How to understand the maturity of crops, please answer in detail. Such as June-September: corn; September-June: wheat; June-September: corn, how to understand?

Generally speaking, the maturity of crops is the number of times that crops (mainly food crops) can be harvested in one year (or two or three years) according to the climate and ecological conditions in different regions.

In China, due to the different climates in different regions, there are many ripening systems. Generally speaking, the farther south the crops go, the more times they ripen in a year. Crops are generally harvested once a year in the Northeast Plain, two or three times a year in the Huang-Huai-Hai Plain, two or three times a year in the middle and lower reaches of the Yangtze River, three times a year in the Pearl River Delta and one time a year in the Qinghai-Tibet Plateau.

You said "June-September: corn; September-June: wheat; June-September: corn ",one crop of corn is harvested from June to September in the first year, one crop of wheat is harvested from September to June in the second year, and another crop of corn is harvested from June to September in the second year. This is a two-year or three-year planting system.