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Effects of amendment application on the amelioration of profile acidity and potassium availability in a strongly acidic soil
|作者:||鄭麗蓉||關鍵字:||amendment;改良質材;profile acidity;potassium availability;剖面酸性;鉀有效性||出版社:||土壤環境科學系||摘要:||
本研究以管柱分層方式模擬強酸性之關西土壤剖面。先將表層0 ~ 10 cm土壤添加200 mg K kg-1的氯化鉀，培育7天後再分別施用質材於土壤0 ~ 10 cm (A)及/或20 ~ 30 cm(B)深處且予以混合，包括施用石膏之G(A)和G(B)、禽畜糞堆肥〔C(A)〕、檸檬酸鈣〔Ca-citrate(A)〕及石膏與禽畜糞堆肥混合施用〔G(A)+C(A)與G(B)+C(A)〕之處理，各處理之質材添加量係以提供相同鈣量為基準，並設一對照組(Check)。模擬台灣一年降雨量(扣除蒸發散及表面逕流量)約2500 mm下，以去離子水加入土柱中且於120個淋洗天完成，並於不同時間測定淋洗液之pH、EC、全氮、鈣、鎂、鉀及鈉濃度。待淋洗完成並靜置7天後，將土壤管柱內土壤由上而下依序分層( 10cm / 層)取出，將土壤風乾、磨碎、過篩後，測定各處理各土層土壤之pH、土壤中Bray—1磷、交換性鈣、鎂、鈉、鋁和易利用態鉀與非交換性鉀，及陰離子(Cl-、NO2-、NO3-及SO42-)的含量。
結果顯示，含鈣之改良質材在降低剖面交換性鋁及增進交換性鈣的效果與其所伴隨之陰離子有關。整體土壤剖面交換性鋁含量的降低效應，以石膏施於20 ~ 30 cm之處理較為顯著，但其對土壤pH卻無提昇之效果且造成剖面易利用態鉀和交換性鎂含量的下降。禽畜糞堆肥含鹽基陽離子，故在剖面酸性改良和土壤交換性陽離子的增進效果比石膏和檸檬酸鈣者佳，而禽畜糞堆肥施於0 ~ 10 cm配合石膏施於20 ~ 30 cm之混合處理，其改良深度及程度為所有處理中最佳者。檸檬酸鈣雖可顯著提昇剖面0 ~ 80 cm土壤之交換性鈣及降低0 ~ 30 cm土壤之交換性鋁含量，惟其成本較高，若於田間大量施用並不經濟。結果亦顯示，改良質材之添加具有促進非交換性鉀的釋出而增加土壤鉀有效性的功效，唯其效果受剖面各層中交換性鈣和鋁含量增減之影響。本試驗結果建議選擇在改良質材時，可考慮作物及改良深度之需求，而推薦選用不同改良質材之組合或將石膏深施。
Strongly acid soil (pH<5.5) is one of the major arable soils in Taiwan, however, the problems of subsoil acidity and low calcium availability often limits the root growth of plants. The objectives of this study was to evaluate the effects of the of amendments combination and application depth on the profile acidity and the availabilities of cations, especially for potassium (K) of an acid soil, in order to establish a suitable practice for both profile acidity amelioration and K fertilization.
A strongly acidic Huan-Si soil with similar properties along the profile was selected to conduct a column leaching experiment. The way of column packed was to simulate the soil profile of Huan-Si soil. 200 mg K kg-1 potassium chloride was mixed with the top 10cm soil of each column and incubated for 7 days, then different amendments was mixed with 0 ~ 10 cm (A) and / or 20 ~30 cm soil separately, the treatments including gypsum 〔G(A) and G(B)〕, compost 〔C(A)〕, mixed gypsum and compost〔G(A)+G(A) and G(B)+C(A)〕, and calcium citrate〔Ca-citrate (A)〕addition. The amount of amendment in each treatment was conducted to provide the same amount of Ca, and a black treatment (Check) was also done. Deion-water approximately 2500 mm was adding for simulating the amount of one-year rainfall (subtracted the amounts from evapotranspiration and runoff ) in Taiwan, through 120 leaching days, and some items of the leachate (pH, EC, N, Ca, Mg, K, and Na) at different incubation time were determined. After the leaching experiment and standing for 7 days, the soil column divided into 10 cm section and then be taken out. After air-dried, milled, and meshed, some properties of the soil were determined, including pH, the contents of Bray — 1 P, exchangeable Ca, Mg, Na, and Al, readily available K, non-exchangeable K, and anions (Cl-, NO2-, NO3-, and SO42-).
The results showed that the effects of added amendments containing calcium on reducing exchangeable Al and increasing exchangeable Ca in the soil profile were related to their containing anions. The treatment with gypsum applied in 20 ~ 30cm depth was more significant in reducing the contents of exchangeable Al, readily available K and exchangeable Mg, but there was no effect on the change of soil pH. Animal compost containing base cations was found to have higher ability in correcting the profile acidity and increasing exchangeable cations than those of gypsum and citrate calcium treatments. In addition, the treatment that animal compost applied in the soil of 0 ~ 10 cm depth combined with gypsum applied in the soil of 20 ~ 30 cm depth was better than other treatments based on corrected the depth and the degree of amelioration. Results also indicated that all treatments with amendment had abilities in releasing non-exchangeable K and increasing potassium availability, however, the effect was affected by the changed contents of exchangeable Ca and Al along soil profile. The calcium citrate addition increased the content of exchangeable Ca down to 80 cm depth and decreased the content of exchangeable Al down to the 30 cm depth of the soil profile significantly, but it was not suitable to be used in the field due to its high cost.
Out results suggest that the choice of amendments should consider the requirement of the crop and the ameliorated depth of soil, and combination application of different amendments or deeper application of gypsum could be recommended.
Keyword：amendment, profile acidity, potassium availability.
|Appears in Collections:||土壤環境科學系|
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