Monday, March 18, 2013

Responsible Agriculture

The energy demand for growing fruits and vegetables hydroponically can be prohibitive, but before we label local urban agriculture impractical and unsustainable there are a few things we need to consider.  

The United States provides subsidies for oil and agriculture. If the produce at your grocery store is not directly subsidized by the government, the fuel required to get your produce to the store is. This makes it difficult to calculate the real cost-per-pound of produce at your local grocery store. What you save on your grocery bill comes out of your taxes.

Problems with American Agriculture About 20 cents from every dollar spent on produce at the grocery store reaches the farm. The other 80 cents represents the cost of labor, marketing and distribution.  

We’ve built an agriculture system in the United States that is high-input. The bulk of agricultural produce is grown on enormous farms where the same species is planted continuously for miles. These monocultures are susceptible to the same infections, diseases and pests. The only defense we have to a national food-supply catastrophe is maintained with industrial fertilizers, pesticides, and genetic manipulation. We’ve exported these technologies all over the world, where the cost of labor is low and environmental restrictions are lax, or non-existent. We import about 25 Million tons of produce (of fruits, vegetables, nuts) from farms overseas.

From the University of Michigan:

“Researchers have recently demonstrated that combinations of agricultural chemicals(pesticides and nitrate) are capable of altering immune, endocrine, and nervous system parameters in mice at concentrations of the same order of magnitude as current groundwater maximum concentration levels. These same researchers suggest that current testing protocols for pesticide approval are deficient in six identified testing arenas and do not adequately address the potential for biological effects under real world exposure scenarios (such as mixed and pulse dosages). They further raise the question of whether pesticides and/or other environmental chemicals might be associated with developmental concerns such as the surge in learning disabilities, attention deficit disorders, and orthopedic problems exhibited by children in the United States.”

Industrial Fertilizers The major source of industrial fertilizer is anhydrous ammonia: a chemical gas most abundantly derived from non-renewable fossil fuels, that is injected into soil, or used to derive water-soluble fertilizers that contaminate the water supply. Much of the nitrogen in industrial fertilizer escapes into the atmosphere before it is absorbed by plants, in the form of nitrous oxide: the third major contributor to greenhouse gasses.

“Effectively farmers unknowingly became 100% dependent on 'bought in' water soluble, inorganic fertilizers since the sterilization of soil microflora including its mycorrhiza, reduced the availability of other natural and trace minerals within the soil.”

Problems with GMOs There is a continuing debate about genetically modified foods and their safety. I am against GMOs for the following reasons: GMOs are designed to prevent the problems inherent in monoculture farming, namely the uniform susceptibility of plants within the same species. GMOs have a shelf-life of little more than a decade, because nature itself is a diversifying force. A plant engineered specifically to produce a subtle insecticide, within 10 years of planting, will meet with an insect especially tolerant of that insecticide that never existed before. The geneticists will need to return to the lab and increase the insecticide or create a new splice.

The other problem with genetic manipulation (and I expect some contention on this one) has to do with the difference between genotypes and phenotypes. The genotype is all the dna material packed into a seed, while the phenotype represents the traits the plant exhibits as it grows. Genetically identical plants grown in even the same environment will express unique phenotypes. No scientist  to-date on planet earth has successfully modeled and predicted the complete phenotypic expression of even a single-cell organism from it’s genetic material. GMOs are not meant to hybridize with other species or leak genetically-spliced traits into the natural environment, but they do. Put simply, industrial GMOs are a threat to our global ecosystem.

Organic Farming Local, sustainable agriculture provides surprisingly simple solutions to these billion-dollar problems.

Organic farmers use a process called companion planting which is shown to reduce the vulnerability of plants to pests and diseases without insecticides. Plants will have a stronger immune system in gardens with a wide diversity of species, including beneficial insects.

Organic soil is rich with nitrogen-fixing bacteria(diazotrophs) that convert atmospheric Nitrogen and composted organic material into compounds that are available to plants: Ammonia and Nitrates. Organic farmers use Nitrogen sources like poultry litter, compost, worm-castings or wastewater from aquaponics to fertilize their crops. None of these fertilizers are “hot” like industrial fertilizers, and will not kill the microflora in soil. Organic fertilizers also release nutrients more slowly, providing a sustained nutrition source for growing plants.

Sustainable Hydroponics

According to the USDA the thriftiest family of 4 will spend over $500 a month on food for the household. Double that if you are committed to foods that are highly nutritious like organic fruits and vegetables.

If you live in an area with a favorable climate, nothing beats an organic soil garden in full sunlight. If your goal is to produce your own food, look for space outside that can easily convert to raised garden beds with good drainage. We use hydroponic trays filled with soil in our yard to grow fruit and vegetables that have longer life cycles, and feed them with organically-derived nutrients.

Saving Electricity

Inside we use lower-wattage metal halide lighting systems to grow high-yield, perpetually producing plants like salad greens, strawberries and tomatoes.

We don’t get any breaks on electricity, but here in Arizona our power company is fully invested in renewable and emission-free energy sources. SRP produces 20% of their energy emissions-free, and uses the most efficient energy sources first including hydropower, solar, and nuclear.

To run a 400W hydroponic system 12 hours a day where we live costs between $20 and $30/month. That assumes the cost of a kWh varies seasonally between $0.13 and $0.20.

Hydroponics is also dramatically water efficient.