Drip fertigation improves biophysical and economic water productivity of turmeric (Curcuma longa)

Abstract

A field experiment was conducted to find out 1) optimum drip irrigation and fertigation rate to realize potential yield of turmeric; 2) to quantify water saving and yield improvement under drip fertigation over control during 2014–15. The experiment was laid out in randomized complete block design, keeping combinations of three drip irrigation {60, 80 and 100 reference evapotranspiration (ETo)} and three fertigation rate {60, 80 and 100% recommended dose of fertilizers (RDF), i.e. 62.5, 25, and 25 kg/ha N, P2O5 and K2O, respectively} under drip with an extra control (surface flood irrigation and soil application of RDF). Drip irrigation at 100% ETo recorded maximum processed turmeric yield which was statistically at par with that drip irrigation at 80% ETo but significantly better than 60% ETo. Fertigation at 80 and 100% RDF resulted in 12.7 and 17.6% higher processed turmeric yield than fertigation at 60% RDF. Drip fertigation at 80% ETo with 80% RDF recorded 18.9% higher processed turmeric yield than control. Irrigation water input was 162.9 mm lesser under 80% ETo than 100% ETo and processed turmeric yield was 8.6 q/ ha higher under 80% ETo than 60% ETo. Actual crop evapotranspiration (ETa) was 96.6 and 187.5 mm higher under drip irrigation at 80 and 100% ETo than 60%, respectively. Drip fertigation at 80% ETo with 80% RDF recorded 18.9% higher processed turmeric yield, 7.7% higher biophysical water productivity, 71.7% higher apparent water productivity, 21.6% higher water use efficiency and 77740 ₹/ha higher net returns along with saving of 311.1 mm irrigation water than control.