spring · 120 days · drip irrigation
Predicted Yield
0.04 kg
per plant
Survival Probability
8%
estimated chance
Confidence Score
91%
AI confidence
Plant Setup
Soil Environment
Fundamental botanical incompatibility: Allium (Amaryllidaceae/Alliaceae) onto Prunus insititia (Rosaceae) represents an inter-family graft with no vascular cambium continuity possible; no successful union documented in peer-reviewed literature
Graft compatibility score of 0.65 likely reflects algorithmic estimation rather than empirical data; real-world compatibility is effectively 0.0 for this cross-family combination
Soil pH of 8.1 exceeds both scion (6.0–7.5) and rootstock (5.5–7.5) pH tolerances, inducing severe micronutrient deficiencies (Fe, Mn, Zn, B) via alkaline immobilization
High calcium carbonate content in Karoo Calcisol will severely restrict phosphorus availability through calcium phosphate precipitation, rendering applied P largely unavailable
Y-axis: plant height (cm) · max 2 cm
| Week | Stage | Height | Notes |
|---|---|---|---|
| W1 | Graft union attempt / callus initiation failure | 2 cm |
This graft combination represents one of the most agronomically untenable scenarios possible: an Allium scion (family Alliaceae/Amaryllidaceae, monocot) grafted onto a Prunus insititia rootstock (family Rosaceae, dicot). The phylogenetic distance between these taxa is insurmountable for grafting purposes; monocots lack a vascular cambium in the conventional dicot sense, and no compatible plasmodesmata or vascular tissue continuity can form at the union interface. The graft compatibility score of 0.65 appears to be a modelling artifact rather than an empirical measure, as no successful Allium-on-Prunus graft has been reported in the scientific literature. The applied vigor boost of 0.75x and yield modifier of 0.65x, while reducing theoretical output, still overestimate achievable performance. The stress tolerance overrides (drought 4/10, salinity 3/10, heat 4/10) are appropriately penalized but the baseline situation is worse still — effective tolerances are near zero once graft failure is accounted for. Survival probability is estimated at 0.08, acknowledging only the marginal possibility that the Prunus rootstock itself persists as a standalone plant while assigning near-zero probability to any Allium scion survival beyond week 3.
The Karoo Chalky Calcisol presents a hostile edaphic environment compounding the graft incompatibility. At pH 8.1, both rootstock and scion exceed their upper pH tolerances, triggering cascading micronutrient deficiencies — iron, manganese, zinc, and boron become progressively immobile above pH 7.5. The high calcium carbonate content will precipitate a substantial fraction of the applied phosphorus (80 kg/ha) into insoluble calcium phosphate compounds, rendering it biologically unavailable within days of application. Organic matter at 0.8% is critically insufficient, providing negligible cation exchange capacity, poor water retention, and minimal microbial biomass for nutrient mineralization. The low water retention characteristic of Calcisols, combined with drip irrigation every 3 days, is unlikely to sustain adequate soil moisture in a semi-arid climate with temperatures reaching 38°C — effective evapotranspiration demand will far exceed supply. Applied nitrogen at 150 kg/ha is excessive for this low-OM, high-pH soil where immobilization and volatilization losses will be high; a reduced rate of 80 kg/ha with split application is recommended, though this is largely academic given the graft failure prognosis.
Stress tolerance overrides reduce drought tolerance to 4/10 and heat tolerance to 4/10, critically insufficient for semi-arid Karoo conditions reaching 38°C
Salinity tolerance override of 3/10 combined with 1.2 dS/m soil salinity approaches threshold stress for Allium allaicum
Low water retention of Karoo Calcisol combined with drip irrigation every 3 days is inadequate for shallow-rooted Allium scion in high-evapotranspiration semi-arid climate
Organic matter at 0.8% is critically low, providing poor buffering capacity, minimal CEC, and inadequate microbial support for nutrient cycling
Vigor boost modifier of 0.75x and yield modifier of 0.65x compound the intrinsic incompatibility penalties, further suppressing any theoretical output
Spring planting in Karoo exposes plants to rapid temperature escalation toward 38°C summer extremes within the 120-day simulation window
Shallow calcium carbonate hardpan typical of Calcisols will physically restrict root development of St. Julien A, which requires medium root depth
Prunus insititia growth cycle of 1095 days is incompatible with a 120-day simulation and Allium growth cycle of 100 days, creating phenological mismatch
Risk of Fusarium basal rot and White rot (Sclerotium cepivorum) elevated in waterlogged microsites around drip emitters in alkaline soil
Silver leaf disease (Chondrostereum purpureum) risk increased by graft wound stress on Prunus rootstock
Nutrient uptake efficiency penalties from failed graft union mean even applied NPK will not be translocated effectively to scion tissue
Irrigation Notes
If any trial is conducted under controlled conditions, reduce irrigation interval to every 1–2 days given very low water retention of Calcisol and semi-arid evapotranspiration rates. Apply acidified water (pH 6.0–6.5 via sulfuric or phosphoric acid injection) to counteract alkaline soil and improve nutrient solubility at the root zone. Drip placement should be precise to avoid waterlogging that promotes Sclerotium cepivorum and Fusarium. Total seasonal water requirement for Allium in semi-arid conditions is approximately 350–450 mm; current protocol likely delivers insufficient volume per event.
Additional Notes
This graft combination is agronomically non-viable and should not be implemented in field or commercial settings. If research purposes demand a trial, it must be conducted in a controlled greenhouse environment with pH-amended substrate (target 6.5–7.0 using sulfur amendment or acidified compost at minimum 5% OM incorporation). Phosphorus application should be increased substantially and applied as monocalcium phosphate or acidulated forms to overcome calcium fixation. A soil acidification pre-treatment with elemental sulfur (200–300 kg/ha applied 3–6 months prior) would be prerequisite for any Allium cultivation in this soil. The Prunus rootstock should be regarded as a nurse plant at best; any scion survival would depend entirely on autonomous Allium root initiation at the graft point, which is not supported by evidence. Zinc, iron (as chelated EDTA forms), and manganese foliar supplementation would be required due to alkaline-induced micronutrient lock-up. This scenario represents an extremely high-risk, near-zero-viability combination of incompatible graft partners in an inhospitable soil environment.
| Graft union attempted; cambial cells of Allium and Prunus are structurally and biochemically incompatible. No vascular bridge formation expected. Scion may appear turgid initially due to residual water in tissues. |
| W2 | Scion desiccation onset | 1.5 cm | Without functional xylem continuity, scion water supply fails. Allium leaf tissue begins to wilt and desiccate. Alkaline soil stress initiates chlorosis in any surviving foliar tissue. Rootstock shows no visible distress. |
| W3 | Scion necrosis / rootstock wound callus | 0.5 cm | Scion tissue likely necrotic. Prunus rootstock forms wound callus around graft point but cannot bridge to Allium tissue. Bacterial canker risk at wound site increases. Soil pH-induced Fe and Mn chlorosis visible if any tissue survives. |
| W4 | Scion loss / rootstock survival assessment | 0 cm | Allium scion effectively dead in nearly all scenarios. Prunus rootstock may continue growing as a standalone shrub. No harvestable Allium biomass. Heat and drought stress beginning as temperatures rise in spring Karoo. |
| W6 | Rootstock-only persistence | 0 cm | Prunus insititia rootstock may persist if supplied with adequate water, but is not productive as a standalone crop in this system. Soil pH continues to limit nutrient availability. Rootstock foliar chlorosis likely. |
| W8 | Rootstock stress decline | 0 cm | Sustained heat (approaching 38°C) and alkaline soil stress begin to compromise Prunus rootstock. Calcium carbonate hardpan restricts deeper root exploration. No Allium scion contribution to system. |
| W10 | System failure / possible rootstock survival only | 0 cm | The graft system as intended has completely failed. Rootstock may survive at reduced vigor with intensive management. Yield from Allium scion is zero. |
| W12 | Simulation end — no harvestable yield | 0 cm | At 120 days, no Allium yield is achievable. Prunus rootstock may be alive but non-productive. Total system viability as a graft crop is confirmed at near-zero. Harvest of any Allium bulb material is not possible. |
The overall prognosis for this system is strongly negative. The combination of inter-family graft incompatibility, alkaline calcium-rich soil exceeding both partners' pH tolerance, semi-arid heat stress, low water retention, insufficient irrigation frequency, and critically low organic matter creates a cascade of failure modes that are mutually reinforcing. Even if the graft were botanically possible, this soil-climate combination would require extensive remediation (sulfur acidification, large-scale organic matter incorporation, increased irrigation frequency, chelated micronutrient supplementation) before Allium cultivation could be contemplated. The predicted yield of 0.04 kg/plant reflects a near-zero but non-zero value assigned to the remote possibility of partial autonomous Allium bulb development from basal shoots if the graft interface allows any transient moisture transfer in the first days post-grafting — this is speculative and should not be relied upon. Confidence in the failure assessment is high (0.91); the residual uncertainty reflects the impossibility of ruling out entirely novel outcomes in highly unusual experimental conditions.