Abstract
Field experiments were performed in Southern Finland on three soil types: fine sand (1989-1991), clay (1989) and mull (1990-1991). The following soil mechanical treatments were applied to autumn ploughed land: soil loosening by ridge preparation (ridge distance 45 cm), rotary harrowing (to a depth of 20 cm, clay 15 cm), and soil compaction track by track by a tractor weighing 3 Mg (1 or 3 passes, wheel width 33 cm) before seed bed preparation. One plot was untreated. These treatments were set up in April (on clay in May) under moist soil conditions. Sprinkler irrigation (one application of 30 mm) was applied to clay and fine sand when soil moisture in top soil had decreased to around 50% of plant-available water capacity. PVC cylinders (r = 15 cm, h = 60 cm) were fixed in the experimental areas during the growing periods. At harvest, these cylinders were removed for specific analysis of tap and fibrous roots of carrot. Length and width of fibrous roots were quantified by image analysis in the USA. The impacts of soil loosening and partial compaction were determined by measuring soil physical parameters to a depth of 25 cm in mineral soils, and to greater depths in organic soil. Dry bulk densities of the plough layers increased with increasing tractor passes by 8%, 10% and 13% for fine sand, mull and clay soils, respectively. The lowest dry soil bulk density in the plough layer was obtained by rotary harrowing to a depth of 20 cm. Comparison of gamma ray transmission and gravimetric analysis indicated that dry soil bulk density was slightly lower when determined by gravimetric analysis. Increased soil bulk densities were reflected by increased water retention capacity (matric suction ≤ 10 kPa) and greater penetrometer resistance. Relatively similar increases in bulk density increased the penetrometer resistance much less in mull than in fine sand. In contrast, greater bulk densities in the mull soil affected soil air composition adversely by decreasing the O2 content to 10% when the subsoil had high wetness. In other soils, the lowest soil oxygen contents of 16-18% were recorded in early summer (compacted clay) and during periods of vigorous plant growth (fine sand) when soil water contents were high. Even though the highest degree of soil compactness (D) in a plough layer approached 93 (gravimetric) in all soils, only clay soil was compacted to a soil macro-porosity below 10% (pore diameter > 30 μm). Soil compaction promoted crop establishment and early growth as compared with loose soil beds. Optimum soil compactness for carrot yield (D = 82) was observed only in clay field where excess loosening or compaction affected yield quantity adversely at different stages of growth. During biomass accumulation, excessive penetrometer resistances limited tap root growth in compacted fine sand without irrigation. Water applications promoted shoot growth, but did not affect final shoot and tap root yield. Among the three soil types tested in this study, compaction of mull soil had the least effect on carrot growth and external quality. This paper presents evidence that the internal quality of carrots is only slightly affected by changes in soil physical properties, while the adverse effects of soil compaction on carrot external quality (short, deformed and conical tap roots with greater maximum diameters) are clear. Even though compacted clay soil greatly limited the biomass accumulations in the tap root, which had a high crude fibre content, the carotene (10 mg/100 g carrots) and sugar contents (5%) reached acceptable levels. The lowest carotene contents (4 mg/100 g carrots) were observed in loose mull, following a cool late summer in 1990. The effect of irrigation on carotene content varied from one year to another. High sugar and carotene contents appeared to respond to the high below-ground absorption surface. The fibrous root system of carrots, consisting of mostly very fine roots (diameter 0.15 mm), had total lengths of 150 m in loose fine sand at a soil depth of 0-50 cm (rotary harrowed), 200 m and 300 m in fine sand and mull soils subjected to 3 passes by a tractor wheel. The maximum dry weight (60 μg), length (1.2 cm) and surface area (0.05 cm2) of the fibrous root system per soil volume (cm3) were observed in compacted or irrigated soil to a depth of 30 cm, and also in relation to tap root dry weight. This suggests a capacity of carrot plant for high below-ground absorption potential and optimal biochemial maturation of tap root tissue even when surface soils are compacted. This is supported by higher leaf area, as the early shoot growth was promoted by partial soil compaction. Soil compaction affected the soil physical properties and carrot external quality in agreement with previous studies. Carotene and sugar contents appeared to be unaffected or were slightly increased in riper and firmer carrots of compacted soils. This is consistent with the earlier information about the internal quality of carrot which is shown to be highly dependent on genetic factors and developmental stage of carrot. The present study emphasizes the surface area of carrot fibrous root system as a beneficial factor for maintaining high levels of carotene and sugar contents in tap roots after partial soil compaction.
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Claims 20
Claim · model-written summary
Dry bulk density of the plough layer increased by 8% in fine sand with increasing tractor passes.
- Taxon
- carrot
Daucus carotat0 - Treatment
- tractor passese1
- Outcome
- Dry bulk densities of the plough layerse1
- Direction
- increasede1
- Value
- 8%e1
- Qualifier
- fine sande1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“growth and quality of carrot”
e1“Dry bulk densities of the plough layers increased with increasing tractor passes by 8%, 10% and 13% for fine sand, mull and clay soils, respectively”
Claim · model-written summary
Dry bulk density of the plough layer increased by 10% in mull soil with increasing tractor passes.
- Taxon
- carrotDaucus carotat0
- Treatment
- tractor passese1
- Outcome
- Dry bulk densities of the plough layerse1
- Direction
- increasede1
- Value
- 10%e1
- Qualifier
- mulle1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“growth and quality of carrot”
e1“Dry bulk densities of the plough layers increased with increasing tractor passes by 8%, 10% and 13% for fine sand, mull and clay soils, respectively”
Claim · model-written summary
Dry bulk density of the plough layer increased by 13% in clay soil with increasing tractor passes.
- Taxon
- carrotDaucus carotat0
- Treatment
- tractor passese1
- Outcome
- Dry bulk densities of the plough layerse1
- Direction
- increasede1
- Value
- 13%e1
- Qualifier
- clay soilse1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“growth and quality of carrot”
e1“Dry bulk densities of the plough layers increased with increasing tractor passes by 8%, 10% and 13% for fine sand, mull and clay soils, respectively”
Claim · model-written summary
Greater bulk densities in mull soil decreased soil O2 content to 10% when the subsoil was wet.
- Taxon
- carrotDaucus carotat0
- Treatment
- greater bulk densities in the mull soile4
- Outcome
- O2 contente4
- Direction
- decreasinge4
- Value
- 10%e4
- Qualifier
- when the subsoil had high wetnesse4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“growth and quality of carrot”
e4“greater bulk densities in the mull soil affected soil air composition adversely by decreasing the O2 content to 10% when the subsoil had high wetness”
Claim · model-written summary
Optimum soil compactness for carrot yield was observed only in the clay field, at D = 82.
- Taxon
- carrotDaucus carotat0
- Treatment
- soil compactnesse6
- Outcome
- carrot yielde6
- Value
- D = 82e6
- Qualifier
- only in clay fielde6
- Setting
- clay fielde6
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“growth and quality of carrot”
e6“Optimum soil compactness for carrot yield (D = 82) was observed only in clay field where excess loosening or compaction affected yield quantity adversely at different stages of growth”
Claim · model-written summary
Compacted clay soil gave carrot tap root carotene content of 10 mg/100 g, which reached an acceptable level.
- Taxon
- carrotDaucus carotat0
- Organ / stage
- tap roote1
- Outcome
- carotenee1
- Value
- 10 mg/100 g carrotse1
- Setting
- compacted clay soile1
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“growth and quality of carrot”
e1“Even though compacted clay soil greatly limited the biomass accumulations in the tap root, which had a high crude fibre content, the carotene (10 mg/100 g carrots) and sugar contents (5%) reached acceptable levels”
Claim · model-written summary
Compacted clay soil gave carrot tap root sugar content of 5%, which reached an acceptable level.
- Taxon
- carrotDaucus carotat0
- Organ / stage
- tap roote1
- Outcome
- sugar contentse1
- Value
- 5%e1
- Setting
- compacted clay soile1
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“growth and quality of carrot”
e1“Even though compacted clay soil greatly limited the biomass accumulations in the tap root, which had a high crude fibre content, the carotene (10 mg/100 g carrots) and sugar contents (5%) reached acceptable levels”
Claim · model-written summary
The lowest carotene content of carrot, 4 mg/100 g, was found in loose mull soil after a cool late summer in 1990.
- Taxon
- carrotDaucus carotat0
- Outcome
- carotene contentse1
- Direction
- loweste1
- Value
- 4 mg/100 g carrotse1
- Qualifier
- following a cool late summer in 1990e1
- Setting
- loose mulle1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“growth and quality of carrot”
e1“The lowest carotene contents (4 mg/100 g carrots) were observed in loose mull, following a cool late summer in 1990”
Claim · model-written summary
The maximum fibrous root dry weight of carrot was 60 μg per soil volume, in compacted or irrigated soil to 30 cm depth.
- Taxon
- carrotDaucus carotat0
- Organ / stage
- fibrous root systeme1
- Outcome
- dry weighte1
- Direction
- maximume1
- Value
- 60 μge1
- Setting
- compacted or irrigated soil to a depth of 30 cme1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“growth and quality of carrot”
e1“The maximum dry weight (60 μg), length (1.2 cm) and surface area (0.05 cm2) of the fibrous root system per soil volume (cm3) were observed in compacted or irrigated soil to a depth of 30 cm”
Claim · model-written summary
The maximum fibrous root length of carrot was 1.2 cm per soil volume, in compacted or irrigated soil to 30 cm depth.
- Taxon
- carrotDaucus carotat0
- Organ / stage
- fibrous root systeme1
- Outcome
- lengthe1
- Direction
- maximume1
- Value
- 1.2 cme1
- Setting
- compacted or irrigated soil to a depth of 30 cme1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“growth and quality of carrot”
e1“The maximum dry weight (60 μg), length (1.2 cm) and surface area (0.05 cm2) of the fibrous root system per soil volume (cm3) were observed in compacted or irrigated soil to a depth of 30 cm”
Claim · model-written summary
The maximum fibrous root surface area of carrot was 0.05 cm2 per soil volume, in compacted or irrigated soil to 30 cm depth.
- Taxon
- carrotDaucus carotat0
- Organ / stage
- fibrous root systeme1
- Outcome
- surface areae1
- Direction
- maximume1
- Value
- 0.05 cm2e1
- Setting
- compacted or irrigated soil to a depth of 30 cme1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“growth and quality of carrot”
e1“The maximum dry weight (60 μg), length (1.2 cm) and surface area (0.05 cm2) of the fibrous root system per soil volume (cm3) were observed in compacted or irrigated soil to a depth of 30 cm”
Claim · model-written summary
Rotary harrowing to 20 cm gave the lowest dry soil bulk density in the plough layer.
- Taxon
- carrotDaucus carotat0
- Treatment
- rotary harrowing to a depth of 20 cme2
- Outcome
- dry soil bulk density in the plough layere2
- Direction
- loweste2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“growth and quality of carrot”
e2“The lowest dry soil bulk density in the plough layer was obtained by rotary harrowing to a depth of 20 cm”
Claim · model-written summary
Increased soil bulk density increased water retention capacity (matric suction ≤ 10 kPa).
- Taxon
- carrotDaucus carotat0
- Treatment
- Increased soil bulk densitiese3
- Outcome
- water retention capacitye3
- Direction
- increasede3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“growth and quality of carrot”
e3“Increased soil bulk densities were reflected by increased water retention capacity (matric suction ≤ 10 kPa) and greater penetrometer resistance”
Claim · model-written summary
Increased soil bulk density gave greater soil penetrometer resistance.
- Taxon
- carrotDaucus carotat0
- Treatment
- Increased soil bulk densitiese3
- Outcome
- penetrometer resistancee3
- Direction
- greatere3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“growth and quality of carrot”
e3“Increased soil bulk densities were reflected by increased water retention capacity (matric suction ≤ 10 kPa) and greater penetrometer resistance”
Claim · model-written summary
Excessive penetrometer resistance limited carrot tap root growth in compacted fine sand without irrigation during biomass accumulation.
- Taxon
- carrotDaucus carotat0
- Treatment
- excessive penetrometer resistancese7
- Outcome
- tap root growthe7
- Direction
- limitede7
- Setting
- compacted fine sand without irrigatione7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“growth and quality of carrot”
e7“excessive penetrometer resistances limited tap root growth in compacted fine sand without irrigation”
Claim · model-written summary
Soil compaction promoted carrot crop establishment and early growth compared with loose soil beds.
- Taxon
- carrotDaucus carotat0
- Treatment
- Soil compactione5
- Outcome
- crop establishment and early growthe5
- Direction
- promotede5
- Comparator
- loose soil bedse5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“growth and quality of carrot”
e5“Soil compaction promoted crop establishment and early growth as compared with loose soil beds”
Claim · model-written summary
Water applications promoted carrot shoot growth.
- Taxon
- carrotDaucus carotat0
- Treatment
- Water applicationse1
- Outcome
- shoot growthe1
- Direction
- promotede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“growth and quality of carrot”
e1“Water applications promoted shoot growth, but did not affect final shoot and tap root yield”
Claim · model-written summary
Water applications did not affect final carrot shoot and tap root yield.
- Taxon
- carrotDaucus carotat0
- Treatment
- Water applicationse1
- Outcome
- final shoot and tap root yielde1
- Direction
- did not affecte1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“growth and quality of carrot”
e1“Water applications promoted shoot growth, but did not affect final shoot and tap root yield”
Claim · model-written summary
Soil compaction had adverse effects on carrot external quality, with short, deformed and conical tap roots of greater maximum diameter.
- Taxon
- carrotDaucus carotat0
- Treatment
- soil compactione1
- Outcome
- carrot external qualitye1
- Direction
- adversee1
- Qualifier
- short, deformed and conical tap roots with greater maximum diameterse1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“growth and quality of carrot”
e1“the adverse effects of soil compaction on carrot external quality (short, deformed and conical tap roots with greater maximum diameters) are clear”
Claim · model-written summary
The surface area of the carrot fibrous root system is a beneficial factor for maintaining high carotene and sugar contents in tap roots after partial soil compaction.
- Taxon
- carrotDaucus carotat0
- Organ / stage
- fibrous root systeme1
- Outcome
- carotene and sugar contentse1
- Qualifier
- surface area of carrot fibrous root system as a beneficial factore1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“growth and quality of carrot”
e1“The present study emphasizes the surface area of carrot fibrous root system as a beneficial factor for maintaining high levels of carotene and sugar contents in tap roots after partial soil compaction”
The same questions in other papers
tillage · quality: general · Daucus carota (carrot)Positive and negative results
1 paper in the same direction as this paper · 1 in the opposite direction
- positive
- negative
tillage · growth · Daucus carota (carrot)Results agree
3 papers in the same direction as this paper
- positive
- positive
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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.