湘西植烟土壤pH和主要养分特征及其相互关系

为了解湘西烟区植烟土壤pH和主要养分特征及其相互关系,于2015年采集烟区1 242个土壤样本,研究了植烟土壤pH、有机质、碱解氮、有效磷和速效钾的适宜性分布、县域分布以及pH与这些养分指标的量化关系。结果表明:1湘西烟区植烟土壤pH平均值为6.12,有20.77%样品偏酸和18.20%的样品偏碱;有机质和碱解氮含量的平均值分别为28.42 g/kg和145.63 mg/kg,总体上处于适宜水平;有效磷含量的平均值为28.94 mg/kg,有近40%样品偏高;速效钾含量平均值为198.76 mg/kg,有近45%的样品偏低。2主产烟县植烟土壤pH和养分差异极显著。3土壤主要养分含量与pH之间呈现曲线关系;当pH5.5时或pH8.0时,随土壤pH变化,主要养分含量变化较大;当pH在5.5~8.0时,随土壤pH变化,主要养分含量变化平缓。当pH5.5时,随土壤pH升高,有机质、碱解氮、有效磷和速效钾含量快速下降;当pH在5.5~8.0时,随土壤pH升高,有机质、有效磷和速效钾含量缓慢升高,碱解氮含量缓慢下降;当pH8.0时,随土壤pH升高,有机质、碱解氮、有效磷含量快速下降,速效钾含量快速升高。

pH and Main Nutrients of Tobacco-growing Soils and Their Relations in Western Hunan

A total of 1242 soil samples were collected from the main tobacco-growing areas in Xiangxi in 2015, and the suitability distribution and county regional distribution of tobacco-growing soil pH, organic matter, hydrolytic nitrogen, available phosphorus and available potassium and their quantitative relation were studied to understand the characteristics of tobacco-growing soil pH and main nutrients and their relation. The results were as follows:(1) pH of tobacco-growing soil in Xiangxi is generally suitable for tobacco cultivation, with a mean of 6.12. About20.77% of the soil samples has pH less than 5.0,and about 18.20% of the soil samples has pH greater than 7.5.The mean of organic matter content is 28.42g/kg, and the mean of hydrolytic nitrogen content is145.63mg/kg, they are generally suitable for tobacco cultivation. The mean of available phosphorus content is 28.94mg/kg, approximately 40% of the soil samples of available phosphorus content is too high for high quality tobacco cultivation. The mean of available potassium content is 198.76mg/kg, approximately 45% of the soil samples of available potassium content is too low for high quality tobacco cultivation. (2) There were extremely significant difference among different counties for the tobacco-growing soil pH and main nutrients.(3) It is not a simple linear relationship between main soil nutrients and pH, but curvilinear relationship. When the tobacco-growing soil pH is less than 5.5 or pH greater than 8.0, along with the soil pH change, the main nutrient change is rapidly. When the tobacco-growing soil pH is 5.5 to 8.0, with the soil pH changes, mainly nutrients slowly changing. (4) When the tobacco-growing soil pH is less than 5.5, with the increase in soil pH, organic matter, hydrolytic nitrogen, available phosphorus and available potassium content decreased rapidly. When the tobacco-growing soil pH is 5.5 to 8.0, with the increase in soil pH, organic matter, available phosphorus and available potassium content increased slowly, hydrolytic nitrogen content decreased slowly. When the tobacco-growing soil pH is greater than 8.0, with the increase in soil pH, organic matter, hydrolytic nitrogen and available phosphorus content decreased rapidly, available potassium content increased rapidly.