Yuma Ag and You: Rain + Desert Agriculture = Disaster

Bobbi Stevenson-McDermott   January 8, 2017  publication

‘Here comes the sun, here comes the sun’ and it’s alright’ with me! It is amazing what a few gloomy, rainy days do to attitudes and agriculture. At my house, we had an inch and a half in the rain gauges. That’s a lot of rain for an area with barely a 2 inch per year total precipitation. In comparison to many areas of the country, over an inch of rain over four days is hardly noticed but in our 24-7 winter agriculture it can be a disaster.

Looking at the crops in the field ready for harvest it equates to wet, cold work under muddy conditions. Food safety requires that there is no mud or other contaminant on the packed boxes, pallets, or trailers used to transport vegetables to the cooler or salad plants.

The farm fields are also a victim of the wet weather. The crops have been irrigated throughout the growing season and have the needed moisture for plant growth, and irrigation is manipulated so that fields are relatively dry at time of harvest. Rain destroys all those carefully made plans. In many cases, the rain water stands on the soil surface, rather than going into the soil. This is partly because the irrigation water used has some dissolved salts which cause the soil surface to seal. Rain water has no salts and will stand until it evaporates in some areas.

Driving through the county, many fields harvested during the rain and after are deeply rutted from the tractors and harvest aids used to facilitate harvest. There is no way that growers and harvesters can postpone the harvest until conditions are better, since the customers they serve want the same quantity and quality of produce every day of the year. The mud also causes concerns because the equipment must be cleaned off before it can be moved from one field to another for sanitation purposes as well as food safety reasons. Moving soil from field to field could spread disease and insect pests and create future problems for the growers.

Under normal operating conditions, the harvest aids, tractors and field trucks are relatively clean when they leave a field. During rainy weather, there is mud everywhere. While there are continuing efforts to keep the roads clear of mud, it is impossible during wet harvest conditions. Time becomes a critical factor to the harvesters since normally harvest is slower and the equipment gets bogged down, necessitating use of additional tractors to move the equipment through the fields. There is no time or means to wash all the equipment used if the market orders are to be met.

The soils in the farm fields that are harvested during wet conditions suffer the most damage. Whether it is foot traffic or equipment, there is tremendous compaction, destruction of the soil structure, reduction of the rate that air and water enters the soil and sealing of the soil surface that takes place. In addition, spring produce crops are being planted necessitating field preparation, sprinkler installation, planting and tillage operations. It will be extremely important that growers plant summer crops like Sudan, grass, wheat or other grass type crops to help restore the soil structure and health. The addition of composted manures or other organic matter in large quantities will help the soil microorganisms replenish themselves before the fall produce season. It takes millions of years for an inch of soil to be produced and working to improve and maintain the soil quality and health is an ongoing job for farmers. While having no water equates to no food, poorly managed soils results in reduced yields, poorer quality products and increased cost of production of food and fiber. Poor soil quality can also reduce the variety of crops that can be grown. Remember, we cannot treat soil like dirt!