Aluminum and nutrient interplay across an age-chronosequence of tea plantations within a hilly red soil farm of subtropical China

Figures & data

Table 1 General properties of the 19 research plots in this study

Planting year (yr)	Replicate 1	Replicate 2	Replicate 3
CK (0)	Wild shrubs; eastern area	Wild shrubs; southern area	Wild shrubs; western area
< 10	D = 1.5 cm, H = 70 cm; eastern area	D = 1.5 cm, H = 60 cm; southern area	D = 2.0 cm, H = 55 cm; southern area
10~20	D = 1.5 cm, H = 75 cm; eastern area	D = 1.0 cm, H = 70 cm; southern area	D = 1.5 cm, H = 60 cm; western area
20–30	D = 1.5 cm, H = 80 cm; southern area	D = 2.0 cm, H = 80 cm; southern area	D = 2.0 cm, H = 50 cm; western area
30–40	D = 2.0 cm, H = 100 cm; eastern area	D = 1.5 cm, H = 70 cm; southern area	D = 2.0 cm, H = 100 cm; southern area
40–50	D = 2.0 cm, H = 80 cm; southern area	D = 2.0 cm, H = 100 cm; southern area	D = 2.5 cm, H = 50 cm; western area
> 50	D = 2.5 cm, H = 100 cm; eastern area

CK, control treatment. D and H represent average ground diameter and height of tea plant (Camellia sinensis L.), respectively. Eastern, southern and western areas represent the different locations within a hilly red soil farm, southern China.

Figure 1 Soil Al fractionation sequential extraction procedure and its corresponding fractions (Revision according to Duan et al. 2012). KCl = potassium chloride, CuCl₂ = copper chloride, NH₄OAc = ammonium acetate, HCl = hydrochloric acid, NaOH = sodium hydroxide, Al = aluminium, Al³⁺ = trivalent aluminum ion, AlOM = organic aluminum, Al(OH)²⁺ = bivalent aluminium hydroxide ions, Al(OH)₂⁺ = monovalent aluminium hydroxide ion, Al(OH)₃ = aluminium hydroxide, AlHC = humus aluminum.

Figure 2 Soil Al fractions varied with planting year and soil layer within a hilly red soil farm, southern China. PY = planting year, SL = soil layer, CK, control treatment. ^NS not significant, * P < 0.05, ** P < 0.01, ***P < 0.001. ^NS, *, **, and *** show the results of analysis of variance (ANOVA).

Table 2 Average values of soil chemical properties across an age-chronosequence of tea (Camellia sinensis L.) plantations within a hilly red soil farm, southern China

Planting year (yr)	pH	CEC (cmolc kg^−1)	Organic C (g kg^−1)	Total N (g kg^−1)	Total P (g kg^−1)	C/N	N/P
CK (0)	4.87 ± 0.11a	9.31 ± 0.94e	6.69 ± 0.69e	0.56 ± 0.13b	0.27 ± 0.04c	15.90 ± 4.19a	2.11 ± 0.43a
< 10	4.63 ± 0.07b	11.90 ± 0.87d	8.00 ± 0.47d	0.59 ± 0.09b	0.44 ± 0.09b	14.78 ± 1.75a	1.49 ± 0.21a
10–20	4.55 ± 0.07bc	12.44 ± 0.86cd	9.05 ± 0.55c	0.83 ± 0.11a	0.52 ± 0.10a	11.72 ± 1.17a	1.85 ± 0.33a
20–30	4.51 ± 0.07bc	14.23 ± 1.94bc	9.69 ± 0.70bc	0.84 ± 0.12a	0.58 ± 0.05a	12.37 ± 1.20a	1.51 ± 0.25a
30–40	4.44 ± 0.07c	15.24 ± 1.30b	10.03 ± 0.72ab	0.86 ± 0.12a	0.53 ± 0.09a	13.24 ± 1.44a	1.73 ± 0.20a
40–50	4.14 ± 0.09d	17.38 ± 1.49a	11.01 ± 0.62a	0.83 ± 0.13a	0.55 ± 0.08a	13.61 ± 1.54a	1.63 ± 0.24a
> 50	4.30 ± 0.04cd	13.93 ± 1.20c	10.43 ± 1.13ab	0.78 ± 0.25a	0.55 ± 0.14a	14.38 ± 3.17a	1.39 ± 0.10a
Variance analysis of F-statistics^#
PY	6.42**	5.56*	28.00***	3.98*	6.84**	1.11^NS	2.25^NS
SL	6.21*	22.9***	87.14***	87.92***	45.70***	43.63***	5.36*
LO	0.58^NS	0.09^NS	1.42^NS	0.05^NS	0.63^NS	1.05^NS	3.32^NS
PY × SL	0.30^NS	0.34^NS	0.77^NS	0.44^NS	2.39^NS	1.79^NS	6.91**
PY × LO	2.31^NS	0.13^NS	4.92*	0.34^NS	0.84^NS	1.64^NS	1.45^NS
SL × LO	0.23^NS	0.24^NS	4.58*	0.20^NS	2.19^NS	3.81^NS	2.18^NS
PY × SL × LO	0.11^NS	0.22^NS	5.37*	0.83^NS	3.90*	1.74^NS	6.23*

Mean ± standard error, n = 6 except n = 2 for > 50-year tea plantation. The different letters represent significant difference among the different planting year in soil chemical properties (P < 0.05). ^# Significance level of F values: ^NS not significant, * P < 0.05, ** P < 0.01, ***P < 0.001. Note: CEC = Cation exchange capacity, Organic C = Organic carbon, Total N=Total nitrogen, Total P = Total phosphorus, PY = Planting year, SL = Soil layer, LO = locations.

Figure 3 The concentrations of total Al and nutrients varied with planting year and plant organs within a hilly red soil farm, southern China. Note: The different letters represent significant differences in five plant organs among the plantations of different planting year (P < 0.05).

Figure 4 Biplot diagram for redundancy analysis (RDA) among the extractable aluminum (Al), total Al and chemical properties in (a) topsoil and (b) subsoil. The X and Y axes represent the percentages of total variations in extractable Al fractions that are explained by soil chemical properties. The plots represent 19 sampling sites in the distribution of the four quadrants. The projection location of plots to soil chemical properties arrows can express the value of soil chemical properties in these plots. OC = organic carbon, TN = total nitrogen, TP = total phosphorus, Ec-Al = exchangeable aluminum, Or-Al = organic aluminum complexes, So-Al = sorbed inorganic aluminum, Hy-Al = hydrous oxide and hydroxide aluminum, Hu-Al = humic acid aluminum, Ex-Al = extractable aluminum, CEC, soil cation-exchange capacity.

Figure 5 Biplot diagram for redundancy analysis (RDA) among total aluminum (Al) in plant organs and extractable Al fractions in (a) topsoil and (b) subsoil. The X and Y axes represent the percentages of variations in total Al in plant organs that are explained by soil extractable Al fractions. The plots represent 19 sampling sites in the distribution of the four quadrants. The projection location of plots to soil extractable Al fractions arrows can express the value of soil extractable Al fractions in these plots. Ec-Al = exchangeable aluminum, Or-Al = organic aluminum complexes, So-Al = sorbed inorganic aluminum, Hy-Al = hydrous oxide and hydroxide aluminum, Hu-Al = humic acid aluminum, Ex-Al = extractable aluminum. Total Al = total aluminum concentration in soils, R-Al = total aluminum concentration in roots, S-Al = total aluminum concentration in stems, T-Al = total aluminum concentration in twigs, M-Al = total aluminum concentration in mature leaves, N-Al = total aluminum concentration in new leaves.

Duan XH, Hu X, Chen F, Deng Z 2012: Bioactive ingredient levels of tea leaves are associated with leaf Al level interactively influenced by acid rain intensity and soil Al supply. J. Food Agric. Environ., 10, 1197–1204.

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