Abstract
Abstract Starking apple trees on M793 rootstocks were grown in a low phosphorus (P) soil treated prior to planting in 1982 with different rates of P (as superphosphate) and, commencing three years after planting, nitrogen (N) as limestone ammonium nitrate (LAN). The object was to improve vigour, yields, and ftuit quality. Trunk circumferences increased progressively with superphosphate application rates up to 4,730 kg/ha. Susceptibility to bitter pit also increased as did fruit size, and leaf P and magnesium (Mg) levels. Some improvements in colour were also apparent. Yields increased at superphosphate applications up to 2,240 kg/ha, but at 4,730 kg/ha were little different to the yields at 2,240 kg/ha. Leaf potassium (K) tended to decrease with increasing rate of applied superphosphate. The levels of Bray 2‐extractable P in the soil decreased with time. Reapplying superphosphate to the 0, 1,180, and 2,420 kg/ha treatments at the rate of 1,286 kg/ha in 1989 resulted in some of the differences between the initially applied superphosphate treatments becoming non‐significant. No interaction between N and P was observed, and there were no consistent, significant differences between treatments which received 110 kg LAN/ha at full bloom, 50 kg LAN/ha 40 d after full bloom, and 110 kg LAN/ha post harvest and treatments which received LAN at double these rates. In the 1989/90, 1990/91 and 1991/92 seasons, the LAN application rates in the low and high N treatments were reduced to 80, 40, 80, and 160, 80, 160 kg/ha at full bloom, 40 d after full bloom and post harvest, respectively. In 1991 and 1992, leaf and fruit N contents were significantly lower in the 80, 40, and 80 kg LAN/ha treatments than in the 160, 80, and 160 treatments. The incidence of bitter pit was lowest in the higher N treatments. Under South African orchard conditions, Starking apple trees appear to require a Bray 2‐extractable soil P level of 30–40 mg P/kg. Applications of LAN equivalent to 160 kg/ha at full bloom, 80 kg/ha 40 d after full bloom, and 160 kg/ha after harvest would appear to be sufficient for a 25 t crop.
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Claims 17
Claim · model-written summary
Trunk circumferences increased with superphosphate rates up to 4,730 kg/ha.
- Taxon
- apple
Malus domesticae0 - Material
- Starkinge0
- Treatment
- superphosphate application rates up to 4,730 kg/hae1
- Outcome
- Trunk circumferencese1
- Direction
- increasede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Starking apple trees on M793 rootstocks”
e1“Trunk circumferences increased progressively with superphosphate application rates up to 4,730 kg/ha”
Claim · model-written summary
Bitter pit susceptibility increased with superphosphate rate.
- Taxon
- appleMalus domesticae0
- Treatment
- superphosphate application rates up to 4,730 kg/hae1
- Outcome
- Susceptibility to bitter pite1
- Direction
- increasede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Starking apple trees on M793 rootstocks”
e1“Trunk circumferences increased progressively with superphosphate application rates up to 4,730 kg/ha. Susceptibility to bitter pit also increased”
Claim · model-written summary
Fruit size increased with superphosphate rate.
- Taxon
- appleMalus domesticae0
- Outcome
- fruit sizee1
- Direction
- increasede1
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Starking apple trees on M793 rootstocks”
e1“Susceptibility to bitter pit also increased as did fruit size”
Claim · model-written summary
Leaf phosphorus and magnesium levels increased with superphosphate rate.
- Taxon
- appleMalus domesticae0
- Outcome
- leaf P and magnesium (Mg) levelse1
- Direction
- increasede1
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Starking apple trees on M793 rootstocks”
e1“Susceptibility to bitter pit also increased as did fruit size, and leaf P and magnesium (Mg) levels”
Claim · model-written summary
Fruit colour showed some improvement with superphosphate.
- Taxon
- appleMalus domesticae0
- Outcome
- coloure1
- Direction
- improvementse1
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Starking apple trees on M793 rootstocks”
e1“Some improvements in colour were also apparent”
Claim · model-written summary
Yields rose with superphosphate applications up to 2,240 kg/ha.
- Taxon
- appleMalus domesticae0
- Treatment
- superphosphate applications up to 2,240 kg/hae1
- Outcome
- Yieldse1
- Direction
- increasede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Starking apple trees on M793 rootstocks”
e1“Yields increased at superphosphate applications up to 2,240 kg/ha”
Claim · model-written summary
Yields at 4,730 kg/ha superphosphate were little different from yields at 2,240 kg/ha.
- Taxon
- appleMalus domesticae0
- Treatment
- 4,730 kg/hae1
- Outcome
- yieldse1
- Direction
- little differente1
- Comparator
- 2,240 kg/hae1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Starking apple trees on M793 rootstocks”
e1“at 4,730 kg/ha were little different to the yields at 2,240 kg/ha”
Claim · model-written summary
Leaf potassium tended to decrease with increasing superphosphate.
- Taxon
- appleMalus domesticae0
- Treatment
- increasing rate of applied superphosphatee1
- Outcome
- Leaf potassium (K)e1
- Direction
- decreasee1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Starking apple trees on M793 rootstocks”
e1“Leaf potassium (K) tended to decrease with increasing rate of applied superphosphate”
Claim · model-written summary
Bray 2 extractable soil phosphorus decreased over time.
- Taxon
- appleMalus domesticae0
- Outcome
- Bray 2‐extractable P in the soile1
- Direction
- decreasede1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Starking apple trees on M793 rootstocks”
e1“The levels of Bray 2‐extractable P in the soil decreased with time”
Claim · model-written summary
Superphosphate reapplication made some differences among initial treatments nonsignificant.
- Taxon
- appleMalus domesticae0
- Treatment
- Reapplying superphosphate to the 0, 1,180, and 2,420 kg/ha treatments at the rate of 1,286 kg/ha in 1989e1
- Outcome
- differences between the initially applied superphosphate treatmentse1
- Comparator
- initially applied superphosphate treatmentse1
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Starking apple trees on M793 rootstocks”
e1“Reapplying superphosphate to the 0, 1,180, and 2,420 kg/ha treatments at the rate of 1,286 kg/ha in 1989 resulted in some of the differences between the initially applied superphosphate treatments becoming non‐significant”
Claim · model-written summary
No nitrogen by phosphorus interaction was observed.
- Taxon
- appleMalus domesticae0
- Outcome
- interaction between N and Pe1
- Direction
- No interactione1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Starking apple trees on M793 rootstocks”
e1“No interaction between N and P was observed”
Claim · model-written summary
The initial low and doubled LAN schedules showed no consistent significant differences.
- Taxon
- appleMalus domesticae0
- Treatment
- 110 kg LAN/ha at full bloom, 50 kg LAN/ha 40 d after full bloom, and 110 kg LAN/ha post harveste1
- Outcome
- differences between treatmentse1
- Direction
- no consistente1
- Comparator
- LAN at double these ratese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Starking apple trees on M793 rootstocks”
e1“there were no consistent, significant differences between treatments which received 110 kg LAN/ha at full bloom, 50 kg LAN/ha 40 d after full bloom, and 110 kg LAN/ha post harvest and treatments which received LAN at double these rates”
Claim · model-written summary
Lower LAN treatment significantly reduced leaf nitrogen content relative to higher LAN treatment in 1991 and 1992.
- Taxon
- appleMalus domesticae0
- Treatment
- 80, 40, and 80 kg LAN/ha treatmentse1
- Outcome
- leaf and fruit N contentse1
- Direction
- lowere1
- Comparator
- 160, 80, and 160 treatmentse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Starking apple trees on M793 rootstocks”
e1“In 1991 and 1992, leaf and fruit N contents were significantly lower in the 80, 40, and 80 kg LAN/ha treatments than in the 160, 80, and 160 treatments”
Claim · model-written summary
Lower LAN treatment significantly reduced fruit nitrogen content relative to higher LAN treatment in 1991 and 1992.
- Taxon
- appleMalus domesticae0
- Treatment
- 80, 40, and 80 kg LAN/ha treatmentse1
- Outcome
- fruit N contentse1
- Direction
- lowere1
- Comparator
- 160, 80, and 160 treatmentse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Starking apple trees on M793 rootstocks”
e1“In 1991 and 1992, leaf and fruit N contents were significantly lower in the 80, 40, and 80 kg LAN/ha treatments than in the 160, 80, and 160 treatments”
Claim · model-written summary
Higher nitrogen treatments had the lowest bitter pit incidence.
- Taxon
- appleMalus domesticae0
- Treatment
- higher N treatmentse1
- Outcome
- incidence of bitter pite1
- Direction
- loweste1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Starking apple trees on M793 rootstocks”
e1“The incidence of bitter pit was lowest in the higher N treatments”
Claim · model-written summary
Authors recommend a soil phosphorus level of 30–40 mg P/kg for Starking apple trees under South African orchard conditions.
- Taxon
- appleMalus domesticae0
- Material
- Starkinge0
- Outcome
- Bray 2‐extractable soil P levele0
- Value
- 30–40 mg P/kge0
- Setting
- South African orchard conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Under South African orchard conditions, Starking apple trees appear to require a Bray 2‐extractable soil P level of 30–40 mg P/kg”
Claim · model-written summary
Authors consider LAN applications of 160, 80, and 160 kg/ha at successive timings sufficient for a 25 t crop.
- Taxon
- appleMalus domesticae0
- Outcome
- Applications of LAN equivalent to 160 kg/ha at full bloom, 80 kg/ha 40 d after full bloom, and 160 kg/ha after harveste1
- Qualifier
- 25 t crope1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Starking apple trees on M793 rootstocks”
e1“Applications of LAN equivalent to 160 kg/ha at full bloom, 80 kg/ha 40 d after full bloom, and 160 kg/ha after harvest would appear to be sufficient for a 25 t crop”
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