Depth distribution of soil organic C and N after long-term soybean cropping in Texas · Knowledge Library

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Depth distribution of soil organic C and N after long-term soybean cropping in Texas · Knowledge Library

soil total N

↑ 6= 17

increase
no tillage (NT) vs. conventional tillage (CT)significant · 0–5 cm · October 2002 · Burleson County, Texas · All sequences; LSD161
Numbers
- treatment 1,735 vs. control 1,051 mg kg-1 (+65.08 %) · SWS
- treatment 1,595 vs. control 1,151 mg kg-1 (+38.58 %) · WS
- treatment 1,359 vs. control 761 mg kg-1 (+78.58 %) · CS
Source · p. 4
“For all cropping sequences, total N was higher under NT than CT at 0–5 and 15–30 cm, but not at 5–15 cm.”
no effect
no tillage (NT) vs. conventional tillage (CT)not significant · 5–15 cm · October 2002 · Burleson County, Texas · Intensive sequences only; CS exception to prose excluded, LSD116
Numbers
- treatment 898 vs. control 838 mg kg-1 (+7.16 %) · SWS
- treatment 857 vs. control 826 mg kg-1 (+3.753 %) · WS
Source · p. 4
“For all cropping sequences, total N was higher under NT than CT at 0–5 and 15–30 cm, but not at 5–15 cm.”
increase
no tillage (NT) vs. conventional tillage (CT)significant · 30–55 cm · October 2002 · Burleson County, Texas · SWS and WS; LSD103
Numbers
- treatment 460 vs. control 174 mg kg-1 (+164.4 %) · SWS
- treatment 343 vs. control 157 mg kg-1 (+118.5 %) · WS
Source · p. 4
“Total N was higher under NT at depths to 55 cm for sorghum–wheat– soybean and wheat–soybean, but only to 30 cm for continuous soybean.”
increase
intensive cropping sequences vs. continuous soybeansignificant · 0–5 cm · October 2002 · Burleson County, Texas · SWS/WS in both tillages; LSD161
Numbers
- treatment 1,051 vs. control 761 mg kg-1 (+38.11 %) · SWS,CT
- treatment 1,735 vs. control 1,359 mg kg-1 (+27.67 %) · SWS,NT
- treatment 1,151 vs. control 761 mg kg-1 (+51.25 %) · WS,CT
- treatment 1,595 vs. control 1,359 mg kg-1 (+17.37 %) · WS,NT
Source · p. 4
“From 0 to 30 cm, sorghum–wheat–soybean and wheat–soybean had higher total N than continuous soybean for both tillage regimes.”
increase
intensive cropping sequences vs. continuous soybeansignificant · 5–15 cm · October 2002 · Burleson County, Texas · CT only supported, LSD116
Numbers
- treatment 838 vs. control 675 mg kg-1 (+24.15 %) · SWS
- treatment 826 vs. control 675 mg kg-1 (+22.37 %) · WS
Source · p. 4
“From 0 to 30 cm, sorghum–wheat–soybean and wheat–soybean had higher total N than continuous soybean for both tillage regimes.”
increase
no tillage (NT) vs. conventional tillage (CT)significant · 15–30 cm · October 2002, after soybean harvest · Burleson County, Texas · Marginal tillage comparison across all three cropping sequences, not a crop-specific pair. Table 1 binary NT/CT main effect P<0.01; crop-by-tillage interaction NS. No marginal means printed and none calculated. The Table 3 individual-sequence gaps do not exceed row LSD0.05=212; this result establishes no individual-sequence significance.
Source · p. 4
“For all cropping sequences, total N was higher under NT than CT at 0–5 and 15–30 cm, but not at 5–15 cm.”
increase
intensive cropping sequences vs. continuous soybeansignificant · 30–55 cm · October 2002, after soybean harvest · Burleson County, Texas · Sorghum–wheat–soybean and wheat–soybean are agreeing intensive-sequence variants, each compared with continuous soybean under NT using Table 3 row LSD0.05=103. CT counterparts are excluded; their differences do not exceed the LSD. Abstract/conclusion subsurface intensive-cropping result, restricted to supported treatment pairs.
Numbers
- treatment 460 vs. control 203 mg kg-1 (+126.6 %) · 30–55 cm · sorghum–wheat–soybean versus continuous soybean; NT
- treatment 343 vs. control 203 mg kg-1 (+68.97 %) · 30–55 cm · wheat–soybean versus continuous soybean; NT
Source · p. 1
“Intensive cropping increased SOC and total N at depths to 55 cm compared to continuous soybean, regardless of tillage regime.”
Source · p. 5
“| 30–55 | 174 | 460 | 157 | 343 | 168 | 203 | 103 |”

dissolved organic C (DOC)

↑ 5= 16

increase
no tillage (NT) vs. conventional tillage (CT)significant · 0–5 cm · October 2002 · Burleson County, Texas · SWS and CS; WS pair does not exceed LSD65 despite prose.
Numbers
- treatment 408 vs. control 263 mg kg-1 (+55.13 %) · SWS
- treatment 194 vs. control 114 mg kg-1 (+70.18 %) · CS
Source · p. 4
“For all cropping sequences, DOC was higher under NT than CT at 0–5 cm”
no effect
no tillage (NT) vs. conventional tillage (CT)not significant · 5–15 cm · October 2002 · Burleson County, Texas · All sequences; LSD52
Numbers
- treatment 218 vs. control 181 mg kg-1 (+20.44 %) · SWS
- treatment 106 vs. control 112 mg kg-1 (-5.357 %) · WS
- treatment 159 vs. control 150 mg kg-1 (+6 %) · CS
Source · p. 4
“tillage effects were not observed at 5–15 cm.”
increase
no tillage (NT) vs. conventional tillage (CT)significant · 15–30 cm · October 2002 · Burleson County, Texas · All sequences; LSD12
Numbers
- treatment 105 vs. control 89 mg kg-1 (+17.98 %) · SWS
- treatment 96 vs. control 81 mg kg-1 (+18.52 %) · WS
- treatment 90 vs. control 76 mg kg-1 (+18.42 %) · CS
Source · p. 4
“NT produced higher DOC from 15 to 55 cm for sorghum–wheat– soybean and wheat–soybean, and from 0 to 30 cm for continuous soybean.”
increase
no tillage (NT) vs. conventional tillage (CT)significant · 30–55 cm · October 2002 · Burleson County, Texas · SWS and WS; LSD12
Numbers
- treatment 92 vs. control 62 mg kg-1 (+48.39 %) · SWS
- treatment 88 vs. control 58 mg kg-1 (+51.72 %) · WS
Source · p. 4
“NT produced higher DOC from 15 to 55 cm for sorghum–wheat– soybean and wheat–soybean”
increase
sorghum–wheat–soybean vs. continuous soybeansignificant · 0–30 cm · October 2002 · Burleson County, Texas · NT0–30; CT0–5 only; CT5–15 does not exceed LSD52
Numbers
- treatment 263 vs. control 114 mg kg-1 (+130.7 %) · 0–5 cm · CT
- treatment 408 vs. control 194 mg kg-1 (+110.3 %) · 0–5 cm · NT
- treatment 218 vs. control 159 mg kg-1 (+37.11 %) · 5–15 cm · NT
- treatment 105 vs. control 90 mg kg-1 (+16.67 %) · 15–30 cm · NT
Source · p. 4
“At 0–15 cm, sorghum–wheat– soybean had higher DOC than wheat–soybean and continuous soybean for both tillage regimes, while continuous soybean had the lowest DOC at 15–30 cm.”
increase
sorghum–wheat–soybean vs. wheat–soybeansignificant · 0–15 cm · October 2002 · Burleson County, Texas · Both tillages; LSD65 at0–5,52 at5–15
Numbers
- treatment 263 vs. control 154 mg kg-1 (+70.78 %) · 0–5 cm · CT
- treatment 408 vs. control 179 mg kg-1 (+127.9 %) · 0–5 cm · NT
- treatment 181 vs. control 112 mg kg-1 (+61.61 %) · 5–15 cm · CT
- treatment 218 vs. control 106 mg kg-1 (+105.7 %) · 5–15 cm · NT
Source · p. 4
“At 0–15 cm, sorghum–wheat– soybean had higher DOC than wheat–soybean and continuous soybean for both tillage regimes”

Sites

Burleson County, Texas

Location: Burleson County, Texas30.53° N, 94.43° W
Climate: 20 °C mean annual temperature980 mm annual precipitation
Soil: Haplustepts (Udifluventic, fine-silty, mixed, superactive, thermic) · USDA
Land use: cropping sequencesArable land

Soil layers
Depth	Texture	Clay	pH	Organic C	Bulk density
soil (depth not stated)	silty clay loam	–	8	–	–