本文利用「動差法」研究日本1996-2003期間，重要稻米產地的稻作農家利潤、成本和產量之均數、變異數和偏態係數，及其影響因素。實證結果顯示：稻農的利潤、成本和產量的機率分配多是傾向左偏。技術進步、氣候條件、農場規模、轉作比率、租地比率、資本裝備率和農業依存度等因素，不僅會影響利潤、成本和產量的均數和變異數，同時也會影響其偏態係數。在稻農利潤方面，技術進步、租地比率和農業依存度的提升，可以增加利潤的均數；提高轉作比率則會降低利潤均數。其次，技術進步、氣候條件改善和轉作比率的提高，會增加利潤的變異數；擴大農場規模、提高資本裝備率和農業依存度，則可降低利潤的變異數。

A moment-based approach was applied to the data of Japanese rice-growing farms during 1996-2003 to study the influences of technical progress, weather condition, farm size, conversion policy, ratio of rented land, ratio of capital to labor, and degree of agricultural dependence on the risks of the farms' profits, costs, and production. In order to analyze the structure and contents of farms' risk in a deeper degree, the risks were decomposed into three factors: mean, variance, and skewness. The empirical results show that technical progress, an increase in ratio of rented land and degree of agricultural dependence would increase the mean of profits while a higher level of ratio of land conversion would result in a lower mean of profits. Technical progress, weather improvement, and an increase in the ratio of land conversion would raise the variance of profits; the expansion of farm size, an increase in the ratio of capital to labor, and degree of agricultural dependence would decrease the profit risk.