Remediation of heavily saline-sodic soil with flue gas desulfurization gypsum in Arid-Inland China

Figures & data

Table 1. Physical and chemical properties of the soil for this study.

Soil Depth (cm)	pH	EC (ms·cm^−1)	ESP (%)	CEC (cmol·kg^−1)	OM (g·kg^−1)	TN (g·kg^−1)	Olsen-P (mg·kg^−1)	Av-K (mg·kg^−1)	BD (g·cm^−3)	SHC (cm·h^−1)
0 ~ 10	10.12	4.45	51.8	15.4	2.43	0.20	18.7	64	1.72	0.10
10 ~ 20	10.06	2.81	48.2	10.5	1.83	0.21	14.1	70	1.64	0.05
20 ~ 30	10.07	2.13	48.0	12.2	1.96	0.17	12.8	73	1.59	0.07
30 ~ 40	10.03	2.85	44.6	16.8	2.50	0.22	9.2	63	1.66	0.01

OM: organic matter; TN: total nitrogen; Av-K: available-K; BD: soil bulk density.

SHC, saturated hydraulic conductivity at 10°C.

Figure 1. Undisturbed soil column and leachate collection design.

Table 2. Schedule of watering and sampling.

Date	Amount of irrigation water (mL/column)	Amount of irrigation water (m^3/ha)	Leachate collection	Soil sampling
2014.5.11–5.15	3000	600
2014.5.26			First time
2014.5.26–5.28	1500	300
2014.6.12			Second time	First time
2014.6.12–7.12	1500	300
2014.7.12			Third time	Second time
2014.7.12–8.13	1500	300
2014.8.13			Fourth time	Third time

Figure 2. Soil bulk density and SHS as affected by different FGDG treatments at different sampling depth.

Figure 3. Soil pH as affected by different FGDG treatments at different sampling depth and dates.

Figure 4. Soil EC as affected by different FGDG treatments at different sampling depth and dates.

Figure 5. Soil Ex-Na⁺ as affected by different FGDG treatments at different sampling depth and dates.

Figure 6. Soil ESP as affected by different FGDG treatments at different sampling depth and dates.

Table 3. Changes of water-soluble Na⁺ content in soil and amount of Na⁺ from leachate.

Time (d)	Treatment	Water-soluble Na^+ content in soil （cmol/kg）				Amount of Na^+ from leachate (g)	Total Na^+ from leachate (g)
		0–10 (cm)	10–20 (cm)	20–30 (cm)	30–40 (cm)
30	CK	5.00 ± 0.02b	3.45 ± 0.06b	2.74 ± 0.02b	3.20 ± 0.29a	10.172
	T1	4.77 ± 0.13b	2.39 ± 0.01a	2.27 ± 0.16b	2.07 ± 0.18a	16.602
	T2	3.32 ± 0.17a	2.34 ± 0.02a	2.14 ± 0.37b	2.10 ± 0.08a	18.572
	T3	3.16 ± 0.04a	2.17 ± 0.07a	1.40 ± 0.26a	2.72 ± 0.21a	15.533
60	CK	3.45 ± 0.01c	3.17 ± 0.12c	2.41 ± 0.17b	2.78 ± 0.22a	3.884
	T1	3.04 ± 0.21bc	2.88 ± 0.14bc	2.21 ± 0.21b	2.83 ± 0.27a	2.567
	T2	2.72 ± 0.05b	2.13 ± 0.23b	2.10 ± 0.27b	3.18 ± 0.45a	2.946
	T3	2.22 ± 0.02a	1.44 ± 0.18a	1.27 ± 0.21a	3.25 ± 0.25a	2.263
90	CK	2.34 ± 0.03b	2.12 ± 0.14b	2.01 ± 0.13b	2.64 ± 0.34a	1.844	15.900
	T1	2.08 ± 0.02b	1.96 ± 0.09b	1.85 ± 0.18b	2.35 ± 0.34a	0.643	19.812
	T2	1.50 ± 0.02ab	1.28 ± 0.26a	1.01 ± 0.08a	2.31 ± 0.08a	0.713	22.231
	T3	1.20 ± 0.01a	1.16 ± 0.14a	0.79 ± 0.06a	2.79 ± 0.67a	0.586	18.382

Values are means of three measurements; means in column followed by the same letter are not significantly different (P > 0.05). Amount of Na⁺ from leachate was the value of different treatment at day 30, 60, and 90, respectively. Total Na⁺ from leachate was the sum of Na⁺ in three sampling periods with different treatments.

Table 4. Effects of FGDG on maize growth.

Treatment	Emergence rate (%)	Plant height (cm)	Shoot fresh weight (g.column^−1)	Shoot dry weight (g.column^−1)	Root fresh weight (g.column^−1)	Root dry weight (g.column^−1)
CK	50.0 ± 1.5c	48.50 ± 1.9d	25.96 ± 2.5d	9.35 ± 2.0c	20.33 ± 3.5c	5.08 ± 1.0b
T1	85.0 ± 1.3b	59.60 ± 2.0c	38.87 ± 3.1c	13.99 ± 1.5bc	33.67 ± 3.2b	8.45 ± 1.6ab
T2	92.5 ± 1.3a	92.50 ± 2.5a	56.95 ± 2.0a	20.19 ± 2.5a	42.70 ± 3.0a	12.30 ± 2.5a
T3	90.5 ± 1.7a	85.40 ± 2.0b	49.42 ± 2.5b	18.14 ± 2.5ab	35.16 ± 3.5ab	9.33 ± 2.1ab

Values are means of three measurements; means in column followed by the same letter are not significantly different (P > 0.05).