Replacement of Synthetic Nitrogenous Fertilizer by Human Hair Hydrolysates in Cultivation of Mung Bean (Vigna radiata L.)

Abstract

Purpose: To explore the potential of alkali hydrolysis techniques for valorizing waste human hair (WHH) into nitrogenous fertilizer and evaluation of their impact on growth, yield of mung bean and its rhizospheric soil. Methods: WHH were thermochemically hydrolyzed by potassium hydroxide or mixed potassium hydroxide and calcium hydroxide solutions and resultant hydrolysates (HK and HKC, respectively) were treated as alternative source of nitrogenous fertilizer in different doses for cultivation of mung bean. Results: The results showed that alkali mediated human hair hydrolysates (HHH) were rich in N and S and among them HKC had significantly higher N content. Soil amendment of 8 mL of HKC solution (WHH and water in 1:10 ratio and pH was adjusted to 7.5) per pot resulted in 20 and 9% higher grain yield and protein content of mung bean, respectively over recommended dose of N fertilizer. Application of HHH also enhanced available nutrient (N, P, K and S) contents in soil. Conclusions: Our results suggested that alkali hydrolysis could be considered as an efficient valorization technique for WHH. Soil amendment of HKC render superior effects on growth and yield of mung bean in respect of recommended dose of N fertilizer and also maintain availability nutrients in soil. Graphical Abstract: [Figure not available: see fulltext.] © 2022, The Author(s), under exclusive licence to Springer Nature B.V.