Tuesday, July 20, 2010

irrigating ?

I mentioned on Wonderings from Walnut Prairie I had been out one evening irrigating.  Some of my friends and family don't understand what that means, so I'll pause here a bit and try and explain a little.  We are blessed and cursed to farm some ground on the edge of the Wabash River floodplain with gravel under it.  The cursed part has to do with flooding (naturally) and the poor water holding capabilities of these soil types. If you don't get an inch of rain a week it is very difficult to get a good corn crop.

The blessing is there is an abundant supply of water close to the surface.   Put a driven point on a pipe and stick it 20-30 feet in the ground and you can't pump it dry

So we can have a well dug less than 100 feet deep and pump hundreds of gallons a minute out of it.
That's great, but what do you do with it?  Various delivery systems have been used, hand stringing pipes and putting up sprinklers, using hose reels and towable guns, in some parts of the country they mechanically level the ground and just flood it.  The best way we have found is a center pivot irrigator

Now lest anyone think this is all great and easy, let me refer you to a statement I made one day that nobody has ever argued with "The only thing worse than having an irrigator is NEEDING an irrigator".  You are placing a machine hundreds of feet long out in the open, in all types of weather, that seems like an ideal nesting spot for mice and other rodents,  and expecting it to work flawlessly at critical times in your growing season. Yeah, right.

A "for example" is this connection box at one pivot.  Somehow the fitting on the conduit came off, broke, something that made just enough of a space for a mouse to get in.

All that nest on the ground was inside that box!  And see the nice shiny wire?  The mice chewed all the insulation off those 480 volt wires.  I was really surprised we didn't find fried mice in the box.  Lighting also causes fun times
But these are not the day to day things that cause me to be out at night.  We have one pump that supplies 2 systems

Sounds cost effective and efficient?  It is .. but when you are switching to or from the remote system you're a long walk to and from it.  It's not complicated, just shut one down, open and close some valves to redirect the water, unplug and plug in the 480 volt wire and the safety wire, bring the system up to pressure and voltage, drive 3/4 mile to the other pivot, start it, drive 3/4 mile back to the pump and set the safety switch ... nothing to it.  The real tricky part is because the remote system is a towable.  The field is 1/2 mile long and 1/8 mile wide with an 1/8 mile long pivot on one side of it.  So you water one end, move to the other end and do it again.
This photo was taken from up on the pivot. Yes, it goes WAY down there.  The pivot isn't too hard to move.  Disconnect the 480 volt line, the safety wire, removed the ground wire, take off the water pipes, unhook the tie down chains, and pull it.  It's even on wheels

Oh yeah, forgot something,  The 3 towers need the wheels turns sideways.  You raise each tower off the ground, trip a latch and rotate the wheel assembly 90 degrees.  Then you pin it in place and hang up the drive shafts.  Tow it WAY down there and do it all in reverse.  But you don't do this in the middle of the night.  Because this is supplied from the other system and because it has to be in the right place to move it, there is a timing issue. You have to coordinate running this system with running the big system.

One good thing about this system is it waters the dry corners on the field beside it. However, that means that 11-12 hours after you start it you have to reverse its direction.  and about a hour later you have to park it in just the right place in the alley so it can be moved.   That usually happens about 14 hours after you start it.  So usually we start it late in the evening and let it run all night so we can shut it down first thing in the morning so after lunch we can move it.   That's where I was coming from at 9PM the other night.

Plus you don't just turn them on and forget them.  Every few hours you need to put eyes on them, check out the engine, make sure it is all working properly.  Because stuff happens

That gearbox is supposed to be on the left side of the frame.  The phrase designed obsolescence comes to mind.  And that is why at certain times of the year Jimmy C says "!@# $%^& you go through town a lot".

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