Studies on NPK drip fertigation in field grown tomato (Lycopersicon esculentum Mill.)

A field experiment was conducted during the summer seasons of 1999-2000 and 2000-2001 at the Main Research Station, University of Agricultural Sciences, Hebbal, Bangalore to study the effect of fertigation with sources and levels of fertilizer and methods of fertilizer application on growth, yield and fertilizer-use efficiency of hybrid tomato in red sandy loam soil. There were eight treatments including furrow-irrigated and drip-irrigated controls, which was replicated three times. The investigations revealed that the total dry matter (TDM) production and leaf area index (LAI) were significantly higher in drip irrigation (165.8 g and 3.12, respectively) over furrow irrigation (140.2 g and 2.25, respectively). Water-soluble fertilizer (WSF) fertigation recorded significantly higher total dry matter and LAI (181.9 g and 3.69, respectively) over drip irrigation. Chlorophyll concentration was significantly higher in fertigation treatments over soil applied treatments at 90 DAT. The fruit yield of tomato was 19.9% higher in drip irrigation (71.9 Mg ha(-1)) over furrow irrigation (59.50 Mg ha(-1)). Fertigation with 100% WSF increased the fruit yield significantly (79.2 Mg ha(-1)) over furrow-irrigated control and drip irrigation. Subsurface drip fertigation (76.55 Mg ha(-1)), nitrogen-potassium fertigation (76.57 Mg ha(-1)) and 1/2 soil-1/2 fertigation (76.51 Mg ha(-1)) had given fruit yields similar to WSF fertigation. Significant yield reduction was recorded with 75% rate fertigation (72.7 Mg ha(-1)) and normal fertilizer fertigation (73.27 Mg ha(-1)) compared to WSF fertigation. WSF fertigation recorded significantly higher number of fruits per plant (56.9) and fertilizer-use efficiency (226.48 kg yield kg(-1) NPK) compared to drip- and furrow-irrigated controls. Fertigation resulted in lesser leaching of NO3-N and K to deeper layer of soil. Subsurface drip fertigation caused higher assimilable P in deeper layer. Root growth and NPK uptake was increased by WSF fertigation.