旱田土壤中尿素肥料之轉化

Abstract

本研究探討旱田狀態下尿素及裹硫尿素在土壤中之水解及轉化情形。 供試土壤為臺北砂頁岩質沖積土（低鹽基淡色弱育土，Dystrochrepts），pH6.1（原pH為4.0，試驗前施用碳酸鈣將其提高為6.1)，及彰化粘板岩質沖積土（簡育浸水弱育土，Haplaquepts), pH7.4。兩種土壤之質地，均屬份質壤土。The Patterns of urea transformation in soils under upland condition were studied in laboratory. The soils studied were: (1) an acidic Taipei sandstone and shale alluvial soil (Dystrochrepts) with pH 4.0 (the pH, however, was adjusted to 6.1 by CaCO3 before the experiment), and (2) a calcareous Changhua slate alluvial soil (Haplaquepts) with pH 7.4. Ninety grams each of soils placed in 100 CC-beaker was applied, respectively with different rates of nitrogen (corresponding to 0, 30, 60 and l50mg/l00g soil) in the forms of urea and sulfur coated urea, mixed thoroughly and incubated under 30℃. The soil moisture was kept at Ca. 50% of the saturation capacities of soils.