Abstract This study compares two methods for evaluating precipitation effects on wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) yield, which have been cultivated for 30 years under two different climate conditions (semi-arid and Mediterranean). The distribution and amount of precipitation were indexed and their relationship with the corresponding crop yields (1984–2013) was investigated. The concentration index (CI), i.e. the contribution of the days of greatest precipitation to the total amount of precipitation, was also calculated as an alternative approach. Both methods were used to analyze the whole crop growing season, from planting to harvest, and for two critical growth stages, germination and anthesis. It was observed that there was a significant correlation between yield and the average daily precipitation (ER; rwheat=0.74** and rbarley = 0.75**) during the whole growing season, irrespective of the crop type, whereas there was no significant impact on crop yield due to the non-uniformity of precipitation distribution (UR). However, when a critical stage like anthesis was evaluated over a shorter period, a significant correlation between UR and crop yields (rwheat=0.56** and rbarley=0.64**) was found. The results indicated that these indexes are very effective for predicting crop yields based on their association with final yield within critical growth stages. In addition, it was also found that a proposed model using both indexes (ER and UR), with high correlation (r = 0.84**) can be very effective in estimating crops performance. The results also showed that the sensitivity of crop yield to the uniformity of precipitation during the critical growth stages was lower than when the whole growing season was considered. The CI index was less effective in reflecting the distribution of precipitation in the semi-arid and Mediterranean conditions compared with the UR.

中文翻译：

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作物产量与降水的关联；两种方法的比较

摘要 本研究比较了两种评估降水对小麦 (Triticum aestivum L.) 和大麦 (Hordeum vulgare L.) 产量影响的方法，这两种方法已经在两种不同气候条件下（半干旱和地中海）种植了 30 年。对降水的分布和数量进行了索引，并研究了它们与相应作物产量（1984-2013 年）的关系。浓度指数 (CI)，即最大降水天数对降水总量的贡献，也作为替代方法计算。这两种方法都用于分析整个作物生长季节，从种植到收获，以及两个关键的生长阶段，发芽和开花。据观察，产量与平均日降水量之间存在显着相关性（ER；rwheat=0. 74** 和 rbarley = 0.75**) 在整个生长季节，与作物类型无关，而由于降水分布 (UR) 的不均匀性，对作物产量没有显着影响。然而，当在较短的时间内评估开花等关键阶段时，发现 UR 与作物产量（rwheat=0.56** 和 rbarley=0.64**）之间存在显着相关性。结果表明，这些指标根据它们与关键生长阶段的最终产量的关联，对于预测作物产量非常有效。此外，还发现使用具有高相关性 (r = 0.84**) 的两个指标（ER 和 UR）的拟议模型可以非常有效地估计作物性能。结果还表明，作物产量在关键生长阶段对降水均匀性的敏感性低于考虑整个生长季节时的敏感性。与 UR 相比，CI 指数在反映半干旱和地中海条件下的降水分布方面效果较差。