Robert Dailey's Blog
Posted by Robert Dailey
Desert soils are notoriously lacking in micro-organisms. Dried by winds and constantly pounded by ultra-violet rays from the sun, lack of rain, and many other factors contribute to the dirth of these microbes.
However, in good garden soil, there are millions of these organisms in cubic inch. Bacteria, fungi, algae, viruses, nematodes, actinomycetes, protozoa and yeast are all living organisms which help break down soil into nutrients that plant roots can absorb.
In fact, a couple of pounds of good organic soil will include almost two trillion organisms.
A gram of good soil will usually have the following ranges of microbes”
- Three million – 50 million bacteria
- One million – 20 million actinomycetes
- 5,000 – one million fungi
- 1,000 – one million yeast
- 1,000 – 500,000 protozoa
- 1,000 – 500,000 algae
- 10 – 50,000 nematodes
Posted by Robert Dailey
Green manure is generally planted in the fall, and then incorporated into the soil in the spring. In addition to adding organic material to the soil, these cover crops also help prevent erosion and loss of topsoil.
Legume crops such as hairy vetch can supply 50 to 100 percent of all the nitrogen needed for tomatoes. And, they help reduce the need for synthetic fertilizers.
Green manure crops, when grown for a full season, have been known to break up hardpan (caliche), and improve the air and water conductivity of the soil.
The general practice is to incorporate green manure crops two to three weeks before you plant vegetables. You could also take the temperature of the soil and incorporate the cover crop when the top four inches of soil reaches 50 degrees F. Don’t allow the cover crops to go to seed, though, because the seeds will germinate and cause problems later.
There are several ways to incorporate green manure crops. One way is to till the plants in with a tiller. Another way is to simply hoe them down, and then shovel or rake them into the soil. A third way is to “double dig,” that is, use a shovel to dig the area, turning the cover crops onto the bottom as you dig.
Posted by Robert Dailey
Ready to build up the soil in your desert garden? Look around! There are good sources of organic material all over.
What you want is un-decomposed organic material that can be broken down by organisms in the soil. If your soil is sterile or near sterile, don’t worry. Many organic materials that you add carry their own micro-organisms. Other organisms will be drawn to the richer soil.
Good organic matter includes manure (cattle, sheep, horse and chicken manure make good soil additives). Don’t use manure from animals that can carry organisms that might be harmful to humans, such as pigs and pets.
Leaf mold, sawdust and straw are also good organic materials to use in building up your soil.
In order to help the organisms decompose the materials, you will need to keep the soil moist. You will also need to add nitrogen, to aid the decomposition. (Soil microbes require nitrogen for their metabolisms to work.) If you also add green material (grass clippings and the like) you may not need to add nitrogen, because it’s already present.
You can also add compost to the soil. You can either make compost by building a compost pile, or you can buy it from your local garden supply store.
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Posted by Robert Dailey
During November, Desert Gardens conducted an online poll asking the question: Speculators and big companies are buying up the world’s fresh water supply.
There were five possible responses. Below are the responses, and the percentage of readers who voted for each. The responses are ranked from most popular response to the least popular response.
- (77.6%) It’s an abomination. Water should be kept in the public domain.
- (5%) I don’t think it’s a good idea. Water will cost as much as gas.
- (3.4%) It’s okay if they don’t charge too much for it.
- (5%) I wish I were one of those speculators. It’s capitalism.
- (0%) So what? There’s no water shortage anyway.
Nevertheless, there is no indication that the buyers of the world’s fresh water supplies will back off anytime soon.
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Posted by Robert Dailey
Despite the fact that desalination of seawater can provide needed freshwater to certain areas of the world, there are problems associated with it.
There are over 7,500 desalination plants in the world, converting billions, if not trillions of gallons of sea water.
60 percent of all the desalination plants are in the Middle East while 12% of desalinated water is produced in the Americas, including several plants in the Caribbean.
Despite the fact that desalination plants can produce fresh water, usually by reverse osmosis, there are some serious drawbacks to desalination.
- Destruction of fish and crab larvae. It is estimated that one plant in California alone is responsible for killing 53 million fish larvae and 14 million crab larvae per year.
- What to do with the brine? When seawater is desalinated, salty brine remains. Currently, this brine is being dumped into the sea, sent to wastewater plants, injected into saline aquifers, or injected into oil wells. But problems exist. Sinking brine plumes threaten sea life, particularly those at the lower end of the food chain. Injected, it runs the risk of polluting groundwater.
- Toxic metals. The brine may also contain toxic metals which can also contaminate ground and surface water.
- Chemicals used in defouling process. Desalination plants use chemicals to defoul, kill bacteria and algae that tend to grow in pipes and systems. These chemicals must be removed before the water is used as potable water, or water for irrigation.
- Cost. The cost of water produced by desalination plants is significantly higher than that obtained from reservoirs or aquifers. In general, desalinated water costs anywhere from $700 per acre-foot to $6,000 per acre foot. Water from aquifers costs around $200 per acre-foot. Water in reservoir basins costs about $35 per acre-foot.
