Soil and phosphorus redistribution along a steep tea plantation in the Feitsui reservoir catchment of northern Taiwan

Figures & data

Figure 1  Catchment of the Feitsui reservoir showing the three sampling locations.

Figure 2  Cross-section of the studied tea plantation and total radionuclide inventories along the slope (n, number of replicate soil cores). Error bars represent standard deviation and the letters a, b and c indicate statistically significant differences (anova, Duncan's test, α = 0.05).

Figure 3  Depth distribution of 137Cs at different landscape positions, and 137Cs activity in the sediments. Error bars represent the standard deviation of three subsamples.

Figure 4  Depth distribution of 210Pbex at different landscape positions, and 210Pbex activity in the sediments. Error bars represent the standard deviation of three subsamples.

Table 1 Chemical and physical properties of the studied soils and sediments

Sample location^†	pH in H2O	Sand	Silt	Clay	Textural class^‡	H2O adsorbed at 19% RH (g g^−1)	Ren
		(%)
Reference site	3.9	22	44	34	CL	0.027	0.59
Tea plantation, upper slope	3.7	13	50	37	SiCL	0.023	0.64
Tea plantation, middle slope	3.8	19	46	35	SiCL	0.022	0.66
Tea plantation, lower slope	3.8	17	49	34	SiCL	0.019	0.72
Toeslope	4.4	22	46	32	CL	0.017	0.77
Floodplain sediment	5.0	83	2	15	SL	0.006
Reservoir sediment	4.6	8	65	27	SiL	0.011
	EC (dS m^−1)	OC	Total N	Exch. K (cmolc kg^−1)	Inorganic P	Organic P	Total P
		(g kg^−1)			(mg kg^−1)
Reference site	0.14	48	3.6	0.28	84	187	271
Tea plantation, upper slope	0.20	37	3.0	0.61	654	107	761
Tea plantation, middle slope	0.24	36	3.1	0.77	944	211	1155
Tea plantation, lower slope	0.17	27	2.4	0.59	500	460	960
Toeslope	0.07	28	2.6	0.42	473	330	804
Floodplain sediment	0.10	4 ± 0.7^§	0.6 ± 0.05	0.15 ± 0.01	298 ± 6	83 ± 16	380 ± 10
Reservoir sediment	1.64	12 ± 2.9	1.5 ± 0.2	0.21 ± 0.1	400 ± 48	106 ± 28	506 ± 29
^†Samples from reference site, tea plantation and toeslope are composite topsoil samples (0–10 cm). The sediment samples are composed of three subsamples each, with the following depth increments: 0–12, 12–24, 0–24 cm (floodplain) and 0–5, 25–30, 50–55 cm (reservoir); for the parameters in the upper half of the table and for EC, the three subsamples were combined and analyses were carried out on the resulting composite samples.
^‡According to Soil Survey Staff (2006): CL, clay loam; SiCL, silty clay loam; SL, sandy loam; SiL, silt loam.
^§Arithmetic mean ± standard deviation. EC, electrical conductivity; Exch. K, exchangeable potassium; OC, organic carbon; Ren, enrichment/depletion ratio of the reservoir sediment relative to the soils (Eq. 1); RH, relative humidity.

Figure 5  Depth distribution of inorganic and organic phosphorus (P) at different landscape positions, and P concentration in the sediments. Error bars represent the standard deviation of three subsamples.

Soil Survey Staff . 2006 . Keys to Soil Taxonomy, , 10th edn , Washington : United States Department of Agriculture-Natural Resources Conservation Science .

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