Impact of temperature on cotton crop water requirement in Sabzevar

Subject Areas : Geopolitic

Hossein Mohammadi ¹ , Morteza Miri ² , Mojtaba Rahimi ³ , Safiyeh Tayebi ⁴

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Received: 2015-10-05 Accepted : 2015-10-05 Published : 2014-01-21

Keywords: Mann-Kendall, penman-montith, Evapotranspiration, cropwat, Cotton,

Abstract :

The goal of this study is to determine the temperature on time scales of years, seasons, months, and its relation to the rate of evapotranspiration and crop water requirement of cotton in Sabzevar city. The minimum climatic data of temperature, the mean average and maximum temperature, wind, solar radiation, relative humidity and rainfall from the archives of meteorological synoptic stations Sabzevar 56-year period (2010-1956), was received. In order to investigate the thermal parameters of the test I was Man Kendall and Sen Stimstor. For estimating evapotranspiration and water requirement of the crop watts were used. The results showed that the rate of increase of temperature trends in Sabzevar city is strong and it’s maximum to minimum temperature, because in all three scale annual, seasonal and monthly maximum increase in this parameter is observed. Behavior similar to the behavior of the minimum average mean temperature. Seasonal temperature trends follow the trend of the increasing trend in annual minimum temperature is remarkable. Evaluation of evapotranspiration rates for the study period may indicate a trend in this parameter. Maximum amount on monthly evapotranspiration due to the occurrence of maximum temperature in July and August and the lowest was in January. Cotton crop irrigation requirements estimated using a model W for each year showed that over the period studied, the average irrigation requirement is 1371.83 mm. Meaningful verification process to increase the water requirement by 95% for the tests I Man Kendall and age of the plant, respectively. Maximum water requirement was estimated at flowering and boll development. In general we can say at this station increasing the temperature increases the rate of evaporation and transpiration. The cotton crop irrigation requirements are calculated based on the estimated evapotranspiration during the study period in the time scale, long-term and short-term increased. �دال و سن استیمیتور در سطح 95% برای این گیاه بدست آمد. بیشترین نیاز آبی گیاه در مرحله گلدهی و رشد غوزه برآورد شد. بطور کل می‌توان گفت در این ایستگاه با افزایش پارامترهای دمایی، میزان تبخیر و تعرق نیز افزایش پیدا کرده است. از طرف دیگر محاسبه نیاز آبیاری گیاه پنبه بر اساس تبخیر و تعرق برآورد شده طی دوره مورد مطالعه در مقیاس زمانی طولانی مدت و کوتاه مدت افزایش یافته است