International Journal of Plant & Soil Science

The use of plants as natural dyes in the textile industry has gained significant attention in recent years. Indigofera tinctoria L., a member of the Fabaceae family native to India, has emerged as a promising sustainable dye source. Beyond its applications in textiles, I. tinctoria also holds significance in herbal medicine, highlighting its multifaceted utility. A two-year field experiment (2022 and 2023) in split-split plot design was conducted at the College of Agriculture, Vellanikkara, Kerala Agricultural University, to investigate the effects of farmyard manure (FYM) [5, 7.5, and 10 t ha^-1], NPK levels [10:10:20, 20:10:40, 30:10:60, and 40:10:80 kg ha^-1], and foliar nutrition [water spray, nano urea 0.4%, and seaweed extract 0.4%] on the indican content and nutrient content of indigo plants. The results showed that FYM [10 t ha^-1] increased the indican content [by 8.73%], nitrogen [by 11.02%], phosphorus [by 9.9%], and potassium [by 11.27%]. NPK levels [30:10:60 kg ha^-1 and 40:10:80 kg ha^-1] showed similar effects on indican and nutrient content. Foliar application of seaweed extract [0.4%] increased indican and phosphorus content. The interaction between FYM, NPK levels, and foliar nutrition significantly affected the indican, nitrogen, and potassium contents. The study suggests that integrated use of FYM [10 t ha^-1], NPK [30:10:60 kg ha^-1], and foliar nutrition with seaweed extract [0.4%] can improve plant chemical and biochemical parameters.