A new approach to soil solarization: Addition of biochar to the effect of soil temperature and quality and yield parameters of lettuce (Lactuca Saliva L. Duna)

Soil solarization is a non-chemical method used to destroy soil borne pathogenic, harmful, and weed seeds in agricultural field and greenhouses. Solarization is generally applied in regions with high summer air temperatures and high solar radiation. Organic materials obtained as a result of the pyrolysis process in an anaerobic environment is called biochar. It can be produced from a wide range of plant and animal origin biomass sources. Lettuce plants are an important vegetable species grown after the application of solarization because of their high value and compatibility with autumn growing. Researchers reported that lettuce yields increased following soil solarization. The aims of this work were to examine different mulch materials and addition of biochar (a new approach in soil solarization) of soil temperature change, and determine which month is more effective according to temperature difference, and also effect of solarization application on yield, quality, and leaf nutrient content characteristics of lettuce plant. The experimental site was located at the University of Suleyman Demirel University in Isparta and the study was conducted during summer and autumn of 2016. Two different polyethylene (PE) mulch materials have been tested. Four different treatments and non-solarization were performed in this research. There were PE mulch, bubble PE mulch, PE + biochar, bubble PE+ biochar and non-solarization treatments. In the parcels where biochar application is used, it was applied 150 g m(-2) of the soil surface as a thin mulch. Biochar added bubble solarization mulching film was determined to be more effective with regard to temperature increase and heat conservation in comparison with the traditional mulch material. Solar radiation played an important role in rising soil temperature with mulch material. With the fall of solar radiation in August, temperatures under mulching films decreased. But, temperature inside the greenhouse and the temperature of the bare soil did not change or it was affected less. Yield increase of 100% was attained for lettuce yield increase with biochar added bubble solarization mulch in comparison with the control. Thus, the study reached the determined objective and it has been determined that biochar use plays an important role in the effectiveness of solarization applications.