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

Control

Feb 2010

2,091 ± 132^a

20 ± 1

565 ± 186^a

12 ± 2

101 ± 7^a

Fertilizer

1,618 ± 170^b

22 ± 2

224 ± 43^b

11 ± 2

88 ± 12^ab

Compost

1,528 ± 52^b

20 ± 1

146 ± 21^c

9 ± 1

68 ± 9^b

C + F^a

1,654 ± 85^b

20 ± 1

134 ± 17^c

8 ± 1

68 ± 6^b

F^b

5.78

0.96

4.62

1.79

3.42

P

0.0078

0.4374

0.0177

0.1915

0.0446

Control

Mar 2011

1,444 ± 58^c

17 ± 1^c

204 ± 40^a

9 ± 1^a

47 ± 2^b

Fertilizer

1,519 ± 95^c

25 ± 1^a

61 ± 4^b

10 ± 1^a

42 ± 3^b

Compost

1,958 ± 77^b

21 ± 1^b

71 ± 4^b

7 ± 1^b

43 ± 3^b

C + F^a

2,963 ± 112^a

19 ± 1^bc

101 ± 11^b

9 ± 1^a

57 ± 2^a

F^b

43.93

16.65

10.06

12.90

10.12

P

 < 0.0001

 < 0.0001

0.0007

0.0002

0.0007