Dynamic Changes Of Soil Nutrients And Tobacco Leaf Quality Analysis Under Different Cultivation Modes

To explore suitable for the Yunyan87 cultivation techniques of Wan Zhou mountain area,to carry out the different planting density and fertilizer application processing and field experiment of different harvest maturity,through to the flue-cured tobacco intrinsic chemical composition analysis and evaluation,harvesting time,the study of fertilization,density and harvesting time of soil characteristics and the influence of the quality of flue-cured tobacco.The main conclusions of this study are as follows:1.Influence of planting density on quality of flue-cured tobaccoOn the whole,the planting density of T1 each part of the flue-cured tobacco leaf in the reducing sugar,total nitrogen and potassium content and Schmuck's value values were within the scope of their respective optimum,when planting density increase to T2,each part of the flue-cured tobacco leaf of nicotine and protein content and alkali nitrogen,ratio of length to width,the ratio of potassium chloride than suitable scope,when planting density for T3,each part of the flue-cured tobacco leaf of total sugar,chlorine and alkali ratio of sugar to achieve the optimum range.With the increase of planting density,the contents of intrinsic chemical components in the lower leaves of flue-cured tobacco decreased gradually,while the contents of intrinsic chemical components in the upper middle leaves increased firstly and then decreased on the whole,and all reached the peak value under T2 treatment.The results showed that under different planting densities,T2 treatment,the content of internal chemical components in leaves of different parts of flue-cured tobacco was the most harmonious.2.Effect of fertilization treatment on the quality of flue-cured tobaccoUnder the treatment of T1,the content of leaf reducing sugar in each part of flue-cured tobacco was the best.Under the treatment of T2,the contents of total sugar and total nitrogen in leaves of different parts of flue-cured tobacco were more suitable,but the total sugar content was higher overall.Under the treatment of T3,the contents of chlorine,protein,potassium and Schmuck's value of leaves in different parts of flue-cured tobacco were all in the optimal range.Under CK treatment,the ratio of nicotine,sugar to base,nitrogen to base and potassium to chlorine in each part of flue-cured tobacco leaves were all in the optimum range.The internal chemical composition of upper leaves was more affected by T2 treatment,the internal chemical composition of middle leaves was more affected by T3 treatment,and the internal chemical composition of lower leaves was less affected by T2 treatment.In general,T3 was the most suitable treatment for the contents of various internal chemical components in flue-cured tobacco.3.Effect of harvesting maturity on quality of flue-cured tobaccoWith the increase of harvest maturity,the contents of total sugar,reducing sugar,chlorine,nicotine,potassium and the quality indexes of tobacco leaves,such as schmok value,sugar-alkali ratio and K/Cl ratio,all increased,while the contents of total nitrogen,protein and nitrogen/alkali ratio in all parts of flue-cured tobacco decreased.Under T1(still harvested)treatment,the contents of reducing sugar,nicotine,total nitrogen,protein,ratio of nitrogen to alkali and ratio of potassium to chlorine were all in the optimal range.Under T2(suitable harvest)treatment,the total sugar content and Schmuck's value of leaves in different parts of flue-cured tobacco were the best.The contents of chlorine and potassium and the ratio of sugar to alkali in the leaves of flue-cured tobacco treated with T3(suitable harvest +5 days)were all in the suitable range.The contents of internal chemical components in the upper and lower leaves of flue-cured tobacco were significantly affected by T1 and T2 treatments,while the contents of internal chemical components in the middle leaves were significantly affected by T1.Overall,T1 treatment is the optimal treatment.4.In terms of overall performance,the overall quality of flue-cured tobacco was the best when the planting density was T2,fertilization treatment was T3 and harvest maturity was T1(still ripe harvest).The internal chemical composition was the most harmonious.5.Dynamic changes of soil nutrients under different cultivation measuresWith the increase of planting density,the contents of p H,organic matter,total nitrogen,available phosphorus and available potassium in tobacco growing soil also increased,but the content of alkali-hydrolyzable nitrogen was opposite.Under different fertilization treatments,soil organic matter and total nitrogen contents were the best under conventional fertilization,and soil p H changed in complex trends under the four fertilization treatments,and soil acidification appeared.The contents of soil alkali-hydrolyzable nitrogen,available phosphorus and available potassium increased with the increase of organic fertilizer application.The longer the harvest period of flue-cured tobacco,the more conducive to the accumulation of soil available phosphorus and organic matter,while the soil p H,total nitrogen,alkali-hydrolytic nitrogen and the content of soil available potassium were better at the early stage of tobacco maturity.The content of available nutrients in tobacco growing soil was mainly affected by fertilization treatment,which resulted in dynamic changes.The soil p H value was greatly affected by the harvest period,and the content of available potassium was significantly affected by the density.