“…Nitrate was always dominated in soil inorganic N in urbanized (urban and urban/suburban) sites (Table 2), similar results were reported that nitrate was elevated nearer to the urban core [13] and was dominant N form in urban areas [11,12]. Urbanization producing various urban sources of nitrate and resulting in nitrate enrichment of atmospheric N deposition (> 30 kg N ha -1 yr -1 , Huang et al, 2015a) contributed greatly to soil dominated nitrate.…”
Section: Nitrate Enriching In Urbanized Areassupporting
confidence: 79%
“…Obviously, soil inorganic N availability is not immune to urbanization. The research showed that urbanization increases soil inorganic N availability [11,12], especial for nitrate, which always dominated in urban soils [11] and exhibits an increase pattern from rural to urban core [13].…”
Section: Introductionmentioning
confidence: 95%
“…Enriched nitrate occurs in urban areas suggested potential N loss and N saturation [12,20]. N saturation is a condition where N input to the ecosystems exceeds plant and microbial demand [21].…”
Abstract. Urbanization results in high N deposition and impacts N cycling of forest ecosystems, which increases soil inorganic N pool, including soil N availability, especially for nitrate. However, it is still unknown it is true in south China where ammonium always dominates in soils for long-term traditional agricultural activities. We investigated the changes in soil inorganic N availability responding to urbanization in Pearl River Delta (PRD), China, one of the largest urban areas of the world. Soil total inorganic N levels did not show an obvious growth in urbanized (urban and urban/suburban) sites compared with non-urbanized (suburban/rural and rural) sites based on non-significant differences in their concentrations, but nitrate enriched. Our study demonstrated that urbanization resulting in extra N input does not significantly enhance soil total inorganic N availability instead of the changes in its composition, indicating that N cycling in this region is accelerated and its N status is N-rich even N-saturated, consequently potential ecological risks might happen, including nitrate leaching, eutrophication, and plant preference for nitrate. Therein N pollution dominated by nitrate should be paid special attention in China.
“…Nitrate was always dominated in soil inorganic N in urbanized (urban and urban/suburban) sites (Table 2), similar results were reported that nitrate was elevated nearer to the urban core [13] and was dominant N form in urban areas [11,12]. Urbanization producing various urban sources of nitrate and resulting in nitrate enrichment of atmospheric N deposition (> 30 kg N ha -1 yr -1 , Huang et al, 2015a) contributed greatly to soil dominated nitrate.…”
Section: Nitrate Enriching In Urbanized Areassupporting
confidence: 79%
“…Obviously, soil inorganic N availability is not immune to urbanization. The research showed that urbanization increases soil inorganic N availability [11,12], especial for nitrate, which always dominated in urban soils [11] and exhibits an increase pattern from rural to urban core [13].…”
Section: Introductionmentioning
confidence: 95%
“…Enriched nitrate occurs in urban areas suggested potential N loss and N saturation [12,20]. N saturation is a condition where N input to the ecosystems exceeds plant and microbial demand [21].…”
Abstract. Urbanization results in high N deposition and impacts N cycling of forest ecosystems, which increases soil inorganic N pool, including soil N availability, especially for nitrate. However, it is still unknown it is true in south China where ammonium always dominates in soils for long-term traditional agricultural activities. We investigated the changes in soil inorganic N availability responding to urbanization in Pearl River Delta (PRD), China, one of the largest urban areas of the world. Soil total inorganic N levels did not show an obvious growth in urbanized (urban and urban/suburban) sites compared with non-urbanized (suburban/rural and rural) sites based on non-significant differences in their concentrations, but nitrate enriched. Our study demonstrated that urbanization resulting in extra N input does not significantly enhance soil total inorganic N availability instead of the changes in its composition, indicating that N cycling in this region is accelerated and its N status is N-rich even N-saturated, consequently potential ecological risks might happen, including nitrate leaching, eutrophication, and plant preference for nitrate. Therein N pollution dominated by nitrate should be paid special attention in China.
“…N is a key nutrient required by all living organisms, which controlling the species composition, diversity, dynamics and function of many terrestrial ecosystems (Vitousek et al 1997;Chen et al 2010;Geisseler et al 2010). However, urban soil sealing alternated the biotic and abiotic factors that regulating N transformation and seriously affected soil N pool and flux (Lorenz and Lal 2009).…”
“…The total metropolitan area is 7,402 km 2 with a population that increased from 2.4 million in 1970, to 4.0 million in 1996 and 4.8 million in 2009. The number of motor vehicles increased almost 8-fold between 1995 and 2006 (Chen et al 2010a). The study region has a subtropical monsoon climate (wet and mild) with mean annual precipitation of about 1700 mm and mean annual relative humidity of about 77%.…”
Urbanization has been rapid across the world but the responses of phosphorus (P) cycling to urbanization have not been well-investigated. This study was to understand the influences of rapid urbanization on forest P cycling in a developing country. Soil P fractions and P resportion were determined for nine slash pine (Pinus elliottii Engelm.) forests along a 30-km long urban-suburban-rural gradient in Nanchang City, southern China. The total P stocks in the surface soils in urban and suburban forests were 317% and 182% higher, respectively, than levels found in rural forests. The concentrations of soil available P, labile P, slow P, occluded P and total extractable P were also much higher in urban and suburban forests than in rural forests (P<0.05). Soil weathered P concentrations were highest in urban forests. Annual mean foliar P concentrations were enhanced in urban and suburban forests compared to rural forests. The P resorption efficiency (PRE) was higher in rural forests than in suburban and urban forests, while the P resorption proficiency (PRP) was lower in rural forests than in suburban and urban forests. Urbanization associated with high extraneous P inputs has altered soil P status and plant P uptake. Foliar P concentration, PRE and PRP were largely dependent on soil P availability in our study forests.
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