Why Do We Grow Crops In The Desert?

For those of us who grew up and live in desert agricultural regions this may seem an odd topic, but as I am often reminded when visiting with friends from the Midwest and East, this needs to be explained from time to time.

The answer to the question is: Because it is hard to farm on mountain tops. The growing season is short, and the weather risk is high.

Snow accumulates on mountain tops and naturally flows through streams and rivers to the ocean. This water flows by gravity to the lower elevations where much of it is utilized to grow crops. Desert regions enjoy the longest growing season with the least weather risk. Crop yields produced per gallon of water is inherently higher in the desert regions.

In the west, areas like the Salt River Valley in Arizona are supplied water by a large watershed that encompasses most of the Eastern part of the State. Most rainfall and snowpack flows to Phoenix making it convenient to divert for crops. The Hohokam Indians built canals to capture this water to grow crops for 1,200 years. Today, the primary water supply for the Phoenix region (Salt River Valley) follows the same canal pathways developed by the Hohokam and supports a population of over 4 million people today.

Then we have the Colorado River water shed that captures water from Wyoming, Colorado, New Mexico and Utah, and flows into the lower basin where where water is supplied to Nevada, California, Arizona and Mexico. Agriculture uses 70% of this water supply to grow a highly diversified list of crops generating billions in economic value. So, to the extent possible with this historic water supply, crops are grown in the lower desert where land is suitable for farm development, the growing season is long, and weather risk is low.

Today, we are experiencing drought conditions creating major challenges for AG producers. The average rainfall and snowpack in the key watershed areas of California and Arizona has declined which is forcing growers to either get more efficient or simply fallow land, and most likely both. Average annual flows in the Colorado River watershed have dropped by 20%. This may not sound like a lot, but it brings up challenges as agriculture is the first to be cut, and this is creating conflicts over priority water rights among users of Colorado River water that must be resolved for a stable economic environment in these farming regions.

If the drought continues, central Arizona farmers are first to lose access to Colorado River Water and have already made significant cuts in recent years. Mexico will lose all access which is potentially devastating to Northern Mexico. Municipalities and industrial water users come before AG production.

To survive, some growers will fallow land while others will shift to brackish groundwater. Groundwater? When rivers flow through deserts for thousands of years, underground aquifers accumulate large quantities of water. We have an abundance in Arizona, but pumping is more expensive than capturing gravity flow water from the river. Growers can potentially survive for the long term on groundwater, but the cost goes up the greater the depth to water. Also, managing salt accumulation requires the adoption of appropriate practices.

Another major issue for growers are depleted soils with low water holding capacity. To provide a perspective of this issue, we have enjoyed abundant crop productivity for the past 75 years using heavy tillage and synthetic fertilizers and chemicals. But this has created a problem that needs to be addressed. Our soils are now heavily degraded. The SOM (soil organic matter) is at its lowest point ever, generally less than 1% SOM. As soil health degrades, salts accumulate, water use increases, and nutrient losses become excessive. So, growers are faced with water shortages when soil health and related water holding capacity is at its lowest point.

Irrigation technology and management strategies have helped many growers increase water use efficiency and stay in business in past years, but we need to focus on soil health today to survive a prolonged drought period. Some growers are adopting regenerative practices to recover soil function. Functional soil requires less added water and nutrients for crop production. I like to call the restoration of soil function Microbial Soil Reclamation.

A microbial reclamation program restores the soils' microbial biomass which is essential to cycling carbon and nutrients while holding more water. It is the microbes that aggregate soil particles to create topsoil and hold moisture, while also providing a greater percentage of crop nutrients.

Now more than ever we need healthy and functional soils for improved water use efficiency, and improved nutrient uptake. If a grower faces a 40% reduction in water supply, reducing water use by 40% means the farming enterprise can survive and probably prosper due to higher commodity prices. The combination of soil health and irrigation management are the primary concerns for todays growers. The good news is the cost savings for reduced fertilizer applications and water will cover the cost of inputs used for microbial soil reclamation and putting the land on a path of annual increases in SOM and even the sale of carbon credits for additional income.

So, to conclude, deserts are the right place to efficiently grow high yielding crops with the lowest risk. We are facing a challenging time due to the current drought conditions from which there will be some winners and losers among farmland owners and growers. Those who improve water use efficiency, both mechanically and biologically, will be better off financially and our soil health will return to a state of sustainability that benefits all of society.

Written by Ben Cloud, CEO of Biodel AG Inc. Biodel AG is based in Maricopa, AZ and processes a patented plant extract used as a fertilizer and pesticide ingredient worldwide. Biodel Ag also manufactures its own branded product called Sequester (registered trademark), a biological soil amendment used to rapidly restore soil function and health. See https://sequester.ag or https://biodelag.com