Soluble salts are dominant form at reclaimed tidal saline soil, which can be improved by leaching with excessive irrigation water. The objective of this study was to evaluate the effect of irrigation on soil salinity and corn (Zea mays) growth at reclaimed tidal saline soil. A field experiment was conducted at Saemangeum reclaimed tidal land in Korea, during two successive growing seasons between 2013 and 2014. During the growing season, three different irrigation practices were applied as following; (1) irrigation at −35 kPa, (2) irrigation at −50 kPa, and (3) no-irrigation. Soil salinity was significantly decreased with increasing irrigation rates. Soluble cations were statistically decreased with irrigation; especially the depression of soluble Na was greater than other cations. Corn growth was significant with irrigation practice and the length of stem, panicle number, and stem thickness was statistically greater compared to the control. Although the germination rate was more than 95% in all treatment, withering rate was great in both growing seasons, which was significantly decreased with irrigation practice. Our results indicated that salt control is critical at reclaimed tidal saline soil and irrigation practice based on soil potential could be one of the best management options to alleviate salt damages for stable crop production at reclaimed tidal saline soil.

본 연구는 중금속으로부터 안전한 약용작물을 생산하기 위한 시비방안을 제시하기 위해 토양의 화학 적 특성과 식물이 이용 가능한 형태의 중금속 함량의 관계를 구명하고자 실시되었다. 전국의 173개 지 점에서 재배중인 약용작물 재배지의 토양을 채취하였으며 1M NH4OAc로 식물이 이용할 수 있는 형태의 중금속인 비소(As), 카드뮴(Cd), 납(Pb)의 함량과 토양의 화학적 특성을 분석하였다. pH가 증가함에 따 라 식물이 이용할 수 있는 형태의 Cd과 Pb은 감소하였지만, As는 증가하였다. 유기물 함량이 증가함에 따라 식물이 이용할 수 있는 Cd와 Pb의 함량은 증가했지만, As는 감소하였다. 유효인산의 함량이 증가 함에 따라 식물이 이용할 수 있는 형태의 As 함량은 증가했지만 Cd과 Pb의 함량은 감소하였다. 위의 결과들은 토양의 pH, 유기물 함량, 인산함량의 차이에 따라 식물이 이용할 수 있는 As의 함량과 식물 이 이용할 수 있는 Cd, Pb의 함량이 대조적으로 나타나는 경향을 명확하게 보여준다. 따라서 약용작물 재배지에서 중금속 안전 농산물을 생산하기 위해서는 대상으로 하는 중금속의 종류를 설정 후 시비를 통한 토양의 pH, 유기물 함량, 유효인산 함량의 관리가 필요할 것으로 판단된다.

Crop production in rice paddy fields is of great importance because of declining rice consumption and the low self-sufficiency ratio for field crops in Korea. A controlled drainage system (CDS) is recognized as an effective means to adjust water table (WT) levels as needed and control soil water content to improve the soil environment for optimum crop growth. The present study evaluated the effects of a CDS on soil characteristics, including soil water distribution and soybean development in paddy fields. The CDS was installed with two drain spacing (3 m and 6 m) at the experimental paddy field at the National Institute of Crop Science, Miryang, Korea. It was managed with two WT levels (0.3 m and 0.6 m) during the growing season. Soil water content, electrical conductivity and plant available nitrogen content in the soil were significantly greater in the 0.3 m WT management plots than in the 0.6 m plot and the control. At the vegetative stage, chlorophyll content was significantly lower with higher WT control because of excess soil moisture, but it recovered after the flowering stage. Soybean yield increased with WT management and the 0.6 m WT treatment produced the greatest grain yield, 3.38 ton ha-1, which was 50% greater than that of the control. The CDS directly influenced outflow through the drains, which significantly delayed nutrient loss. The results of this study indicated that WT management by CDS can influence soil characteristics and it is an important practice for high yielding soybean production in paddy fields, which should be considered the crop growth stages for stable crop production.