I'm doing some maintenance and mowing between the citrus trees in the orchard. Everything looks nice and green right now, but I want to get rid of the weeds and plant something between the rows in the orchard. Does anyone have any suggestions for something that might nitrogen fixating, drought resistant, choke out weeds, cheap, etc.

Thanks,
Phillip

In citrus groves there are normally three systems of soil management ---clean cultivation, continuous cover crops, and a combination of these two. Cover crops (green manures) are grown in groves for the organic matter they add to the soil when turned under before they reach maturity. In soils that are naturally low in organic matter, cover crops benefit greatly by regular additions of it, and further, the ability of organic matter to support good tree growth. Other growers attempt to keep the soil constantly covered with grass , or a herbaceous crop in the summer, and a cold resistant crop during the winter months. Know that a permanent ground cover kept year around seriously competes with the trees for nutrients and moisture, and can create a fire hazard in winter. Groves where the soil is covered with vegetation, weeds or mulch, injury to the trees from frost or freezes is greater. Bare cultivated soil radiates heat more freely to the trees than soil covered with vegetation, and so prevents their reaching an injurious temperature as soon. Besides the greater fire danger during the dormant season, groves that keep a ground cover, have a higher pest problem. Plant bugs and grasshoppers are the pest most involved. Two general types of cover crops are used -- leguminous and non-leguminous. Some growers like to plant legumes for the nitrogen that legumes take from the air and deposit into the soil. While it is quite true that legumes do increase soil nitrogen, the amount is negligibly small, so that no difference is made in calculating fertilizer needs in groves with legume cover crops from those with other kinds. But, because of the of the rather small advantages and considerable disadvantages of legumes, many other growers prefer to make no special planting of a cover crop, and simply allow the native or naturalized weeds or cover the ground. I would either keep the soil cultivated bear, or as a second choice, simply plant a native grass, provided you have enough water allocation, to support both the ground cover, and your trees, as any permant ground crop will take a lot of moisture and nutrients from your trees. (Citrus Growing in Florida) - (Millet 1,436-)

Thanks Joe. I'd be interested to see how the tests were performed and if any secondary exposure (say spraying weeds around grapefruit trees and then eating grapefruit showed any problems). I'd also be curious as to the half life of G and AMPA. I'll have to do a web search.

Thanks,
Phillip

With due respect of views other than mine, I use Round Up, as it allows me to spray close to the trunks of trees and around the vines in my vineyard, without the danger of killing the tree or the grapes. I can use it in the farm fields, without sterilizing the soil for extended periods of time. I personally think Round Up offers outstanding weed control, while at the same time offering a level of safety not offered by other herbicides. I will continue to use it, without any concern for my health at all. Breathing the air in Denver, and other large American cities, is probably a 1000 times worse for a person's well being. As Joe's post states, Round Up is by far, and by a very wide margin, the #1 herbicide used by farms in eastern Colorado (my area). Everything in life is a trade off. - Millet (1,435-)

I still use RoundUp but with very extreme care and precautions. Studies like those that I posted are worth looking into further. The studies should be scrutinized.

Well, it's been a long time since I chimed in but here I am. First, the use of mulch and green cover crops in Florida is very different that in CA. Since you are in San Diego, I think the case for both is much stronger.
I use to keep green middles but now my trees are large and there just isn't room between them. When young though, it was as big help. I would cut the green cover and rake it under the trees as mulch. I used a mix of Alfalfa and annual rye. Alfalfa seed can be hard to get unless you know a hay farmer. You can also use white clover, but Alfalfa is by far the leader in nitrogen fixing. All legumes will fix more nitrogen when the right bacteria is present so see if you can get the inoculate too.
Mulch is really more important that green cover. Good mulch adds nutrients to the soil while also helping to bring down the PH (which makes more nutrients available too), helps to regulate water saturation and keeps soil temperatures more even. I use a foot thick layer all around the tree, but not touching the trunk, for the first year. Then each year after that I add about 6 inches worth to "top dress" over what remains of the old mulch. That really does the trick for me. My trees are healthy green and prolific.

Round up? this is the organic board? Round up AARRRGGGGGGGGGGGGGG NO NO NO NO NO NO

This is the organic forum??? Roundup = chemicals.

(Not to mention that Roundups' maker, Monsanto, is EVIL): http://www.cbsnews.com/stories/2008/04/26/eveningnews/main4048288.shtml

What are weeds? They are opportunistic plants that do exactly what nature intends them to do. Nature abhors bare dirt, its not natural.
Large tracts of identical plants out in the open are exactly what attracts insect pests and weeds.
Roundup works by subverting nature and natural processes. The longer you use it, the more you have to use it.
A natural organic system benefits from the relationships between plants and poisons are not necessary.

As example: Who sprays Roundup in forests or other natural areas to keep the weeds down? No one, because it is not necessary, there are no weeds!

Citrus can be grown organically with beneficial cover crops and other permaculture techniques.

Sepp Holzer: http://www.superconsciousness.com/topics/environment/earth-mind

Masanobu Fukuoka: http://www.permaculture.com/node/140

You have to weight the costs versus the benefits for you. If your crop is your living, then I would not fault you for ensuring the best crop possible by using the most effective tools. If it is your hobby, then I suggest going the harder, less productive route. In my opinion agro chemicals are for agro businesses, and not for the home grower. The home grower doesn't need the highest yield possible. I think the healthier yield is better. Safe is relative. Round-up is relatively safe, but I'd still prefer not to consume it if I don't have to. No synthetic chemical floating around in your body is a good thing. Eliminate your exposures where you can.

Several months ago I added an organic mulch under my greenhouse Cara Cara and Marisol Clementine tree. The mulch was made up of things that I normally clean out of the greenhouse (leaves, weeds, trimmings, etc.). I understand that mulch around citrus is not considered a good idea, but I thought I would mulch the two trees as an experiment. The mulch did, of course, keep the soil moist and I'm sure had some advantages. One day I pulled back the mulch to check the soil, and was amazed at the thousands of various bugs that were living under there. It was unbelievable. I had no idea that that number of pill bugs (rolly polly) bugs existed in the would, plus other types that I have no idea what they were. I have since removed all the mulch, to the compost pile outside, and gone back to clean cultivation. - Millet (489-)

Pine straw...