Is this chlorosis? Can it be fixed?

[edweather]

We have five citrus trees in our backyard. All of them are fairly young, 6 years down to two years.  They are growing well for the most part, and we fertilize 3 times per year with citrustone, but I noticed this on the Cara Cara. Is it chlorosis? We live in southeast Georgia, and the soil is mostly sand. This is the dry season, and we water twice a week with tap water, which has a pH of 8.5+. Will a constant supply of alkaline water cause this, or is something else causing it?  Not sure how much the sand/soil buffers the watering. Rainy season starts in June. This is the worst affected, and I've seen a little on the others, but not too much. We had a soil test done 3 years ago and the pH was 4.6. Any suggestions for a cure are greatly appreciated. Thanks,  Ed

[pinkturtle]

Check this post, I think it is the same symptom.

http://tropicalfruitforum.com/index.php?topic=39359.0

[giorgosgr.]

Due to your high pH it cant absord nutrients.

[edweather]

Thanks. So it looks like a manganese deficiency rather than an iron deficiency,  due to the green borders on the green veins. Thanks for the link. Anybody else have low pH soil, with high pH water? Can I assume that the soil/sand isn't buffering the water enough, making it hard to absorb nutrients?

[Oolie]

A lot can change in three years. Micronutrient bioavailability is pH based, and is best within a narrow range.

If your soil has high buffering capacity (clayey or silty or organic matter) you could be too low, if the buffering capacity is low, you could be seeing high pH. Either way, a drier soil promotes extremes, though citrus don't typically favor wet feet.

You've correctly identified the symptoms, the next step is to determine the cause.

Low pH soils are often leached, so you may very well be seeing actual low micronurient presence.

You can foliar feed to remove the symptom, but the cure can't be assessed without more data.

You need an actual pH test.

[Millet]

Threads about manganese deficient leaves are commonly posted at this time of year.  It frequently happens with a new flush of leaves.  In relation to other soil  micrometeorites the amount of manganese in soils is much less. The leaves of a new flush grow faster than the tree can uptake manganese from the soil.  It take a while for the tree to ketch up and provide enough manganese to the new growth.  Normally, the tree eventually takes care of the transit deficiency and cures itself.  A  manganese deficiency can also be caused by high pH.

[edweather]

Thanks everyone.  I'll hang in for a while.  Yeah, most of the older growth is solid dark green.  Anybody ever add a little vinegar to lower the pH of the water?  I used to do that with my container blueberries? I have a feeling it's the high pH of the water.  We've had almost no rain in the past month, and it's been warm and sunny almost every day. The ground dries out fast, and the trees have been getting a good tap water soaking every 4 days or so.  All the trees just got a nice dose of Citrustone a few weeks ago, so imo, the micronutrients are there. There has been heavy new growth this spring too, which adds to the problem, just not enough ability to uptake.