Table 2 Different fractionations of P as affected by N fertilizer and green manures (mg kg−1).

From: Increase phosphorus availability from the use of alfalfa (Medicago sativa L) green manure in rice (Oryza sativa L.) agroecosystem

 

NaHCO3-Pi

NaHCO3-Po

NaOH-Pi

Total labile P

NaOH-Po

HCl-P

Residual-P

Total-P

Olsen-P

2012

 Control

40.63 ± 0.44c

42.32 ± 2.82b

72.06 ± 0.65c

155.01 ± 3.56c

36.42 ± 1.92a,b

193.60 ± 1.18b,c

47.37 ± 3.41b

471.98 ± 3.82c

18.71 ± 0.21c

 Alfalfa

46.33 ± 4.25b

68.13 ± 4.85a

89.43 ± 6.89a,b

203.89 ± 7.46a,b

36.79 ± 1.22a,b

194.94 ± 3.53b,c

60.84 ± 3.36a

536.44 ± 14.26b

21.51 ± 0.30b

 Broad bean

45.54 ± 0.50b

63.43 ± 4.49a

85.32 ± 5.41b

194.29 ± 2.91a,b

38.15 ± 1.79a

192.18 ± 1.23c

50.76 ± 2.21a,b

522.40 ± 7.10b

20.89 ± 1.38b,c

 N fertilizer

42.80 ± 2.58c

30.82 ± 2.74b

84.06 ± 3.60b

157.68 ± 3.93c

35.57 ± 0.54a,b

196.99 ± 0.13b,c

44.43 ± 3.12b,c

494.73 ± 8.07b,c

19.63 ± 1.08b,c

 Alfalfa + N

58.32 ± 1.84a

63.79 ± 5.02a

103.16 ± 8.81a

225.27 ± 15.56a

34.16 ± 2.65a,b

199.54 ± 2.67a,b

47.67 ± 5.21b

601.08 ± 11.10a

24.67 ± 0.83a

 Broad bean + N

48.64 ± 0.51b

62.81 ± 4.51a

95.55 ± 1.64a,b

207.00 ± 6.66a,b

30.41 ± 3.43b

204.72 ± 0.96a

35.27 ± 2.66c

537.33 ± 29.71b

22.05 ± 0.29b

2014

 Control

42.76 ± 1.11c

43.35 ± 0.54b

79.28 ± 2.70c

165.39 ± 3.81c

37.26 ± 0.85a

182.58 ± 4.00b

46.65 ± 0.72b,c

442.15 ± 8.11d

16.16 ± 0.38b,c

 Alfalfa

48.21 ± 1.61b

72.02 ± 0.57a

100.56 ± 4.37a

220.79 ± 5.69a

36.70 ± 2.68a

270.55 ± 17.18a

59.21 ± 3.04a

652.54 ± 22.85a

19.20 ± 0.53a

 Broad bean

47.80 ± 0.89b

63.14 ± 6.19a

104.11 ± 1.08a

215.05 ± 4.82a

32.23 ± 2.29a,b

265.70 ± 16.71a

54.59 ± 3.45a,b

627.56 ± 24.61a,b

18.53 ± 1.456a

 N fertilizer

33.97 ± 2.63d

44.00 ± 3.76b

85.24 ± 1.58b,c

163.21 ± 1.59c

26.59 ± 1.74b

210.92 ± 21.84a

47.20 ± 2.48c

476.27 ± 18.32d

14.22 ± 0.49c

 Alfalfa + N

47.38 ± 0.88b

70.97 ± 5.56a

107.62 ± 3.40a

225.97 ± 4.79a

34.06 ± 2.08a

191.86 ± 9.43b

54.70 ± 0.51a,b

595.77 ± 13.54b,c

17.98 ± 0.65a,b

 Broad bean + N

54.23 ± 1.46a

45.80 ± 4.53b

89.40 ± 4.29b

189.43 ± 9.32b

31.57 ± 0.92a,b

217.23 ± 7.62a

40.76 ± 0.17c

554.19 ± 17.69c

17.70 ± 0.46a,b

  1. Data are means ± standard errors.
  2. aPi: inorganic P, Po: organic P.
  3. bThe total labile P including NaHCO3-Pi, NaHCO3-Po, and NaOH-Pi fractions.
  4. The different letters in the same column in the same year are significant (P < 0.05).