Abstract
Management practices involving legume leys, grain legumes, and no-tillage and stubble retention, along with nitrogen (N) fertiliser application for wheat cropping, were examined for their effectiveness in increasing soil organic matter (0-10 cm depth) from 1986 to 1993 in a field experiment on a Vertisol at Warra, Queensland. The treatments were (i) grass + legume leys (purple pigeon grass, Setaria incrassata; Rhodes grass, Chloris gayana; lucerne, Medicago sativa; annual medics, M. scutellata and M. truncatula) of 4 years duration followed by continuous wheat; (ii) 2-year rotation of annual medics and wheat (Triticum aestivum cv. Hartog); (iii) 2-year rotation of lucerne and wheat; (iv) 2-year rotation of chickpea (Cicer arietinum cv. Barwon) and wheat; (v) no-tillage (NT) wheat; and (vi) conventional tillage (CT) wheat. Fertiliser N as urea was applied to both NT wheat and CT wheat at 0,25, and 75 kg N/ha. year. The CT wheat also received N at 12.5 and 25kg N/ha. year. After 4 years, soil organic carbon (C) concentration under grass + legume leys increased by 20% (650 kg C/ha. year) relative to that under continuous CT wheat. Soil total N increased by 11, 18, and 22% after 2, 3, and 4 years, respectively, under grass + legume leys relative to continuous CT wheat. These increases in soil organic matter were mostly confined to the 0-2.5 cm layer. After the start of wheat cropping, organic C and total N levels declined steadily but were still higher than under CT wheat and higher than initial values in December 1985. Although 2-year rotations of lucerne-wheat and medic-wheat had a small effect on soil organic C, soil total N concentrations were higher than in the chickpea-wheat rotation and continuous CT wheat from November 1990 to November 1992. Soil under chickpea-wheat rotation had organic C and total N concentrations similar to continuous CT wheat, although from the former, about 70 kg/ha. year of extra N was removed in the grain from 1989 to 1993. No-tillage practice had a small effect on soil organic C, although total N concentration was higher than under CT wheat in November 1993. These effects were mainly confined to the surface 0-2.5 cm depth. The C to N ratio was only affected in soil under grass + legume leys, and no-tillage treatments. These data show that restoration of soil organic matter in Vertisol requires grass + legume leys, primarily due to increased root biomass, although soil total N can be enhanced by including legume leys for longer duration in cropping systems in the semi-arid and subtropical environment.
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Claims 15
Claim · model-written summary
After 4 years, soil organic carbon under grass and legume leys increased by 20% relative to continuous conventional-tillage wheat at Warra.
- Taxon
- wheat
Triticum aestivume0 - Treatment
- grass + legume leyse0
- Outcome
- soil organic carbone0
- Direction
- increasede0
- Value
- 20%e0
- Comparator
- continuous CT wheate0
- Setting
- Warra, Queenslandt0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“After 4 years, soil organic carbon (C) concentration under grass + legume leys increased by 20% (650 kg C/ha. year) relative to that under continuous CT wheat. Soil total N increased by 11, 18, and 22% after 2, 3, and 4 years, respectively, under grass + legume leys relative to continuous CT wheat.”
t0“Vertisol at Warra, Queensland”
Claim · model-written summary
After 2 years, soil total N under grass and legume leys increased by 11% relative to continuous CT wheat.
- Taxon
- wheatTriticum aestivume0
- Treatment
- grass + legume leyse0
- Outcome
- Soil total Ne0
- Direction
- increasede0
- Value
- 11e0
- Comparator
- continuous CT wheate0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“After 4 years, soil organic carbon (C) concentration under grass + legume leys increased by 20% (650 kg C/ha. year) relative to that under continuous CT wheat. Soil total N increased by 11, 18, and 22% after 2, 3, and 4 years, respectively, under grass + legume leys relative to continuous CT wheat.”
Claim · model-written summary
After 3 years, soil total N under grass and legume leys increased by 18% relative to continuous CT wheat.
- Taxon
- wheatTriticum aestivume0
- Treatment
- grass + legume leyse0
- Outcome
- Soil total Ne0
- Direction
- increasede0
- Value
- 18e0
- Comparator
- continuous CT wheate0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“After 4 years, soil organic carbon (C) concentration under grass + legume leys increased by 20% (650 kg C/ha. year) relative to that under continuous CT wheat. Soil total N increased by 11, 18, and 22% after 2, 3, and 4 years, respectively, under grass + legume leys relative to continuous CT wheat.”
Claim · model-written summary
After 4 years, soil total N under grass and legume leys increased by 22% relative to continuous CT wheat.
- Taxon
- wheatTriticum aestivume0
- Treatment
- grass + legume leyse0
- Outcome
- Soil total Ne0
- Direction
- increasede0
- Value
- 22%e0
- Comparator
- continuous CT wheate0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“After 4 years, soil organic carbon (C) concentration under grass + legume leys increased by 20% (650 kg C/ha. year) relative to that under continuous CT wheat. Soil total N increased by 11, 18, and 22% after 2, 3, and 4 years, respectively, under grass + legume leys relative to continuous CT wheat.”
Claim · model-written summary
Increases in soil organic matter under the legume leys were mostly confined to the 0-2.5 cm soil layer.
- Taxon
- wheatTriticum aestivume1
- Outcome
- soil organic mattere1
- Qualifier
- mostly confined to the 0-2.5 cm layere1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“These increases in soil organic matter were mostly confined to the 0-2.5 cm layer. After the start of wheat cropping, organic C and total N levels declined steadily but were still higher than under CT wheat and higher than initial values in December 1985.”
Claim · model-written summary
After wheat cropping started, organic C and total N declined but remained higher than under conventional-tillage wheat.
- Taxon
- wheatTriticum aestivume1
- Treatment
- wheat croppinge1
- Outcome
- organic C and total N levelse1
- Direction
- declinede1
- Qualifier
- still higher than under CT wheate1
- Comparator
- CT wheate1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“These increases in soil organic matter were mostly confined to the 0-2.5 cm layer. After the start of wheat cropping, organic C and total N levels declined steadily but were still higher than under CT wheat and higher than initial values in December 1985.”
Claim · model-written summary
Two-year lucerne-wheat and medic-wheat rotations had a small effect on soil organic C.
- Taxon
- wheatTriticum aestivume2
- Treatment
- 2-year rotations of lucerne-wheat and medic-wheate2
- Outcome
- soil organic Ce2
- Qualifier
- a small effecte2
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“Although 2-year rotations of lucerne-wheat and medic-wheat had a small effect on soil organic C, soil total N concentrations were higher than in the chickpea-wheat rotation and continuous CT wheat from November 1990 to November 1992. Soil under chickpea-wheat rotation had organic C and total N concentrations similar to continuous CT wheat, although from the former, about 70 kg/ha. year of extra N was removed in the grain from 1989 to 1993.”
Claim · model-written summary
Soil total N under two-year lucerne-wheat and medic-wheat rotations was higher than under chickpea-wheat rotation and continuous CT wheat from November 1990 to November 1992.
- Taxon
- wheatTriticum aestivume2
- Treatment
- 2-year rotations of lucerne-wheat and medic-wheate2
- Outcome
- soil total N concentrationse2
- Direction
- highere2
- Comparator
- chickpea-wheat rotation and continuous CT wheate2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“Although 2-year rotations of lucerne-wheat and medic-wheat had a small effect on soil organic C, soil total N concentrations were higher than in the chickpea-wheat rotation and continuous CT wheat from November 1990 to November 1992. Soil under chickpea-wheat rotation had organic C and total N concentrations similar to continuous CT wheat, although from the former, about 70 kg/ha. year of extra N was removed in the grain from 1989 to 1993.”
Claim · model-written summary
Organic C and total N under chickpea-wheat rotation were similar to continuous CT wheat.
- Taxon
- chickpea
Cicer arietinume2 - Treatment
- chickpea-wheat rotatione2
- Outcome
- organic C and total N concentrationse2
- Direction
- similare2
- Comparator
- continuous CT wheate2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“Although 2-year rotations of lucerne-wheat and medic-wheat had a small effect on soil organic C, soil total N concentrations were higher than in the chickpea-wheat rotation and continuous CT wheat from November 1990 to November 1992. Soil under chickpea-wheat rotation had organic C and total N concentrations similar to continuous CT wheat, although from the former, about 70 kg/ha. year of extra N was removed in the grain from 1989 to 1993.”
Claim · model-written summary
About 70 kg/ha per year of extra N was removed in the grain of the chickpea-wheat rotation from 1989 to 1993.
- Taxon
- chickpeaCicer arietinume2
- Outcome
- extra N was removed in the graine2
- Value
- 70 kg/ha. yeare2
- Qualifier
- from 1989 to 1993e2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“Although 2-year rotations of lucerne-wheat and medic-wheat had a small effect on soil organic C, soil total N concentrations were higher than in the chickpea-wheat rotation and continuous CT wheat from November 1990 to November 1992. Soil under chickpea-wheat rotation had organic C and total N concentrations similar to continuous CT wheat, although from the former, about 70 kg/ha. year of extra N was removed in the grain from 1989 to 1993.”
Claim · model-written summary
No-tillage practice had a small effect on soil organic C.
- Taxon
- wheatTriticum aestivume3
- Treatment
- No-tillage practicee3
- Outcome
- soil organic Ce3
- Qualifier
- a small effecte3
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e3“No-tillage practice had a small effect on soil organic C, although total N concentration was higher than under CT wheat in November 1993. These effects were mainly confined to the surface 0-2.5 cm depth. The C to N ratio was only affected in soil under grass + legume leys, and no-tillage treatments.”
Claim · model-written summary
Under no-tillage, total N concentration was higher than under conventional-tillage wheat in November 1993.
- Taxon
- wheatTriticum aestivume3
- Treatment
- No-tillage practicee3
- Outcome
- total N concentratione3
- Direction
- highere3
- Qualifier
- in November 1993e3
- Comparator
- CT wheate3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e3“No-tillage practice had a small effect on soil organic C, although total N concentration was higher than under CT wheat in November 1993. These effects were mainly confined to the surface 0-2.5 cm depth. The C to N ratio was only affected in soil under grass + legume leys, and no-tillage treatments.”
Claim · model-written summary
The C to N ratio was only affected under grass and legume leys and under no-tillage.
- Taxon
- wheatTriticum aestivume3
- Treatment
- grass + legume leyse3
- Outcome
- C to N ratioe3
- Qualifier
- only affectede3
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e3“No-tillage practice had a small effect on soil organic C, although total N concentration was higher than under CT wheat in November 1993. These effects were mainly confined to the surface 0-2.5 cm depth. The C to N ratio was only affected in soil under grass + legume leys, and no-tillage treatments.”
Claim · model-written summary
Restoration of soil organic matter under grass and legume leys is primarily due to increased root biomass.
Verbatim
e4“These data show that restoration of soil organic matter in Vertisol requires grass + legume leys, primarily due to increased root biomass, although soil total N can be enhanced by including legume leys for longer duration in cropping systems in the semi-arid and subtropical environment.”
Claim · model-written summary
Soil total N can be enhanced by including legume leys for a longer duration in cropping systems.
Verbatim
e4“These data show that restoration of soil organic matter in Vertisol requires grass + legume leys, primarily due to increased root biomass, although soil total N can be enhanced by including legume leys for longer duration in cropping systems in the semi-arid and subtropical environment.”
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See all 145 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.