Department of Agroecology, Environmental Sciences Research Institute, Shahid Beheshti University, G.C.,P.O. Box 19835-196, Tehran, Iran.
The University of Queensland, Queensland Alliance for Agriculture and Food Innovation (QAAFI), 203 Tor Street, Toowoomba, Queensland, 4350, Australia.
Int J Biometeorol. 2019 Apr;63(4):511-521. doi: 10.1007/s00484-019-01682-5. Epub 2019 Feb 13.
In the semi-arid climatic conditions, water shortage is a key factor to generate crop production. Planting in autumn and winter and using precipitation can help cope with the problem. But in the semi-arid areas with cold winter, frost is another limited factor affecting crop production. For this purpose, in the present study, a simple and universal crop growth simulator (SUCROS) model was used to estimate the potential yield of sugar beets and frost damage from 1993 to 2009 for four autumn sowing dates (2 October, 17 October, 1 November, and 16 November) and two spring dates (6 March and 6 May) in eight locations (Birjand, Bojnord, Ghaen, Mashhad, Torbat-e Heydarieh, Neyshabor, Torbat-e Jam, and Ghochan) of the Khorasan province in northeastern Iran as a semi-arid and cold area. There was a large variability between locations and years in terms of frost damage. The crop failure from frost for the autumn sowing dates ranged from 62.5 to 100% at Neyshabor and Ghochan, respectively. Although autumn sowing dates performed better than spring sowing dates in terms of fresh storage organ yield (~ 109.9 t ha vs. ~ 78.4 t ha), the risk of frost stress under autumn sowing dates was high at all studied locations. To maximize potential yield and minimize frost risk, sugar beet farmers under semi-arid and frost-prone conditions in the world such as Khorasan province should choose optimum sowing dates outside the high frost risk period to avoid crop damage. The last frost day under these areas normally happened between the 15th and 28th of February, after which no frost events occurred. Accordingly, it is recommended to farmers to sow sugar beet after the period during which no frost risk for sugar beet occurred.
在半干旱气候条件下，水资源短缺是影响作物生产的关键因素。秋季和冬季种植并利用降水可以帮助解决这个问题。但是，在冬季寒冷的半干旱地区，霜冻是另一个影响作物生产的限制因素。为此，本研究使用简单通用的作物生长模拟器（SUCROS）模型，估算了伊朗东北部科拉桑省 8 个地点（比尔詹德、博季努尔德、加恩、马什哈德、托巴特-海达里耶、内沙布尔、托巴特-贾姆和戈昌）从 1993 年到 2009 年 4 个秋季播种日期（10 月 2 日、10 月 17 日、11 月 1 日和 11 月 16 日）和 2 个春季播种日期（3 月 6 日和 5 月 6 日）的甜菜潜在产量和霜冻损害。不同地点和年份的霜冻损害差异很大。在尼沙布尔和戈昌，秋季播种日期的作物因霜冻而歉收的比例分别高达 62.5%和 100%。尽管秋季播种日期在鲜贮藏器官产量方面优于春季播种日期（109.9 吨/公顷比78.4 吨/公顷），但在所有研究地点，秋季播种日期都存在高风险的霜冻胁迫。为了最大限度地提高潜在产量并最小化霜冻风险，像科拉桑省这样处于半干旱和易受霜冻影响的条件下的甜菜种植者应该选择高霜冻风险期以外的最佳播种日期，以避免作物受损。这些地区的最后一次晚霜日通常发生在 2 月 15 日至 28 日之间，之后不会再发生晚霜事件。因此，建议农民在没有甜菜霜冻风险的时期之后再播种甜菜。
