Changes in Chemical Properties of Greenhouse Soils Collected from Ganghwa

Abstract

The chemical properties of greenhouse soils in Ganghwa were investigated every year from 2014 to 2018 in order to manage soil fertility and increase crop yield. In 2018, the average concentrations of chemical properties from greenhouse soils were analyzed: 6.4 for pH, 6.72 dS m-1 for EC (electrical conductivity), 23 g kg-1 for OM (amount of organic matter), 187 mg kg-1 for P2O5 (available phosphate), 1.89, 12.09, 4.84 cmolc kg-1 for exchangeable potassium (K), calcium (Ca), magnesium (Mg), respectively. There were no significant changes in the contents of pH and OM from 2014 to 2018. However, the concentration of EC was 3.7 times higher than that of the proper standard recommended by Rural Development Administration in 2018. Further, the excessive frequency ratio about exchangeable cations were 60.6% for K, 93.9% for Ca and 95.9% for Mg based on the recommendation and the contents of exchangeable cations had a tendency to increase according to the years. The frequency ratio of P2O5 which is insufficient in comparison with the standard was 83.8% and the concentration of P2O5 was 1.9 times lower than that of the recommendation in 2018. The P2O5 content had tended to decrease with years. The OM values of cucumber and tomato were higher than those of pepper and water melon, whereas the contents of P2O5 were also insufficient in all crops. Based on principal component analysis, EC was significantly correlated with exchangeable cations, K, Ca and Mg from greenhouse soils in Ganghwa. In order to promote soil fertility of greenhouse in Ganghwa, it is necessary to apply phosphate fertilizer and manage soil nutrients based on the soil tests and analyses. Pearson correlation coefficient matrix comparing paired chemical properties of greenhouse soils in Ganghwa.