Effect of Soil Solarization on Wilt Incidence and Seed Yield in Safflower (Carthamus tinctorius L.)

Effect of soil solarization on safflower (Carthamus tinctorius L.) Fusarium wilt incidence and crop yield was studied in two successive years in an experiment laid out in split-split plot design. Plots were covered with transparent polyethylene sheets with different combinations of irrigation (I) and ploughing (P) treatments for different periods up to six weeks maintaining appropriate controls. It was observed that soil temperature at 5 cm depth varied widely among different treatments and especially in irrigated-ploughed-solarized combination, it had a highest average of 52.5° C and 53.5° C in 1995 and 1996 respectively compared to 44.4° C and 47.1° C in control (No solarization/No 1/No P). At 15 cm soil depth in I/P, highest average over six-week solarization was 46.3° C and 49.3° C compared to 39.2° C and 44.0° C in control, in 1995 and 1996. Initial plant stand in I/P after six-week solarization was significantly (P < 0.05) higher compared to control in both the years (1995–96 and 1996–97) with no disease incidence in the treatment compared to 68.3 and 62.7 per cent in control. After six-week solarization, I/P recorded significantly (P < 0.05) higher plant height and seed-yield compared to control.