Asian Journal of Soil Science and Plant Nutrition

Aim: Humic substances plays a vital role in soil fertility and plant nutrition. Application of humic substances within a fairly wide range of concentration are highly beneficial to plant root development. Humic acid is excellent foliar fertilizer carrier and an activator. The present investigation was conducted to study the response of foliar application of potassium humate extracted from good quality Farm Yard Manure (FYM), on growth parameters, chlorophyll content, yield and quality of cowpea.

Study Design: Completely Randomized Design with three replications and seven treatments.

Place and Duration of the Study: The research was conducted in rabi 2021at the College of Agriculture, Karad, Maharashtra, India.

Methodology: Good quality FYM was used to extract potassium salt of humic acid. The   extracted potassium humate was used as foliar application (at two different growth stages) at different concentrations (100, 200, 300, 400 and 500 ppm) along with General Recommended Dose of Fertilizer (GRDF), comprising seven treatments that were laid in a completely randomized design with three replications. 

Results: The results indicated that two foliar applications of potassium humate @ 400 ppm + GRDF (T₆) to cowpea plants significantly increased growth parameters viz. average number of seeds per pod (18.0), 100 seed weight (9.59 g), seed yield (91.10 g pot^-1) and dry straw yield (113.88 g pot^-1), total chlorophyll content and protein content compared to absolute control (T₁) and GRDF + water spray (T₂).

Conclusion: The study concluded that foliar applications of potassium humate @ 400 ppm + GRDF significantly improved growth parameters, total chlorophyll, yield and protein content (21.42%) of cowpea seed under pot culture condition.