Nitrification Inhibition Studies of Neem Coating on Urea Prills

Sridharan, G.V.; Hazarika, Dhriti; Bhat, Manasa; Suraksha, R.S.; Singh, Srishti

doi:10.14233/ajchem.2017.20376

Cited by 5 publications

(3 citation statements)

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“…1C). The stimulatory effects of neem leaf extract on urea hydrolysis were found to be in line with the former studies of Mohanty et al (2008), Kizilkaya et al (2015), and Sridharan et al (2017). Urea hydrolysis stimulation was explained by Kizilkaya et al (2015), who stated that neem extract acted as a substrate providing C, N, and energy for soil microorganisms.…”

Section: Urea Hydrolysissupporting

confidence: 85%

Effects of neem leaf extract on inorganic nitrogen transformation in sandy soil

Butnan¹,

Duangpukdee²,

Sriraj³

2022

Soil Sci. Ann.

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The inhibitory effects of neem leaf extract on fertilizer nitrogen (N) transformation in soil have not been fully recognized. This study therefore aimed to evaluate the effects of fi ve nitrifi cation inhibitors on the status of soil inorganic N, urea hydrolysis, and nitrifi cation: i) no inhibitor (control); ii) nitrapyrin; and three rates of neem leaf extract based on the dry weight of the raw material: iii) 1 g kg -1 soil; iv) 2 g kg -1 soil; v) 4 g kg -1 soil. Neem leaf extract in all rates increased urea hydrolysis rate on days 5−15. In contrast, nitrapyrin decreased urea hydrolysis on days 5−10, compared to the control. As for nitrifi cation, neem leaf extract showed both stimulatory and inhibitory effects. The stimulation appeared on day 3, whereas inhibition occurred and peaked on days 5−15. Nitrapyrin showed inhibitory effects on days 10−15, reaching its peak on day 15. Increasing rates of neem leaf extract brought about increases in stimulation and inhibition of urea hydrolysis and nitrifi cation. The results conclusively stated that the neem leaf extract had generally faster, stronger, and longer nitrifi cation inhibition than nitrapyrin. The stimulation in the early phase and the inhibition in the later phase of the incubation of neem leaf extract were more pronounced with higher application rates.

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Section: Urea Hydrolysissupporting

confidence: 85%

Effects of neem leaf extract on inorganic nitrogen transformation in sandy soil

Butnan¹,

Duangpukdee²,

Sriraj³

2022

Soil Sci. Ann.

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“…Neem also exhibits other properties of agronomic interest such as nitrification inhibition and pesticide effect [16] . The effect of neem coated urea to reduce urease activity has been demonstrated [17] but some studies noted that neem, or one of its active ingredients – azadirachtin – seems to stimulate urease activity [18] , [19] . Neem has more potential as a nitrification inhibitor [18] , [20] and for this reason all urea used in India since 2015 is mandatorily coated with neem [21] .…”

Section: Introductionmentioning

confidence: 99%

“…The effect of neem coated urea to reduce urease activity has been demonstrated [17] but some studies noted that neem, or one of its active ingredients – azadirachtin – seems to stimulate urease activity [18] , [19] . Neem has more potential as a nitrification inhibitor [18] , [20] and for this reason all urea used in India since 2015 is mandatorily coated with neem [21] . Other non-inhibiting products such as zeolites have shown mixed results in decreasing NH 3 volatilization from urea application [22] or have no effect [23] .…”

Section: Introductionmentioning

confidence: 99%

Agronomic efficiency of NBPT as a urease inhibitor: A review

Cantarella

Otto

Soares

et al. 2018

Journal of Advanced Research

327

225

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Graphical abstractSchematic diagram of urea dissolution, diffusion and hydrolysis in the soil. (a) Without an inhibitor, hydrolysis is fast (dark blue color) causing NH3/NH4+ accumulation and increasing the pH close to the soil surface around the fertilizer granule, driving NH3 volatilization. As the ammonia species are less mobile in soil, diffusion is limited. (b) The inhibitor maintains urea unhydrolyzed for some time. Urea has no electrical charges and diffuses easily into the soil solution. When the effect of the inhibitor phases down and urea starts to hydrolyze, both the pH and the NH3/NH4+ concentrations are lower (light blue color) as a result of dilution. Part of the urea is incorporated into the soil before hydrolysis; the NH3 produced inside the soil is retained by the negative charges of colloidal material and losses are reduced even if no rain or irrigation incorporates urea into the soil.

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