Effect of Deep Ploughing with a Spading Machine and an Excavator on Improvement of Physical Properties in the Highland Applied Saprolite

Abstract

In highland crop fields, saprolite is piled up approximately every three years as deep much as 20 to 30 cm because farmers expect that adding new materials may improve productivity and mitigate hazards by continuous cultivation of a single crop. Piling saprolite, however, has been reported to induce poor soil drainage. Effects of deep ploughing with a spading machine and an excavator were studied in sites located in Daekwanryeong-myeon, Pyeongchang in which soil physical properties were deteriorated by piled saprolite. The soil made of parent material of Samgag series was piled up over surface soil of Haggog series naturally developed in the area. Carrot was cultivated in the field. Productivity and growth factors of carrot were compared among control and deep ploughing by a spading machine and an excavator. Effective soil depth extended to 60 cm or greater by 60 cm deep ploughing by an excavator or 50 cm deep ploughing by a spading machine. On the other hand, effective soil depth was within 50 cm at control plot. Productivity of carrot responded to amelioration of soil physical properties. The productivity was greater in deep ploughing treatments than that of control or 30 cm ploughing. It suggested that increased productivity by deep ploughing was mainly related to breaking plough pan which inhibited extension of rooting zone.

Difference in Soil Biogeochemical Properties of Agricultural Highland by Topographical Characteristic and Soil Management

“…유기물과 관련성이 높은 T-N 역시 이와 비슷하게 해안분지와 대관령이 0.12%로 가장 낮은 수치를 보였다. 대관령과 해안분지의 유기물이 낮은 것은 유실된 표토를 대체하기 위해 sand 함량 이 많고 유기물이 매우 낮은 모재토 (c horizons)인 석비레를 성토하였기 때문이며, 석비레를 성토한 토양의 유기물 함 량은 일반 농경지보다 낮다는 선행 연구결과와 유사한 결과를 보였다(Park et al, 2004;Zhang et al, 2015). 이와 반 대로 산 정상 부근에 위치한 나머지 재배 지역들은 지리적 특성상 대규모 토목 작업이 어려워 자갈이 많이 존재하는 해안분지만 71.7 mg kg -1 로 가장 낮았다.…”