Akademik Veri Yönetim Sistemi
JOURNAL OF FOOD AGRICULTURE & ENVIRONMENT, cilt.9, sa.1, ss.550-556, 2011 (SCI-Expanded)
High soil temperatures achieved with solarization practice used in greenhouses may prevent diseases infested from soils with soil pathogens. Physical manipulations like tillage, increasing soil water content and addition of organic residues to soil increase effectiveness of solarization by way of facilitating downward heat flux and increasing temperature in subsoil. A two-year work assessing importance of soil tillage, soil wetting and CO2 enriched air (for simulating organic residue addition to soil) on solarization was carried out in glass and plastic greenhouses (1 glass and 2 of plastic) with clay and sandy soils in Eastern Mediterranean region of Turkey. Four treatments were tested: (1) with tillage (T), (2) no tillage (NT), (3) with tillage and CO2 addition (TCO2) and (4) no tillage and no CO2 addition (NTCO2). The CO2 enrichment of air under plastic mulch covering soil during the solarization was done using dry ice (i.e. CO2). The levels of the highest temperatures attained under different treatments during solarization period were assessed and recorded. The results showed that the highest temperature was recorded throughout the complete solarization period under the treatment with soil tillage and CO2 addition (TCO2) over all soil depths (5, 20 and 35 cm). The mean highest temperatures recorded for 30 days of solarization period did not exhibit any consistent trend in clay soils (Greenhouse 1 and 2) whereas the ranking of the treatments TCO2>T>NT>NTCO2 was maintained in sandy soil (Greenhouse 3). The highest temperature attained in Greenhouses 1 and 2, with soils of clay texture, and 3 with soil of sandy texture, at soil depths of 5, 20 and 35 cm were 55.4, 45.3 and 41.4 degrees C; 56.8, 46.6 and 42.7 degrees C; 56.6, 48.4 and 44.7 degrees C, respectively. While the CO2 enrichment increased soil temperature only at 5 cm depth, close to soil surface, no significant (P<0.05) benefit was observed at deeper soil depths of 20 and 35 cm. Increase of mean maximum temperature with CO2 addition was of the order 1 to 3.5 degrees C in clay soils (Greenhouse 1 and 2) and 1.2 degrees C in sandy soils (Greenhouse 3). Additionally it was noted that addition of CO2 provided no benefit under no tillage conditions (NTCO2). While temperature at 5 cm soil depth was over 50 degrees C at frequencies of 65 to 95% during 23 days of solarization period, it was not over 45 degrees C at 35 cm soil depth. The results showed that the high soil temperatures obtained with solarization under climatic conditions of Eastern Mediterranean may be adequate to eliminate soil-borne diseases without the need of using chemicals such as methyl bromide.