本文選題：全氮 + 地統(tǒng)計(jì)　； 參考：《中國(guó)農(nóng)業(yè)科學(xué)院》2015年碩士論文

【摘要】：土壤氮素是土壤肥力高低和土壤質(zhì)量的重要標(biāo)志,是全球氮循環(huán)的重要源和匯。土壤全氮的空間變異特征研究,能夠正確地評(píng)估土壤供氮能力,指導(dǎo)區(qū)域土壤資源利用和管理,對(duì)區(qū)域農(nóng)業(yè)生產(chǎn)和環(huán)境管理有著十分重要的意義。土壤氮素在土壤中的分布并非均質(zhì),它受到成土母質(zhì)、地形、生物、時(shí)間、氣候等自然因素和施肥、耕作等人為因素的共同影響,表現(xiàn)出空間異質(zhì)性。在預(yù)測(cè)土壤屬性空間變異特征的研究中,傳統(tǒng)地統(tǒng)計(jì)方法和混合地統(tǒng)計(jì)方法是目前應(yīng)用最廣泛和最有效的方法。以環(huán)境因子為輔助變量指導(dǎo)相關(guān)屬性空間分布的預(yù)測(cè)和制圖成為研究熱點(diǎn)。但在大區(qū)域尺度有限的采樣點(diǎn)條件下用不同地統(tǒng)計(jì)方法進(jìn)行土壤屬性空間分布預(yù)測(cè)的對(duì)比研究,選取適合預(yù)測(cè)模型預(yù)測(cè)大區(qū)域尺度土壤屬性空間分布,這類研究并不多見。本研究選取海南島全島為研究區(qū),結(jié)合地形與遙感指數(shù)等環(huán)境因子,從159個(gè)土壤樣點(diǎn)中,每縣隨機(jī)選1-2點(diǎn),全島選取29個(gè)樣點(diǎn)作為驗(yàn)證數(shù)據(jù)集,剩余的130個(gè)點(diǎn)作為預(yù)測(cè)數(shù)據(jù)集,采用傳統(tǒng)地統(tǒng)計(jì)的普通克里格法和結(jié)合輔助變量的多元線性回歸以及混合地統(tǒng)計(jì)方法的回歸克里格法、協(xié)同克里格法共4種模型進(jìn)行了土壤全氮分布的空間預(yù)測(cè);利用29個(gè)驗(yàn)證數(shù)據(jù)集樣點(diǎn)數(shù)據(jù)進(jìn)行精度驗(yàn)證,并對(duì)比80年代土壤全氮空間分布,探討了時(shí)空變異特征及其成因,結(jié)論如下:(1)除表層(0-5cm)土壤全氮預(yù)測(cè)最優(yōu)模型為協(xié)同克里格法(CK)外,其他三層土壤全氮含量的預(yù)測(cè)最優(yōu)模型均為普通克里格法(OK)。用較少網(wǎng)格樣點(diǎn)對(duì)較大區(qū)域進(jìn)行土壤全氮的空間分布預(yù)測(cè)時(shí),普通克里格法總體精度最高,協(xié)同克里格法僅次于普通克里格法。協(xié)同克里格法預(yù)測(cè)精度優(yōu)于或等于回歸克里格預(yù)測(cè)精度。而回歸克里格法(RK)的預(yù)測(cè)精度始終低于普通克里格法(OK)。協(xié)同克里格法、回歸克里格法與多元線性回歸模型和普通克里格法相比,在極值處存在著一定的消除平滑效應(yīng)的效果。(2)海南島4個(gè)土層全氮含量均有從東向西方向遞減,高值區(qū)向外遞減的分布趨勢(shì),高值主要分布在東北部和南部地區(qū)。耕層土壤(0-5cm和0-20cm)土層全氮含量集總體處于三級(jí)和四級(jí)中等水平。20-40cm和40-60cm土層土壤全氮含量處于六級(jí)較低水平,且該等級(jí)面積比例分別達(dá)到了51.5%和90.9%。空間同一位置的全氮含量隨土壤深度的增加而降低。(3)不同土層土壤全氮含量與不同的環(huán)境因子呈現(xiàn)出不同程度的相關(guān)關(guān)系。0-5cm土層全氮含量與坡度、NDVI等因子均未達(dá)顯著相關(guān),僅與大田這一土地利用方式呈極顯著相關(guān)。20-40cm、40-60cm土壤全氮含量與歸一化植被指數(shù)、坡度呈極顯著或顯著相關(guān),0-20cm土壤全氮含量與歸一化植被指數(shù)呈顯著相關(guān)。(4)時(shí)隔30年,海南島土壤全氮含量整體分布趨勢(shì)雖然相似,高值仍然保持在南部山區(qū)和東北部地區(qū),但全氮含量整體呈下降趨勢(shì)。以瓊中縣為例進(jìn)行成因分析,全氮變化的主要原因?yàn)樵谄露容^大的山區(qū)進(jìn)行人為開墾而造成的氮素隨水土流失。
[Abstract]:Soil nitrogen is an important symbol of soil fertility and soil quality. It is an important source and sink of the global nitrogen cycle. The study of spatial variation characteristics of soil total nitrogen can correctly assess the ability of soil nitrogen supply and guide the utilization and management of regional soil resources. It is of great significance for Regional Agricultural production and environmental management. The distribution of soil is not homogeneous. It is influenced by natural factors such as soil parent material, terrain, biology, time, climate and other natural factors, such as fertilization, and cultivation and other factors, showing spatial heterogeneity. In the study of predicting the spatial variation characteristics of soil properties, traditional statistical methods and mixed statistical methods are the most widely used and most widely used at present. It is an effective method to guide the prediction and mapping of spatial distribution of related attributes with environmental factors as auxiliary variables. But a comparative study on spatial distribution prediction of soil properties is carried out with different statistical methods under the condition of limited sampling points in large regional scale, and a suitable pretest model is selected to predict soil properties in large regional scale. In this study, we select the Hainan Island whole island as the research area, and combine the environment factors such as terrain and remote sensing index. From 159 soil samples, 1-2 points are selected randomly in each county. 29 samples are selected as validation data sets in the whole island. The remaining 130 points are used as the prediction data sets, and the traditional Kriging method is adopted and the traditional Kriging method is used. Combined with the multiple linear regression of auxiliary variables and the regression Craig method of mixed statistical method, the spatial prediction of total nitrogen distribution in soil was predicted by 4 models of CO Craig law, and the accuracy was verified by 29 verifying data collection points, and the spatial distribution of soil total nitrogen in 80s was compared and the characteristics of temporal and spatial variation and its formation were discussed. The conclusions are as follows: (1) the optimal model of soil total nitrogen prediction in surface layer (0-5cm) is cooperative Kriging (CK), and the other three layers of soil total nitrogen content prediction optimal model is common Kriging method (OK). The general Kriging method has the highest overall precision when using less grid sample points to predict the spatial distribution of soil total nitrogen in larger regions. The Kriging method is second only to the common Kriging method. The precision of the cooperative Craig Fa prediction is superior to or equal to the regression Kriging prediction accuracy. The predictive accuracy of the regression Kriging method (RK) is always lower than the common Kriging method (OK). The cooperative Kriging method, the regression Craig Fa and the multiple linear regression model and the ordinary Kriging method, exist at the extreme value. The effect of smoothing effect is eliminated. (2) the total nitrogen content of the 4 soil layers in Hainan Island is decreasing from east to west, and the high value area decreases outward. The high value is mainly distributed in the northeast and south areas. The total nitrogen content of the soil layer of the plough soil (0-5cm and 0-20cm) is in the three and four grade medium level.20-40cm and 40-60cm soil. The total nitrogen content in the soil layer is at the lower level of the six level, and the total nitrogen content of this grade area is 51.5% and 90.9%., respectively, and the total nitrogen content decreases with the increase of soil depth. (3) the total nitrogen content in different soil layers and different environmental factors have different degrees of correlation between the total nitrogen content and slope of.0-5cm soil layer, NDVI No significant correlation was found between the other factors, only the land use mode of the field was significantly correlated with.20-40cm, the total nitrogen content in 40-60cm soil and the normalized vegetation index were very significant or significant correlation. The total nitrogen content in 0-20cm soil was significantly correlated with the normalized vegetation index. (4) the total distribution of total nitrogen in Hainan Island soil was generally distributed after 30 years. Although the potential is similar, the high value remains in the southern and northeastern regions, but the total nitrogen content has a downward trend. The genetic analysis is taken as an example of Qiongzhong County. The main reason for the change of total nitrogen is the nitrogen and soil erosion caused by artificial reclamation in the mountainous areas with large slopes.

【學(xué)位授予單位】：中國(guó)農(nóng)業(yè)科學(xué)院
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：S153.6

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