Morpho-physiological, yield and quality traits in lettuce (Lactuca sativa) as influenced by use of organic manures and biofertilizers

Abstract

A field experiment was carried out in lettuce (Lactuca sativa L.) during 2003 and 2004 to study the effect of organic versus inorganic inputs on physiology, growth, yield and quality attributes. Integrated use of organic manures and inoculated with biofertilizers exhibited significantly higher photosynthesis rate (9.16-9.81 µmol/m2/s) than the sole application of organic manures. Combined application of organic manures and seedling inoculation in Phosphate solubilizing microorganism (PSM) or Vesicular-arbuscular mycorrhizae (VAM) showed stomatal conductance (gs) at par to control. Combined application of organic manures and VAM exhibited the photosynthetic water use efficiency at par to control; rest of the treatments expressed lower photosynthetic water use efficiency than control. The integrated use of organic manures and biofertilizers exhibited significantly higher head length (12.0- 12.6 cm) and diameter (12.2-12.9 cm). Head weight and yield under combined use of organic manures (Farmyard manure + Digested sludge) and biofertilizers were noticed at par to control, and significant reduction (13-20%) in head weight and head yield were recorded under sole application of organic manure. Significantly higher vitamin C content was recorded with application of farmyard manure (20 tonnes/ha) or where organic manures were combined either with Azotobacter or with VAM. There was no significant variation in the total carotenoid content was observed with the application of organic manures or biofertilizers, except under combined use of organic manures and Azotobacter, which showed significantly higher carotenoid content (1.263 mg/100g). The individual or combined application of organic manures and biofertilizers did not influence the crude fibre content in lettuce head, and it varied from 0.90 to 1.16 g/100g.