Tillage methods and microbial fertilizers synergistically enhance soil organic carbon concentration in albic soil

Zhenlin Zhao; Song Cheng; Xiaolin Li; Chang Zhang; Ximing Liu; Jinyao Yan; Jingchao Yuan; Jianzhao Liu; Yao Liang; Wei Fan; Hongguang Cai; Zhenlin Zhao; Song Cheng; Xiaolin Li; Chang Zhang; Ximing Liu; Jinyao Yan; Jingchao Yuan; Jianzhao Liu; Yao Liang; Wei Fan; Hongguang Cai

doi:10.48130/aee-0026-0013

Figures (5) Tables (3)

Figure 1.
Effects of different fertilizer inputs on SOC and MBC in the topsoil and subsoil, including (a) topsoil SOC content, (b) topsoil MBC content, (c) subsoil SOC content, and (d) subsoil MBC content. Different uppercase letters indicate significant differences among tillage methods, and lowercase letters show significant differences between treatments (p < 0.05). Error bars represent the standard deviation of three replicates (n = 3). *, ** represent p < 0.05, p < 0.01, respectively.
Figure 2.
Effects of different fertilizer inputs on aggregate-size distribution in the (a) topsoil, and (b) subsoil. MAG indicates large macroaggregates, LMG indicates small macroaggregates, SMG indicates microaggregates, and SC indicates silt-clay fractions. S indicates only straw return; OH-L indicates low fertilizer input; OH-M indicates medium fertilizer input; OH-H indicates high fertilizer input.
Figure 3.
Effects of different fertilizer inputs on soil aggregate stability, including (a) topsoil MWD, (b) topsoil GMD, (c) subsoil MWD, and (d) subsoil GMD. ** represents p < 0.01. Different lowercase letters show significant differences between treatments (p < 0.05). Different uppercase letters indicate the differences between tillage methods (p < 0.05). Error bars represent the standard deviation of three replicates (n = 3).
Figure 4.
Effects of different fertilizer inputs on aggregate-associated carbon in the (a), (c), (e), (g) topsoil, and (b), (d), (f), (h) subsoil. MAC indicates the carbon content in mega macroaggregates, LMC indicates the carbon content in large macroaggregates, SMC indicates the carbon content in small microaggregates, and SCC indicates carbon content in silt-clay fractions. Different lowercase letters show significant differences between treatments (p < 0.05). Different uppercase letters indicate the differences between tillage methods (p < 0.05). Error bars represent the standard deviation of three replicates (n = 3).
Figure 5.
Correlation network analysis of SOC in relation to tillage methods and microbial organic fertilizer application rates in the topsoil and subsoil. (a) and (b) represent NT topsoil and subsoil; (c) and (d) represent PT; (e) and (f) represent RT. The color scale ranges from −1 (blue, strong negative correlation) to +1 (red, strong positive correlation). Statistical significance is indicated by * (p < 0.05) , ** (p < 0.01), and *** (p < 0.001).
Soil layer
(cm) BD
(g cm⁻³) pH
(1:2.5) SOC TN TP TK Sand Silt Clay

(g kg⁻¹) (%)

0–20 1.4 5.4 11.1 0.83 1.04 12.5 37.3 44.2 18.5

20–40 1.6 5.8 4.9 0.86 0.7 12.9 37.1 41.0 21.9

Table 1.
Basic properties of the experimental soil

Layer (cm)	Treatment	BD (g cm⁻³)	SP (%)	EC (μS cm⁻¹)	pH	TN	TP	TK
Layer (cm)	Treatment	BD (g cm⁻³)	SP (%)	EC (μS cm⁻¹)	pH	(g kg⁻¹)
0–20	NTN	1.48 ± 0.05^a	44.03 ± 1.94^c	93.67 ± 4.07^c	5.43 ± 0.12^b	0.70 ± 0.05^c	0.96 ± 0.08^b	12.57 ± 0.31^c
	NTS	1.42 ± 0.01^ab	46.29 ± 0.44^bc	102.87 ± 2.00^b	5.61 ± 0.10^ab	0.61 ± 0.03^d	1.09 ± 0.11^ab	14.53 ± 1.10^ab
	NTOM-L	1.36 ± 0.01^bc	48.55 ± 0.44^ab	104.40 ± 4.19^ab	5.50 ± 0.22^ab	0.86 ± 0.06^b	1.25 ± 0.09^a	13.77 ± 1.00^bc
	NTOM-M	1.32 ± 0.02^c	50.19 ± 0.65^a	106.70 ± 0.95^a	5.38 ± 0.08^b	1.29 ± 0.02^a	1.33 ± 0.03^a	16.00 ± 1.30^a
	NTOM-H	1.33 ± 0.05^c	49.81 ± 1.96^a	100.53 ± 0.70^b	5.71 ± 0.03^a	0.89 ± 0.04^b	1.01 ± 0.06^b	14.10 ± 0.98^bc
	PTS	1.33 ± 0.07^ab	49.81 ± 2.61^ab	105.50 ± 1.15^a	5.47 ± 0.08^b	1.01 ± 0.02^a	1.26 ± 0.03^b	15.43 ± 0.76^a
	PTOM-L	1.37 ± 0.07^a	48.43 ± 2.73^b	105.90 ± 0.92^a	5.44 ± 0.07^b	0.99 ± 0.06^a	1.24 ± 0.03^b	13.97 ± 0.32^bc
	PTOM-M	1.24 ± 0.03^b	53.33 ± 0.95^a	106.10 ± 1.25^a	6.43 ± 0.10^a	0.73 ± 0.03^c	1.26 ± 0.01^b	14.67 ± 1.17^ab
	PTOM-H	1.33 ± 0.04^ab	49.81 ± 1.51^ab	96.43 ± 4.25^b	6.47 ± 0.02^a	0.88 ± 0.03^b	1.38 ± 0.03^a	12.87 ± 0.15^c
	RTS	1.27 ± 0.02^ab	51.95 ± 0.87^ab	96.87 ± 1.43^b	5.84 ± 0.05^a	0.77 ± 0.05^bc	1.19 ± 0.01^b	12.67 ± 0.61^a
	RTOM-L	1.21 ± 0.07^b	54.21 ± 2.46^a	98.87 ± 7.34^ab	5.82 ± 0.37^a	0.69 ± 0.05^c	1.10 ± 0.07^c	14.43 ± 1.39^a
	RTOM-M	1.35 ± 0.07^a	48.93 ± 2.78^b	104.17 ± 0.67^ab	5.55 ± 0.04^a	0.83 ± 0.06^ab	1.30 ± 0.02^a	12.70 ± 0.75^a
	RTOM-H	1.31 ± 0.08^ab	50.44 ± 3.16^ab	105.60 ± 0.80^a	5.47 ± 0.06^a	0.87 ± 0.05^a	1.09 ± 0.09^c	13.53 ± 1.15^a
20–40	NTN	1.62 ± 0.02^a	38.96 ± 0.77^b	83.77 ± 3.36^c	5.44 ± 0.03^a	0.96 ± 0.08^a	0.76 ± 0.08^a	13.80 ± 0.60^cd
	NTS	1.59 ± 0.02^a	40.07 ± 0.65^b	91.00 ± 1.35^b	5.51 ± 0.04^a	0.95 ± 0.05^a	0.71 ± 0.05^a	15.67 ± 0.76^a
	NTOM-L	1.61 ± 0.03^a	39.09 ± 1.27^b	102.37 ± 0.93^a	5.57 ± 0.02^a	0.72 ± 0.02^b	0.68 ± 0.06^a	15.27 ± 0.71^ab
	NTOM-M	1.55 ± 0.02^b	41.69 ± 0.85^a	79.87 ± 4.51^cd	5.75 ± 0.09^a	0.60 ± 0.02^c	0.40 ± 0.00^b	14.30 ± 0.53^bc
	NTOM-H	1.53 ± 0.02^b	42.45 ± 0.57^a	77.13 ± 2.55^d	5.84 ± 0.03^a	0.98 ± 0.03^a	0.36 ± 0.02^c	12.90 ± 0.44^d
	PTS	1.57 ± 0.01^a	40.60 ± 0.46^b	98.30 ± 0.87^b	5.29 ± 0.03^b	0.95 ± 0.07^b	0.54 ± 0.03^c	15.13 ± 0.59^b
	PTOM-L	1.59 ± 0.04^a	40.10 ± 1.33^b	90.27 ± 3.99^c	5.65 ± 0.32^a	0.86 ± 0.08^b	0.57 ± 0.05^bc	12.97 ± 0.57^c
	PTOM-M	1.47 ± 0.03^b	44.37 ± 0.94^a	102.27 ± 0.47^a	6.14 ± 0.02^a	0.62 ± 0.05^c	0.65 ± 0.03^b	15.20 ± 0.53^b
	PTOM-H	1.47 ± 0.03^b	44.52 ± 1.00^a	65.23 ± 3.02^d	6.02 ± 0.05^b	1.19 ± 0.11^a	0.75 ± 0.03^a	17.17 ± 0.60^a
	RTS	1.60 ± 0.03^ab	39.74 ± 0.95^ab	103.27 ± 0.46^a	5.10 ± 0.02^c	0.51 ± 0.04^a	1.26 ± 0.05^a	12.60 ± 0.79^b
	RTOM-L	1.62 ± 0.02^a	38.74 ± 0.58^c	94.67 ± 0.81^b	5.41 ± 0.02^bc	0.51 ± 0.05^a	0.67 ± 0.04^b	13.53 ± 0.25^b
	RTOM-M	1.57 ± 0.02^b	40.71 ± 0.92^b	65.97 ± 3.03^d	6.00 ± 0.18^a	0.40 ± 0.03^b	0.40 ± 0.00^c	12.60 ± 0.79^b
	RTOM-H	1.53 ± 0.02^c	42.43 ± 0.72^a	86.63 ± 6.74^c	5.60 ± 0.16^ab	0.56 ± 0.02^a	0.43 ± 0.03^c	16.27 ± 0.50^a
ANOVA (0–20)	T	**	**	*	**	**	**	**
	R	**	**	**	**	**	**	**
	T × R	ns	ns	**	**	**	**	**
ANOVA (20–40)	T	**	**	*	**	**	**	**
	R	**	**	**	**	**	**	**
	T × R	ns	ns	**	**	**	**	**
Different letters in the same column indicate significant differences between treatments at p < 0.05 according to Duncan's multiple range test. Values are means ± the standard error (n = 3). , * represent p < 0.05, p < 0.01, respectively, and 'ns' represents p > 0.05. T represents tillage methods (main plot), R represents organic input rate level (subplot), and T × R represents the interaction.

Table 2.

Effect of different fertilizer inputs on soil physicochemical properties

Layer (cm)	Treatment	AG	BG	CBH	XYL
Layer (cm)	Treatment	(μmol d⁻¹ g⁻¹)
0–20	NTN	22.88 ± 0.48^a	22.80 ± 1.10^c	2.03 ± 0.09^ab	47.58 ± 3.48^b
	NTS	22.04 ± 0.68^a	25.92 ± 0.63^b	1.69 ± 0.22^ab	50.90 ± 2.80^b
	NTOM-L	16.77 ± 0.60^c	36.32 ± 3.60^a	1.82 ± 0.29^ab	58.15 ± 3.42^a
	NTOM-M	17.93 ± 0.34^b	22.96 ± 1.11^c	1.46 ± 0.11^b	26.24 ± 4.13^d
	NTOM-H	22.61 ± 3.26^a	40.40 ± 4.02^a	1.58 ± 0.10^a	38.18 ± 0.72^c
	PTS	19.70 ± 0.68^b	30.40 ± 2.01^b	1.83 ± 0.02^ab	42.71 ± 1.13^a
	PTOM-L	19.45 ± 0.30^b	26.08 ± 2.57^bc	1.49 ± 0.12^ab	29.44 ± 3.54^b
	PTOM-M	19.19 ± 0.60^b	25.44 ± 2.29^c	1.44 ± 0.02^b	27.72 ± 4.49^b
	PTOM-H	21.83 ± 1.00^a	41.36 ± 4.02^a	1.98 ± 0.23^a	47.18 ± 2.10^a
	RTS	31.58 ± 3.83^a	44.96 ± 4.43^ab	1.89 ± 0.11^ab	42.89 ± 0.77^a
	RTOM-L	10.40 ± 0.45^c	38.16 ± 3.74^b	1.78 ± 0.13^ab	52.89 ± 2.84^a
	RTOM-M	30.25 ± 1.98^a	44.32 ± 1.60^a	1.90 ± 0.10^b	45.52 ± 1.57^a
	RTOM-H	19.66 ± 0.73^b	28.40 ± 2.77^c	2.00 ± 0.12^a	30.63 ± 2.34^a
20–40	NTN	12.69 ± 0.66^b	29.44 ± 2.04^b	1.20 ± 0.08^d	32.74 ± 2.55^b
	NTS	7.37 ± 0.59^c	37.36 ± 3.61^a	1.43 ± 0.14^c	29.19 ± 2.71^b
	NTOM-L	15.96 ± 0.70^a	38.48 ± 3.81^a	2.07 ± 0.13^b	23.62 ± 1.22^c
	NTOM-M	16.76 ± 0.57^a	23.52 ± 2.29^c	2.28 ± 0.31^ab	58.15 ± 3.42^a
	NTOM-H	15.53 ± 0.52^a	36.80 ± 2.98^a	2.28 ± 0.06^a	32.52 ± 4.08^b
	PTS	21.77 ± 0.55^a	30.00 ± 2.95^a	1.40 ± 0.08^b	31.53 ± 2.91^b
	PTOM-L	16.88 ± 0.69^c	21.20 ± 2.01^b	1.00 ± 0.12^c	25.32 ± 3.64^b
	PTOM-M	19.69 ± 0.40^b	23.68 ± 1.56^b	1.78 ± 0.10^a	45.52 ± 3.79^a
	PTOM-H	17.13 ± 0.52^c	20.08 ± 1.74^b	1.98 ± 0.22^a	42.31 ± 3.39^a
	RTS	13.88 ± 0.28^c	25.20 ± 2.44^c	1.48 ± 0.03^b	28.18 ± 2.72^b
	RTOM-L	14.57 ± 0.43^c	40.96 ± 4.09^a	1.31 ± 0.07^c	44.41 ± 2.88^a
	RTOM-M	19.92 ± 0.63^a	33.44 ± 3.24^b	1.44 ± 0.13^bc	27.42 ± 2.98^b
	RTOM-H	15.50 ± 0.43^b	25.52 ± 2.43^c	1.78 ± 0.02^a	27.09 ± 2.91^b
ANOVA (0–20)	T	**	**	**	**
	R	**	**	**	**
	T × R	**	**	**	**
ANOVA (20–40)	T	**	**	**	**
	R	**	**	**	**
	T × R	**	**	**	**
AG, BG, CBH, and XYL indicate the activities of α-glucosidase, β-glucosidase, cellobiohydrolase, and endo-1,4-β-xylanase, respectively. Different lowercase letters show significant differences between treatments (p < 0.05). ** represent p < 0.01, respectively.

Table 3.

Effect of tillage methods and microbial organic fertilizer inputs on soil enzyme activities

Soil layer (cm)	BD (g cm⁻³)	pH (1:2.5)	SOC	TN	TP	TK	Sand	Silt	Clay
Soil layer (cm)	BD (g cm⁻³)	pH (1:2.5)	(g kg⁻¹)				(%)
0–20	1.4	5.4	11.1	0.83	1.04	12.5	37.3	44.2	18.5
20–40	1.6	5.8	4.9	0.86	0.7	12.9	37.1	41.0	21.9