閉鎖型生態系実験施設CEEF での植物栽培における水循環

摘要

In order to stabilize a carbon flow for analysis of carbon dynamics in plants, animals, humans and a carboncirculation in the combined entire system, it is necessary to establish a steady food production system based onplant cultivation in the Closed Ecology Experiment Facilities (CEEF). The objective of this study is to apply anutrient solution circulation system to the plant cultivation. The circulation system reuse of minerals and water inwaste nutrient solution, with the addition of minerals depleted due to absorption by the plants. Total ediblebiomass of 23 crops including rice, soybean, peanut and sugar beet cultivated by the circulation system in 2006 wasless then that of these cultivated without circulation of nutrient solution in 2005. Because the concentration of totalorganic compound (TOC) did not increase but some elements such as copper increased during the circulation, it isconsidered that depletion of yield could be attributed to the concentration of some micro elements. The result of apreliminary experiment showed that biomass of rice seedling grown with newly prepared nutrient solution(non-circulation system) was more than double of that grown with recycled nutrient solution. Using newly preparednutrient solution only in seedling phase could enhance final biomass production of that grown with recyclednutrient solution after transplanting. Appling this modified method to cultivation would be effective to maintainproductivity of crops without a large amount of disposal nutrient solution waste. This research was performed undercontract with the Aomori Prefectural Government, Japan.