Development of vegetable cultivation system aims to eutrophic lake water purification on lakeside paddy field.

在千叶县的田贺湖的湖滨休闲稻田上尝试开发利用富营养化水的新型蔬菜生产系统。2002年在上一个项目的湖滨生产系统的基础上开发了新的生产系统。引入轨道系统以提高收获劳动效率。新型收割机已研制成功，它能收割较高的作物。同时对供水系统进行了优化，系统上部的空心菜产量高于下部，但系统内EC值和NO3--N含量在系统上部和下部没有差异。根据2004年的试验结果，确定了水葫芦适宜的生产系统，其适宜条件为：（1）水葫芦生产系统中悬浮物（ss）在系统上部的积累量大于系统下部的积累量，SS对水葫芦的生长有一定的影响; 1、系统最大长度为20 m ~ 2，最小供水量为36升/日，试验结果表明，SS的养分含量对植物生长有影响，SS可作为堆肥使用，为保证系统生产的作物安全，2002年对产品进行了重金属含量分析，2004年对产品表面大肠杆菌染色进行了检测。证实了系统产品的安全性。

Try to develop the new vegetable production system using eutrophic water on lakeside fallow paddy fields of Tega-lake in Chiba Prefecture.New production system based on lakeside production system of the last project was developed on 2002. Introduce the rail system for increasing harvest labor efficiency. New type of harvester was developed which can harvest higher crops. Optimization of water supplying system was examined at the same time.Yield of Ipomoea aquatica at upper part of the system was higher than lower part, though EC value or the NO3-N content of the water inside the system didn't different between upper and lower part. Because accumulation amount of suspended solid (ss) in the Tega-lake water at the upper part of the system was bigger than lower part, ss might affect the plant growth in this system.From the result of the experiment on 2004, we decided the suitable production system for Ipomoea aquatica.The suitable condition is as follows ;1,Maximum length of the system is 20m2,Minimum amount of water supply is 36 litter per day per plant.The result indicates nutrient contents of SS effect on plant growth and ss can be used as a kind of compost.To confirm safety of the crops producted by the system, heavy metal contents of the products were analyzed on 2002 and colon bacillus stained on surface of the products were checked on 2004. Safeties of the products from the system were confirmed.