The Nutrient Dynamics of the Suhu Coastal Casuarina Stands

中文摘要 本研究以台灣省林業試驗所四湖海岸林工作站轄內木麻黃人工林為對象，調查林地土壤的養分聚積量、微生物氮量、土壤微生物分布數量及硝化細菌數，並估算木麻黃林分之生物量、淨初生長量及養分吸收量，以及調查降水和枯落物之養分回歸特性，探討海岸林生態系養分條件對生長所造成的影響。 四湖木麻黃林隨著齡級生長，地表枯枝落葉堆積量逐漸增多，地表有機物分解過程中所產生腐質酸及黃酸等，會導致表層土壤pH值降低，而下層土壤則受含鹽量高之地下水影響而呈鹼性反應，且pH(H2O)與pH(KCl)的差異極小。礦質土層之可交換性陽離子，以鈣的鹽基飽和度最高，且由於過低的K+/Ca2+ 比，恐會造成土壤K+, Ca2+, Mg2+間的不平衡，影響幼齡木對鉀離子的吸收利用。 微生物氮量為微生物總數之定量指標，其主要分佈在木麻黃林地表層，隨著土壤深度增加而減少，但隨著林齡逐漸增長而增多。9年生林分之微生物氮量雖較3年生為多，但其數量仍遠較一般森林土壤平均低。砂地土壤有機質受微生物活動的影響，其所生成的無機化氮量對全氮的比例則較其他土壤為高。異營性土壤微生物的細菌數量雖以表層較多，但其值如微生物氮量一樣，仍較一般林地土壤低；而自營性之銨氧化菌及亞硝酸氧化菌則以9年生林分較3年生多，而且相對地較溫帶林土壤高出許多，木麻黃林地土壤在高溫及高濕條件下，礦質土壤表層的硝化作用極為旺盛。 本地區木麻黃林木主根分布主要在30-40 cm深以內，根系的生長因受地下水位較高的影響，而呈水平狀伸展。木麻黃林分葉（木麻黃真正的葉退化成小鱗片狀，圍繞於小枝節上。本文所稱之葉，嚴格應稱為接合小枝，branchlets，以下皆同）生物量隨著林齡增大而明顯增多，9年生林分葉量可達7.4 ton/ha。葉量空間分布方面，3年生從1 m高處起即有分布，而9年生在6 m高以下則幾無葉分布，可見9年生林分冠層受鬱閉影響，林冠下層枝葉因光照不足而逐漸枯死。 木麻黃林分葉、枝條、幹、根之合計生物量乾重，3年生1號及23號種源林分各為30.9及38.7 ton/ha，而9年生林分則為119.3 ton/ha，其年平均生物量生產則為10-13 ton/ha。3年生林分葉量占總生物量的比例各為10.5％及12.4％，而9年生則僅為6.2％，致使9年生林分因行光合作用之葉量比例減低，而降低其生長速度。3年生林分的年生物量增長量為24.4及18.5 ton/ha，而9年生則因下層劣勢木枯死太多，致生物量呈現負成長，不同齡級木麻黃林分葉量分布及其生物量聚積速率已明顯不同。 四湖地區乾季之月平均降水量為38.7 ㎜，而濕季則高達489 ㎜。四湖木麻黃林分全年幹流水及穿落水各為林外雨量之4.1%及78.2%，穿落水對木麻黃林養分輸入貢獻極大。降水的pH值隨著降水量增加而降低，幹流水因淋洗較多樹體所堆積的有機酸，其pH值明顯較穿落水低。降水之懸浮質、電導度及各種陰陽離子濃度，乾季亦較濕季高出極多，顯示四湖木麻黃林內降水所淋洗的落塵量極高；同時，9年生林木由於樹體高大，藉由降水輸入林內的鈉及氯量亦較3年生林分高。 木麻黃林分幹流水及穿落水合計之鉀、鈣、鎂及鈉量分別為27.7-39.9, 25.2-49.4, 20.9-40.9及128.4-231.5 ㎏/ha/yr，銨態氮及硝酸態氮各為28.2-58.0, 33.6-67.2 ㎏ ha-1，氯及硫酸根各為215.7-407.3, 57.8-113.1 ㎏/ha/yr，此為貧瘠砂地林木生長的重要養分來源。 四湖木麻黃林的枯落物量為8.4-11.5 ton/ha/yr，其中葉占87.5-93.6%，枝條占4.6-6.2%，枯落繁殖器官佔1.8-6.3%，總枯落物量中明顯以枯落葉居多，類似於常綠闊葉林之春季枯落型。各部位枯落物之氮、磷、及鈣濃度的季節性變化，大致呈現雙高峰型，而鉀、鎂、鈉濃度則大致與其相反。 3年生木麻黃林之淨初生長量為20.2及37.5 ton/ha，而9年生林分則僅6.5 ton/ha，各林分之淨初生長量中皆以枯落葉所佔的比重最高。由於3年生林分之生物量增長量較枯落物量高，而9年生林分則正好相反，顯示3年生林分尚在幼齡快速生長期，而9年生林分則已達壯齡期，整個林分的增長量與枯死量逐漸相等，林分的成長已趨衰退。 3年生木麻黃林分之淨生產效率（net production efficiency）為6.22及7.81 kg/kg，遠高於9年生林分之0.91 kg/kg，顯示二齡級之林分受到干擾後，所需恢復時間差異很大；相對地，3年生林分之生物量聚積比為1.03及1.53，遠低於9年生林分之17.81；不同齡級林分有機物的輪迴時間也大不相同，3年生僅需1.4-2.1年而已，而9年生則需19.2年，本研究之9年生木麻黃林之有機物循環形態已和3年生林分不同。Summary The objectives of this study were to investigate the soil properties, microbial biomass, nutrient accumulation, standing biomass, net primary production, and nutrient return by litterfall and precipitation of Casuarina stands in the Suhu coastal area, Yunlin County, southwestern Taiwan. The mechanism of nutrient dynamics of these stands, between the 3 and 9-yr-old stage, and the influence of the growth rate by nutrient cycling in each stand were also investigated. Acidity of the surface soil in the 9-yr-old stand was lower than in the 3-yr-old stands. This is because of the decomposition of the litterfall. However, soil in deeper layers influenced by salty ground water is more alkaline than surface soil. The C/N ratio of the soil in these 3 stands is less than 15, indicating that the decomposition rate of organic matter in the Casuarina stands is rapid. Microbial biomass N was mainly distributed in surface soil and decreased with increasing soil depth. It was abundant in the 9-yr-old stand, which was due to the large amount of organic material. Heterotrophic bacteria and nitrifying bacteria were also abundant in the 9-yr-old stand, indicating that vigorous nitrification was progressing. Branchlet biomass of the 9-yr-old stand was 7.4 ton/ha, and it increased with stand growth. The space distribution of Casuarina stands in 2 age classes was quite different; there were branchlet amounts at all tree height levels in the 3-yr-old stands, but there were branchlets below 6 m in height in the 9-yr-old stand. Biomass values of the 3-yr-old stands were 30.9 and 38.7 ton/ha, whereas that of the 9-yr-old stand was 119.3 ton/ha. The percentages of branchlet biomass to total biomass in the 3 stands were 10.5%, 12.4%, and 6.2%, which decreased with stand growth. There was obvious vigorous growth in the 3-yr-old stands, whereas the 9-yr-old stand was experiencing intense competition; the growth increment was offset by the wither amount, with the result that there was almost no additional increment in standing biomass or nutrient content. Dry and wet seasons were divided according to the monthly rainfall during June 1997 to May 1998 on the Suhu coast. In the dry season (October to May), average monthly rainfall was only 38.7 ㎜, while in the wet season (June to September), it was 489 ㎜. Acidity (pH) of stemflow and throughfall solutions decreased as total rainfall increased, and obviously lower pH values in stemflow solution indicated the leaching of greater amounts of hydrogen ions. Suspended solids and conductivity of these 2 solutions in the dry season were about 10-20 times greater than those in the wet season. Moreover, values of these 2 solutions were 5 to 16 times in the dry season and 4 to 11 times in the wet season each greater than that of rainfall collected outside of stands. Concentrations of ions of sodium, potassium, calcium, magnesium, ammonia, or from nitrate nitrogen, chloride, or sulphate acid were greater in the dry than wet season. These ion concentrations of stemflow solution were greater than those of the throughfall solution in the dry season, but opposite results were observed in the wet season. Most ion amounts were similar between the two ages of stands during the study period. Only sodium and chloride were significantly greater in the 9-yr-old stand than in the 3-yr-old stands, indicating that more salt blown from the sea had adhered to the larger surface area of older trees, while concentrations of other ions produced from both ages of stands were not much different. The amount of nutrient input from throughfall within a year was much greater than that from either stemflow or rainfall outside of stands. The average inputs of different ions through precipitation from the 3 stands were 128.4-231.5 kg/ha/yr for sodium, 27.7-39.9 kg for potassium, 25.2-49.4 kg for calcium, 20.9-40.9 kg for magnesium, 28.2-58.0 kg for ammonium-nitrogen, 33.6-67.2 kg for nitrate-nitrogen, 215.7-407.3 kg for chloride, and 57.8-113.1 kg/ha/yr for sulphate. These high nutrient inputs from precipitation are obviously important to Casuarina stands growing on coastal sandy soils. Annual amounts of litterfall in the 3 Casuarina plantations ranged from 8.4 to 11.5 ton/ha, which could be broken down into 87.5-93.6% branchlet litter, 4.6-6.2% branch litter, and 1.8-6.3% organic litter. High litterfall occurred in the months of April, May, and July, and the falling pattern of litter was the same as the spring falling type of evergreen deciduous forests. Seasonal variation in nitrogen and phosphorus concentrations of litterfall was the lowest during September to November, with bimodal peaks in about June or July and the following February. But the nutrient content curves for potassium, magnesium, and sodium of branch litter showed opposite patterns, with the highest values during November and December, and the lowest about April or May. Nutrient return amounts in the Casuarina stands were 123.5-198.0 for nitrogen, 5.0-8.3 for phosphorus, 19.8-44.2 for potassium, 64.5-85.1 for calcium, 54-10.6 for magnesium, and 17.6-33.0 kg ha-1 yr-1 for sodium. The amounts of nitrogen and sodium return by litterfall in the Suhu Casuarina stands were quite remarkable. The net primary productions of the 3-yr-old Casuarina stands were 20.2 and 37.5 ton/ha, but the 9-yr-old stand yielded only 6.5 ton/ha. Branchlet litter made up the highest proportion in the net primary production of each stand. Biomass increments were higher than the corresponding litterfall in the 3-yr-old stands, whereas the 9-yr-old stand showed the opposite. These data suggest that the 3-yr-old stands were still at a fast-growing stage, while growth in the 9-yr-old stand had slowed considerably, so that increments of the entire stand appeared to almost equal the wither amounts.封面 誌謝 目錄 表目錄 圖目錄 中文摘要 英文摘要 壹、前言 貳、前人研究 一、林分生長與土壤的變化 二、林分生物量與養分聚積 三、降水的養分輸入 四、枯落物回歸與養分循環 參、材料與方法 一、試驗地概況 二、試區設置與調查 肆、結果 一、林地之土壤性質 二、林分生物量與養分聚積量 三、林分降水的養分輸入量 四、林分枯落物回歸與養分循環 伍、討論 一、林地之土壤性質 二、林分生物量與養分聚積量 三、林分降水的養分輸入量 四、林分枯落物回歸與養分循環 五、綜合討論 陸、結論 柒、引用文獻 捌、附

臺中港區木麻黃天然更新之研究

Casuarina spp. is the major windbreak species used to afforest in coastal regions. They grow fast, but have short life and difficult to natural regenerate. In order to dispose of this problem, we set plots in large, medium, small gap and close s現今海岸造林樹種多以生長快速之木麻黃為主，但其有壽命短且不易天然下種更新之缺點，為瞭解此問題，本試驗於台中港北堤區木麻黃防風林內，依大、中、小孔隙及鬱閉林下設置樣區，藉由調查不同孔隙內種實雨、種子庫及微環境狀況，並觀察在干擾土壤與枯枝落葉層後之變化，以釐清木麻黃天然更新所需條件。結果顯示種子庫與種實雨於孔隙間累積情形相似，以大孔隙最少量，而鬱閉林下為最大量，其種實雨落下之種子量約250 seeds m-2 month-1；種實雨之種子的發芽率以播於溫室(約40%) 明顯高於孔隙地內(約

台北五股與台南龍崎綠竹林之林分結構與生物量

This study investigated the plantations of green bamboo (Bambusa oldhami) in Wugu, New Taipei and Longqi, Tainan. Results show that, the frequency of bamboo culms in both sites are the highest at 3~ 4 cm DBH class in Wugu, and at 5~ 6 cm DBH class in Longqi. The number of clumps and culms are 766 ± 153 clumps ha^(-1) and 4,800 ± 1,708 culms ha^(-1) in Wugu, and 700 ± 100 clumps ha^(-1) and 10,766 ± 1,159culms ha^(-1) in Longqi, respectively. The number of culms at 6 ± 2 culms clump^(-1) in Wugu is lower than the number of culms at 16 ± 8 culms clump^(-1) in Longqi. Following this, the average of diameter is significant different between two experimental sites. There are 3.3 ± 0.5 cm and 4.3 ± 1.1 cm respectively in the plantations of Wugu and Longqi. The average height of 11.8 ± 0.3 m in Wugu is the same as 11.7 ± 0.3 m in Longqi. Because of the amount of culms and clumps in the plantations of Wugu is lower, the aboveground biomass is lower than Longqi. The aboveground biomass in Wugu and Longqi are 15.6 ± 5.7 ton ha^(-1) and 54.5 ± 4.2 ton ha^(-1), respectively. The aboveground biomass at different ages are not significant differences between age 1 and age 2 in Wugu and in Longqi, but significant low at age 3 in Longqi only. The results indicate that Wugu's bamboo farmers prefer to cut down old bamboos which over age 3.本試驗調查台北五股與台南龍崎地區綠竹(Bambusa oldhami)林分之生長及生物量。綠竹林分生長分布特性方面，五股樣區之林分株數頻度以胸徑3 ~ 4 cm者佔最多，龍崎樣區則多分佈於5 ~ 6 cm；五股樣區之竹叢數及竹稈數分別為每公頃766 ± 153叢(clumps ha^(-1))、4,800 ± 1,708稈(culms ha^(-1))，竹叢數和龍崎樣區(每公頃700 ± 100叢)無顯著差異，但竹稈數低於龍崎樣區之10,766± 1,159稈(culms ha^(-1))；五股樣區之竹叢稈數為6 ± 2稈(culms clump^(-1))較龍崎樣區16 ± 8稈(culmsclump^(-1))少；林分生長性狀方面，兩試驗地之平均胸徑，五股與龍崎樣區分別為3.3 ± 0.5 cm、4.3± 1.1 cm；而五股樣區之平均竹高為11.8 ± 0.3 m，龍崎地區則為11.7 ± 0.3 m。地上部乾重方面，五股樣區因竹稈數低且竹叢稈數較數少，其地上部林分總生物量亦遠低於龍崎樣區；五股與龍崎樣區之總生物量乾重分別為15.6 ± 5.7 ton ha^(-1)、54.5 ± 4.2 ton ha^(-1)；其中五股及龍崎樣區各齡級之生長及生物量結果，1、2年生之總生物量無顯著差別，而龍崎樣區3年生竹齡之總生物量較低，顯示其與綠竹之經營栽培管理方式有關，五股筍農傾向將3年生以上之老竹伐除

飛砂移動機制之風洞試驗

This study was to explore the mechanism of Aeolian sand wind erosion. By the wind tunnel experiment, we tried to find out the Aeolian sand characteristics including density, diameter, texture, water content, shape etc. and the relationships between wind erosion amount and primary specific site characteristics of sand diameter, wind speed and water content. The study sites located at the near coast area around Houlong, Yuanli, Da-an and Da-jia in the central part of Taiwan. The densities were in the range of 2.62 and 2.67 g/cm^3 and the particle size distribution mainly ranged in 0.25-0.42 mm. Since the sand content was over 96% of all the samples, the soil texture was recognized as sandy soil by USDA soil classification. The water contents of all the samples were less than 1%: the highest highest observation of 0.967% in Houlong and the lowest one of 0.282% in Da-jia. After the shape analysis, Da-an sample was identified as sphere, Da-jia as flat shape and the others were between. According to the results of wind tunnel, the starting wind speeds of erosion in different diameters were as follows: 5.5-7.0 m/s of 0.15-0.84 mm and 5.0 m/s of <0.15 mm. Furthermore, when the water content below 1.22%, we had the maximum amount of wind erosion. The further study showed Aeolian wind erosion amount would be decreased from 1.22% to 1.84% and the minimum amount was exhibited of 1.84%. This study not only to demonstrate the severe wind erosion in the area but also concluded and identified several important mechanism characteristics of Aeolian sand erosion. We hope the knowledge and the research method could help our government to the urgent preventive contingency process of Aeolian wind erosion.本試驗為瞭解砂粒之移動機制，因而利用風洞進行不同砂粒粒徑、風速及含水率之觀測，實驗用砂取自於後龍、苑裡、大安及大甲濱海地區。砂粒物性實驗結果：各樣區土壤之質地皆為砂土，其密度介於2.62~2.67g/立方公分之間；粒徑分布在0.25~0.42mm者最多；而土壤含水率皆在1%以下，其中後龍樣區0.967%最高，大甲樣區0.282%最低；再由形狀係數得知，大安樣區砂粒接近球形，而大甲樣區則較為扁平。至於風洞實驗結果：砂粒粒徑介於0.15~0.84mm時，其起始風速為5.5~7m/s，又粒徑在0.15mm以下之砂粒，其起始風速為5m/s；當砂粒含水率低於1.22%時，飛砂量達到最大值；含水率由1.24%遞增至1.84%時，飛砂量急遽遞減；而含水率達1.84%時，對砂粒起動之抑制作用達到最大值

A+Study+on+Estimate+of+Wind+Aeolian+Sand+Flux+at+Yuanli+Coastally+in+Miaoli+County

The purpose of this study which is discussed about grain size, grain density, grain water content, wind velocity and Aeolian sand at Yuanli coastally. In this paper, the Aeolian sand flux is catch by sand sampler, and wind velocity data which is measure by multi-layer anemometer. Meanwhile, this paper of examination that use regression analysis to discuss the Aeolian sand factor in influence. The results of regression analysis that can be derived by line expression between wind velocity and Aeolian sand, the grain size, grain density have negative relationship with Aeolian sand. However, the grain water content have no relationship with Aeolian sand at 0.3% water content. in addition to estimates of Aeolian sand flux by π Theorem which is:**: significance 1% *: significance 5%本研究之目的在以現地觀測方法從事苑裡海岸飛砂量之調查，探討砂粒比重、密度、含水率及風速與飛砂量之關係。研究中以BSNE集砂器，配合多層風速計進行飛砂量與風速之觀測，進而對影響飛砂量之因子進行線性迴歸分析。綜合研究所得結果得知，風速與飛砂量呈線性顯著關係，而砂粒密度及中值粒徑則與飛砂量呈負相關；又飛砂量與0.3%極低含水率之砂粒，彼此間並無顯著關係。另依柏金漢π定理進行因次分析所得之飛砂量推估式為：**：顯著水準1% *：顯著水準5