Effect of Temperature on Frost-Free Days and Length of Crop Growing Season across Southern Ontario

Climate change has an impact on various climatic variables. In this study our focus is mainly on temperature characteristics of climate parameter. In temperate and humid regions like southern Ontario, the effect of climate change on Frost-free days in winter is distinctive. The average annual temperature is going upward but the extreme increase is in the winter temperature. Winter average temperature is going up by about 2˚C. However, extreme daily minimum temperature is going up by more than 3˚C. This climate effect has a great impact on the nature of precipitation and length of frost-free days. The snowfall over winter months is decreasing and the rainfall is increasing. However, the number of frost-free days during late fall months, early winter months, late winter months and early spring months are increasing. This result reveals an increase in length of the growing season. This research focuses on the effect of change in climatic variables on Frost-free days in Southern Ontario. Therefore, special attention should be given to the effect of change in climate Frost-free conditions on length of crop growing in winter season for potential investigation.

Temporal and Spatial Variation Characteristics of Precipitation during Crop Growing Season in Northeast China

[Objective] The aims were to understand variation characteristics of water resources and provide theoretical guidance for the formulation of agricultural irrigation methods.[Method] Taking the precipitation records during crop growing season（from April to September）observed by 177 weather stations from 1971 to 2008 in the three provinces of Northeast China（Heilongjiang,Jilin and Liaoning）as research data,annual change and spatial distribution characteristics of precipitation during crop growing season were analyzed by means of small grid interpolation and climatic trend rate.[Result] The precipitation during crop growing season general exhibited the decreasing trend and the precipitation trend rate was-8.6 mm/10a in Northeast China.In addition,there was lack of rain from 1971 to 1980 and relatively abundant of rain during 1981 and 1990 respectively.Moreover,the precipitation obviously exhibited decreasing trend from 1991 to 2008.But the decreasing trend was inconsistent in spatial distributions,that was,the precipitation slightly increased in relatively rainless areas and obviously decreased in relatively rainy areas.[Conclusion] The areas with obvious decreasing trend of precipitation during crop growing season are the main grain producing zones in Northeast China,so the problem of food production security caused by the precipitation changes should be paid enough attention.

Precipitation Variation during the Crop Growing Season and Analysis of the Trend of Agricultural Drought and Flood in Dalian City in Recent 60 Years

[Objective] The aim was to study the precipitation changes and agricultural flood and drought degree of crops in Dalian City in recent 60 years. [Method] The monthly precipitation and average temperature data from April to October during 1951-2010 in Dalian observation station were selected. By dint of linear regression, climate tendency rate and humidity index, the growth changes and agricultural flood and drought degree of crops in recent 60 years in Dalian City were expounded from the aspects of natural precipitation tendency changes and agricultural water satisfaction degree of crops in growth period. [Result] In recent 60 years, the precipitation of crops during growth period in Dalian City had decreasing tendency. The inclination rate was -15.888 m/10 a. Precipitation decreased 95.3 mm in recent 60 years; precipitation increased a little in spring and decreased a lot in summer, then decreased in autumn. The monthly precipitation in each month distributed unevenly. Precipitation in July and August increased, taking account of 53.8% of the total precipitation during the growth period of crops. The K value of humidity index during the growth period of crops in Dalian in recent 60 years was 0.90 in general. It was light drought climate. The humidity index was decreasing. Climate developed toward drought direction; the drought occurrence frequency was 59%. It was mild drought climate in spring and autumn. The climate was generally wet in summer. Seen from the yearly means, besides of July and August, it reached mild drought degree in other months. [Conclusion] The study provided reference for the regional agricultural production, agricultural structure adjustment and drought and flood disaster prevention.

Impact of Climate Warming and Drying on Crop Growing Season in Northwestern Liaoning

Based on the observation data of the average temperature and precipitation of 8 national meteorological stations in the northwest region of Liaoning Province from April to October during 1961-2015,methods such as linear trend estimation,moving average,standard deviation and Mann-Kendall test are used to analyze the characteristics of average temperature and precipitation during the crop growing season in northwestern Liaoning.The results show that the average temperature during the crop growing season in the study area showed an upward trend,and the climate tendency rate was 0.193 ℃/10 a( P < 0.01).The largest contribution rate to temperature increase was in September,with a climate tendency rate of 0.27 ℃/10 a;the smallest contribution rate to the temperature increase was in July,with a climate tendency rate of 0.10 ℃/10 a.The warming trend was the most obvious in the second base year,with a climate tendency rate of 0.413 ℃/10 a( P < 0.01).The temperature was the lowest in the 1970s and the highest in the 2010s.The warming trend changed suddenly in 1996,and the sudden change reached a significant level of α = 0.05 after 2002.Precipitation was generally decreased,and the climate tendency rate was -7.68 mm/10 a.The decrease in precipitation was the most in July,and the climate tendency rate was -12.08 mm/10 a.The average temperature in the four base years failed to pass the correlation significance test.Among them,it showed an increasing trend in the second and third base year and a decreasing trend in the first and fourth base year.Rainfall was the highest in the 1960s and the lowest in the 1980s.After the abrupt change in 2002,precipitation decreased significantly.The research results provide reference for effective utilization of climate resources,rational adjustment of agricultural planting structure,and improvement of ecological environment quality.

Analysis on the Satisfaction Degree of Agricultural Water Demand in Semiarid Area of Western Liaoning

[Objective] The satisfaction degree of agricultural water demand was analyzed to provide climate basis for the agricultural structure adjustment and good harvest.[Method] By using integral humidity index and climatic tendency rate,the satisfaction degree of water demand of crops and its trend variation were studied.[Result] The precipitation in the growing season of crops showed decrease trend in western Liaoning,and the climatic tendency rate was-8.660--18.560 mm/10 a,with the precipitation decrease of 43-93 mm in recent 50 years.The satisfaction degree of agricultural water demand was up to 72%-88% in average,and over 80% satisfaction degree accounted for 30%-60%,while water shortage probability reached 68%-90%.The satisfaction degree of Chaoyang,Lingyuan and Beipiao was the lowest,while that of Jianchang and Jiangping was relative higher.The satisfaction degree of gross agriculture water demand went down with the time,and climate tendency rate was up to-2.490%--3.863%/10 a,with the decrease of 12%-19% in recent 50 years.[Conclusion] With the reduction of precipitation,the satisfaction degree of water demand of crops went down,and the climate in western Liaoning became more and more dry.