Deep ploughing and freezing is a kind of leisure field in winter. Deep ploughing should be carried out in autumn and winter to promote loose and mature soil. After thawing in spring, plough and harrow to conserve moisture, and furrow to build the border. When planting in summer, choose the stubble of early-maturing crops to rush to plant.
In addition, the records of Changning County, Yongzhou Prefecture and Xingning County in Qing Dynasty also recorded the methods of improving cold-dipped fields with lime.