湘西植烟土壤pH和主要养分特征及其相互关系

摘要

1242 soil samples were collected in 2015 from tobacco-growing areas in western Hunan, and the suitability distribution, county regional distribution of tobacco-growing soil pH, organic matter, hydrolytic nitrogen, available phosphorus and available potassium as well as the quantitative relations between soil pH and soil nutrients were studied. The results were as follows: 1) Soil pH was generally suitable for tobacco cultivation, with a mean of 6.12. pH of 20.77% of the soil samples was less than 5.0, while pH of 18.20% of the soil samples was greater than 7.5. Mean contents of organic matter and hydrolytic nitrogen were 28.42 g/kg and 145.63 mg/kg, respectively, generally suitable for tobacco cultivation. Mean content of available phosphorus was 28.94 mg/kg, available phosphorus content of about 40% of the soil samples was higher for high quality tobacco cultivation. Mean content of available potassium was 198.76 mg/kg, available potassium content of about 45% of the soil samples was lower for high quality tobacco cultivation. 2) There were extremely significant differences in pH and soil nutrients among different counties. 3) Soil nutrients had curvilinear relationship with pH, when pH<5.5 or >8.0, soil nutrient contents changed rapidly with pH change, but when pH was 5.5–8.0, soil nutrient contents changed slowly with pH change. When pH<5.5, contents of organic matter, hydrolytic nitrogen, available phosphorus and available potassium decreased rapidly with pH increase; when pH was 5.5–8.0, contents of organic matter, available phosphorus and available potassium increased slowly but content of hydrolytic nitrogen decreased slowly with pH increase; and when pH>8.0, contents of organic matter, hydrolytic nitrogen and available phosphorus decreased rapidly but content of available potassium increased rapidly with pH increase.%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1242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pH<5.5时或pH>8.0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pH<5.5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pH>8.0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.