关键词: 种粮收入, 最优种粮面积, 收入—面积比

Abstract: Based on field surveys about crop earning in Shandong and Ningxia provinces,the paper analyzes the various factors that affect farmers' income gaining from crops.Basing on the research the authors believe that the major factors effecting farmer planting income are the quantity of the farming area,the investment in agricultural machinery and the scale of labor force,among which the first factor plays the most essential role on planting earning.Furthermore,the paper discusses the optimal amount of planting area in Shandong and Ningxia at a given agricultural production level,and provides comparative static methods for optimum cropping area calculation.

Key words: crop earning, optimal planting area, income-area ratio