- 期刊
土壤水分境況對土壤鉀型態及鉀有效性的影響
Effects of Soil Moisture Regime on the Forms and Availability of Potassium in Soils
摘要
在一般的田間狀態下，土壤的水分境況並非恆定而為變動的。瞭解土壤水分的變動對土壤中鉀行為之影響，有助於研擬鉀肥之施用對策，本研究之目的即在探討土壤水分境況與濕乾效應對土壤鉀行為之影響。本試驗取用強酸性之大肚山土壤，以及石灰性之鹿港土壤，在添加鉀肥（150Ing/kg）及不添加鉀肥的情況下，於25℃及不同水分含量下，分別以濕土培育及濕乾交替培育各三週；其中大肚山土壤設為在-33 kPa水勢能之水分含量的100%及150%兩處理，而鹿港土壤則分別設為在-33 kPa 水勢能之水分含量的60%、100%和150%下。培育後，測定各處理土壤之溶液鉀，交換性鉀與非交換性鉀含量，並探討各型態鉀之消長情形。結果顯示，施鉀肥於強酸性大肚山土壤且在-33 kPa 水勢能水分含量的100%和150%培育下者，均會增加易利用態鉀含量及降低緩利用態鉀含量，而後者可釋出較多的非交換性鉀量。對石灰性鹿港土壤而言，在三種水分含量培育下，各型態鉀含量皆有增加的趨勢。在濕乾交替之處理下，三次的風乾作用使強酸性大肚山土壤的非交換性鉀釋放量減少，但對石灰性鹿港土壤而言，則出現鉀含量降低和交換性鉀含量增加的現象。試驗結果顯示，兩種供試土壤在不同水分境況下之土壤鉀行為的改變與其所含黏土礦物的種類有關。
並列摘要
Under general field conditions, the status of soil moisture regimes are variable. To investigate the changes of the forms and availability of potassium (K) affected by moisture regime will be useful to develop the suitable management of potassium fertilization. The purposes of this research were to study the effects of soil moisture regime and drying and/or wetting on the behaviors of potassium in two soils varied with soil properties. A strongly acid soil (Da-Du Shan) and a calcareous soil (Lugang) were sampled, followed by addition of K (150 mg K/kg) or none, and then incubated with different moisture conditions (Da-Du Shan:100% and 150% of the water content at -33 kPa water potential; Lugang: 60%, 100%, and 150% of the water content at -33 kPa water potential) under wetting-drying and continuous wetting incubations for three weeks at 25 °C. After the incubations, the contents of solution K, exchangeable K, and nonexchangeable K were measured, then the transformation of K forms in the soils of each treatment were investigated. Results showed that the amount of readily available K increased and the amount of slowly available K decreased after strongly acidic Da-Du Shan soil was applied with KCI and incubated attwo levels (100% and 150%) of water content at -33 kPa water potential. However, three forms of K all increased for calcareous Lugang soil under the same conditions of incubation. Under the wetting-drying incubation, three times of air-dry processes all reduced the released amount of nonexchangeable K in Da-Du Shan soil, and the contents of soluble K were increased and the contents of exchangeable K in Lugang soil were reduced. It indicated that the the change of K behavior under different water regimes seemed to be related to the kinds of clay minerals contained in the soils.