【摘要】：耕地是人類賴以生存和發(fā)展的最重要的資源之一,伴隨著全球變化研究的興起,區(qū)域土地利用變化是全球變化研究的熱點(diǎn)之一,耕地變化作為土地利用變化的核心內(nèi)容之一,也已經(jīng)成為全球變化研究的重要組成部分。特別是進(jìn)入21世紀(jì)以來,全球經(jīng)濟(jì)和人口高速增長(zhǎng),在巨大的發(fā)展壓力面前,耕地的質(zhì)量以及利用方式正經(jīng)歷著前所未有的變化。非洲是世界糧食安全的重要研究區(qū)之一,目前非洲的耕地變化研究主要集中在經(jīng)濟(jì)發(fā)達(dá)地區(qū)和生態(tài)脆弱地區(qū),全非洲尺度的耕地變化研究尚未開展。已開展的非洲重點(diǎn)研究區(qū)的耕地變化研究主要是采用遙感與實(shí)地調(diào)查相結(jié)合的數(shù)量統(tǒng)計(jì)和空間分析,對(duì)耕地利用變化與環(huán)境背景之間的關(guān)系研究較少。采用的遙感信息源也以空間分辨率為250米及1000米的中低分辨率遙感影像為主。以非洲為研究區(qū),采用空間分辨率為30米的遙感信息源,利用遙感和地理信息系統(tǒng)空間分析相結(jié)合的方法,運(yùn)用土地利用變化率、單一土地利用動(dòng)態(tài)度雙向模型和土地利用相對(duì)變化率等數(shù)學(xué)模型定量的分析了耕地利用變化特征,揭示了非洲耕地的時(shí)空演變規(guī)律以及耕地利用變化與環(huán)境因子之間的關(guān)系,為研究區(qū)土地利用結(jié)構(gòu)和農(nóng)業(yè)布局調(diào)整、耕地可持續(xù)利用和生態(tài)環(huán)境保護(hù)提供決策依據(jù),也為全球糧食安全研究提供了典型區(qū)域基礎(chǔ)。主要研究?jī)?nèi)容包括：資料收集,建立包括氣溫、降水、高程、坡度、坡向、生態(tài)分區(qū)在內(nèi)的環(huán)境背景數(shù)據(jù)庫：下載覆蓋非洲全區(qū)的遙感影像,解譯遙感影像,建立2000年和2010年兩期非洲耕地利用專題數(shù)據(jù)庫；基于經(jīng)緯度、區(qū)域、國(guó)家等不同視角對(duì)非洲耕地利用的數(shù)量和空間變化分析研究,揭示耕地在不同研究視角下的變化特征；基于不同視角下的耕地轉(zhuǎn)移以及流向進(jìn)行了分析研究；耕地變化與生態(tài)環(huán)境因子之間的關(guān)系研究,揭示耕地利用變化與環(huán)境因子之間的關(guān)系等。主要研究成果如下：(1)耕地分布特征：2000年和2010年耕地面積分別為2.00×106平方千米和2.23×106平方千米。在經(jīng)緯向上面積集中出現(xiàn)在34°E和12°N附近；不同區(qū)域的耕地面積由大到小排序?yàn)闁|非、西非、北非、南非、中非；在國(guó)家視角看耕地主要集中在少數(shù)國(guó)家,耕地面積排名前十五的國(guó)家其耕地面積占非洲耕地總面積占75%左右。(2)耕地變化特征：2000-2010年非洲耕地面積增加了2.25×105平方千米。耕地面積增加在經(jīng)度上主要集中在4°E到19°E和31°E到39°E之間；在緯度上集中在22°S到1°S以及9°N到14°N之間；在區(qū)域視角上新增耕地主要集中在東非和西非；在國(guó)家視角上新增耕地主要集中在尼日利亞、坦桑尼亞、蘇丹、乍得、肯尼亞、莫桑比克、安哥拉等國(guó)。(3)耕地轉(zhuǎn)移特征：非洲2000年減少的耕地去向主要轉(zhuǎn)出為林地、草地,部分地區(qū)轉(zhuǎn)化為灌叢地和裸地,2010年新增加的耕地主要來自林地、草地和灌叢地。各地理分區(qū)耕地轉(zhuǎn)入轉(zhuǎn)出特征與非洲全域轉(zhuǎn)入轉(zhuǎn)出特征大致相似,但也有自己的特點(diǎn)。(4)氣溫和降水對(duì)耕地的分布有顯著影響,耕地主要集中分布在氣溫21-29℃之間、降水300-1200mm區(qū)間。坡度對(duì)耕地的分布具有絕對(duì)的影響,90%以上的耕地都分布在坡度0-2。之間,但耕地分布變化與坡向關(guān)系不大。生態(tài)分區(qū)綜合地反映了區(qū)域生態(tài)環(huán)境狀況,耕地主要分布在水熱組合良好的熱帶和亞熱帶的草原和灌叢區(qū)�？傊�,論文首次采用空間分辨率為30米的高分辨率影像數(shù)據(jù)開展了全非洲耕地利用變化研究,并分析了全非洲耕地分布與生態(tài)環(huán)境因子之間的關(guān)系,為研究區(qū)耕地布局調(diào)整提供了科學(xué)依據(jù),是全球糧食安全研究的重要組成部分。
[Abstract]:Cultivated land is one of the most important resources for the survival and development of mankind. Along with the rise of global change research, regional land use change is one of the hot spots of global change research, and the change of cultivated land is one of the core contents of land use change. It has also become an important component of global change research. Especially since the twenty-first century, the global economy and population have grown at a high rate, and before the great development pressure, the quality of cultivated land and the way of utilization are experiencing an unprecedented change. Africa is one of the most important research areas in world food security, and the study on cultivated land change in Africa is mainly concentrated in economically developed regions and ecologically fragile regions. The study of cultivated land change in key research areas in Africa is mainly based on the quantitative and spatial analysis of remote sensing and field survey, and the relationship between land utilization change and environmental background is relatively small. The spatial resolution is mainly based on the mid-low resolution remote sensing image with spatial resolution of 250m and 1000m. taking Africa as a research area, adopting a spatial resolution of 30 meters as a spatial information source, utilizing a method combining the spatial analysis of remote sensing and geographic information system, and applying the rate of change of land use, The characteristics of land utilization change are analyzed quantitatively by mathematical models such as a single land-use attitude two-way model and a land use relative change rate, and the spatial-temporal evolution rule of the cultivated land in Africa and the relationship between the change of the cultivated land utilization and the environmental factors are disclosed, In order to provide decision-making basis for the adjustment of land use structure and agricultural land use, sustainable utilization of cultivated land and ecological environment protection, it also provides a typical regional basis for global food security research. The main research contents include: data collection, setting up an environment background database including temperature, precipitation, elevation, slope, slope direction and ecological partition: downloading remote sensing images covering the whole area of Africa, interpreting remote sensing images, and establishing thematic databases for the utilization of arable land in Africa in 2000 and 2010; Based on the analysis of the quantitative and spatial variation of cultivated land utilization in Africa based on different perspectives, such as latitude and longitude, region and country, the change characteristics of cultivated land under different research perspectives were revealed; The relationship between change of cultivated land and environmental factors reveals the relationship between change of cultivated land and environmental factors. The main results are as follows: (1) Distribution of cultivated land: The cultivated land in 2000 and 2010 is 2. 00 to 106 square km and 2. 23 to 106 square kilometers, respectively. in that area of longitude and latitude, the area is concentrated in the vicinity of 34 擄 E and 12 擄 N; the arable land in different areas is ranked from large to small to east Africa, West Africa, North Africa, South Africa and Central Africa; in the national perspective, the cultivated land is mainly concentrated in a few countries, In the first 15 years of arable land, the arable land accounts for about 75% of the total cultivated land area in Africa. (2) Characteristics of cultivated land change: The cultivated land area of Africa increased by 2.25-105 square kilometers in 2000-2010. The increase in cultivated land area is mainly concentrated in longitude of 4 擄 E to 19 擄 E and 31 擄 E to 39 擄 E; in latitude, concentrated at 22 擄 S to 1 擄 S and 9 擄 N to 14 擄 N; new cultivated land at the regional perspective is mainly concentrated in East Africa and West Africa; At the national perspective, new arable land is mainly concentrated in Nigeria, Tanzania, Sudan, Chad, Kenya, Mozambique, Angola and other countries. (3) Cultivated land transfer characteristics: Africa's reduced cultivation of cultivated land in 2000 is mainly transformed into shrub land, grassland, and parts of the area. The newly increased cultivated land in 2010 mainly comes from forest land, grassland and shrub land. The transfer feature of the cultivated land in each geographical area is similar to that of Africa's global transfer, but also has its own characteristics. (4) The temperature and precipitation have a significant effect on the distribution of cultivated land, and the main concentration of cultivated land is between 21-29 鈩，

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