Spatial Variations in Salinity and Sodicity of Reclaimed Tideland Paddy Soils in Coastal Areas of Southwestern Korea

Abstract

Reclaimed tidelands (RTLs) in the southwestern coastal areas of South Korea has been used for rice (Oryza sativa L.) cultivation due to high salinity of the soils. However, there is increased social pressure to utilize the RTLs for upland crop cultivation due to decreased rice consumption. In this study, salinity and sodicity of 16 RTLs located were investigated to explore the suitability of RTLs for upland crop cultivation. Surface (0 -20 cm) soil samples were collected from 241 paddy fields in the 16 RTL districts and analyzed for electrical conductivity of saturated soil paste extracts (EC e ), exchangeable sodium percentage (ESP), and pH at 1:5 of soil:water ratio (pH 1:5 ). The EC e (range: 2.5 -15.8 dS m -1 ), ESP (1.6 -67.2%), and pH 1:5 (6.6 -9.0) of the RTL soils differed (P < 0.001) with RTL districts. Though there are indications of decreased EC e , ESP, and pH 1:5 with rice cultivation year after reclamation, this pattern was not statistically significant, suggesting that land management practices such as liming and organic matter application are required to facilitate desalinization and desodification of RTLs. Of the 16 RTLs, normal soils (EC e < 4.0 dS m -1 , ESP < 15%, and pH 1:5 < 8.5) were found in seven RTLs including Wolchen, Sanae, and Baiksoo RTLs. The proportion of normal soils in these three RTLs were 75%, 56%, and 47%, respectively. Therefore, these RTLs are found to be more suitable for upland crop cultivation than other RTLs. However, because the growth of upland crops are also susceptible to soil moisture stress, more information such as groundwater levels and soil drainage is required for successful upland crop cultivation in these RTLs.

Evaluation of nutrient loading technique potential of domestic tree species to promote forestation

“…이와 더불어 산림청과 농식품 부에서는 생태 ‧ 경관을 개선하고, 비산먼지 저감 및 풍해 예방을 위해 새만금 간척지에 2026년까지 228 ha 면적에 나 무심기를 확대할 계획이며, 이는 농생명용지 묘묙장 (55 ha), 강 유역 방수제 도로사면 (73 ha), 농생명 용지 내부도로 (100 ha)를 포함한다 (KFS, 2021). 간척지 토양은 염농도가 높고, 지하수위가 높으며, 토양 구조 발달이 잘 되지 않아 배수가 불량하며 양분 함량이 낮아 밭 작물이나 나무가 자라기에는 적합하지 않다 (Jeong et al, 2020;Seo et al, 2023). 따라서 간척지 토양에 나무를 재배하기 위해서는 양분 공급을 위한 개량제 투입은 물론 잡초 제거를 위한 제초 제 살포나 잡초매트 피복 등의 추가 비용이 필요하다.…”

Agroecological Transformation in the Salt Composition of Soil under the Phosphogypsum Influence on Irrigated Lands in Ukraine

“…Gypsum application has been established to increase the content of exchangeable calcium and significantly reduce the amount of sodium absorbed. However, even with high doses of gypsum, it is not possible to achieve the required level of saturation of the soil solution with calcium in the absence of irrigation [25,26]. By displacing sodium from the soil-absorptive complex with calcium or other divalent or trivalent cations, the mobility of soil colloids decreases, alkalinity decreases, and the availability of nitrogen, phosphorus, potassium, and calcium for plants increases, while microbiological processes are activated [27][28][29][30][31].…”