Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/27356
標題: 台灣代表性土壤粘粒之表面電荷對層間銨離子固定之影響
Effects of Surface Charge of Taiwan Representative Soil Clays on Interlayering Ammonium Fixation
作者: 陳鴻基
Chen, Horng-Ji
關鍵字: Ammonium fixation;銨固定;Clay mineral;Surface charge;粘土礦物;表面電荷
出版社: 土壤學系
摘要: 
氮素是作物生長所需的重要元素,土壤對銨的吸附、固定與釋放為影
響土壤氮素供應能力之重要因素。氮素能以固定態銨離子的方式儲存在土
壤中,以供作物生長時持續性地吸收與利用。同時由於土壤對銨離子的固
定,間接上也減少銨離子的硝化,減少因硝酸根、亞硝酸根的多量累積所
造成的土壤環境污染問題。因此無論從理論上或農業應用上而言,土壤對
銨離子的固定有其重要的研究背景存在。針對粘土礦物導源四面體層與八
面體層之層面電荷、淨表面負電荷、二八面體與三八面體構造之粘土礦物
的層面電荷非均勻性與銨離子交換選擇性等特性上的不同,研究其在台灣
西部耕地主要土類土壤對銨固定上的影響與銨固定機構上的探討。以3 M
LiCl 飽和後300℃加溫處理來中和掉膨脹性粘土礦物中的八面體層電荷,
比較四面體層電荷與八面體層電荷對銨固定量上的差異。試驗結果得知所
有試驗土壤粘粒均會因處理而減少對銨離子的固定,其中以二林系因八面
體層電荷被中和掉使銨固定量減少的百分率最大(94.4%);而以中壇系銨
固定量減少的百分率為最小(40.0%)。顯示大部分試驗土壤粘粒層面電荷
對銨離子的固定以八面體層電荷為主。由X-射線繞射圖亦能說明鋰飽和加
溫處理在台灣主要土類土壤粘粒八面體層電荷上中和的效應。土壤粘粒表
面膠結物質的存在明顯影響土壤粘粒層面電荷對銨離子的固定量。以Na與
Cl離子吸附方法測定不同pH下土壤粘粒的表面電荷,探討PZNC(Point of
Zero Net Charge)、PZNC時的負電荷與pH9時的淨負電荷量與銨固定間的
關係。試驗結果得知所有試驗土壤粘粒的淨零電荷點(PZNC)範圍是3.3
∼5.9,其會隨土壤粘粒中蒙特石含量之增加而降低,而隨游離氧化鐵含
量之增加而增加。試驗土壤粘粒在PZNC時的負電荷量範圍是-3.6∼-7.0
cmol/kg。當有土壤膠結物存在時,四面體層電荷所固定的銨量(NH)會隨
著高嶺石類含量的增加而降低。在pH9時的淨負電荷量範圍是-6.4∼-28.4
cmol/kg,此部份可變性電荷量與高嶺石類含量及游離氧化鋁含量間的關
係較為密切。NH隨pH9時的淨負電荷量之增加而減少的趨勢較為明顯,顯
示高嶺石與膠結物上的可變性電荷會減少層間有效固定位置對銨離子的固
定。以固定有銨離子之土壤粘粒經不同溫度處理後,利用傅立葉轉換紅外
線光譜儀(FTIR)照射,探討層面電荷非均勻性在銨固定上的影響。試驗結
果指出崁子頭系、五魁寮系(13)、善化系等,其波數在3450 cm 處的吸收
帶強度隨溫度升高而減弱的情形較為明顯,其土壤粘粒層面電荷性的非均
勻性較大,其導源於四面體層電荷所固定的銨量較高;而二林系波數
在3450 cm處的吸收帶隨溫度升高而強度減弱的變化不大,其對銨離子固
定的層面電荷較為均勻性,其導源於四面體層電荷所固定的銨量較低。由
FTIR圖譜也顯示層面電荷非均勻性愈大者,其對銨離子固定的穩固性愈低
;層面電荷均勻性愈大者,其對銨離子固定的穩固性愈大。以伏安儀還原
電流技術探討固定性銨的釋出與層面電荷非均勻性間的關係,並利用X-射
線繞射技術鑑定土壤粘粒中礦物晶性的變化。試驗結果証實固定性銨的釋
出與前面利用FTIR技術所測得的釋放潛勢相符合。此可由崁子頭系、五魁
寮系(13)與善化系土壤粘粒導源於四面體層電荷所固定的銨離子量是試驗
土系中較高者,其在FTIR圖譜中波數在3450 cm-1 處的吸收帶隨溫度升高
而強度減弱上的改變也較明顯,其層面電荷的非均勻性較大,這些土系土
壤粘粒中固定性銨所釋出的銨量是所有土系中較高者得知。固定性銨的釋
放並非取決於總固定性銨量的多寡,固定性銨的釋放量與四面體層電荷所
固定的銨量間之相關性較為明顯。大部份試驗土壤粘粒中固定性銨的釋放
量有隨四面體層電荷所固定銨量在加入固定性銨量上的比率之增加而增大
。所有試驗土壤粘粒中所含主要粘土礦物種類的晶性並未因還原電流處理
而使晶體破壞或晶性發生改變,固定性銨離子的釋出確由固定在膨脹性粘
土礦物層間的銨離子所釋出。以不同銨離子濃度吸附法求取銨離子之Q/I
圖,以探討銨離子交換選擇性與銨固定間的關係。試驗結果指出大部份試
驗土壤之Gapon 選擇性係數(KG)隨蒙特石含量的增加而降低,且KG值大小
多少也受高嶺石類礦物含量所影響。當雲母類、蛭石類與高嶺石類整體含
量上較為優勢時,則銨鈣活度比(AR)較低,顯示銨離子在層狀矽酸鹽礦物
邊緣位置的機率會較大。加入固定銨量隨AR之增加而增加,表示銨離子在
層狀矽酸鹽礦物的層面上的量愈多則加入固定銨量愈大。當AR大時非特殊
吸附基上的銨量(-NH)會較大,顯示層狀矽酸鹽礦物層面位置上的銨離子
愈多,則土壤粘粒表面非特殊性吸附基上的銨離子量會較多。鉀離子的存
在會使KG值有減少的趨勢。以AR>AR顯示鉀離子在邊緣位置的吸附會減少
銨離子在邊緣位置的量而增加其在層面位置的量。-NH<-NH也顯示有鉀
離子存在會使土壤粘粒表面非特殊性吸附基上的銨離子量增加。以上試驗
結果期望能作為未來從事於台灣耕地主要土類土壤對氮素的儲存與供應能
力、土壤中之銨離子動態,以及減少銨離子硝化,降低因硝酸根、亞硝酸
根累積所造成的土壤環境污染等研究的一個無機礦物背景之理論基礎。同
時,也希望由此結果更能夠強調氮肥適地、適時及適量施用,以達到土壤
永續肥力的觀念。

Nitrogen is an important element of nutrition for crop
growing.Adsorption, fixation, and release of ammonium on the
soil are im-portant factors affecting the supplying ability of
soil nitrogen.Cropcan continually uptake and use the nitrogen
fixed by soilduring the growth. Simultaneously, the
nitrification of ammoniumdecrease indirectly because the
ammonium is fixed by soil, andreduce the extent of pollution in
the soil environment due to thereduce of large accumulation of
NO and NO. Therefore fromwhether the viewpoint of theory or
agricultural application, thathas an importantstudying
background for ammonium fixation ofsoils.Based on the difference
of layer charge derived from tetra-hedral or octahedral layer of
clay minerals, net negative surfacecharge, heterogeneous layer
charge of dioctahedral and trioctahedral clay minerals, and
exchangeable selectivity of ammonium, we studythe ammonium
fixation and mechanism of main soil groups of cultivatedland in
western Taiwan. A reduction in octahedral charge of swelling
clay minerals wasobserved after treatment with 3 M LiCl and
heating at 300℃ tocompare the difference between ammonium
fixation of tetrahedral andoctahedral layer charge. The
experimental results indicated thatamounts of ammonium fixation
of twelve soil clay representing Taiwan''s cultivated land were
reduced after treatment with 3 M LiCl andheating. The largest
percentage of reduction was 94.4% for Erhlinseries; The
smallest percentage of reduction was 40.0% for Chungtanseries.
This suggested that ammonium fixation is affected apparentlyby
octahedral layer charge of layer charge in twelve soil clay.The
octahedral layer charge of Taiwan''s soil clays was
neutralizedafter treatment with 3 M LiCl and heating at 300℃
that were inagreement with X-ray diffraction analysis.The
ammonium fixation on clay mineral surface was also affected by
cemented materialssuch as carbonates, organic matter, and free
iron oxides.To studythe relationships between ammonium fixation
and PZNC(Point of ZeroNet Charge), negative charge at PZNC, and
net nega-tive charge at pH 9 with adsorptive method of Na and Cl
withdifferent pH. The results showed that the range of PZNC of
allsoil clays was 3.3∼5.9, that decreased with increase of
montmori-llonite content and increased with increase of free
iron oxidescontent. The range of negative charge at PZNC was
-3.6∼-7.0 cmol/kg. When soil cemented materials existed, the
ammonium were fixedby tetrahedral layer charge(NH) decreased
with increaseof kaolins content. The range ofnet negative charge
at pH9 was-6.4∼-28.4 cmol/kg, thathad apparent relationships
with contentof kaolins and free aluminum oxides. NH apparently
decreasedwith increase of net negative charge at pH 9. It showed
that vari-able charge of kaolins and cemented materials
decreased ammoniumfixation of interlayer on effective fixed
sites. To study the effects of heterogeneous layer charge on
ammoniumfixation with FTIR(fourier transform infrared)
photometer to scansoil clay with fixed ammonium after treatment
of different temper-ature. The results indicated that decreasing
variation of band at3450 cm with the increase of temperature was
remarkable forKantsetou series, Wukueiliao(13) series, and
Shanhua series, theheterogeneity of layer charge was larger for
these soilclay, andfixed amounts of ammonium derived from
tetrahedral layer chargewere higher. Whereas, the decreasing
variation of band at3450cm with the increase of temperature was
not remarkable forErhlin series, that indicated the homogeneity
of layer charge onthe ammonium fixation, and amounts of fixed
ammonium derived fromtetrahedral layer charge were lower.The
FTIR spectra indicatedthat heterogeneityof layer charge was
larger, and the stabilityof fixed ammonium was lower; The
homogeneity of layer charge waslarger, and the stability of
fixed ammonium was higher.To study the relationships between
release of fixed ammoniumand heterogeneous layer charge with the
technique of voltammetry''sreductive current, and to identify
crystal character of mineralsin soil clay with thetechnique of
X-ray diffraction. Experimentalresults verified that release of
fixed ammonium agreed with thepotential of release was
determined byFTIR technique. It could beknown by amounts of
fixed ammonium derived from tetrahedral layercharge were higher
and decreasing variation of bandat 3450 cmwith the increase of
temperature was remarkable and the heteroge-neity of layer
charge was larger and released amounts of fixedammonium were
higher for Kantsetou series, Wukueiliao(13) series,and Shanhua
series. Released amounts of fixed ammonium did notincrease with
total amounts of fixed ammonium increased, and therelationships
was significant between released amounts of fixedammonium and
ammonium fixed by tetrahedral layer charge. Releasedamounts of
fixed ammonium in most experimental soil clay increasedwith the
ratio of ammonium fixedby tetrahedral layer charge/addedfixed
ammonium increased. Crytal character of main clay mineralsin all
experimental soil clay didn''t change due to the treatmentof
reductive current, and release of fixed ammonium really comefrom
release of interlayer''s ammonium in swelling clay minerals.
To study the relationships between exchangeable selectivityof
ammonium and ammonium fixation with Q/I diagram of
ammoniumobtained by adsorptive method of different concentration
of ammo-nium. The results indicated that Gapon exchangeable
selectivityconstant(KG) decreased with of montmorillonite''s
content in-creased for most experimental soils, and KG was
somewhat affectedby kaolins''s content. When whole content of
mica, vermiculite andkaolins were dominant, ratio of ammonium
activity and calciumactivity(AR) was lower. It indicated that
ammonium had mostopportunity to appear on edges of layer
silicates. Added fixedammonium increased with AR increased,
showed that amounts ofammonium on layer surface of layer
silicates were larger, andadded fixed ammonium were larger. When
AR was larger, amountsof ammonium on nonspecific adsorptive
sites(-NH) were larger.It also showed that ammonium on layer
surface of layer silicateswere larger,then amounts of ammonium
on nonspecific adsorptivesites were larger. KG was lower when
potassium existed. AR>AR showed that potassium adsorbed on
edgesdecreased ammonium ofedges and increased ammonium of layer
surface. -NH<-NHalso indicated that ammonium of nonspecific
adsorptive sites onsurface of soil clay increased when potassium
existed. The results were expected to be a basic background
of inorga-nic minerals for studying store and applying ability
of soil ni-trogen, ammonium dynamic in soil, and decrease of
ammonium nitri-fication to reduce the extent of pollution in
soil environment dueto accumulation of NO and NO.
Simultaneously, the results werealsoexpected to emphasize the
concept of proper applying nitrogenfertilizer with suitable
amounts to a suitable land in a suitabletime and attaining
perpetual soil fertility.
URI: http://hdl.handle.net/11455/27356
Appears in Collections:土壤環境科學系

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