Effect of different levels of seaweed extract and humic acid granules on soil properties and productivity of Bengal gram (Cicer arietinum L.) in Alfisols

A field experiment was conducted at ZARS, UAS, GKVK, Bengaluru during Rabi, 2021. Two species (Ascophyllum sp. and Sargassum sp.) of seaweed extract (SWE) and humic acid granules (HAG) were applied to the soil at three levels (20, 30 and 40 kg ha-1) and two times (basal and 30 days after sowing) to assess the effect of these granules on soil properties and productivity of Bengal gram. The experiment was laid out in RCBD with twelve treatments replicated thrice. Soil application of 100% NPK + SWEG (Sargassum sp.) @ 40 kg ha-1 recorded significantly higher grain yield (18.65 q ha-1) followed by soil application of 100% NPK + humic acid granules @ 40 kg ha-1 (18.40 q ha-1) and both were significant over control treatment with the application of 100% NPK along with FYM @ 7.5 t ha-1(16.10 q ha-1) and soil application of 100% NPK + SWEG (Ascophyllum sp.) @ 40 kg ha-1 (14.15 q ha-1). Absolute control recorded significantly lower grain yield (5.73 q ha-1). There was no significant variation was noticed upon application of different rates of seaweed extract and humic acid granules soil reactivity, electrical conductivity and organic carbon content of the soil. Soil application of S-SWEG @ 40 kg ha-1 along with 100% NPK showed higher available nitrogen, phosphorus and potassium at 60 DAS and at harvest which was on par with control treatment and T12: 100% NPK + HAG @ 40 kg ha-1. Hence, treatment involving 100% of NPK + SWEG (Sargassum sp.) @ 40 kg ha-1 was found to be superior in improving Bengal gram productivity over all other treatments.