Table 5 Significance of AP content in different soil layers under different fertilization timing sequences in 2020–2021.

From: Effect of different NPK fertilization timing sequences management on soil-petiole system nutrient uptake and fertilizer utilization efficiency of drip irrigation cotton

Growth stage

Soil depth

2020 Soil AP content (mg/kg)

2021 Soil AP content (mg/kg)

S1

S2

S3

S4

S5

S6

S7

S1

S2

S3

S4

S5

S6

S7

FBS

0–5

24.89bc

26.54a

26.84a

25.37b

24.36b

24.94bc

25.49b

28.81ab

27.11de

27.59cd

29.06a

26.91e

28.23bc

27.91c

5–15

22.33b

21.49cd

21.04d

21.89bc

22.88a

22.30b

21.14d

24.06bc

24.31b

23.88bcd

23.57d

25.11a

24.13bc

23.69cd

15–25

19.58b

18.74de

18.59e

19.10cd

20.57a

19.36bc

18.38e

20.85c

21.97b

21.59b

20.70c

22.75a

21.85b

20.92c

FFS

0–5

22.68ab

21.28de

21.58cde

22.88a

21.05e

22.14bc

21.81cd

24.77ab

24.14c

24.06c

25.11a

23.21d

23.75cd

24.26bc

5–15

17.95d

19.28b

18.25d

18.85c

20.34a

19.24b

17.10e

20.71cd

22.03ab

21.21c

20.63d

22.42a

21.79b

20.27d

15–25

17.42cd

18.49b

17.67c

16.75e

20.64a

18.03bc

16.99de

18.53cd

19.32b

18.82bc

18.17d

20.78a

19.23b

17.99d

PBS

0–5

20.69a

19.66c

20.50ab

20.82a

19.00d

19.24d

20.18b

22.91a

21.46d

22.72ab

23.04a

21.22d

21.88c

22.40b

5–15

17.78cd

18.32ab

17.14e

16.84e

18.74a

18.14bc

17.35de

18.58cd

20.21a

19.22bc

18.36d

20.03a

19.51ab

18.06d

15–25

16.67de

18.09b

17.14cd

16.37e

18.94a

17.53c

15.67f

17.56d

19.16b

18.42c

17.26d

20.58a

18.83bc

16.56e

BOS

0–5

22.90ab

22.49b

22.37b

23.23a

22.19b

22.78ab

22.27b

25.77ab

25.44ab

25.57ab

25.89a

24.89c

25.72ab

25.38b

5–15

20.87a

21.33a

20.38b

20.24bc

21.20a

20.99a

19.90c

23.09a

22.47bc

23.22a

22.60b

23.55a

23.42a

22.12c

15–25

20.06c

20.72b

20.42b

19.96c

21.52a

20.57b

19.86c

22.40de

23.16b

22.76cd

22.29e

23.87a

22.90bc

22.19e

AVE

0–5

22.79

22.49

22.82

23.08

21.65

22.28

22.44

25.57

24.54

24.99

25.78

24.058

24.90

24.99

5–15

19.73

20.11

19.20

19.46

20.79

20.17

18.87

21.61

22.26

21.88

21.29

22.78

22.21

21.04

15–25

18.43

19.01

18.46

18.05

20.42

18.87

17.73

19.84

20.90

20.40

19.61

22.00

20.70

19.42

  1. Different lowercase letters mean significant differences (P < 0.05) among the different fertilization timing sequence under the same soil layer. FBS, FFS, PBS and BOS represent full bud stage, full flower stage, peak boll stage and boll opening stage, respectively. AP, AVE represent soil available phosphorus and the average value of soil AP content.
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