Effects of climate change on the suitable sowing dates for peanut under mulched drip irrigation in Xinjiang

Abstract: Global warming has posed a great threat to agricultural production, as the worldwide climate changes dramatically. As such, the temperature can be one of the key factors to influence the growth of crops in arid and semiarid areas. In this study, the peanut was taken as the research crop in the main production areas of Xinjiang in China. The optimal sowing date of peanuts was proposed under mulched drip irrigation in the different study areas under the condition of climate change. The ground and average temperature were first collected in the same period in the experimental areas of North and South Xinjiang. The relationship was then determined between the average daily ground temperature and the average daily air temperature before sowing peanuts. The meteorological data of 51 stations was also collected from the establishment of stations in 2020. A systematic analysis was made to explore the influence of ever-increasing temperature on the sowing date of peanuts. The result showed that there was a strong linear correlation between the farmland surface soil temperature and meteorological temperature before the sowing. Further analysis showed that the farmland surface soil temperature increased with the increase of the average daily air temperature after spring, and the soil temperature in the root zone increased rapidly with the increase of air temperature after the sowing. Once the surface soil temperature was maintained at more than 12, 13, 14, and 15 ℃ for five consecutive days, the optimal daily Ordinal Numbers of sowing time were 106.94, 109.79, 112.39, and 114.39 in eastern Xinjiang, while 108.53, 111.44, 114.36, and 117.02 d in the southern Xinjiang, as well as 121.09, 124.10, 126.65, and 128.58 in the northern Xinjiang. The average root zone soil temperature was above 20 ℃ within 0-20 days after peanut sowing with drip irrigation under mulch in the peanut production area. Furthermore, the root zone soil temperature fully met the demand for peanut seed germination, only under the condition of suitable soil moisture in the root zone. In addition, the average daily ground temperature of peanuts in the suitable sowing period increased in Xinjiang oasis after spring over 70 years. The average sowing date of peanuts was also advanced by 1.44-1.75, 1.13-1.43, and 1.05-1.88 days per decade under mulched drip irrigation in East, South and North Xinjiang, respectively. A comprehensive analysis was also performed on the change trends of the soil temperature before sowing and the soil ground temperature in the root zone after the sowing. The suitable sowing date of peanuts under mulched drip irrigation was about two days earlier in the production areas of the East than the South Xinjiang, while about 12 days earlier in the South than the North Xinjiang. The suitable sowing time was early May in the production areas of North Xinjiang. The findings can provide theoretical guidance for the selection of suitable sowing dates in different production areas of peanut in Xinjiang oasis.