粮食市场化改革以来农户粮食经营行为及其对粮食市场的影响研究

After China's grain market liberalization reform in 2004, its grain market has been fully liberalized, and the farm households' behavior of grain production and marketing has become market-oriented. As a large number of rural labors moved to non-agricultural sectors, the farm households' motivation and willingness to produce grains has been gradually changed, which results in the adjustment of crop planting structure, staple food grain is gradually replaced by maize or other labor saving crops, hence the grain stock also changes from wheat or rice to maize or other grains, which means more and more farmers need to buy food grain from market, this will cause greater pressure on China's food grain supply. Firstly, this research will decompose farm households' grain management behaviors to three parts-consumption, storage and sale. Using field survey data on more than 1000 farm households of different scales from different grain producing areas, we will build intertemporal farm household decision model to study how farm households to make decision of consumption, storage and selling to maximize their utilities. Following this, the price adaptive expectation model and grain stock partial adjustment model will be used to analyze farm households' grain storage behaviors, test the major motivation of farm household's grain storage across major regions, including transaction cost minimization, speculation and grain security motives. Finally, based on the participation of farm households in grain market, we will try to explore the potential impacts of grain storage behavior on grain market supply and demand, some suggestions will be provided to policy makers.

2004年我国粮食购销市场化改革以来，农户的粮食生产经营行为也日益市场化。随着大量农业劳动力的转移，农户种粮意愿、动机及粮食种植结构也发生了变化（省力省劳型粮食种植增加），农户的储粮行为也随之发生改变，这意味着将有更多的农户需要走向市场购买口粮，因而会给我国粮食市场供给增加更大的压力。本项目将在对粮食主产区、主销区和产销平衡区不同规模农户的种粮意愿和动机分析的基础上，对农户的粮食经营行为进行分解，由农户效用最大化出发，运用不确定条件下的农户动态规划模型，考察农户如何进行粮食的消费、储备和市场交易决策。同时，运用价格适应性模型和储备偏调整模型对农户的粮食储备行为进行进一步分析，检验不同地区和不同规模农户的储粮动机，分析哪一种动机是影响农户储粮的主要因素，进而说明农户的粮食储备变化对粮食市场带来的影响，最后提出相关政策建议。

自2004年我国粮食购销市场化改革后，农户的粮食生产经营和储备行为也市场化了。本项目在对农户的种粮意愿和动机分析的基础上，围绕着农户粮食规模经营意愿及影响因素、农户粮食适度经营规模、农户家庭粮食收支与储备变化趋势、农户家庭粮食储备的经济作用、农户家庭粮食储备动机、以及影响农户粮食储备的主要因素六个方面展开相关研究。本项目研究发现：（1）尽管当前多数农户的农地规模仍处在一个“小规模”经营阶段，但农户希望扩大种植规模的意愿强烈，大多数农户都有实行规模经营的主观动机。（2）当前样本区域农户的粮食经营规模偏小，远远低于其理论上的最佳经营规模。（3）过去十多年里，在农户家庭粮食产量增加的情况下，农户家庭的粮食储备量下降明显；农户粮食储备意识越来越淡化，对市场的依赖程度越来越高；（4）农户粮食储备一方面可以缓解粮食市场价格波动，另一方面也可以减轻粮食市场价格波动对农户粮食消费行为的影响程度，对农户家庭粮食消费起到“安全器”和“稳定器”的作用。（5） 在控制了农户粮食产量、人口变量等因素后，农户粮食储备量主要受农户对真实利率预期（或通货膨胀率预期）的影响，粮食价格及非农收入的影响也比较显著。近年来，通货膨胀率及CPI在波动中居高不下，对农户粮食储备行为带来显著的不利影响，农户经常盲目对待粮食价格波动，产生“惜售心理”，给粮食市场供给带来不利影响。（6）中国农户粮食储备行为的决定因素很多，价格并不是唯一的决定因素，尤其是粮食市场越发达的地区，投机活动越多，价格对农户粮食储备的边际作用越小。（7）在中国，农户倾向于用一般储备理论的偏调整模型来决定粮食储备行为。消费安全和市场交易成本最小化都是农户进行粮食储备的重要考虑因素，因此家庭人口、养殖牲畜、市场便利程度等都是农户粮食储备主要影响因素。（8）粮食产量与农户粮食储备量呈显著正相关关系，这意味着，对粮食供给的冲击很大程度上可以被农户粮食储备能力所吸收。