Changes in Soil Chemical Properties of Rice Paddy, Upland Field, and Greenhouse in Incheon from 2015 to 2019

Abstract

Received: April 24, 2021 Revised: May 19, 2021 Accepted: May25, 2021 ORCID Seong Heo https://orcid.org/0000-0003-4485-8810 This study was performed with the monitoring data of soil chemical properties of rice paddy, upland field and greenhouse soils in Ganghwa, Incheon metropolitan city from 2015 to 2019. Soil pH values tended to increase gradually in three soils, but there was no significant change in that of greenhouse soil. The concentration of organic matter (OM) and available phosphate (Av. P2O5) have fluctuated from 2015 to 2019, showing significant differences. In 2019, the average value of OM and Av. P2O5 were distributed within the appropriate level suggested by Rural Development Administration. In rice paddy field, the available silicate (SiO2) were found to be proper within the standard concentration every year. The contents of exchangeable cations were higher than the proper standard, showing significant differences among the years, except greenhouse soil. The mean concentration of EC for five years in upland and greenhouse soils were 2.5 and 5.9 dS m-1 above the proper standard. The optimal frequencies of pH were 46.8% and 47.1% at rice paddy and upland soil, but the excessive frequency ratio of pH was 48.5% at greenhouse soil in 2019. The exchangeable cations seemed to be seriously disproportionate exceeding the optimal level by 95%. In Pearson correlation matrix, the value of exchangeable Ca had a significantly positive correlation with exchangeable Mg content at upland and greenhouse soils. By principal component analysis, the exchangeable K, Mg and OM could distinguish between greenhouse and other soils on the first principal component and the pH and Av. P2O5 could differentiate between rice paddy and upland soils on the second principal component.