Assessing the Effects of Nitrification Inhibitor DMPP on Acidification and Inorganic N Leaching Loss from Tea (Camellia sinensis L.) Cultivated Soils with Increasing Urea–N Rates

Abstract

The effects of nitrification inhibitor in tea gardens with different urea–N rates have rarely been assessed. For eight months, a glasshouse experiment was conducted to investigate the effects of a nitrification inhibitor (3, 4–dimethylpyrazole phosphate, DMPP) on the changes of soil pH and inorganic N loss. Urea (0, 300, 500, and 800 kg N ha−1) with or without DMPP (1% of urea–N applied) were added to pots that hosted six plants that were three years old. Next, three leaching events were conducted with 600 mL of water after 7, 35, and 71 days of intervention while soil samples were collected to determine pH and inorganic N. Averaged across sampling dates, urea–N application at an increasing rate reduced soil pH with the lowest values at 800 kg urea–N ha−1. Adding DMPP increased soil pH up to a rate of 500 kg ha−1. Irrespective of the addition of DMPP, gradient urea–N application increased the leaching loss of inorganic N. On overage, DMPP increased soil pH and decreased leaching losses of total inorganic N, suggesting a higher soil N retention. Therefore, we believe that this increase in soil pH is associated with a relatively lower proton release from the reduced nitrification in the DMPP–receiving pots. This nitrification reduction also contributed to the N loss reduction (NO3−–N). Altogether, our results suggest that DMPP can reduce N leaching loss while maintaining the pH of tea–cultivated soils. Therefore, DMPP application has a significant potential for the sustainable N management of tea gardens.

Nitrification inhibitor 3,4-Dimethylpyrazole phosphate improves nitrogen recovery and accumulation in cotton plants by reducing NO3− leaching under 15N-urea fertilization

“…The reduction of N2O emissions by DMPP is therefore attributed to reduced nitrification process and a reduced NO3pool available in soil for denitrification (Ruser and Schulz, 2015;Suter et al, 2020). Thus, nitrification inhibitors are substances that delay the oxidation of NH4 + to NO3 -, preventing N losses through nitrification and denitrification (Luchibia, 2020;Qiao et al, 2021), as verified in our study. This delay maintains the applied N fertilizer in the less mobile form of NH4 + , and thereby limits the build-up of mobile NO3in the soil (Friedl., et al, 2017;Padilla et al, 2018).…”

“…The DMPP is related to delay the oxidation of NH4 + to NO3thereby preventing N losses through nitrification and denitrification (Shi et al, 2016;Luchibia et al, 2020;Qiao et al, 2021). This delay maintains the applied N fertilizer in the less mobile form of NH4 + , limiting the buildup of mobile NO3in the soil (Friedl., et al, 2017;Padilla et al, 2018).…”

Identifying Sustainable Nitrogen Management Practices for Tea Plantations

“…+ for longer and alleviate soil acidification, Wang et al (2020) recommended that when fertilising with urea, urease and nitrification inhibitors are applied to limit N losses [46]. Qiao et al (2021) found that with the application of DMPP (3,4-dimethylpyrazole phosphate, a nitrification inhibitor), soil pH increased at a urea application rate of 500 kg N ha −1 and above, due to reduced nitrification and increased plant uptake of NO 3 − [86]. The leaching losses of nitrates and total inorganic N were also noticed to decrease with the addition of DMPP.…”

Potential application of urease and nitrification inhibitors to mitigate emissions from the livestock sector: a review

“…The DMPP treatment seemed to stimulate CH4 oxidation more than DCD treatment because the soil clearly acted as a CH4 sink rather than as a source [50]. Significant reduction due to inhibition of nitrification may take more than a week after DMPP addition [59]. DMPP could increase soil N retention, improve plant N use efficiency, and potentially stimulate the shoot yield of tea trees [59].…”