Effects Of Potassium Fertilizer Rate And Ratio Of Base And Topdressing On Growth Features Of Flue-cured Tobacco

Yan'an is the main producing area of tobacco in Shaanxi province and is an important economic crop in the local.The field experiments were carried out in Nanniwan of Baota area and Yichuan from April to November of 2017.Flue-cured tobacco,Yan'an No.1,was selected as the research object to analyze the effects of potassium fertilizer rate and ratio of base and topdressing on growth features,yield and quality of flue-cured tobacco.Application rates included low potassium level(5g/ plant),medium potassium level(7.5g/ plant)and high potassium level(10g/ plant).The main results were shown as follows:(1)Effects of different potassium application rates on growth,yield and quality of flue-cured tobaccoThe effects of potassium application rate on growth and yield and quality of flue-cured tobacco were different from growing season and study area.In the experimental plots of Nanniwan,the low potassium treatment was relatively good,while the best potassium application rate was at a moderate level in the Yichuan experimental plot.The response of different soil physical and chemical properties to the amount of potassium fertilizer was different,pH was less influenced by the fertilizer amount,and the organic matter was higher in the low potassium level.The available phosphorus and available potassium of rosette stage and fast growth period were higher in the high potassium level while the mature period was higher in the medium potassium level.The highest alkali hydrolysable nitrogen content of Nanniwan in the mature period occured in the middle fertilization level while the highest soil alkali hydrolysable nitrogen of Yichuan was in the low potassium.The chemical properties of upper leaves and middleleaves showed similar responses to potassium fertilizer application.With the increase of potassium fertilizer level,nicotine and protein content showed a downward trend,and total nitrogen,potassium,reducing sugar and total sugar showed an upward trend.The application of potassium fertilizer at medium level is helpful to increase the yield of flue-cured tobacco.The top tobacco leaves have the best quality under the high potassium level while the middle leaves are better at low potassium level.(2)Effects of ratio of base and topdressing at low potassium level on growth,yield and quality of flue-cured tobaccoThe effect of ratio of base and topdressing at low potassium level on the growth of flue-cured tobacco was different from growing season and experimental plots.In Nanniwan,the single basal application would promote the improvement of the agronomic traits in the fast growth and mature stages.In Yichuan experimental plots,the ratio of base fertilizer to topdressing of 5:5 could promote most agronomic characters of the plant.In the Nanniwan,the proportion of organic matter and available phosphorus in the mature period was highest in the ratio of base fertilizer to topdressing of 5:5,while the maximum value of alkali hydrolysable nitrogen appeared at the ratio of base fertilizer to topdressing of 7:3.In the Yichuan sample,the high value of soil organic matter and available phosphorus appeared in the single basal applied area,and the available potassium and alkali hydrolysable nitrogen appeared in the ratio of base fertilizer to topdressing of 7:3.The content of nicotine and reducing sugar in the upper tobacco leaves was highest in the ratio of base fertilizer to topdressing of 3:7,while the protein content was the highest in the single basal applied field.The content of total nitrogen and potassium in the middle tobacco leaves was the largest under in the ratio of base fertilizer to topdressing of 3:7,and the reducing sugar and total sugar content was higher under the in the ratio of base fertilizer to topdressing of 7:3.The value of the yield of flue-cured tobacco in the ratio of base fertilizer to topdressing of 5:5 was the largest.The quality of the upper leaf quality was the best under the ratio of base fertilizer to topdressing of 7:3,while the quality of the middle tobacco leaf quality was the best in the single basal applied field.(3)Effects of ratio of base and topdressing at middle potassium level on growth,yield and quality of flue-cured tobaccoThe response of flue cured tobacco growth to basal dressing rate was affected by growing season and trial plots.In the experimental plots of the Nanniwan,the ratio of base fertilizer to topdressing of 5:5 is beneficial to the improvement of agronomic traits in various growth periods,and the agronomic traits are less affected by ratio of base fertilizer to topdressing in Yichuan experimental plots.In the mature period,the proportion of soil nutrient in the mature period in the Nanniwan was higher than that of other fertilized plots,and the highest value of organic matter,available phosphorus and available potassium in the fast growth and mature period of Yichuan test was the ratio of base fertilizer to topdressing of 3:7.At the middle potassium level,the content of nicotine and potassium in the upper tobacco leaves was higher than those in the basal fertilizer,while the total nitrogen,reducing sugar,total sugar and protein content were higher.The content of nicotine,total nitrogen,reducing sugar and total sugar in the middle tobacco was less affected by the ratio of base fertilizer to topdressing.The content of potassium was higher in the topdressing fertilized plots,but the content of protein was larger in the non adding topdressing fertilizer sample.The yield of flue-cured tobacco was the largest in the ratio of base fertilizer to topdressing of 5:5,and the quality of upper leaf quality was the best under the ratio of base fertilizer to topdressing of 5:5;the quality of the middle tobacco leaf quality was the best in the single basal fertilized areas.(4)Effects of ratio of base and topdressing at high potassium level on growth,yield and quality of flue-cured tobaccoThe effects of high potassium level and ratio of base and topdressing on growth of flue-cured tobacco were affected by experiment and growth period.In the Nanniwan and Yichuan experimental plots,most of the agronomic traits in the growing season were higher in the 5:5 or 3:7 plots.In the Nanniwan,adding basal fertilizer at a time was helpful to increase the soil nutrient content,while the proportion of 5:5 in the fast growth and mature period was helpful to improve soil nutrient.In Yichuan experimental plot,the highest of ratio of base and topdressing in the fast growth and mature period,was 3:7.The proportion of base and topdressing of 5:5 or 3:7 helped to increase the content of nicotine,potassium,reducing sugar and total sugar in the upper part,while the proportion of 7:3 was beneficial to the increase of protein content.The content of nicotine,total nitrogen and reducing sugar in the middle tobacco leaves was less influenced by the proportion of base and topdressing.The content of total sugar and protein was the highest in the ratio of base and topdressing of 7:3.The ratio of base and topdressing 7:3 value of the yield of flue-cured tobacco was the largest.The quality of the upper leaf quality was the best under the ratio of base and topdressing of 5:5,and the quality of the middle tobacco leaf quality was the best in the single basal fertilized plots.