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Outdoor water deprivation methods

Posted by PersianMD2Orchard none (My Page) on
Fri, May 24, 13 at 16:04

Hello all,

I've been meaning to post this for a while just got some free time so I've been storming up a bunch of posts.

I think a bunch of us agree that water deprivation (not to the point of irrevocably damaging the plant of course) is great for fruit quality. In places where it rains a lot like near my home outside of DC and when you've planted outside... what are some simple tricks we can use to prevent water getting to the roots?

This is very important for figs the last week or two of ripening... but important for most fruit throughout the season.

First of all, I virtually never water anything around here unless plant is just planted recently, or crazy extended dry hot spell. I do however look at my plants pretty often so can see stress very early on.

My ideas mainly stem from physical barrier but perhaps French drain stuff would also work...

Physical barrier:
-Putting down rock hard/cement like dirt barrier as the very top layer for inch or less...possibly as I get more gutsy I'll put it down thicker. This is that dirt where you see bits of it dirt and pebbles cemented together in chunks. Perhaps leave some crevices like right around the trunk. Let most of rain splash right off and more of it getting evaporated before reaching soil. I actually did this to a fig recently when I had a bunch of really hard cement like dirt laying around.

-Maybe better than above, laying a couple cement squares around the base with just a bit crevices here and there spread out.

-Laying out tarp? I think some do this, but sounds more tedious than the above one and done.

-Some sort of special mulch?? Plastic mulch?


Follow-Up Postings:

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RE: Outdoor water deprivation methods

  • Posted by fruitnut z7b-8a,4500ft SW TX (My Page) on
    Fri, May 24, 13 at 16:42

Laying down rocks or cement squares will actually increase the available water to the tree. That's what we do here to reduce evaporation and runoff. You'd be better off with grass sucking out as much water as possible.

So anything you put down like that needs to carry the water out of the root zone. And the roots can extend out way past the dripline.

If you put the trees on a raised bed sloping to a trough between rows you might direct water into the trough and out of the orchard.

I think you'd also need an irrigation system for when it gets too dry. Also it's easy to panic when the trees start dropping leaves and cycle between too wet and too dry, don't ask how I know....;-)


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RE: Outdoor water deprivation methods

Never heard about the deprivation improves the fruit taste. I have 27 fig tree producing the most delicious most figs ans they get water regularly. Remember 75% of alive orgasms including humans are water. May be the plant content is more than 75%. Do you have any scientific research to prove your point.


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RE: Outdoor water deprivation methods

@Fruitnut, how about laying out plastic tarp method--perhaps only limited time before big rains and removing soon after in case that prevents evaporation from ground???

@Treehugger, It's a principle I'm not sure why isn't more widely acknowledged yet in the US but it has its following both in the US and abroad. The basic premise is that (over)watering and overfertilizing produces marketable large, reliable, but bland fruit--water can go straight to the fruit and dilute the flavor in addition to causing splitting/cracking. Many fruit originally come from dry climates and taste truly, truly out of this world when grown with no irrigation. However, according to some, even water depriving fruit native to wetter climates (like the blueberry) still has a dramatic improving effect on flavor. I believe the deficit of water becomes more influential on flavor the closer the fruit is to ripe.

It can be referred to as dry farming, deficit irrigation, etc. In regards to literature, I think there is plenty if you sleuth around... here's a tiny understated shout out to it from UC Davis (link below):

'In some circumstances, however, a slight water stress induced at specific growth stages can improve fruit flavor, enhance sugar or oil content, and limit vegetative growth.'

And here's some recent buzz article about it catching on:
http://ae.cqrollcall.com/farmcredit/latest-news/ybs-news/dry-farming-draws-interest-of-small-growers-in-central-valley-2/

Here is a link that might be useful: UC Davis watering fruit

This post was edited by PersianMD2Orchard on Sat, May 25, 13 at 8:42


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RE: Outdoor water deprivation methods

Treehugger,

If you've followed this forum long enough, you'd have known that this topic (withholding water to improve fruit quality) has been discussed here before. I remember one about peach quality.


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RE: Outdoor water deprivation methods

I know I've discussed it here and the tarp idea is something I've mentioned but never gotten around to trying. Ample water improves fruit quality in spring- it is at some later point during the ripening process that water deprivation increases brix- I'm guessing this is when cell numbers of fruit stops increasing and greater size comes from larger cells. I wish I had the information about the best point to cut off water.

I have observed that lighter soils tend to produce sweeter fruit- but not in all species. Plums don't seem affected by available water much. Probably most of the available research on the subject has been done on wine grapes.

I believe that if you want to effectively reduce access to water you may need to also do a bit of root pruning at the perfect time. If the roots extended beyond the tarp, the tarp might have little affect on access to water.

One thing I have tried was to stop mowing after June, but that year there was so much rain that even tall weeds couldn't dry out the soil.


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RE: Outdoor water deprivation methods

  • Posted by fruitnut z7b-8a,4500ft SW TX (My Page) on
    Sat, May 25, 13 at 14:31

It's easy to visualize using tarps or heavy black poly to drain nearly all water away from the trees root zone. If the orchard floor has the proper grades, the water can be directed between the rows and then out of the orchard. If the poly runs from row to row it could cover the entire area between trees or part of the area to allow some rewetting. A drip line on each side of each row would complete the system.

I'd have the area uncovered in winter to rewet the soil. Then cover as growth starts and uncover as needed to wet some of the rootzone. You could also leave it covered all summer and drip as needed, basically what I do.

This would probably work best on deeply rooted trees. With deep soil they would probably need minimal water during the summer. This has been tried with corn in the Midwest and a good crop was grown on good soil with no rain.

What you want is a gradually increasing water deficit in the plant over at least a month or two and then a constant deficit all summer. In my greenhouse I develop a deficit in February, March, and April. This probably pulls about 5-6 inches water out of the soil. Then maintain that by applying one inch every 10 days all summer.

What it would take to make it work is an ability to spot the right level of water deficit at which the tree needs more water. Then you'd need to figure out how much to apply after the tree is in deficit mode. My numbers above would be starting points.

Could it be made to work and is it worth the effort, I don't know. But if your fruit isn't sweet enough to suit your taste then a good place to start would be using a refractometer to see where your fruit stands on brix.


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RE: Outdoor water deprivation methods

  • Posted by mrclint z10SoCal Valley (My Page) on
    Sat, May 25, 13 at 16:02

Yes, water stressing fruit trees on purpose has been discussed here many times. I prefer to keep even moisture with mulch and deep watering as needed. A decent moisture meter can help take some of the guess work out of over/under watering. In my hot/dry locale playing around with water stress can be a dangerous game (it is already a factor even with frequent watering).


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RE: Outdoor water deprivation methods

PersianMD2Orchard,

Maybe that's why Colorado peaches are so good. Could you please send your extra water my way:) I can't imagine having too much water.


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RE: Outdoor water deprivation methods

  • Posted by fruitnut z7b-8a,4500ft SW TX (My Page) on
    Sat, May 25, 13 at 17:11

I think there are probably quit a few outdoors locations especially in hot dry climates where you don't have to try in order to develop a water deficit in your trees. In fact my issue outdoors has been too much water deficit. In the greenhouse, where light levels are a fraction of outdoors, the contrast is stark. Same soil and I'm applying about 1/3 the water in order to maximize brix.

I've got some over watered trees in the greenhouse this year. Issue is trying to nurse along newly planted trees right next to old deeply rooted trees. You either have to over water the deeply rooted or under water the newly planted. The difference in fruit quality is huge on my Arctic Star nectarine. They run 22-28 brix with superb flavor grown with a water deficit. In contrast when over watered and 14 brix they have zero flavor and aren't worth eating.

I don't know where you guys stand growing outdoors in a humid climate. If you'd test and report brix numbers we might all find out.

This post was edited by fruitnut on Sat, May 25, 13 at 17:14


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