本文選題：土壤結(jié)構(gòu)　切入點：機械耕作　出處：《南京農(nóng)業(yè)大學》2015年碩士論文

【摘要】：土壤耕作的目的是創(chuàng)建良好的苗床,而對土壤結(jié)構(gòu)或苗床質(zhì)量的精確定量又是正確評價耕作機具作業(yè)性能的重要途徑。目前評價苗床質(zhì)量多用感官評定,如使用現(xiàn)場打分評價或土壤視覺打分等感官評價農(nóng)業(yè)土壤的質(zhì)量狀況,但是感官評價仍存在主觀性較強、規(guī)范性差等狀況。用于評價耕作機具的碎土性能及土壤耕作質(zhì)量的常規(guī)指標是碎土率及土壤破碎體尺度分布等指標,通常較少對耕作生成的土壤結(jié)構(gòu)進行精細分析,然而精細的土壤結(jié)構(gòu)分析更利于提供豐富的信息。本文使用數(shù)字圖像分析技術(shù)定量土壤結(jié)構(gòu)并提供3個外觀幾何指標,進而分別從土壤結(jié)構(gòu)的棱角性、形狀指數(shù)、矩形度、尺度分布4個方面評價土壤結(jié)構(gòu)。本研究首先探討土壤結(jié)構(gòu)的數(shù)字圖像處理方法與指標,針對自然地理過程形成的土壤結(jié)構(gòu),研究其圖像獲取及計算分析方法。對土壤結(jié)構(gòu)的外觀幾何指標(棱角性、形狀指數(shù)、矩形度)進行計算,定量了自然地理過程形成的土壤結(jié)構(gòu)特征。結(jié)果表明自然地理過程作用下黃棕壤呈塊狀分布,且隨土壤結(jié)構(gòu)的尺度增大其形狀指數(shù)及棱角性呈增大的趨勢,而矩形度則不斷降低。將提供的數(shù)字圖像處理方法分別應(yīng)用于水稻土的犁耕和旋耕生成的土壤結(jié)構(gòu)分析。對比冬夏季犁耕和旋耕的土壤結(jié)構(gòu),統(tǒng)計分析棱角性、形狀指數(shù)以及矩形度指標。結(jié)果表明棱角性和形狀指數(shù)能很好地區(qū)分不同耕作方式的土壤結(jié)構(gòu),而矩形度這個指標不能很好地區(qū)分耕后土壤結(jié)構(gòu)。對土壤結(jié)構(gòu)的圖像信息與體積(質(zhì)量)信息的關(guān)系進行進一步研究,將不同尺度區(qū)間的土壤結(jié)構(gòu)體分別進行不同俯視角度拍攝,建立投影面積與質(zhì)量的對應(yīng)關(guān)系,然后在此基礎(chǔ)上分析土壤結(jié)構(gòu)體的質(zhì)量-尺度分布。試驗結(jié)果表明在俯視角60°條件下,各尺度區(qū)間的土壤結(jié)構(gòu)體投影面積與質(zhì)量擬合效果都是最好。用數(shù)字圖像法分析水稻土犁耕耕作下土壤結(jié)構(gòu)質(zhì)量-尺度分布模型為F(dD)=(d/252.102)0.77。最后再進一步探究圖像法原位測試耕作的土壤結(jié)構(gòu),研究圖像獲取及計算方法,并將原位測試獲取的土壤結(jié)構(gòu)指標與非原位的進行對比。結(jié)果表明兩種方法各幾何指標存在很好的相關(guān)性,但是各指標也存在差異性,尤其是矩形度的差異顯著。本文所提供的數(shù)字圖像分析方法快捷方便,能夠提供更多的土壤結(jié)構(gòu)信息,所得土壤結(jié)構(gòu)尺度分布模型更加準確。
[Abstract]:The purpose of soil tillage is to create a good seedling bed, and the accurate quantification of soil structure or seedling bed quality is an important way to correctly evaluate the working performance of tillage machines and tools.At present, sensory evaluation is used to evaluate the quality of seedling bed, such as field scoring or soil visual scoring, etc., but sensory evaluation still has strong subjectivity and poor standardization.The conventional indexes used to evaluate the soil fragmentation performance and soil tillage quality of tillage tools are the rate of soil fragmentation and the size distribution of soil fragments, and the fine analysis of soil structure produced by tillage is usually rare.However, fine soil structure analysis is more helpful to provide rich information.In this paper, the digital image analysis technique is used to quantify soil structure and provide three geometrical indexes of appearance, and then the soil structure is evaluated from four aspects of the soil structure, such as prism, shape index, rectangle degree and scale distribution.In this study, the digital image processing method and index of soil structure were discussed, and the methods of image acquisition and analysis were studied for the soil structure formed by natural geographical process.The appearance geometric indexes of soil structure (angularity, shape index, rectangle degree) were calculated, and the soil structure characteristics formed by natural geographical process were quantified.The results show that yellow brown soil distributes in blocks under the action of natural geography, and its shape index and angularity increase with the scale of soil structure increasing, but the rectangle degree decreases continuously.The digital image processing method is applied to the soil structure analysis of paddy soil produced by ploughing and rotary tillage, respectively.Comparing the soil structure of ploughing and rotary tillage in winter and summer, the angularity, shape index and rectangle index were analyzed statistically.The results showed that the prism and shape index could distinguish the soil structure of different tillage methods well, but the rectangular degree index could not distinguish the soil structure after tillage very well.The relationship between the image information of soil structure and the information of volume (quality) is further studied. The corresponding relation between projection area and mass is established by taking different overlooking angles of soil structure with different scales.Then the mass-scale distribution of soil structure is analyzed.The experimental results show that the fitting effect of the projection area and the quality of soil structure is the best under the condition of the overlooking angle of 60 擄.The numerical image method was used to analyze the soil structure quality and scale distribution model under ploughing tillage in paddy soil.Finally, the soil structure of in situ testing tillage by image method is further explored, the method of image acquisition and calculation is studied, and the index of soil structure obtained by in situ test is compared with that obtained by in situ test.The results show that there is a good correlation between the two methods, but there are also differences among them, especially the difference of rectangular degree.The digital image analysis method provided in this paper is quick and convenient, and can provide more information of soil structure, and the scale distribution model of soil structure is more accurate.
【學位授予單位】：南京農(nóng)業(yè)大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：S152.4

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