The paramount step for land utilization planning is to determine the plowland index, which requires a prediction of preserved plowland quantity.

• 文章结合辽阳市土地利用总体规划的要求，运用了回归分析法、长期趋势法、灰色系统法对辽阳市耕地保有量进行了科学的预测分析研究。