Experimental tests on new materials and techniques for soil solarization and mathematical models for the prediction of soil temperature

In order to test innovative, environmentally sustainable materials and higher energy efficiency techniques for soil solarization field experiments were carried out during July and August 1993 using photodegradable plastic film (0.012 mm thick) for mulching both in single and double layer with enclosed air. Alter 30 days from the beginning of the trial, the film began to degrade and to break, and was completely deteriorated alter two months. Field temperatures were measured at different depths (1, 10, 20, 30, and 50 cm) in the mulched soil, and mathematical models for the prediction of mulched soil temperatures under the two different solarization techniques were developed. The results obtained by means of the simulation were compared with the measured data. The standard errors or estimation, calculated between experimental and predicted data for the depths from 10 to 50 cm, were in the range of 0.93-1.43 °C, and 0.87-1.99 °C for the single and double layer solarized soil respectively. The efficacy of the double layer solarization technique produced an increase of soil temperature of 8-10% with respect to the single mulching system, and a higher mortality rate of soilborne pathogens. The mortality rate of sclerotia buried in the soil at 10, 20, 30, and 50 cm depths before the solarization was 0; for solarized soil it was 46% for the single layer and 100% for the double layer at different depths. Finally. the reduction in weed natural infestation, at the soil depths between 0 and 40 cm, was 15-58% for the single layer and 21-55% for the double layer.