Winter wild oat [Avena sterilis ssp. ludoviciana (Durieu) Gillet & Magne; referred to as A. sterilis here] is one of the major weed species of the Avena genus, given its high competitive ability to infest cereal crops worldwide, with special concern in Spain. A nine-location field experiment was established across Spain where a total of 400 A. sterilis seeds per location were sowed in four replicates in autumn 2016 to monitor the emergence during two growing seasons in dryland conditions. The data were used to test the prediction ability of previously published thermal (TT) and hydrothermal time (HTT) models and to develop new models, if required. Overall, the average percentage of emergence was 30% during the first season and 21% during the second season. In both seasons, the main emergence flush occurred between November and February. According to the phenological stage, A. sterilis achieved the tillering earlier in southern sites, between November 25 and the end of December, compared with northern sites, where this stage was reached at the end of January. The newly developed model described the emergence with precision, using three cardinal temperatures to estimate the TT. The three cardinal points were established at −1.0, 5.8, and 18.0 C for base (Tb), optimum (To), and ceiling temperature (Tc), while the base water potential (Ψb) was established at −0.2 MPa for the HTT estimation. This study contributes to improving prediction of the emergence of A. sterilis and provides knowledge for decision support systems (DSS) for the control of this weed.

中文翻译：

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半干旱条件下不育燕麦 (Avena sterilis ssp. ludoviciana) 的模拟出现

冬季野燕麦 [燕麦ssp。卢多维恰纳(Durieu) Gillet & Magne; 称为是A. sterilis这里]是主要的杂草种类之一燕麦属，鉴于其在世界范围内侵染谷类作物的高竞争力，西班牙受到特别关注。在西班牙建立了一个 9 个地点的现场实验，总共有 400A. sterilis每个地点的种子在 2016 年秋季以四次重复播种，以监测旱地条件下两个生长季节的出苗情况。这些数据用于测试先前发布的热 (TT) 和水热时间 (HTT) 模型的预测能力，并在需要时开发新模型。总体而言，第一季的平均出苗率为 30%，第二季为 21%。在这两个季节，11 月至 2 月期间出现了主要的出苗潮。根据物候阶段，A. sterilis南部地区在 11 月 25 日至 12 月底之间实现了较早的分蘖，而北部地区则在 1 月底达到了这一阶段。新开发的模型精确地描述了出现，使用三个基本温度来估计 TT。三个基点分别设定在 -1.0、5.8 和 18.0 C吨b）， 最佳 （吨○) 和天花板温度 (吨C），而基水势（Ψb) 建立在 -0.2 MPa 用于 HTT 估计。本研究有助于改进对A. sterilis并为控制这种杂草的决策支持系统 (DSS) 提供知识。