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Table 1 Soil available carbon, nitrogen, and phosphorus, soil cations, as well as fine root biomass under different treatments

From: Different responses of soil respiration and its components to nitrogen and phosphorus addition in a subtropical secondary forest

  Year CK N P NP
Available C&N&P
 DOC (mg·kg− 1) 2014 299.2 ± 8.3 a 281.6 ± 6.1 a 310.4 ± 19.1 a 314.1 ± 28.3 a
2015 294.8 ± 2.8 b 288.9 ± 5.5 b 316.0 ± 3.1 a 324.3 ± 5.3 a
 MBC (mg·kg− 1) 2014 571.7 ± 3.8 a 557.1 ± 3.5a 589.3 ± 2.9 a 588.2 ± 19.6 a
2015 563.4 ± 15 ab 545 ± 10.3 b 593.2 ± 4.8 a 587.0 ± 1.7 a
 NH4+ (mg·kg− 1) 2014 8.1 ± 0.2 b 10.9 ± 0.6 a 6.8 ± 0.1 b 7.4 ± 0.5 b
2015 7.7 ± 0.1 a 8.7 ± 0.6 a 6.7 ± 0.1 b 8.1 ± 0.03 a
 NO3 (mg·kg− 1) 2014 38.4 ± 0.9 b 42.4 ± 1.1 a 35.0 ± 0.3 c 37.1 ± 0.9 bc
2015 40.6 ± 0.1 b 48.1 ± 2.3 a 36.9 ± 0.3 b 41.6 ± 0.7 b
 AP (mg·kg− 1) 2014 27.5 ± 8.4 b 24.8 ± 4.3 b 149.3 ± 11.9 a 150.6 ± 21.4 a
2015 29.3 ± 3.6 b 22.3 ± 4.1 b 139.4 ± 12.8 a 131.9 ± 9.8 a
Soil cations
 Soil pH 2014 4.7 ± 0.04 a 4.5 ± 0.07 a 4.6 ± 0.03 a 4.5 ± 0.1 a
2015 4.6 ± 0.08 a 4.2 ± 0.04 b 4.4 ± 0.1 b 4.3 ± 0.01 b
 Al3+ (mmol·kg− 1) 2014 38.0 ± 1.0 c 50.2 ± 1.0 a 42.4 ± 0.8 b 44.8 ± 0.9 b
2015 38.4 ± 3.2 c 60.4 ± 0.4 a 48.7 ± 0.8 b 61.0 ± 1.4 a
 Ca2+ (mmol·kg− 1) 2014 33.6 ± 3.1 a 25.1 ± 1.8 b 28.8 ± 0.3 ab 25.0 ± 0.7 b
2015 30.3 ± 2.9 a 20.1 ± 0.5 c 26.0 ± 0.2 ab 22.6 ± 0.5 bc
 Mg2+ (mmol·kg− 1) 2014 4.7 ± 0.4 a 4.3 ± 0.2 a 4.2 ± 0.4 a 4.2 ± 0.1 a
2015 4.2 ± 1.0 a 3.5 ± 0.6 a 3.7 ± 0.1 a 3.3 ± 0.1 a
 Na2+ (mmol·kg− 1) 2014 1.5 ± 0.2 a 1.4 ± 0.04 a 1.3 ± 0.3 a 1.3 ± 0.2 a
2015 1.2 ± 0.2 a 1.3 ± 0.4 a 1.2 ± 0.1 a 1.2 ± 0.1 a
Plant
 Fine root biomass (g·m− 2) 2014 172.2 ± 1.3 a 147.4 ± 4.0 c 161.9 ± 0.7 b 152.2 ± 1.5 c
2015 178.9 ± 1.9 a 142.6 ± 1.7 d 159.7 ± 1.4 b 148.6 ± 1.2 c
  1. Notes: Values are means with SE. The different lowercase letters in the same row indicate significant differences among the four treatments at P < 0.05 level. CK, control; N, nitrogen addition; P, phosphorus addition; NP, nitrogen and phosphorus addition