Soil Fertility Characteristics And Comprehensive Evaluation Of Tobacco Planting Area In Tieling City

Flue-cured tobacco is a kind of cash crop with both quality and quantity,and there are many factors that affect its growth and quality.When the climate,variety,cultivation management and other conditions are constant,soil is the primary environmental factor that affects the quality and yield of flue-cured tobacco.Soil fertility is one of the essential characteristics of the soil,and it is also an important measure of nutrient regulation during tobacco cultivation.Tieling City is the area with the largest tobacco planting area in Liaoning Province.In recent years,due to unclear foundations and improper fertilization mode,a series of problems such as soil compaction,acidification,uneven nutrient enrichment or depletion,and low fertilizer utilization have been seriously restricted.Sustainable development of the local tobacco industry.In this study,through the determination of soil physical and chemical indicators in Tieling tobacco-growing area,the current status of the local tobacco-growing soil fertility was basically found out,and the local tobacco-growing soil fertility level was evaluated on the basis of measured data combined with scientific evaluation standards and appropriate evaluation methods.At the same time,it draws a soil nutrient content classification map,and proposes targeted fertilization strategies.This work has certain guiding significance for the local construction of a scientific and reasonable fertilization technology system,and has certain practical significance for the healthy development of the local tobacco industry.Research indicates:（1）The soil has a shallow plough layer and a large bulk density.The average thickness of the cultivated layer is 14.09 cm,which is 10.91 cm lower than the optimal thickness of the cultivated layer,and this point is in the suitable range without any other;the average soil bulk density is 1.35 g?cm^-3,which is 0.08 g?cm^-3higher than the optimal range,which is the most suitable The appropriate range of sample points accounted for 37.61%.（2）Soil acidification is serious and the organic matter content is low.The average soil p H is 4.89,which is 0.61 lower than the optimum range.The sample points with extremely low or low levels account for 25.90%and 62.94%respectively.The organic matter content averaged 22.16 g?kg^-1,and samples with very low or low levels accounted for 3.57%and39.73%,respectively,and samples with suitable levels accounted for 43.31%.（3）The soil nitrogen content is low,the phosphorus is excessive,and the potassium is unevenly enriched or lacking.The average total nitrogen content is 1.21 g?kg^-1,the sample points in the appropriate range account for 66.07%,and the sample points with extremely low or low levels account for 2.68%and 27.68%,respectively.The average content of available phosphorus is 79.29 mg?kg^-1,which is 49.29 mg?kg^-1higher than the suitable range,and the proportion of samples with extremely high levels is as high as 84.82%.The average content of available potassium was 253.88 mg?kg^-1,which was 33.88 mg?kg^-1higher than the suitable range,but the proportion of sample points within the suitable range was only 17.86%,and the remaining sample points were higher or lower than the suitable range.（4）The soil is lack of trace elements.The average contents of exchangeable calcium and magnesium were 71.14 mg?kg^-1and 9.62 mg?kg^-1,respectively,and the proportions of sample points with extremely low levels were 100%and 95.28%respectively.The average effective copper and zinc contents are 0.80 mg?kg^-1and 1.54 mg?kg^-1,respectively.The sample points with extremely low effective copper content account for 54.72%,and the samples with extremely low and low effective zinc content Points accounted for 35.85%and 18.87%respectively.The average water-soluble chlorine content is 13.14 mg?kg^-1,and the sample points at an appropriate level account for 76.42%,which is relatively suitable overall.（5）Tieling tobacco planting area has no first-class land,the second-class and third-class land account for 54.72%and 42.45%respectively.The comprehensive soil fertility index（IFI value）averages 0.59,which is lower than the second-class land classification standard（IFI0.6-0.8）.The existing second-class land has a low IFI value,and the risk of degrading to a third-class land if improperly managed.（6）Based on the above results,the following suggestions are made for soil improvement and fertilization in Tieling tobacco-growing areas:build a reasonable farming layer,increase lime,adjust acid and calcium,reduce the amount of chemical fertilizer,and increase the amount of organic fertilizer.At the same time pay attention to the application of middle and trace elements.