Effects Of Clay Mixed With Sands On Root Zone Soil Environment And Yield And Quality Of Tobacco

Through the improvement of tobacco growing soil texture, improve the habitat of rootsand nitrogen, potassium nutrition and photosynthesis, and in order to provide technicalguidance to improve tobacco production and theoretical basis. Pot experiments wereconducted using flue-cured tobacco cultivar Qinyan96to investigate effect of mixingdifferent mass fraction of sand into clay soil i.e. S0(control,0), S1(10%), S2(20%), S3(30%)and S4(40%) on soil physical properties, nitrogen and potassium contents of roots and leaves,agronomic traits,photosynthetic characteristics and yields of flue-cured tobacco in ShaanxiProvince.The results showed that:1.With the increasing of mass fraction of sand mixed in clay soil, soil bulk densitydecreased whereas soil porosity increased.2.With the increasing of mass fraction of sand mixed in clay soil, microorganisms, thenumber of soil microorganism, soil enzyme activity, carbon and nitrogen ratio of tobacco leaf allhave the trend: increased firstly and then decreased, the number of microbe and soil enzymeactivity were higher in S2(20%) and S3(30%) treat(no significant difference); potassiumcontent in flue-cured tobacco are highest in S3(30%)treat.3.The amount of soil microorganisms, soil enzyme activity, carbon and nitrogen ratio oftobacco leaf and potassium content were all higher in luonan than longxian in these treatmentswith mixing sand.4.By analysis field soil mixed with sand test enzymes can be concluded that, at the samemixed with sand mass fraction, soil enzyme activity were different at different growth stagesof flue-cured tobacco, and at different treatments different soil enzyme activities were alsodifferent. The best performance of Catalase and invertase activity occurred in S4(40%)treatment. Catalase and invertase activity of S2(20%) treatment is the highest at the dome andthe harvest period; phosphatase and urinary enzymes activity of S0(0) treatment is the highestat topping period, S3(30%) treatment showed the highest activity at dome; phosphataseactivity of S0(0) is the highest and urease activity of S4(40%) is the highest at the harvestperiod; with the advance of the growth period, invertase and phosphatase activity clearlyshow the trend firstly and then decreased. 5.With the increasing of mass fraction of sand mixed in clay soil, the root activity,nitrogen and potassium contents of roots and leaves, net photosynthetic rate (Pn), chlorophyllcontent, transpiration rate (Tr) and intercellular CO2concentration (Ci) and yield productionall showed the trend of increase firstly and then decrease. The best performance occurred inS3(30%) treatment.6.From the simulation equation, the optimal mass fraction of sand mixed in clay soil was23.62%under the current condition.