• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.56 no.2
• /
• pp.177-181
• /
• 2011

This research was carried out to establish perfect-drainage time in order to stabilize rice yield and improve rice quality. Treatments of perfect-drainage were conducted 5 days interval during 25 days to 50 days after heading date in the field of Saemangeum Gyehwa, newly reclaimed land. Accumulated temperature after heading date in 2010 increased about $100^{\circ}C$ and precipitation amount decreased a little compared to normal year harvesting time. Average panicle number was 16.5 and spikelet per panicle was 88. Perfect drainage time treatment after 40~50 days was 3% higher in percent ripened grain and 0.6 g heavier in 1,000 grain weight than treatment after 25~35 days. There was no difference of rice yield between perfect drainage time treatment after 25 days and 30~35 days, but rice yield was 7~8% higher in treatment after 40~50 days than 25 days. Head rice ratio in treatment after 35 days was the highest and the sooner perfect drainage time, the lower protein content. Soil moisture negatively correlated with soil hardness and EC in this result. With this results, we proposed that the time of perfect drainage in newly reclaimed land to stable rice production is 40~50 days after heading date.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2005.04a
• /
• pp.44-45
• /
• 2005

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.19 no.4
• /
• pp.669-683
• /
• 2017

The objective of this study is to propose a modification of the previously proposed drainage system for catching the partial leakage of underground concrete structures. Two techniques were proposed for applying the drainage system only to the leaking parts. One was for conveying leaking groundwater to the collection point in the drainage system and the other was for conveying the collected groundwater to the primary drainage system of the underground concrete structure. Four waterproofing materials for conveying leaking groundwater to the catchment point of the drainage system, Durkflex made of porous rubber material, KE-45 silicone adhesive with super strong adhesion, Hotty-gel made of polymeric materials and general silicone adhesive were evaluated for waterproofing performance. Hotty-gel only showed perfect waterproof performance and the other three waterproof materials leaked. The modified drainage system with Hotty-gel and drainage pipe with fixed saddle to convey the leaking groundwater from the catchment point to the primary drainage system were tested on the concrete retaining wall. The waterproof performance and the drainage performance were evaluated by injecting 1,000 ml of water in the back of the modified drainage system at the 7-day, 14-day, 21-day, 28-day, 2-month and 3-month. There was no problem in waterproof performance and drainage performance of the modified drainage system during 3 months. In order to evaluate the construction period and construction cost of the modified drainage system, it was compared with the existing leaching repair method in surface cleaning stage, leakage treatment stage, and protective barrier stage. Total construction period and construction cost were compared in considering the contents of work, repair material, construction equipment, working time, and total number of workers. As a result of comparing and analyzing in each construction stage, it was concluded that the modified drainage system could save construction period and construction cost compared to the existing leaching repair method.