Studies on the range of production limits and control scheme for greenouse soils.

土壤退化，包括盐分积累，是日本农业生产，特别是蔬菜和花卉温室栽培的严重问题之一。本文首先对三种不同使用年限的温室土壤的物理因子和化学成分进行了分析。离子色谱法、原子吸收法和分光光度法的分析结果表明，温室土壤EC值、阴离子（SO_4^-、NO_3^-、Cl^-）和阳离子（Ca^2+、Mg^2+、K^+）的积累速率与温室土壤的老化时间在5%水平上有显著相关性。然后，我们试图估计生产限制的温室土壤EC的年增长率和一些离子含量从实验结果计算的范围。最后，作为温室土壤盐渍化的对策，我们开发了一种新的方法，利用附着在土壤表面的片状材料来捕获积累在土壤表面的盐。溶质运移的一些基本特性，以及在片材上捕获的盐的量，实验观察到三种不同类型的片材。

Degradation of soils, including salt accumulation, is one of the seriou problems on agricultural production, particularly greenhouse culture for vegetables and flowers in Japan. This problem still remains as one of the major subjects in horticulture to be solved.In this report, we firstly analyzed some physical factor and chemical components of soils collected from three types of greenhouses with diferent periods of usage. From the analytical results with the ion chromatography, atomic absoption and spectrophotometry, there are significant relations in 5 % levels between the value of EC,accumulated rates of anion (SO_4^-, NO_3^-, Cl^-) and cation (Ca^<2+>, Mg^<2+>, K^+), and the ysage periods of greenhouse soils. Then, we tried to estimate the range of production limits for greenhouse soils using the yearly increasing rate of EC and some ionic contents calculated from the experimental results. Finally, as a countermeasure to the salinization caused in grenhouse soils, we have developed a new method to capture the salts accumulated on the surface of soil with using the sheet materials attached on the soil surface. Some basic characteristics for solute transport, and the amount of salts captured on the sheet, are experimentally observed with three different types of sheets.