召唤旧农机市场农用运输车的管理亟待理顺１．问题的提出（１）农机产品更新换代加快。由于科学技术的进步和农机产品质量的提高，农机户卖旧买新的日益增多。以柴油机为例：７０年代柴油机的额定耗油率为２９９．２ｋｇ／ｋＷ·ｈ，到９０年代则下降为２５０ｋｇ／ｋＷ·... Summon the old farm machinery market management of agricultural vehicles urgently need to straighten out 1. Proposed problems (1) to speed up the upgrading of agricultural machinery products. Due to the progress of science and technology and the improvement of the quality of agricultural machinery, the number of agricultural machinery dealers selling old and buying new ones is increasing. Taking diesel engine as an example: the rated fuel consumption rate of diesel engine in the 1970s was 299.2kg / kW · h, then decreased to 250kg / kW in the 1990s.