View Full Table | Close Full ViewTable 1.

Five-year total C, N, and S applied to subplots in amendments, amount of fertilizer N and S applied, aboveground wheat crop C returned to soil, and grain removed at harvest. Total amendment C varies slightly from the targeted 250 g C m−2 yr−1 due to adjustment for post-application measurement of moisture and C content. In the case of compost, the C, N, and S additions are based on the pre-composted wheat straw plus fertilizer used to speed composting. Values in a column not followed by the same letter are significantly different at P = 0.05, with the Type I error rate protected at 0.05.

 
Treatment
Additions
Grain removed
Main plot Subplot Amendment
Fertilizer
Crop C
C N S N S
g m−2
Fallow biosolid 1253 167 50 0 0 0 0
manure 1229 86 16 0 0 0 0
wood 1247 4 0 0 0 0 0
alfalfa 1253 90 7 0 0 0 0
brassica 1253 20 5 0 0 0 0
wheat 1239 15 3 0 0 0 0
compost 1250 39 8 0 0 0 0
sucrose 1244 3 0 0 0 0 0
check 0 0 0 0 0 0 0
cotton 1242 4 0 0 0 0 0
Wheat biosolid 1253 167 50 0 0 1727ab 2268
manure 1229 86 16 0 0 1556b 2063
wood 1247 4 0 58 9 1693ab 2214
alfalfa 1253 90 7 0 0 1611ab 2137
brassica 1253 20 5 58 9 1657ab 2105
wheat 1239 15 3 58 9 1644ab 1966
compost 1250 39 8 58 9 1766a 2350
sucrose 1244 3 0 58 9 1618ab 2165
check 0 0 0 58 9 1751ab 2161
cotton 1242 4 0 58 9 1634ab 2013
SE 48 90
P > F 0.0181 0.1092
Main plot means
Fallow 1121 43 9 0 0 0 0
Wheat 1121 43 9 41 6 1666 2144



View Full Table | Close Full ViewTable 2.

Soil organic carbon (SOC), organic N, and total S to a depth of 300 kg m−2 (approximately 25 cm) 4 yr after the treatments had stopped. Main plot and subplot effects were highly significant but their interaction was not (P > F = 0.21 for SOC, 0.23 for organic N, and 0.71 for S). Values in a column not followed by the same letter are significantly different at P = 0.05, with the Type I error rate protected at 0.05.

 
Treatment
Final soil sample
Main plot Subplot SOC Organic N Total S
g m−2 in top 300 kg m−2 soil
Fallow biosolid 3984 333 41.0
manure 3696 306 31.2
wood 3941 299 29.7
alfalfa 3658 304 27.7
brassica 3692 294 29.3
wheat 3489 284 26.3
compost 3597 293 26.1
sucrose 3548 288 26.1
check 3460 277 26.9
cotton 3469 285 26.1
Wheat biosolid 4477 371 45.1
manure 4413 355 35.2
wood 4137 305 29.7
alfalfa 4162 337 32.6
brassica 4069 320 30.0
wheat 4147 330 31.0
compost 4015 327 31.1
sucrose 4024 319 30.3
check 4018 324 31.2
cotton 3887 312 30.3
SE 90 8 1.5
Main plot means
Fallow 3653 296 29.0
Wheat 4135 330 32.6
SE 30 2 0.6
P > F <0.0001 <0.0001 <0.0001
Subplot means
biosolid 4230a 352a 43.0a
manure 4054ab 331ab 33.2b†
wood 4038ab 302c 29.7 b
alfalfa 3909bc 320bc 30.2b
brassica 3880bc 307bc 29.7b
wheat 3818bc 307bc 28.7b
compost 3805bc 310bc 28.6b
sucrose 3786bc 304 c 28.2b
check 3738c 300c 29.0b
cotton 3678c 299c 28.2b
SE 63 5 1.1
P > F <0.0001 <0.0001 <0.0001
For total S, in addition to the indicated mean differences, manure and sucrose are significantly different at P < 0.05.