Influence of Climate on Rape Production

(A) the requirements of rape on climatic conditions

The growth of rape generally needs to meet the requirement that the accumulated temperature in the whole growth period is ≥0℃ and above 1300℃; 5438+1the average minimum temperature in June is above -9℃; The average temperature during flowering and pod setting is lower than 22℃. The whole growth period of rape is 150 ~ 230 d, and the seedling stage is the longest, generally 90 ~140 d; It takes 30 ~45d days for bud to blossom and pod to mature. The growing season of rape in Poyang Lake area is from the first ten days of 10 to the second ten days of April, and the time for large-scale sowing is from the first ten days of 10. The climatic conditions in Poyang Lake area meet the normal growth of rapeseed. Lake area is also the main concentration area and the most suitable planting area of rape in the whole province, which is mainly due to the lighter autumn drought and better irrigation conditions in the lake area. In addition, the winter temperature is relatively stable, the number of spring rain days and April rainfall are less than those in other areas, and the solar radiation is more than those in other areas.

Rape growth is generally divided into two stages, and different stages have different requirements for climatic conditions. When sowing, the weather in the lake area is controlled by the subtropical high pressure, and the drought frequently affects the emergence of seedlings, so it is difficult to ensure the sowing area; The cold and rainy weather next spring will seriously lack sunshine, which will affect the flowering of rape branches and increase the number of empty pods. Therefore, we analyze the influence of climatic conditions on rape growth from two stages.

The first stage: from the first ten days of 10 to the first ten days of February of 10, there is more precipitation and less sunshine, which is beneficial to sowing, emergence and seedling growth. If there is more sunshine during this period, it will increase soil evaporation and aggravate the harm of drought. This stage is from the sowing time to the seedling stage of rape in Poyang Lake area, and there is a certain difference between precipitation and sunshine. Among them, the Poyang Lake and the lakeside area of Poyang Lake basin have less precipitation and sufficient sunshine, which is not conducive to rape sowing and seedling emergence. However, in the hilly areas around Poyang Lake, there is relatively more precipitation and less sunshine hours, and there are a lot of arable land suitable for camellia oleifera planting, which is beneficial to rape sowing and seedling emergence.

The second stage: from 5438+February in mid-June to April of the following year, rape changed from vegetative growth to reproductive growth, which required higher and higher light, sufficient sunshine and less precipitation, which was beneficial to rape flowering and pod setting; Too much precipitation and too little sunshine are easy to cause camellia washing, which makes rape unable to pollinate normally and increases the empty rate. The reproductive growth period of rapeseed in Poyang Lake area is from late June of 65438 to April of the following year. During this period, the precipitation basically showed a trend of high in the south and low in the north. The precipitation in the northwest of Poyang Lake area is less than 550mm, and the precipitation in the southwest of the lake area is between 550mm, which is not conducive to rape flowering and pod setting. 12 from the end of February to April of the following year, the sunshine hours in the lake area are basically more in the north and less in the south, and the sunshine conditions in the north of Poyang Lake area are very conducive to the growth and development of rapeseed and the improvement of yield.

(2) Climatic regionalization of rape

According to the rainfall and sunshine conditions in the whole growth period of rape, the rape planting in Poyang Lake area is divided into climate zones, as shown in Figure 4-8 and Figure 6. As can be seen from the figure, except the area around Poyang Lake and the southern part of Poyang Lake, the rest areas are the most suitable and suitable areas for rape planting, especially the hilly area around Poyang Lake in the northern part of Nanchang-Poyang County, which is the main reason for the highest rape yield in the whole province in northern Jiangxi.