|Author: ||K.D. Larson|
|Keywords: ||Fragaria × ananassa, methyl bromide, mulch, strawberry, weed control|
Soil solarization can be an effective preplant soil treatment under high temperature and irradiance conditions, but its effectiveness is poor in coastal California due to cool, cloudy conditons.
Previous reports indicate that use of polyethylene tunnels can enhance soil warming beyond that of standard soil solarization.
From August 31 to October 4, 2007, we monitored soil temperatures as a function of three solarization treatments on non-fumigated strawberry beds in coastal southern California: 1) black polyethylene bed mulch (BP); 2) clear polyethylene bed mulch (CP, control); and 3) a high tunnel covered with clear polyethylene that enclosed beds covered with CP (CPT). Maximum soil temperatures (10 cm depth) were 45.4, 53 and 57.9°C for treatments 1-3, respectively.
At 10 cm soil depth, accumulated temperature-hours ≥37°C were 82.5, 235, and 520.3 for treatments 1-3, respectively, while at soil depth of 30 cm, accumulated temperature-hours ≥37°C were 0, 51.5 and 525 for treatments 1-3, respectively.
The tunnel cover was removed on October 4 and strawberry plants (‘Ventana’) were established in all plots.
Weed populations were determined on November 15, and yield performance determined from December, 2007 until May 5. Results indicate complete weed control with use of CPT, and an abundance of various weed species in CP and BP plots.
Yields to May 5 were lowest for BP treatment, intermediate for CP and CPT treatments, and greatest for an adjacent parcel treated with methyl bromide: chloropicrin.
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