Evaluation of selected medicinal plant materials and dicyandiamide on nitrification of urea‐derived ammonium under laboratory conditions

Abstract

Background: Poor utilization of urea fertilizer and N losses from agriculture lands demands alternate fertilization practices to reduce N losses and improve utilization, i.e., application of nitrification inhibitors. Aims: This study was aimed to evaluate and compare the influence of dicyandiamide (DCD) and selected medicinal plant materials and on N transformations, nitrification inhibition and recovery of applied N. Methods: Treatments included: urea nitrogen (UN), UN + DCD, UN + Gingiber officinale, UN + Viola odorata, UN + Sewertia chirata, UN + Azadirachta indica, UN + Sphaenathus indicus, UN + Allium sativus, UN + Artemisia absenthium, UN + Fumaria indicus, UN + Caesalpinea bondusella, UN + Barberis lyceum, and an un‐amended control. Urea was applied at 200 mg N kg−1 soil, while DCD and medicinal plant materials were applied at of 1% and 20% of applied urea, respectively. Results: Medicinal plant materials inhibited nitrification of urea‐derived NH4 + - N. On an average of medicinal plant materials treatments, 51% of NH4 + - N was still present in soil compared to 17% NH4 + - N in UN treatment without medicinal plant materials after 28 days. Similarly, NO3 - - N was 76.54 mg kg−1 in UN treatment compared to 34.40 mg kg−1 in UN + medicinal plant materials treatments, indicating 55% reduction in nitrification. Apparent nitrogen recovery (ANR) in UN treatment was 65% compared to 74% in UN + DCD treatment. ANR in treatments, where UN was amended with medicinal plant materials, varied between 58 to 70%. Conclusions: The use of DCD and medicinal plant materials with UN significantly reduced NH4 + - N oxidation and nitrification ( NO3 - - N). In general, medicinal plant materials were more effective in regulating N transformations and, thus, offer a suitable alternate fertilization practice to reduce N losses and improve fertilizer utilization.

An optimized hydroponic pipeline for large‐scale identification of wheat genotypes with resilient biological nitrification inhibition activity

“…Because root‐exudated BNI compounds are organic, they are often considered as environmentally friendly alternatives to their synthetic counterparts. However, some organic compounds limiting nitrification can have broad antimicrobial activity (Lodhi & Killingbeck, 1980; Tahir et al ., 2021). Several well‐characterized BNIs have also been shown to inhibit bacteria species besides the AOB in the soil (Bending & Lincoln, 2000; Sarr et al ., 2020; Schandry et al ., 2021; Wang et al ., 2021).…”