Table 3 Mean (± SE) concentrations of plant micronutrients in onion soil amended with conventional fertilizer, compost, and compost + conventional fertilizer during two growing seasons, Hidalgo County, Texas, 2009–2011 (n = 6 replications)

Control

Oct 2009

93 ± 5

4 ± 0.3

0.4 ± 0^c

3 ± 0.2^b

0.5 ± 0^b

Fertilizer

98 ± 3

5 ± 0.2

0.7 ± 0^bc

9 ± 0.8^a

0.9 ± 0.1^a

Compost

84 ± 3

4 ± 0.6

1.1 ± 0.1^ab

8 ± 0.7^a

0.8 ± 0.2^ab

C + F^b

95 ± 6

5 ± 0.4

1.3 ± 0.1^a

8 ± 0.7^a

0.9 ± 0.1^a

F^c

2.54

0.63

15.8 2

15.61

4.44

P

0.0958

0.6075

0.0001

0.0001

0.0201

Control

Mar 2010

105 ± 5

4 ± 0.1

0.4 ± 0^b

3 ± 0.2^c

0.6 ± 0.1

Fertilizer

91 ± 6

4 ± 0.2

0.4 ± 0.1^b

6 ± 0.5^b

0.8 ± 0.1

Compost

86 ± 2

4 ± 0.2

1.0 ± 0.1^a

5 ± 0.2^bc

0.8 ± 0.1

C + F^b

92 ± 5

4 ± 0.2

1.2 ± 0.1^a

9 ± 1.1^a

0.8 ± 0.1

F^c

2.80

0.47

24.39

15.68

1.96

P

0.07054

0.7057

 < 0.0001

0.0001

0.1627

Control

Nov 2010

122 ± 6^a

4 ± 0.2

0.5 ± 0.1^b

5 ± 0.2b

0.7 ± 0.1

Fertilizer

124 ± 6^a

4 ± 0.3

0.5 ± 0.1^b

6 ± 0.2^ab

0.7 ± 0.1

Compost

80 ± 4b

4 ± 0.2

1.0 ± 0.1^a

6 ± 0.5^ab

0.7 ± 0.1

C + F^b

81 ± 5b

4 ± 0.2

1.1 ± 0.1^a

7 ± 0.3^a

0.7 ± 0.1

F^c

17.75

0.99

40.76

6.00

0.21

P

 < 0.0001

0.4232

 < 0.0001

0.0068

0.8882

Control

Mar 2011

197 ± 9^a

4 ± 0.1

0.5 ± 0.1^c

5 ± 0.1^b

0.6 ± 0.1^b

Fertilizer

187 ± 10^a

4 ± 0.2

0.6 ± 0.1^c

9 ± 1.4^a

0.6 ± 0.1^b

Compost

116 ± 12^b

4 ± 0.1

0.9 ± 0.1^b

5 ± 0.1^b

0.7 ± 0.1^a

C + F^b

135 ± 13^b

4 ± 0.3

1.2 ± 0.1^b

8 ± 0.9^ab

0.7 ± 0.1^a

F^c

12.31

2.02

142.61

7.35

4.50

P

0.0003

0.1538

 < 0.0001

0.0030

0.0193