기성간척농지(旣成干拓農地)의 토양염도(土壤鹽度), 재식실적(栽植實績) 및 수확량(收穫量)에 대(對)한 실태조사(實態調査) = Report on Study for Soil Salinity, Plantation and Yields in the Existing Polders

다국어 초록 (Multilingual Abstract)

1. For the purpose of analyzing the plan of new reclamation project and its evaluation, actual studies for the existing polders are required.
2. The variations of the salt content of soil, yields and status of its plantation have been studied for six areas reclaimed in relatively recent years, including Kangwha, Daechon, Chopo, Eushin, Kwangyang and Chinkyo.
3. The annual yields from the project were only 52 percent in the first year as compared with kilograms per 10 a. in the Hachirogata polder in Japan.
4. Such a low productivity in the existing polders in Korea is chiefly by the high ground water table, unfavourable conditions of subdrain-age in the root zone, and saline damages of exist-ing high salt content. That is because the depth of drainage ditches is too shallow and layout distance between every drainage ditches is also too long.
5. In order to overcome such a uncertiainties, the drainagedistance suitable for these areas has been Calculated by using the Donnans formula. App-lying to the formula, drainage facilities are so densie that land use capability may be decreased.
6. For the purpose of ensuring the effective desalinization and high land use capability, feasible interval to establish the culvert has been studied in accordance with both formulas of Donnan and Hoogan.
7. In order to accomplish the early desalinization in both areas of new reclamation or existing polders, the problems of internal drainages should be resolved. for this puprose in addition to the en-deavour of the personnels actually engaged in such works. The actual support of the related agencies for financial assitance is required.