Abstract
Tea ( Camellia sinensis ) in Sri Lanka is grown predominantly on sloping highlands. Incorporating trees as hedgerows along contours is aimed at reducing erosion and improving soil fertility through addition of prunings as mulch. However, there could be significant competition for essential growth resources between the hedgerows and tea. The primary objective of this study was to determine the influence of six hedgerow species ( Calliandra calothyrsus , Senna [ Cassia ] spectabilis , Eupatorium inulifolium , Flemingia congesta , Gliricidia sepium and Tithonia diversifolia ) on mature (6-year-old) and young (6-month-old) tea. This study had three on-farm, long-term (from Nov 1998 to Dec 2002) field experiments. Experiment 1 had 12 treatment combinations with the six shrub species and two mulching treatments (i.e. hedgerow prunings added to the tea plot as a mulch, and unmulched) on mature tea plus a sole tea crop as control. The same was repeated on young tea in Experiment 2 to determine whether resource competition on young tea was greater than that on mature tea. Experiment 3 examined the effects of removing tree root competition on tea by cutting a 1-m deep trench between hedgerows and tea. In all experiments, total tea yields of hedgerow intercrops, cumulated over the 50-month experimental period, were significantly lower (by 3–50%) than sole tea crops, thus indicating significant resource competition except in the case of mulched hedgerow systems involving Eupatorium and mature tea (18% yield increase). Removal of below-ground competition significantly increased tea yields by 11–19%. Addition of hedgerow prunings as a mulch significantly increased yields of both mature and young tea by 13–21%. Tea yields of hedgerow systems with Calliandra , Flemingia and Eupatorium showed greater yield reductions in young tea than in mature tea, but the opposite was shown with other hedgerow species. There was a significant negative linear relationship between tea yield and pruned biomass of hedgerows. Tea yields of all experiments showed significant negative correlations with several hedgerow characters, which are indicators of their competitive ability. These included hedgerow root density, canopy lateral spread, height and cross-section. In a majority of hedgerow systems, the available phosphorus content of topsoil (0–20 cm depth) was up to 51% lower compared to sole crops. It is concluded that incorporation of contour hedgerows in to an existing tea crop could result in significant resource competition with tea and thereby cause tea yield to decrease. However, there is scope for selection of hedgerow species that minimize competition through spatial and temporal complementarity with tea in resource capture.
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Claims 10
Claim · model-written summary
Hedgerow intercrops reduced cumulative tea yield by 3–50% relative to sole tea, except for the mulched Eupatorium mature-tea system.
Verbatim
e0“total tea yields of hedgerow intercrops, cumulated over the 50-month experimental period, were significantly lower (by 3–50%) than sole tea crops”
e1“Tea ( Camellia sinensis )”
e2“mulched hedgerow systems involving Eupatorium and mature tea (18% yield increase)”
Claim · model-written summary
Mulched Eupatorium with mature tea increased tea yield by 18%.
- Taxon
- teae0
- Treatment
- mulched hedgerow systems involving Eupatoriume0
- Interactor
- Eupatorium
Eupatoriume0weed - Outcome
- yielde0
- Direction
- increasee0
- Value
- 18%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“mulched hedgerow systems involving Eupatorium and mature tea (18% yield increase)”
Claim · model-written summary
Removing below-ground hedgerow competition increased tea yields by 11–19%.
- Taxon
- teae0
- Treatment
- Removal of below-ground competitione0
- Interactor
- hedgerowse1weed
- Outcome
- tea yieldse0
- Direction
- increasede0
- Value
- 11–19%e0
Not reportedComparator
Verbatim
e0“Removal of below-ground competition significantly increased tea yields by 11–19%”
e1“between hedgerows and tea”
Claim · model-written summary
Hedgerow pruning mulch increased yields of mature and young tea by 13–21%.
- Taxon
- teae0
- Treatment
- Addition of hedgerow prunings as a mulche0
- Outcome
- yields of both mature and young teae0
- Direction
- increasede0
- Value
- 13–21%e0
Not reportedComparator
Verbatim
e0“Addition of hedgerow prunings as a mulch significantly increased yields of both mature and young tea by 13–21%”
Claim · model-written summary
Yield reductions with Calliandra, Flemingia and Eupatorium hedgerows were greater in young than mature tea.
- Taxon
- Teae0
- Interactor
- Calliandra , Flemingia and EupatoriumEupatorium
Calliandra
Flemingiae0weed - Outcome
- yield reductionse0
- Direction
- greatere0
- Comparator
- mature teae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Tea yields of hedgerow systems with Calliandra , Flemingia and Eupatorium showed greater yield reductions in young tea than in mature tea”
Claim · model-written summary
For the other hedgerow species, yield reductions were greater in mature than young tea.
Not reportedDirection
Verbatim
e0“but the opposite was shown with other hedgerow species”
e1“young tea than in mature tea”
e2“Tea yields of hedgerow systems with Calliandra , Flemingia and Eupatorium showed greater yield reductions in young tea than in mature tea”
Claim · model-written summary
Tea yield had a significant negative linear relationship with hedgerow pruned biomass.
Verbatim
e0“significant negative linear relationship between tea yield and pruned biomass of hedgerows”
Claim · model-written summary
Tea yields were significantly negatively correlated with hedgerow root density, canopy spread, height and cross-section.
Verbatim
e0“Tea yields of all experiments showed significant negative correlations with several hedgerow characters, which are indicators of their competitive ability. These included hedgerow root density, canopy lateral spread, height and cross-section”
Claim · model-written summary
Most hedgerow systems had up to 51% less available topsoil phosphorus than sole crops.
Verbatim
e0“In a majority of hedgerow systems, the available phosphorus content of topsoil (0–20 cm depth) was up to 51% lower compared to sole crops”
e1“between hedgerows and tea”
Claim · model-written summary
The authors recommend selecting hedgerow species that minimize resource competition with tea.
Verbatim
e0“there is scope for selection of hedgerow species that minimize competition through spatial and temporal complementarity with tea in resource capture”
The same questions in other papers
competition · yield · Camellia sinensis (black tea)Positive and negative results
1 in the opposite direction
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pruning · yield · Camellia sinensis (black tea)Positive and negative results
2 papers in the same direction as this paper · 1 in the opposite direction
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intercropping · yield · Camellia sinensis (black tea)Positive and negative results
4 in the opposite direction
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1 paper more in this group
See all 5 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.