Influence of Organic Amendments and Fertigation on Growth, Yield, Quality of Watermelon (CitrulluslanatusThunb.) and Available Nutrient Status in Their Land (Red Sand Dune) of Southern Tamil Nadu

The present investigation was carried out at Thirumaraiyur village, Sattankulamtaluk, Thoothukudi district, to study the effect of organic amendments with the recommended dose of fertilizers on the growth and yield of watermelon in Ther isoil (red sand dunes) during the year 2017 and 2018. The experiment was laid out in Randomized Block Design with Factorial concept (FRBD). There were three factors as organic amendments with 6 treatment combinations for each factor, which were assigned at random in each plot with three replications. The recommended dose of fertilizers in treatments was two levels 75 and 100 percent. Among the treatment combinations, the tank silt application @ 100 t ha-1 with 100 per cent recommended fertilizer as 200:100:100 kg of NPK ha-1 through Fertigation at 7 days interval (A1N5) produced the maximum number of branches (10.67), longest vine (362.0 cm), number of fruits plant-1 (2.57), the weight of fruit (5.27 kg), fruit yield (68.77 t ha-1), total soluble solid (TSS) 10.94%), ascorbic acid (8.08 (mg 100g-1), gross return ( 4,09,320/ha), B:C ratio (2.45), uptake of NPK 41.51, 3.93 and 31.94 kg ha-1, respectively) compared to other treatments. Significant built-up of organic carbon (0.52%), available N (253.47 kg ha-1 ), P (16.40 kg ha-1) and K (218.40 kg ha-1) were registered with the application of tank silt application @ 100 t ha-1 with 100 per cent recommended fertilizer as 200:100:100 kg of NPK ha-1 through Fertigation at 7 days interval (A1N5).