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【Objective】In order to provide scientific references for fragrant taro planting, reasonable fertilization and improvement of fragrant taro quality, the present paper studied soil profile and nutrient characteristics of fragrant taro. 【Method】Through field soil profile observation and laboratory test, the soil profile characteristics and nutrient content vertical distribution of fragrant taro were studied by SPSS software and Origin software. 【Result】(i) The soil thickness of 6 soil profiles was deep. The depth of the topsoil and the heartsoil was between 65 and101 cm, were all mature soil, the configuration includes the plough layer and plough pan, the redox deposition layer and the maternal layer, the topsoil was affected by artificial farming and forms the plough layer and plough pan, colors are mainly black and brown. The heartsoil was relatively stable, influenced by soil factors, the soil presents orange and red color. The structure respectably presents the obvious iron and manganese film;(ii) The particle composition was mainly composed of granules. The silt content was between 40 % and 67 %. The texture was mainly clay loam, silty loam and loam; The weathering of soil profile is not high, and the degree of weathering decreases with the depth of profile. The nutrients content of the 6 soil profiles decreased as the depth increased.【Conclusion】In the fragrant taro, the soil horizon is deep, the degree of weathering is not high and nutrient elements present the distribution of surface agglomeration. [ABSTRACT FROM AUTHOR]

【Objective】In this paper, the spatial variation and spatial distributions of soil nutrient in main areas of fragrant taro planting in Shaoguan were studied to provide scientific references for fragrant taro planting, reasonable fertilization and improvement of fragrant taro quality.【Method】The soil nutrient content, spatial variation and spatial distributions of fragrant taro by SPSS software, semivariance of GS + and geostatistics of GIS were studied.【Result】( i) The mean contents of organic matter( OM), available N( AN), available P( AP), available K( AK) of fragrant taro were 2. 98 %, 109. 79 mg/kg, 40. 30 mg/kg, 81. 60 mg/kg, ranging of 0. 89 %-6. 65 %, 27. 79-257. 25 mg/kg, 5. 79-108. 44 mg/kg, 15. 03-270. 18 mg/kg, and variable coefficient were 35. 2 %, 46 %, 64. 7 %, 62. 4 %. There were the differences of soil nutrient contents in different towns.( ii) The nugget coefficients of soil nutrients in towns were AK( 49. 98 %) > OM( 47. 8 %) > AN( 37. 6 %) > AP( 32. 5 %), mainly between 30 % and 50 %, all belonged to moderate spatial dependence, the spatial variabilities of the nutrients were affected by structural and random factors synchronously, structural variation was the main, and random variation was second. 【Conclusion】Overall, the AP contents of soil was abundant, the OM and AN contents were at medium level, the AK was a lack of level, and soil nutrient generally presented a trend of low in the north and high in the southern. [ABSTRACT FROM AUTHOR]

[Objective] The extraction and change monitoring of cultivated land information is one of the hotspots of remote sensing application research. Northern Guangdong is the main grain base of Guangdong Province, and is the key area of cultivated land change monitoring by business management departments.[Method] In the present paper, using GF-2 and Sentinel-2 remote sensing images, combined with the phenological period of late rice in the study area, the vegetation index, humidity index, brightness index, color index and texture features were extracted for multi-scale segmentation, and the multi-scale image of paddy field extraction was constructed. The index difference image and time series multi feature difference image were classified to extract the paddy field area and evaluate the results.[Result]（i) The highest extraction accuracy of paddy field in time series multi feature difference image was 0.98,and the minimum difference between paddy field area and late rice sowing area was 240.05 hm2,and the best paddy field extraction effect was based on time series multi feature difference image;（ii）The difference of index feature needed to use the key phenological characteristics of crops and combine with multi-scale segmentation of image to improve the accuracy of paddy field extraction;（iii）The machine forest method has faster operation speed and higher classification accuracy in data classification with high dimensional features. [Conclusion] The research of the paper is to explore the method of high-resolution remote sensing in rapid and accurate updating of cultivated land information, which can provide support for the application of cultivated land management business. [ABSTRACT FROM AUTHOR]