Tough lessons

Features - Cover feature: The Top 50 Nurseries

L.E. Cooke Co. made several irrigation changes because of California’s four-year drought.

October 12, 2015
NM Staff

California is no stranger to drought. They happen, rather frequently actually. It is called a Mediterranean climate. Politics make it worse, but that is a story for another time. This story is how we cope with it and keep a quality crop growing in spite of it.

The L.E Cooke Co. irrigates all the crops with well water on clean, fumigated lands. It is clean water and not dependent upon canal supplied water from snow runoff contaminated with weed seed and nematodes. That is where the politics came in. They turned off the canals which supply more than half the farmers of this ag rich valley with water. And that water also percolates into the ground for future use. So the water table has been dropping as more farmers tap their straws into the shared pool of water without replenishment.

We had already shifted our production methods from furrow/flood irrigation to buried drip systems. It was expensive to do. We did it to save on water use and we benefitted with superior root systems. In anticipation of the wells running dry, in 2014 we connected multiple wells across common blocks of fields with piping. Some newer wells are deeper than the older wells. As feared, the water table dropped another 15-25 feet and, in the course of that summer, eight older wells temporarily ran out of water until we could get the bowls lowered.

We learned some lessons the summer of 2014. Drip systems are marvelous, but not the total answer to extreme dry conditions. Until 2014, there has always been residual moisture below the surface of the soil from winter rains. That has given us adequate moisture in the soil profile for planting in the spring and supplementing with the drip systems through the year. Although our trees thrive on the drip systems we use, it is now obvious that they also must have used more water and nutrients from further away in the soil profile which were not there in extreme droughts. One lesson learned: pre-irrigate in the early spring if we do not get winter rains.

Drip systems are also not as forgiving when water is not applied exactly when needed. When we used to flood irrigate, we irrigated every 10-14 days with lots of water residing in the soil profile below the surface. With drip, there is only the small amount in the immediate root zone. We water on drip every couple of days. With no extra moisture in the soil profile, the trees will stress and shut down if water is not available in a timely fashion.

When a pump draws water from the bottom of the well, it also pumps sand. Although we have filters (we had to clean some of them every 20 minutes), sand still gets into the drip. We had to abandon the drip on two fields and quickly convert it back to furrow irrigation. With drip running on a healthy well, we can water 100+ acres all at one time from one well. Furrow irrigation can water about 15 acres at a time. On these two fields in 2014, because of the added time to get the first furrow irrigation across to all the trees, we lost some of the water-loving trees. Some of the other trees in the field had a midsummer shutdown (and slow restart) making for smaller sizes. Babylonica willow clearly is not drought tolerant and the harvest quantities were reduced. On the other hand, the Chilopsis (desert willow) and Cercis occidentalis (western redbud) loved it.

Late summer of 2014 through summer of 2015 we have been drilling new wells (the waiting list is long and the cost is steep — supply and demand at work). On each major block of land we have drilled one well extra big and extra deep. And the water systems on these fields are all tied together. By the time all the bills come in, we will have spent well over $650,000 to keep the water flowing this year and for the future.

I am proud of the extra efforts our production and maintenance staff put in to reduce the effects of weather conditions beyond our control. We are committed to serving our customers with quality trees now and into the future. In the meantime, keep praying for rain, or build a “Keystone” pipeline of water for California.

 

— Ron Ludekens, president, L.E. Cooke Co.