Korean Journal of Soil Science and Fertilizer ISSN:0367-6315(Print) 2288-2162(Online) 한국토양비료학회 학회지

The chemical properties of upland fields in Gyeonggi province were monitored every 4 years from 2001 to 2017 in order to provide basic information for soil fertility management of upland fields. In 2017, the soil chemical properties of upland fields were 6.3 in pH, 22 g kg^-1 in organic matter (OM), and 651 mg kg^-1 in available phosphate (Avail. P₂O₅). Exchangeable (Exch.) potassium (K), calcium (Ca) and magnesium (Mg) were 0.83, 6.2 and 1.7 cmol_c kg^-1, respectively, and electrical conductivity (EC) was 0.86 dS m^-1. In the long-term analysis, the contents of OM, Exch. Ca and pH of upland soils showed increasing tendency. However, the contents of Avail. P₂O₅ tended to decrease, and there were no significant changes in the contents of Exch. K and EC. The optimal range of pH of upland fields changed to 45% in 2001, 48% in 2005, 53% in 2009, 51% in 2013 and 47% in 2017. The optimal range of OM was 41% in 2001 and 2005, 40% in 2009, 33% in 2013, and 43% in 2017, respectively. The optimal range of Avail. P₂O₅ content increased from 19% in 2001 to 23% in 2005, but decreased to 15% in 2009 and increased to 22-23% in 2013 and 2017. The optimal range of Exch. K tended to decrease, showing 26% in 2001, 26% in 2005, 23% in 2009, 20% in 2013 and 19% in 2017. Therefore, in order to maintain the soil chemical properties of the upland soil in an appropriate range, it is necessary to fertilize the lime and fertilizer by the soil test. Also soil management such as the cultivation of green manure crop or application of rice straw and compost will be necessary to increase the organic matter content of upland soil.

The Frequency distribution of excess, optimal and deficient ranges of chemical properties of upland soils in Gyeonggi province (n=190).