The change of rice planting structure in rice-oilseed rape rotation mode in Jiangxi Province under the background of climate change

In recent years, it is promoted vigorously to expand rape production on winter fallow field in Jiangxi in order to satisfy the fast growing demand for edible vegetable oil in China, but the phenomenon of rice and winter rapeseed competing for land appeared in different areas in the actual development process. This paper studied the changing characteristics of rice planting structure and double-cropping rice maturity collocation under the background of climate change and focused on the combination of rice planting structure and double-cropping rice maturity collocation after 2011 on the base of considering the number of days required for agricultural activities such as rape harvesting and rice transplanting in actual rice oil production by using the meteorological data from 85 meteorological stations in Jiangxi Province from 1961 to 2022. Under the condition of ensuring the normal growth of rapeseed, the research results show that: 1) The harvest date of rapeseed (rice transplanting) was different from north to south, which was early in the south and late in the north and showed an advance trend which was 13 days earlier than in the 1960s after 2011 under the background of climate warming. Beyond 2011, the date of rape harvest was first ten days of April in southern Jiangxi, first ten days of May in Jiujiang, and last twenty days of April in other regions. And then the date of rice transplanting was Mid—April in mostly southern Jiangxi Province, last ten days of April and first ten days of May in north and central Jiangxi Province. 2) The planting areas of single-season rice, recycled rice and double-season rice had little change from 1961 to 1990, but at the beginning of 1991, the northern boundary of single-season, recycled and double-season rice was advancing to the north, and the planting scope of single-season rice was gradually shrinking, while the planting scope of recycled and double-season rice was gradually expanding under the condition of ensuring the normal growth of rape. After 2011, the double-season rice can be grown in southern Ji’an and southern Gannan, the recycled rice can be planted in southern part of northern Jiangxi and most of central Jiangxi, and the single-season rice can be planted in the rest of country. 3) Since 1991, the northern boundary of the maturity combination of double-cropping rice has been moving northward. After 2011, the combination of early and early maturing varieties can be planted in the south of Ji’an and the southern edge of Fuzhou, the combination of early and medium maturing varieties can be planted in the north of southern Jiangxi and the combination of early and late maturing varieties or medium and medium maturing varieties can be planted in the central and southern parts of southern Jiangxi. The results can provide reference for the balanced development of rice and rapeseed, and also help meteorological department to do a good job for meteorological service of rice-oilseed rape rotation mode in Jiangxi Province.