Spinach is a fast-maturing, cool-season vegetable crop. In California, most conventional and organic spinach fields are irrigated by sprinkler irrigation. However, sprinkler irrigation could contribute to the speed and severity of downy mildew epidemics, as the most important disease in spinach, within a field when other conditions such as temperature are favorable.

Although fungicides are available for the control of downy mildew in conventional production systems, products with similar efficacy are not available for organic spinach. Adapting drip irrigation for high-density spinach plantings may be a possible solution to reduce yield losses from downy mildew and enhance resource-use efficiency in organic spinach...

Plants lose water through their leaves and it's called transpiration.  People lose water off their skin and it's called evaporation or sweating.  When a plant stops losing water and when people cant produce enough sweat to cool off, both overheat.  The weather influences that drive this water loss - water that needs to be replaced or the bodies begin to go into heat stress - are the amount of light (day length, cloud cover), relative humidity (it dries faster when air is dry and slower when humid - think desert versus Florida),  and windy (more wind, more drying).  Temperature is important, but not as much as these other drivers. Think freeze-drying  - a very successful process for removing water from...

Irrigated agriculture must always contend with salts. Five years of drought and its effects can magically disappear, but it will be back again. Low rainfall is the norm for California. We rely on winter rainfall to leach the salts from root zones that have accumulated salts from previous irrigations.  Salinity affects plant growth and understanding what it is and how it is measured and evaluated need to be understood.  Just having wet soil that is full of salts is not going to help a plant, it's going to add stress and eventually physiological and disease problems - 

A tensiometer is a very useful tool for monitoring soil moisture status of vegetable and berry crops.   Compared to other sensors that often require equipment such as dataloggers or a computer to collect readings, tensiometers can be easily read by irrigators in the field.   Also, tensiometer readings are not affected by variations in soil texture, temperature, and salinity and they can operate without electricity (no batteries needed).

What is tension? Tensiometers measure soil moisture in units of negative pressure also known as tension.  Tension is a measure of the force that plant roots need to exert to pull water from the soil pores.  Large pores hold water with less force...