Analysis And Evaluation Of Physicochemical Properties In Qianxinan Tobacco-growing Soil

Soil nutrient was an important factor in determining the quality of tobacco.The flue-cured tobacco was the dominant economic industries of Qianxinan.For this purpose of this research taked Qianxinan state's planted tobacco area as study area,analyzed and researched mainly planted tobacco area's soil physical and chemical status,the spatial distribution characteristics,the soil nutrient status,the suitability and changing regularity.And provide the basis for the tobacco fertilization and nutrition regulation for the flue-cured tobacco planting in Qianxinan.Results were as follows:1.The tobacco-growing soil is dominated by yellow soil in Qianxinan,accounted for 92.00%,followed by limestone soil and yellow-brown soil.Soil testure is mainly heavy clay,accounted for 52.69%,followed by clay,accounted 39.78%.2.According to analyzing fertility of tobacco-growing soil in Qianxinan,the result shows:The pH value of tobacco-growing soil was between 6.55 and 6.86,and the total level was suitable.The organic matter contents of tobacco-growing soil were generally high,mainly distributed in the area of 36.61?43.42g/kg.The average content of total nitrogen was 2.44g/kg,which was higher than that on the whole.The contents of alkali-hydrolyzable nitrogen,ammonium nitrogen and nitrate nitrogen were suitable,and the alkali-hydrolyzable nitrogen contents were mainly in the area of 189.15?215.18mg/kg,and the contents of ammonium nitrogen and the nitrate nitrogen were mainly distributed between 8.69?17.15mg/kg.The total phosphorus contents were higher,but the available phosphorus contents were in the middle low level,the total phosphorus contents were mainly distributed in 0.71?0.87g/kg,and the available phosphorus contents were mainly distributed between 10.54?17.08mg/kg.The contents of slowly available potassium and available potassium were slightly lower,the contents of slowly available potassium were between 395.16?516.80mg/kg,and the contents of available potassium were between 122.64?191.92mg/kg.3.According to the overall variability of tobacco-growing soil nutrient in Qianxinan indicated that:The variation of available phosphorus was the biggest,its coefficient of variation was 110.65%.Followed by nitrate nitrogen,ammonium nitrogen and available potassium,the coefficients of variation were 89.87%,59.15%and 75.60%.Their varibility was the biggest,which belonged to strong varibility.While the variation coefficient of pH value was 11.72%,which was weak varibility.The variations of organic matter,total nitrogen,alkali-hydrolyzable nitrogen,total phosphorus,and slowly available potassium were similar,and the coefficient of variation was between 27.74?44.26%,which was moderate intensity variation.4.According to the spatial distribution of tobacco-growing soil nutrient in Qianxinan indicated that:The distribution of pH value had a decreasing trend from south to north.The general distribution trend of organic matter content decreased from the northeast and southwest to the middle.The total nitrogen content had a tendency to decrease from the north and south to the middle.The content of alkali-hydrolyzable nitrogen decreased from southeast to northwest.The content of ammonium nitrogen decreased from the middle part to the northeast and southwest.The content of nitrate nitrogen decreased from the northeast to the southwest.The contents of total phosphorus and available phosphorus decreased from the middle part to the northwest and southeast respectively.The slowly available potassirm and available potassium contents decreased from the southwest to the northeast.5.The average of soil feasibility index was 61.16 in Qianxinan tobacco-growing soil,which was mainly Grade 2 and Grade 3.The soil feasibility index decreased from middle to north and south respectively.