In the current situation, climate change has substantially disturbed precipitation occurrence in the Mediterranean region, by increasing its variability and decreasing the total annual amount, which both negatively affect rainfed crop productivity. We hypothesize that a simple cost-effective method for enhancing crop adaptation to new climate conditions would consist of modifying the crop sowing date. Traditional nitrogen (N) fertilization rates could also be adjusted to the current situation given the interdependent water/N relation in plant nutrition. Based on this hypothesis, during a 4-year field experiment with bread wheat (Triticum aestivum L., var. Pistolo), the effects of three sowing dates (October, November, February) and three N fertilization rates (54 kg N ha−1, 27 kg N ha−1, 0 kg N ha−1) on crop development, yield, grain quality, soil N content and N use efficiency were analyzed. The results showed that water scarcity was the predominant limiting factor, because it outweighed N deficiency with half-fertilized crops being as productive as fully fertilized treatments. Nevertheless, sowing date was the most influential factor, with up to a 30 % yield increase noted for the November-sown wheat compared to that sown in October, while delaying wheat sowing to February decreased crop yields. Grain protein content remained the same between the November- and October-sown crops, but increased in the February one crops. Optical sensor measurements showed that an optimal assessment of the current water/N nutritional status of crops can be achieved with these tools.

中文翻译：

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氮肥和播期作为地中海条件下小麦气候变化适应工具


在当前形势下，气候变化通过增加其可变性和减少年度总量，严重扰乱了地中海地区的降水发生，这两者都对雨养作物的生产力产生了负面影响。我们假设，一种提高作物对新气候条件的适应能力的简单且具有成本效益的方法包括修改作物播种日期。鉴于植物营养中相互依存的水/氮关系，传统的氮 （N） 施肥率也可以根据当前情况进行调整。基于这一假设，在对面包小麦 （Triticum aestivum L.， var. Pistolo） 进行为期 4 年的田间试验中，分析了三个播种日期（10 月、11 月、2 月）和三个氮肥施用量（54 kg N ha-1、27 kg N ha-1、0 kg N ha-1）对作物发育、产量、粮食质量、土壤氮含量和氮利用效率的影响。结果表明，缺水是主要的限制因素，因为它超过了氮缺乏，半施肥作物的生产力与完全施肥的处理一样高。尽管如此，播期是影响最大的因素，与 10 月播种相比，11 月播种的小麦产量提高了 30%，而将小麦播种推迟到 2 月会降低作物产量。11 月和 10 月播种的作物之间的谷物蛋白质含量保持不变，但在 2 月一季作物中增加。光学传感器测量表明，使用这些工具可以实现对作物当前水/氮营养状况的最佳评估。