| The high-carbon-based soil remediation fertilizer is a compound fertilizer containing organic,inorganic and biological active substances,and has the functions of regulating the ratio of soil carbon to nitrogen,improving the microbial environment,improving the utilization rate of fertilizers,and the quality of tobacco leaves.The Guiyang tobacco area is a karst landform,with thin plough layers,coupled with continuous cropping of land in the tobacco area,unreasonable chemical fertilizer application,and insufficient organic manure,resulting in degraded ploughing soil,soil compaction and organic matter content,and reduced soil microbial activity.The utilization rate of nutrients decreased,resulting in a decline in the yield and quality of flue-cured tobacco.This paper studied the effects of high-carbon fertilizers on soil nutrient and tobacco quality in Guiyang tobacco-growing areas.In 2017,it was conducted at the test site of Xindian Village,Qingzhen City,Guiyang City.Six treatments were applied to reduce the amount of 1/4 base fertilizer used: CK1(regular fertilization,no high-carbon-based fertilizer),and CK2(conventional)Basic fertilizer application rate 3/4,no high-carbon base fertilizer,T1(conventional base fertilizer 3/4,high-carbon base fertilizer 1650 kg/hm2),T2(high-carbon base fertilizer 1500 kg/hm2),T3(high Carbon-based fertilizer 1350 kg/hm2),T4(high-carbon-based fertilizer 1200 kg/hm2).To explore the effects of different fertilizer application rates of high-carbon-based soils on the changes in soil nutrient and the quality of flue-cured tobacco in tobacco-planting soil,the main findings are as follows:1.The application of high-carbon-based fertilizers can increase the organic content in later stage of tobacco-planting soil,and increase with time.The content of organic matter in the middle and later stages of treatment is gradually higher than that of the control treatment,and the contents of T2 and T4 are the highest.The application of high-carbon-based fertilizers could increase the available potassium content in tobacco-planting soil in the middle and late period.The potassium content of T3 and T4 treatment at 120 d after transplanting still maintained at a higher level and was significantly higher than that of the control treatment.2.The invertase activity was significantly higher in all treatments from 30 d to 60 d after transplanting than that of the control,indicating that the nutrient levels of each treatment during this period were higher than that of the control;the sucrose activity of the soil treated with T3 at 90 d to 120 d after transplanting was still maintained at a relatively low level.High levels indicate that T3 treatment can significantly increase soil-soluble nutrients.3.The application of high-carbon-based fertilizers can increase soil microbial biomass carbon content.The 60 d T1,T2,and T3 treatments were significantly higher than the control,and the microbial biomass carbon content was significantly higher between the 90d-120 d treatments than the control,indicating that application of high-carbon-based fertilizers could increase microbial biomass carbon content,with T2 treatment and T3 treatment being better..Application of high-carbon-based fertilizers can increase soil microbial biomass nitrogen content.The amount of microbial biomass nitrogen was higher in the 30-90 d treatments than in the control,and the amount of microbial biomass nitrogen decreased from the T1 treatment to the T4 treatment 90 days after transplanting,indicating that the content increased with the increase of high-carbon-based fertilizers.4.Increasing the application of high-carbon-based fertilizers can effectively reduce the soil bulk density and increase the moisture content.With the increase of high-carbon-based fertilizers,the soil bulk density shows a decreasing trend,and the soil moisture content shows an increasing trend.5.There was no significant difference in plant height and stem circumference with high carbon-based fertilizer treatment in the early growth stage of tobacco plants compared with the control,while the number of leaves and leaf area were significantly higher than that of the control treatment.High-carbon-based fertilizer-treated strains were used in the later growth stages of the tobacco plants.The difference in height was not significant.The number of leaves treated with T3 was the highest,and the leaf area treated with T2 was significantly higher than that of the control treatment.The stem circumference of T1 treatment was significantly higher than that of the control treatment.6.The total sugar and reducing sugar content of each treatment was higher than the control treatment,indicating that the application of high-carbon-based fertilizers can increase the total sugar and reducing sugar content,but the control treatment of the highest nicotine content.The potassium content of T1~T3 treatment was higher than that of the control treatment,which effectively increased the ratio of potassium to chlorine in tobacco leaves.7.The application of high-carbon-based fertilizers can increase the content of carotenoids,cembrane-like and neophytadiene in the middle leaves,thus increasing the total amount of neutral aroma components,of which T2,T3 and T4 have a better treatment effect and are mainly increased.The materials are: beta-dihydrodamascone,farnesyl acetone,solanone and neophytadiene.8.Compared with CK2,the yields of T1 treatment,T2 treatment,T3 treatment,and T4 treatment were 3169.7 kg/hm2,3107.00 kg/hm2,3144.5 kg/hm2,and 3019.70 kg/hm2,respectively;Above the CK2 treatment,it increased by 10.63%,16.25 %,18.15 % and 9.28 % respectively;the economic benefits of T2,T3 and T4 treatments were positive,among which the new benefit of T3 treatment was the highest,reaching 5859.5 RMB/hm2.To sum up,reducing the application of high-carbon-based fertilizers in the case of a quarter base fertilizer can significantly improve the physical and chemical properties of the soil,increase the content of organic matter in the soil in different degrees,and increase the content of available potassium in the later stage of the tobacco-planting soil.The available phosphorus content in tobacco-planting soil;the high carbon-based application rate of 1350 kg/hm2 can significantly increase the soil sucrose enzyme activity,and the application amount of 1200 kg/hm2 to 1350 kg/hm2 can increase the previous soil urease activity;and increase the soil microbial biomass carbon content.Microbial nitrogen content increased and its content increased with the increase of high-carbon-based fertilizers.It also has certain influence on the increase of stem area and leaf area of tobacco plants.At the same time,it increases total sugar,reducing sugar and potassium content in tobacco leaves,increases the content of neutral aroma components,and economic indicators have been further improved. |
