Tag Archives: irrigation management

Irrigating

Posted on by
Reply

In the Sacramento Valley it rains in the winter (hopefully) and is dry in the summer. Without irrigation the landscape would be brown. So irrigation is a necessary task throughout the summer. March was so dry this year that the irrigation district filled the canals and started the season earlier than usual. We irrigated March 20. There was some rain in April, but at this point in mid-May we were overdue for getting water on the field.

Graph that shows water levels in the pasture.

Part of the pasture renovation project (thanks to NRCS–search for Pasture Renovation here to see all the posts) was installation of two soil moisture sensors. This chart indicates measurements at 3 depths on a sensor in the south west (in bold colors) and one towards the east (lighter colors). They indicate soil moisture levels at 4″ (green), 8″ (purple) and 12″ (blue). The red line indicates flow through the irrigation system. All soil moisture levels were high after February precipitation, but you can see how the 4″ content drops fairly quickly and then responds to rain events. By this time in May it was very low and the 8″ readings were getting low as well.

The goal is to measure soil moisture in the root zone and use that to plan irrigation. We’re still learning to use it appropriately. If we irrigate too frequently we run the risk of running out of our water allotment by the end of the season, and who knows how long the dry season will last.

Irrigation ditch with trees on the right and dirt on the left.

This photo is the view looking west from just beyond the corner of our property. The water in the canal is leftover discharge from irrigation further up.

Irrigation ditch with some and trees and grass at the end.

Turning around, this is where the water enters our property. The half pipe on the right is an outlet for the discharge water so that it runs under the dirt road and into canal that goes south along the west edge of our pasture. When we irrigate we block that pipe off with boards to keep the water flowing west.

Cement-lined Irrigation canal.

I walked up that road to the west and then turned north to get to this point where the water is released from a bigger canal. The water goes south until it gets to a bend…

Cement-lined irrigation canal with water.

…where the canal turns east. This canal is mostly dirt, but the corners are concrete.

This is the other view of that canal

Dirt irrigation ditch with water beginning to flow.

Here is the water I asked for flowing down the canal (lower left) where it will meet up with the water that was already there but not flowing into our field.

When the water gets here it will start to fill our pipeline.

I came out a few times to clear debris away from the inlet. Before we put this screen up there were issues with larger weeds and branches impeding the flow into our system.

This shows the valves across the north pasture after the water started yesterday. I was out here many times yesterday to monitor how far the water had gone. It was much slower than the last time, probably because it is so dry and it takes more water to fully soak the soil. That March irrigation took only 24 hours for the whole place. We started yesterday about 8 a.m., and I didn’t finish this field until evening. I started the south pasture around 7 p.m. and went out to monitor it at 9 p.m., midnight, and 4 a.m. I already extended this as much as I could for today, but it won’t get everything irrigated.

Here’s the graph now showing that the moisture sensor on the west has been activated, but not the east one so far. This feels like a FAIL. We’ll need to get that water flowing again, but you can see it’s not as simple as turning on a faucet.

Pasture and Irrigation Renovation – Part 12 – Watching Grass Grow

Posted on by
Reply

Yesterday’s post described seeding on November 19, just before the 4″ of rain that we got over the next 3 days. Now we’re waiting for grass to grow.

This was grass growing on December 1.

Yes, it’s there, but you have to be paying attention to see what’s happening. We’re not just watching for grass. We want to see those broad-leaf plants too.

This is three days later on December 4.

Rodents at work.

The next day the irrigation crew came back to install the flowmeter and soil moisture sensors. That tube on top of the concrete box has a something that looks like a fan or propellor on the end of it.

That is the part that is now in the pipe and the rod is mounted to the concrete box.

The pole outside the box has solar panels and some other kind of gadget on it. At this point I don’t know how any of it works. We’re going to have a lesson about how to interpret the data it will provide to my phone.

There are two soil moisture sensors at the other end of the field. We had them place those poles where there will be fence lines so the sheep won’t be tempted to rub on them.

That white spot that looks like a quarter, at the bottom of the photo, is a rod that will measure moisture at 3 depths.

That data will also be transmitted to my phone.

This is the south end of the field. It is still wet enough that when the workers drove back and forth between these moisture sensors they created deep ruts. That’s unfortunate but there is nothing that can be done now. I think we have to wait until next year and then maybe disc this and the west side of the field where there is also compaction from vehicles during the final installation. We’ll wait and see.

Now we’re just waiting for more rain and grass.