Harvest timing in olive orchards has a strong effect on the quality and quantity of oil yield, but many farmers still lack simple and affordable quantitative tools for rationally deciding appropriate harvest dates. This study presents and tests a conceptual model for predicting fruit oil content (O_f, g oil fruit⁻¹) from inexpensive measurements of fruit dry weight (w_f). The model presents two physiologically relevant parameters, the fruit dry weight at the onset of the oil accumulation phase (w_f0) and the ratio of accumulated oil per unit of fruit dry weight increase during the oil accumulation period (β), the latter assumed invariable throughout ripening. A compilation of data on w_f and O_f dynamics collected from four experiments including six olive cultivars and contrasting conditions of water supply and crop load was used to test the model. Our results suggest that β could be fairly independent of crop load or watering regime and, probably, genetically controlled. By contrast, w_f0 is clearly affected by both the cultivar and the availability of assimilates for fruit growth preceding oil accumulation, which makes it orchard- and year-specific. According to those premises, once cultivar-specific β values are available w_f0 could be easily calibrated by either a single determination of O_f and w_f at any time during the oil accumulation phase (Approach A) or by directly measuring w_f0 if the date for the onset of oil accumulation can be estimated (Approach B). Validation tests with an independently calibrated β showed an excellent performance for reproducing O_f patterns from w_f data using Approach A. Approach B satisfactory predicted oil accumulation rates, but absolute estimates of O_f were less reliable. Regardless of the calibration approach, the model is easy to implement and has a minimal cost, which satisfies the demand for inexpensive tools for monitoring oil accumulation dynamics.

橄榄园的收获时间对产油的质量和数量有很大影响，但是许多农民仍然缺乏简单，负担得起的定量工具来合理地确定合适的收获日期。这项研究提出并测试了一种概念模型，该模型可通过廉价的水果干重（w _f）测量来预测水果油含量（O _f，g油果^-1）。该模型提出了两个生理相关的参数，即油脂累积阶段开始时的果实干重（w _f0）和油脂累积期间（β）的每单位果实干重增加的累积油脂比率（后者假定不变）整个成熟。关于w的数据汇编从四个实验（包括六个橄榄品种）收集的_f和O _f动力学以及供水和农作物负载的对比条件用于测试模型。我们的结果表明，β可能与农作物负荷或灌溉方式完全无关，并且可能是遗传控制的。相比之下，w _f0明显受品种和同化物在油积累之前用于水果生长的同质性的影响，这使其成为果园和年份特定。根据这些前提，一旦获得了特定品种的β值，就可以通过单次确定O _f和w _f来轻松地校准w _f0。在积油阶段的任何时候（方法A），或者可以直接测量w _f0（如果可以估计出积油的开始日期）（方法B）。使用独立校准的β进行的验证测试表明，使用方法A可以从w _f数据复制O _f模式，并且具有出色的性能。方法B可以令人满意地预测油的累积速率，但是O _f的绝对估计值不太可靠。无论采用哪种校准方法，该模型都易于实现且成本最低，可满足对用于监控油藏动态的廉价工具的需求。