Drip irrigation on productivity, water use efficiency and profitability of turmeric (Curcuma longa) grown under mulched and non-mulched conditions

Abstract

Turmeric cultivation primarily thrives in India, with significant presence in Bangladesh, Thailand, Cambodia, China, Indonesia, Philippines, and Malaysia. India leads globally in both area (0.19 Mha) and production (0.844 MT) of turmeric. Despite this, there's a recognized gap in research regarding the combined effects of mulching and drip fertigation on turmeric growth in Tamil Nadu conditions. Therefore, this study aims to assess how mulching and drip fertigation impact water usage, turmeric growth, productivity, and post-harvest soil health via field experiments. The treatments comprise of different mulching techniques (M1-25 μm Plastic Mulching, M2-50 μm Plastic Mulching, M3- Organic Mulching, M4-No Mulching) as the main plot, coupled with various irrigation regimes as the sub plot (S1-100% of pan evaporation, S2- 80% of pan evaporation, S3- 60% of pan evaporation), in a split plot design. Findings show that 50-μm Plastic Mulching (M2) notably enhances turmeric growth parameters, including plant height, biomass, leaf count, and yield attributes such as tillers and rhizomes, compared to no mulch. Significantly, when 80% of pan evaporation is utilized in drip irrigation, it showcases the most pronounced plant growth and yield characteristics, with plastic mulch at this level significantly improving water and nutrient use efficiency while increasing beneficial compounds like Curcumin and oleoresin. The highest fresh rhizome yield is observed with 50-μm plastic mulch and 80% pan evaporation (M2S2), displaying a 39.79% increase compared to the control. Additionally, the study notes effects on microbial populations and mulch degradation. Economically, M2S2 exhibits the highest profitability with a benefit-cost ratio of 3.23 compared to other treatments. Implementing these practices not only enhances yields but also conserves water (estimated at 9.15 mm3) while emphasizing the importance of drip irrigation, fertilizer application, and mulching in boosting turmeric productivity, optimizing resource efficiency, and ensuring economic and environmental sustainability.