Spotlight on SWEEP in Citrus
Shulamit Shroder, UCCE climate smart agriculture specialist - Kern County
In 2014, Bruce Kelsey in Kern County received a grant through the California Department of Food and Agriculture's State Water Efficiency and Enhancement Program (SWEEP). He used the funds to set up 8-foot-wide plastic weed mats underneath his mature organic citrus trees. He also decreased his electrical consumption by about 30% and installed soil moisture sensors, a water flow meter, and a pressure-sustaining device.
Labor: The installation of the weed mat was a labor-intensive process, but it ended up paying off in the long term. It diminished weed populations so that he no longer has to weed under his citrus trees. Now he only mows with a small mower in the lanes between his trees.
Water usage: His overall water usage decreased by about 10%. The weed mat decreased evaporation and weed pressure while the other devices allowed him to better manage and schedule his irrigation.
Pests: Bruce experienced an increase in earwigs in the weed mat orchard. The plastic covering provided the perfect humid environment for the insects.
Organic certification: The weed mats will eventually start to disintegrate, which could contaminate his soil. To maintain his organic certification, he will have to rip them up once they start to break down. Smaller, younger trees do not protect the plastic from the sun, which quickly destroys the plastic. For this reason, he recommended against using weed mat in immature orchards.
Figure 1. Weed mat in place.