The Tropical Fruit Forum

I am not convinced that the grass is a significant competitor for nutrients. Are there any scientific papers about this?

I'm in the same boat here.  If anything, I think the low-nutrient soil that is watered as heavily as it is would have more to do with the yellowing of the leaves, in my own opinion.

Still thinking it through and trying a few things, though.

Your trees need at least a 3 foot radius free of grass/weeds.

Healthy, highly productive citrus trees exist all over the low desert in flood irrigated lawns, and grass is commonly understood to condition the soil over time, due to the lack of other decomposing organic matter we have.  The soil in flood irrigated commercial groves here are also commonly covered in grass and weeds, as it's generally not cost effective to remove them and the alluvial floodplains in which citrus are grown are typically weedy with the addition of water.

I presume the reason you make this claim is that the grass will compete with the tree for nutrients.  I struggle with this idea, however.  Can you elaborate and we can discuss?  I have never heard of planting a tree in a mesic setting in the low desert producing foliar chlorosis because of the surrounding vegetation except in cases of desert-native trees (or ones with otherwise low nutrient requirements or seasonally wet-dry soil needs, like Eucalyptus camaldulensis) planted in chronically wet soil conditions.

First post.

I am fairly new to raising citrus, have some experience with other trees.  I live in Wickenburg, AZ, in a 9a climate.  The soil in my yard is, for the most part, really good.  This area is in a floodplain that was a cottonwood and mesquite forest for who knows how long, then - about a hundred years ago - was converted to crop farmland.  Afterwards, it was turned into a subdivision, and the house that formerly sat where mine is now had a lawn for 50 years or something.  The soil is, largely, a nice, dark loam that holds moisture well and is generally full of earthworms.

Unfortunately, however, there is one place where my soil isn't great.  This is underneath my lawn, where my grass is.  I had to buy a fair amount of screened fill dirt to build up the lawn area in order to elevate the lawn to a flat plane.  The area is flood irrigated, currently 3x per week (it's a small area, about 35ft x 10ft).

I have two citrus planted in this lawn.  One is a Nagami Kumquat - rootstock unknown but a presumed to be a product of Sunset Nurseries in Yuma - and an Owari Satsuma.  I have noticed that the Kumquat took on a fairly yellow color over the winter, and the new leaves are a bright, neon green.  The Satsuma has remained mostly dark green, but the new growth is - similarly - vibrant.  Photos are attached.

Anyways, I'm thinking this is foliar chlorosis.  I applied some 10-10-10 fertilizer earlier this month, and today added some Kerex as well.  If it is foliar chlorosis, I don't know if it's because I'm water the area too much, or if it's just because the soil is poor.

Can anyone offer some insight?  Does this appear to be foliar chlorosis, or just normal colors of new citrus growth?  Is there anything I should be doing beyond applying Kerex and 10-10-10?  Should I apply a liquid iron fertilizer to the leaves, or cut back on watering?

Let me know, thanks!

Adam