民勤荒漠区气候特征对瓜类作物生长的影响

对民勤县西沙窝 1 961 - 2 0 0 0年相关气象观测资料分析显示 ,该地区终霜期在 3月上旬 - 5月中旬 ,其中 4月份频次最高。40年以来 5 - 8月总降水量、相对湿度有逐渐增大的趋势 ,日照时数和积温逐渐减少 ,90年代日照时数是 60年代的 78.2 % ,积温为 91 .2 % ;从 5月到 8月月平均降雨量逐步增大 ,相对湿度逐渐上升 ,日平均温度 5 - 7月上升 ,8月开始下降。 6- 8月阴雨天 ,晴天 (有露 )和晴天日气温和相对湿度变化曲线表明 ,6月份一天中大部分时间气温和相对湿度较低 ,7月份两者均有所上升 ,2 0℃左右温度和高湿环境持续时间较长 ,8月份气温有所下降 ,而相对湿度较高。对照瓜类作物生长和病虫害发生特点认为露地瓜类作物适宜播种期为 5月初 ,7月的阴雨天和转晴后的最初晴朗夜间是多种病害发生与流行的最适宜时期 ,而日照时数的明显降低可能影响厚皮甜瓜果实的品质

Effect of Climatic Characteristics on Cucurbit Crops in Minqin

Climatic data of Minqin of 1961-2000 showed that the latest frosts dates were from March 6 to May 19 in this area,the most times of latest frosts were in April (It was 19),rainfall and relative humidity had a little increase and sunshine hours and accumulated temperature (stable average temperature of day and night ≥10℃) had a obvious decrease from 1961 to 2000,the sunshine hours in 1990s was 78.2% of 1960s,the accumulated temperature was 91.2%.The rainfall and relative humidity gradually increased from May to August.Rainfall in Aaugust was 1/4 of whole year.Average temperature of month increased from May to July and decresed in August.Curvilineal diagram of temperature and relative humidity of day and night in June,July and August show that both temperature and relative humidity were below in June,more high in July,especilly the time of around 20℃ and relative humidity ≥80% were longer in rain day and night of fine, temperature was below and relative humidity was high in August. Compared with characteristic of cucurbit crops and diseases and insect pests, the best sowing time is in the early May and the suitable time for disease is rain day and high humidity night in July.Shotter sunshine hours may affect fruit quality of melon.