trying to cut out of my life as much as possible because of it’s extreme impact on the environment, even if recycled. Some drip tape will only be used for one season, and then thrown out. It is prone to being punctured and broken by things like tools, tractors, and even coyotes, who apparently like to chew on them. The tape could also break or get blocked, which might result in only part of your crop getting watered, and if you don’t notice quickly enough, you may lose some of that crop.

Overhead

Overhead is what most people use at home, that is to say, sprinkler systems. Overhead seems much less complicated to me, in the sense that you can see exactly where the water is ending up. Sprinkler systems are much quicker to set up, and can be used each season.

Of course, overhead uses more water, since less water will make it to the root of the plants. On hot days, water may evaporate quicker on the surface of the soil, before penetrating to the crop roots. And sprinkler systems often leave some areas, like right around the base of the sprinkler, soaking wet, while outer edges of the field are dry.

Water Pressure

Laying out the drip tape

Laying out the drip tape

The numbers involved in this piece of irrigation went a bit over my head – talk of PSI, GPM, LPM, etc, were all a bit much for me. But suffice to say, for each piece of equipment you buy, you need to be aware of what kind of water pressure it can handle, and how much it needs. Too much water pressure, and your lines will blow, causing flooding. Too little water pressure, and some things aren’t getting the water they need. Irrigation involves a lot of trial and error, troubleshooting, and paying attention.

Most farmers seems to use a combination of the two systems, deciding what works best for each crop.

As DeLisa continues to tell us, an extremely important thing is to continuously walk your farm – know it well, look out for problems and issues so you can fix them when they are small. Small scale organic farmers have a lot of challenges, but working on smaller pieces of land mean we should know it well, and recognize when something isn’t working the way it’s supposed to.

The happy robin that follows us around as we work, scooping up exposed grubs

The happy robin that follows us around as we work, scooping up exposed grubs

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