What is wrong with my orange tree?

boy i'm going to be the odd one out here hey, maybe i just let this one slip by?

your soil looks pretty miserable to me, at the very least it needs lots more organic material added. have you ever had a PH test done? maybe get an opinion from the local plant/garden centre on what they think the soil is missing. most do free PH tests so take a good sample along the sample should be from around 6"s down.

to me (and we've planted a lot of citrus in alot of gardens with total success) the citrus looks less than as healthy as it should be, the green is yellowish incipid, could mean wrong PH as well as lack of nutrient level around the plant.

as for never using amendments when preparing a planting position for citrus, that is a new one to me and goes against our successes. for one when planting citrus in a poorly drained heavy clay spot (common problem here), we generally dig a whole about twice the size of the pot of the potted plant then we back fill tamping down to minimise settlement to create a planting mound, to create drainage for the feeder roots.

all our 6 or 7 citrus in this poorly drained garden are about 4 years old from the pot and all are producing full crops of fruit (have done for 3 years now)on acontinuing basis. we mulch heavily around them we don't feed them, and do very little pruning (probably slack on my part), there is no bug attacks.

our ammendment was mushroom compost from the farm, around 3 to 4 bags per planting position. now they are all established we don't water, they get rain water only around 1100mm per year av'.

so if that citrus was mine i'd dig it up, dig a larger hole ammend the hole, just in case you get lots of water that is slow to drain i would plant it in a raised position, and mulch heavily. buy yourself a PH test kit if the PH is too acid say then use dolomite at the prescribed rate to amend the hole and the planting area.

we are gypsum fans so all plantings here get at least a good dose of it, works in our area for us.

that's how we do it i guess.

len

Here is a link that might be useful: lens garden page

It looks to me like you have about 0.03 percent organic matter in your soil, way low. You want between 5 and 8 percent, so you need to amend that soil with compost and other types of organic matter, vegetative waste.
Many California soil are sodic, because of lack of rain to wash the soil, so possibly gypsum might be of value depending on your soil pH.

Liquid dish soap is not what you need to use as an antiflocculant. You need something that doesn't foam, like dish washer powder, plain Calgon, or washing soda (laundry booster).

What would be an economical, effective way to remedy this soil? Mixing in 1-2 yards of "compost," or "bedding mix," from a local soil supplier? Using the bedding mix for ~18" high mounds or raised beds, at least for this season?

Tomatoes have grown well in this soil in the past, but I'd really like the orange tree and some other vegetables to thrive this year.

What kind of organic matter is available to you?
What is the cost of that organic matter?
Is something from a garden shoppe the only organic matter available to you or is there other yard waste you can use?
I, much too often, see people clean up their yard and bag that waste to have someone haul it away to throw in a landfill someplace instead of recycling that yard waste right on site. This is compounded by very short sighted local ordinances, or homeowners association rules, that prohibit composting or even recycling yard waste.
I have some people that I correspond with that live in the San Diego area that tell me that maintaining sufficient organci matter in the soils there is much harder because the soil bacteria never stop working, but by planting cover crops and making sure they reuse all the yard waste they can (even getting some from neighbors) helps.

Our county promotes yard recycling and composting. I could till all of the grass and weeds into the soil, but that would be a substantial amount of work and I'm not sure how much it would help the soil.

The place in the link (local to me) sells composted green matter for ~$30-$35/cubic yard, and bedding mixes for $30-$50/cubic yard.

Here is a link that might be useful: American Soil & Stone - Amendments

art_1 there is no reason to till all of your grass clippings and "weeds" into your soil but you could mulch mow them back in, or collect them form the lawn and use them as mulch on the garden and while that is a small amount of what most soils need it is a start. Compost around here, from commcercial sources, sells for $16.00 per cubic yard, when sold in 5 yd3 loads.

You could dig holes, too, and bury kitchen veg/fruit scraps. Fall leaves are a great amendment if any are available in your area. A bale of straw is cheap and makes good mulch too. Use any yard waste.

Karen