Effects of Integrated Soil Amelioration Techniques to Mature Newly Established Research Fields

Abstract

The Rural Development Administration moved to Jeonju for the balanced development of the land. This situation required establishment of new research fields with soils appropriate to cultivation. We applied a variety of amelioration techniques to mature soils of new research fields of the National Institute of Agricultural Science (NAS) and evaluated effects of the integrated amelioration techniques. The schedule of amelioration was following: 1) location of research fields was determined, 2) surface and subsoil samples were collected separately, 3) after aligning the top level of research fields, subsoil and surface soil were re-established with soil amendment, 4) the green manure crops were grown four seasons to improve the uniformity and increase the organic content of the research field, and 5) drainage canal and/or underdrainage were applied to poorly drained fields. The last green manure crop was rape in RDA fields and green barley in NAS fields. The average height, fresh weight, and dry matter weight of rape in good condition were 123 cm, <TEX>$3,938kg\;10a^{-1}$</TEX>, and <TEX>$651kg\;10a^{-1}$</TEX>, respectively. The height, fresh weight, and dry matter of green barley, on average, were 97 cm, <TEX>$3,013kg\;10a^{-1}$</TEX>, and <TEX>$1,004kg\;10a^{-1}$</TEX>, respectively. In the chemical properties of paddy field, pH and levels of silicate, calcium, magnesium, and potassium were in appropriate range but organic matter content of <TEX>$16g\;kg^{-1}$</TEX> was less than the optimum level. In the chemical properties of upland field, pH and levels of phosphorus, calcium, magnesium, and potassium were appropriate range but organic matter content of <TEX>$12g\;kg^{-1}$</TEX> was less than the optimum range. Evaluation of well-adapted soil was performed. The field in RDA was classified into the superior class with points ranging from 90 to 95 by the field evaluation test. The fields in NAS were mainly evaluated as the superior class with points greater than 85. However, some fields in NAS remained low quality with scores between 80 and 83. Further soil amelioration practices were suggested to fields with low soil quality.