Fractions and spatial distributions of agricultural riparian soil phosphorus in a small river basin of Taihu area, China

Figures & data

Table 1. Characteristics of the soil profile of three different riparian zones. Values are the mean of three replicate samples, each a composite of three replicate cores.

	Depth (cm)	pH	Water Content (%)	Bulk density	ORP	Capillary porosity	Noncapillary porosity	Organic Matter (%)
RH	0–10	6.2 ± 0.8	34.10 ± 3.62	0.76 ± 0.35	705.26 ± 70.43	0.769 ± 0.108	0.107 ± 0.011	12.45 ± 1.65
	20–30	6.3 ± 0.5	27.23 ± 2.55	1.23 ± 0.28	900.54 ± 99.64	0.523 ± 0.097	0.053 ± 0.002	10.13 ± 1.63
	50–60	6.5 ± 0.7	26.42 ± 4.92	1.25 ± 0.26	672.16 ± 68.43	0.752 ± 0.184	0.021 ± 0.006	7.38 ± 0.93
	80–90	7.0 ± 0.4	24.16 ± 3.76	1.37 ± 0.33	752.13 ± 82.45	0.546 ± 0.086	0.015 ± 0.008	8.45 ± 0.59
	110–120	6.8 ± 0.5	26.72 ± 4.58	1.46 ± 0.25	710.98 ± 69.43	0.495 ± 0.062	0.009 ± 0.002	7.92 ± 0.96
RW	0–10	5.9 ± 0.5	25.55 ± 3.93	1.29 ± 0.31	2496.45 ± 135.89	0.558 ± 0.065	0.029 ± 0.003	9.74 ± 1.13
	20–30	6.2 ± 0.7	19.25 ± 2.35	1.36 ± 0.51	1347.72 ± 175.43	0.560 ± 0.101	0.028 ± 0.00	5.57 ± 1.23
	50–60	6.6 ± 0.7	23.63 ± 3.58	1.27 ± 0.56	5277.64 ± 78.43	0.582 ± 0.079	0.034 ± 0.007	8.41 ± 1.67
	80–90	6.0 ± 0.3	24.92 ± 3.94	1.30 ± 0.47	2333.81 ± 562.82	0.595 ± 0.082	0.023 ± 0.005	7.27 ± 0.64
	110–120	6.5 ± 0.8	28.33 ± 5.17	1.44 ± 0.59	5581.37 ± 400.63	0.541 ± 0.114	0.014 ± 0.008	8.64 ± 0.93
RY	0–10	6.1 ± 0.9	30.61 ± 4.52	1.21 ± 0.58	835.46 ± 100.79	0.484 ± 0.093	0.028 ± 0.009	10.58 ± 1.67
	20–30	6.4 ± 0.8	25.15 ± 2.99	1.36 ± 0.61	892.36 ± 89.64	0.486 ± 0.096	0.022 ± 0.006	8.73 ± 0.98
	50–60	6.8 ± 0.5	23.61 ± 4.85	1.53 ± 0.64	896.75 ± 74.95	0.436 ± 0.094	0.015 ± 0.007	6.75 ± 1.02
	80–90	7.6 ± 0.5	28.38 ± 2.73	1.39 ± 0.55	871.92 ± 84.18	0.560 ± 0.108	0.020 ± 0.006	7.66 ± 1.24
	110–120	7.6 ± 0.7	33.86 ± 5.58	1.42 ± 0.35	820.42 ± 82.64	0.520 ± 0.121	0.012 ± 0.007	7.45 ± 0.95

Annotation: RH-Riparian Hejiabang; RW-Riparian Wuxidang; RY-Riparian Yincunggang.

Figure 1. Distribution of TP in different riparian soils.

Table 2. Total extracted phosphorus determined as the sum of sequential fractions (mg kg⁻¹) and the proportion (%) of each fraction in soil profiles of three riparian zones.

	Depth (cm)	TP mg kg^−1	NaHCO3-Pi %	NaOH-Pi %	HCl-Pi %	Residual Pi %	NaHCO3-Po %	NaOH-Po %	Residual Po %
RH	0–10	736 ± 50	23.56 ± 2.31	36.37 ± 3.40	23.19 ± 1.77	10.11 ± 1.09	0.82 ± 0.12	2.24 ± 0.41	3.72 ± 0.27
	20–30	326 ± 21	18.68 ± 1.84	20.66 ± 2.15	30.34 ± 2.76	21.84 ± 2.15	1.46 ± 0.61	3.96 ± 0.31	3.06 ± 0.31
	50–60	689 ± 82	24.71 ± 2.32	35.78 ± 3.19	22.51 ± 1.60	8.91 ± 1.02	1.30 ± 0.29	2.42 ± 0.29	4.37 ± 0.58
	80–90	487 ± 27	20.80 ± 2.26	27.76 ± 2.46	23.82 ± 2.46	15.90 ± 1.85	2.03 ± 0.31	2.83 ± 0.21	6.85 ± 0.82
	110–120	473 ± 49	19.17 ± 2.33	24.84 ± 2.33	6.17 ± 1.27	37.48 ± 3.38	1.73 ± 0.27	3.34 ± 0.32	7.26 ± 0.63
RW	0–10	455 ± 26	11.73 ± 1.10	21.82 ± 1.98	28.07 ± 2.42	25.77 ± 2.42	3.16 ± 0.22	5.70 ± 0.55	3.76 ± 0.22
	20–30	157 ± 32	7.85 ± 3.82	16.81 ± 3.18	24.04 ± 3.82	31.71 ± 3.82	2.21 ± 0.64	2.05 ± 0.64	15.32 ± 1.91
	50–60	317 ± 35	4.14 ± 0.95	8.34 ± 1.26	21.62 ± 2.52	38.45 ± 3.47	2.85 ± 0.47	8.50 ± 0.95	16.09 ± 0.95
	80–90	359 ± 34	4.86 ± 0.84	9.61 ± 1.95	25.09 ± 3.06	35.45 ± 3.06	0.16 ± 0.08	5.16 ± 0.56	19.67 ± 1.11
	110–120	345 ± 33	5.92 ± 1.45	12.01 ± 1.74	16.39 ± 2.32	40.55 ± 3.77	0.40 ± 0.14	4.19 ± 0.58	20.55 ± 1.16
RY	0–10	455 ± 41	15.46 ± 1.76	28.22 ± 2.42	21.72 ± 1.76	0.50 ± 0.22	6.42 ± 0.29	12.51 ± 0.66	15.17 ± 0.66
	20–30	157 ± 19	8.86 ± 3.82	18.86 ± 3.18	26.49 ± 3.82	1.86 ± 1.27	1.86 ± 0.64	4.43 ± 1.27	37.64 ± 3.82
	50–60	317 ± 28	9.15 ± 1.89	20.16 ± 1.89	17.85 ± 1.58	11.64 ± 1.26	1.71 ± 0.16	1.81 ± 0.32	37.70 ± 1.26
	80–90	359 ± 35	8.91 ± 1.39	16.32 ± 1.11	20.25 ± 2.51	34.58 ± 2.51	2.36 ± 0.08	3.43 ± 0.28	14.15 ± 0.56
	110–120	347 ± 34	5.02 ± 0.87	7.87 ± 0.87	53.93 ± 3.19	25.44 ± 2.32	0.15 ± 0.03	1.13 ± 0.26	6.47 ± 0.58

Annotation: RH-Riparian Hejiabang; RW-Riparian Wuxidang; RY-Riparian Yincunggang.

Figure 2. Distribution of P_i fractions in different riparian soils.

Table 3. Correlation between contents of fractions of phosphorus and soil physicochemical characteristics.

	PH	Water content	Organic matter	Bulk density	ORP	Capillary porosity	Noncapillary porosity
NaHCO3-Pi	−0.184	0.342	0.662**	−0.631*	−0.378	0.726**	0.508
NaOH-Pi	−0.246	0.362	0.624*	−0.680*	−0.343	0.755**	0.544*
HCl-Pi	−0.242	0.459	0.491	−0.699*	−0.159	0.741**	0.551*
Residual Pi	−0.081	−0.093	0.098	0.071	0.523*	0.167	−0.072
NaHCO3-Po	−0.350	0.061	0.627*	−0.256	−0.103	−0.008	0.067
NaOH-Po	−0.546*	0.138	0.527*	−0.373	0.266	0.101	0.164
Residual Po	−0.236	−0.239	−0.151	0.237	0.366	−0.280	−0.259
TP	−0.325	0.336	0.666**	−0.653**	−0.100	0.756**	0.496

^* p < 0.05

^** p < 0.01.

Figure 3. Distribution of P_o fractions in different riparian soils.

Figure 4. Changes in the SOM:OP and IP:OP ratios along the soil profiles in the three sampling zones (SOM = soil organic matter).