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Phosphate addition enhanced soil inorganic nutrients to a large extent in three tropical forests.

Zhu F, Lu X, Liu L, Mo J - Sci Rep (2015)

Bottom Line: In contrast, besides great elevation in soil available P, P treatments induced 60%, 50%, 26% increases in sum of exchangeable (K(+)+Ca(2+)+Mg(2+)) in the old-growth and the two younger forests, respectively.These positive effects of P were closely related to P-stimulated microbial biomass and litter nutrient input, implying possible stimulation of nutrient return.Our results suggest that N deposition may result in decreases in soil inorganic nutrients (except N) and that P addition can enhance soil inorganic nutrients to support ecosystem processes in these tropical forests.

View Article: PubMed Central - PubMed

Affiliation: 1] Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China [2] Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110164, China.

ABSTRACT
Elevated nitrogen (N) deposition may constrain soil phosphorus (P) and base cation availability in tropical forests, for which limited evidence have yet been available. In this study, we reported responses of soil inorganic nutrients to full factorial N and P treatments in three tropical forests different in initial soil N status (N-saturated old-growth forest and two less-N-rich younger forests). Responses of microbial biomass, annual litterfall production and nutrient input were also monitored. Results showed that N treatments decreased soil inorganic nutrients (except N) in all three forests, but the underlying mechanisms varied depending on forests: through inhibition on litter decomposition in the old-growth forest and through Al(3+) replacement of Ca(2+) in the two younger forests. In contrast, besides great elevation in soil available P, P treatments induced 60%, 50%, 26% increases in sum of exchangeable (K(+)+Ca(2+)+Mg(2+)) in the old-growth and the two younger forests, respectively. These positive effects of P were closely related to P-stimulated microbial biomass and litter nutrient input, implying possible stimulation of nutrient return. Our results suggest that N deposition may result in decreases in soil inorganic nutrients (except N) and that P addition can enhance soil inorganic nutrients to support ecosystem processes in these tropical forests.

Show MeSH
Relationship between soil exchangeable Ca2+ and Al3+ with data from the mixed and the pine forests pooled together.Y = −6.70·X +130.06, R2 = 0.1681, P = 0.005.
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f4: Relationship between soil exchangeable Ca2+ and Al3+ with data from the mixed and the pine forests pooled together.Y = −6.70·X +130.06, R2 = 0.1681, P = 0.005.

Mentions: In the two younger forests, N additions had no effects on soil pH, NH4+-N or NO3−-N concentrations, but reduced available P by 80% in the mixed forest (Fig. 1). N additions resulted in elevated soil exchangeable Al3+ in the mixed forest, but lower exchangeable Ca2+ and sum of exchangeable (K++Ca2++Mg2+) in the pine forest (Fig. 2; Table 2, S1). Neither of MBC, annual litterfall production or litter nutrient input was altered by N treatments in the two younger forests (Fig. 3; Table 1, 2). Linear model analysis showed significantly negatively correlated exchangeable Ca2+ and Al3+ in the mixed and the pine forests (R2 = 0.16; N = 40; P = 0.005; Fig. 4).


Phosphate addition enhanced soil inorganic nutrients to a large extent in three tropical forests.

Zhu F, Lu X, Liu L, Mo J - Sci Rep (2015)

Relationship between soil exchangeable Ca2+ and Al3+ with data from the mixed and the pine forests pooled together.Y = −6.70·X +130.06, R2 = 0.1681, P = 0.005.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4300498&req=5

f4: Relationship between soil exchangeable Ca2+ and Al3+ with data from the mixed and the pine forests pooled together.Y = −6.70·X +130.06, R2 = 0.1681, P = 0.005.
Mentions: In the two younger forests, N additions had no effects on soil pH, NH4+-N or NO3−-N concentrations, but reduced available P by 80% in the mixed forest (Fig. 1). N additions resulted in elevated soil exchangeable Al3+ in the mixed forest, but lower exchangeable Ca2+ and sum of exchangeable (K++Ca2++Mg2+) in the pine forest (Fig. 2; Table 2, S1). Neither of MBC, annual litterfall production or litter nutrient input was altered by N treatments in the two younger forests (Fig. 3; Table 1, 2). Linear model analysis showed significantly negatively correlated exchangeable Ca2+ and Al3+ in the mixed and the pine forests (R2 = 0.16; N = 40; P = 0.005; Fig. 4).

Bottom Line: In contrast, besides great elevation in soil available P, P treatments induced 60%, 50%, 26% increases in sum of exchangeable (K(+)+Ca(2+)+Mg(2+)) in the old-growth and the two younger forests, respectively.These positive effects of P were closely related to P-stimulated microbial biomass and litter nutrient input, implying possible stimulation of nutrient return.Our results suggest that N deposition may result in decreases in soil inorganic nutrients (except N) and that P addition can enhance soil inorganic nutrients to support ecosystem processes in these tropical forests.

View Article: PubMed Central - PubMed

Affiliation: 1] Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China [2] Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110164, China.

ABSTRACT
Elevated nitrogen (N) deposition may constrain soil phosphorus (P) and base cation availability in tropical forests, for which limited evidence have yet been available. In this study, we reported responses of soil inorganic nutrients to full factorial N and P treatments in three tropical forests different in initial soil N status (N-saturated old-growth forest and two less-N-rich younger forests). Responses of microbial biomass, annual litterfall production and nutrient input were also monitored. Results showed that N treatments decreased soil inorganic nutrients (except N) in all three forests, but the underlying mechanisms varied depending on forests: through inhibition on litter decomposition in the old-growth forest and through Al(3+) replacement of Ca(2+) in the two younger forests. In contrast, besides great elevation in soil available P, P treatments induced 60%, 50%, 26% increases in sum of exchangeable (K(+)+Ca(2+)+Mg(2+)) in the old-growth and the two younger forests, respectively. These positive effects of P were closely related to P-stimulated microbial biomass and litter nutrient input, implying possible stimulation of nutrient return. Our results suggest that N deposition may result in decreases in soil inorganic nutrients (except N) and that P addition can enhance soil inorganic nutrients to support ecosystem processes in these tropical forests.

Show MeSH