Characterization of vegetable nitrogen uptake and soil nitrogen transformation in response to continuous molybdenum application

Abstract

Molybdenum (Mo), a plant micronutrient, is involved in nitrogen (N) cycling of global ecosystem, but little is known about its effect on soil N transformation especially the key processes nitrification and denitrification. A long-term field experiment was carried out to investigate the effects of continuous sufficient soil available Mo on vegetable N uptake and soil N transformation. The experiment consisted of three treatments: control (CK), Mo deficiency (NPK), and Mo application (NPK+Mo). The results show that (1) after a 7-year-experiment, continuous Mo application significantly increased soil available Mo content. (2) Compared to the NPK treatment, NPK+Mo treatment showed an increase of 11, 18, and 8% in the cumulative crop yield, plant N uptake, and N fertilizer use efficiency. (3) With continuous Mo application, the soil NO À 3 -N, NH þ 4 -N, microbial biomass N, and total N contents were reduced by 14, 29, 40, and 12%, the soil nitrate reductase (NR) and nitrite reductase (NiR) activities were reduced by 14 and 8%, as well as the potential denitrification activity (PDA) and gross nitrification rate (GNR) were decreased by 64 and 80%, respectively. Additionally, continuous Mo application decreased the abundance of ammonia-oxidizing archaea (AOA) and increased the abundance of narG-containing denitrifiers (narG) and nirK-type nitrite reducers (nirK) significantly. The data suggest that a deficiency in soil available Mo may induce the risk of soil N accumulation and environmental N emission in vegetable soil, whereas continuous Mo application could mitigate this risk by increasing crop yield and N uptake and, by decreasing soil N residues, soil nitrification and denitrification.

Molybdenum‐induced effects on nitrogen uptake efficiency and recovery in wheat (Triticum aestivum L.) using 15N‐labeled nitrogen with different N forms and rates

“…N is one of the most growth‐limiting nutrients in crop production, and its availability is strongly and positively correlated with available Mo in the soil (Wen et al., 2018, 2019). Mo plays a vital role in N uptake and its assimilation pathways through NR regulation (Imran, Sun, et al., 2019; Imran et al., 2021), indicating that Mo application might trigger an increase in N uptake or accumulation through efficient N acquisition, which might lead to an alteration in the overall response of the plant to N availability.…”

“…The available Mo in soil was estimated by the polarographic catalytic wave analysis as detailed by Wen et al. (2018). The pots were distributed in a completely randomized design.…”

Mo-Inefficient Wheat Response Toward Molybdenum Supply in Terms of Soil Phosphorus Availability

“…During the continuous experiment, no Mo fertilizer was applied for Mo-deficient (−Mo) treatment. The complete detailed experimental field history can be found in our previously published paper (Wen et al 2018). The experiment was setup in a randomized complete block design (RCBD) with an average plot size of 18 m 2 (9 m × 2 m).…”

“…Microbial biomass P (SMP) was analyzed by fumigation with CHCl 3 for 24 h, as designated by Brookes et al (1984) and Sakurai et al (2008). The Mo contents in soil and plant samples were determined respectively according to the methods of Wen et al (2018) and Imran et al (2019a), Imran et al (2019b), and Ismael et al (2018) by JP-2 oscilloscope polarography.…”

Microbial Biofertilizers and Micronutrients Bioavailability: Approaches to Deal with Zinc Deficiencies

“…There is very less knowledge about use of molybdenum in soil microbial activity (Wen et al 2018) and changes in soil P relative to soil P-enzyme production in longterm experimental soil rhizosphere (Wei et al 2017). Legumes are fixing atmospheric nitrogen into available form by their root nodule due to the involvement of Rhizobium bacteria.…”