Effects Of Different Chlorine Dosage And Duration On Chlorine Content,Yield And Quality Of Soil And Tobacco Leaves

In view of the low water-soluble chlorine content and insufficient chlorine content of tobacco leaf in Hunan tobacco planting soil,field experiment and simulated(pot)experiment were used to study the chlorine content of soil with different amount of chlorine application,different amount of chlorine in soil and different amount of chlorine in the soil during the period of use.The effects of tobacco leaf chlorine content,growth and development of tobacco plants and physical,chemical and economic properties of flue-cured tobacco leaves were studied.The leaching effect and intensity of soil water movement on soil chlorine were studied by simulated field irrigation.The main results are as follows:1.Under pot conditions,the leaching loss and accumulation of chlorine in soil were affected by different amount of chlorine application and time of chlorine application.If all chlorine was applied as base fertilizer,the leaching loss ratio of chlorine was 48.0%～56.2%,respectively.The amount of chlorine leaching will increase with the increase of chlorine application.If 50%chlorine was used in basal fertilizer and 50%in top fertilizer,the leaching loss ratio of chlorine was 28.3%～30.2%,and the leaching loss ratio and leaching amount of chlorine decreased obviously compared with the treatment of all chlorine as base fertilizer,but with the increase of chlorine application,the leaching loss ratio of chlorine did not change much,but the amount of leaching increased obviously.Therefore,the combination of basal fertilizer and topdressing can improve the content of water-soluble chlorine in soil.2.Under pot conditions,the peak absorption of chlorine in flue-cured tobacco was 30days after transplanting,chlorine was applied as basal fertilizer and 50%chlorine was applied to base fertilizer,and the chlorine content of tobacco leaves with 50%chlorine application increased with the increase of chlorine application rate.Under the same amount of chlorine,the chlorine content of tobacco leaves could be increased more effectively by applying 50%chlorine to basal fertilizer and topdressing than all chlorine as basal fertilizer.When all chlorine was used as base fertilizer,the water soluble chlorine content in soil of flue-cured tobacco increased obviously in the early stage of flue-cured tobacco,and increased with the increase of chlorine application rate,but decreased sharply with the loss of chlorine and the absorption of flue-cured tobacco.At the middle and late stages of flue-cured tobacco growth,the soil dissolved in water.There was no significant difference in the content of sexual chlorine between the two groups.The application of 50%chlorine in basal fertilizer and topdressing could obviously increase the content of water-soluble chlorine in soil of flue-cured tobacco in the middle and late stages of flue-cured tobacco,which was beneficial to the absorption of chlorine in tobacco leaves and thus to the increase of chlorine content in tobacco leaves,but there was also a risk of excessive chlorine in tobacco leaves.Different chlorine dosage and life had little effect on dry matter accumulation of flue-cured tobacco.3.Under field conditions,the content of water soluble chlorine in the soil treated with chlorine(0～60 kg/hm~2)increased with the increase of the amount of chlorine applied,and the content of water soluble chlorine in the soil at the harvest stage of tobacco leaves increased by 1.7～32.0 mg/kg.However,the changes of each test site are different,and there are also great differences among different years and regions.There was a significant or extremely significant positive correlation between the chlorine content and the amount of chlorine applied in all treatments of basal fertilizer(0～60 kg/hm2).The chlorine content in the upper leaves increased by 0.07%～0.91%and 0.06%～0.60%,respectively,at most of the test sites.The increase of chlorine content in tobacco leaves was not significant,and the chlorine content and potassium chlorine content of tobacco leaves were more suitable when the amount of chlorine applied in the base fertilizer of Liuyang test site was 30 kg/hm~2,and when the amount of chlorine application exceeded 45 kg/hm~2,the chlorine content of tobacco leaves exceeded the standard.In Taoyuan,Cili and Longshan test sites,when the amount of chlorine applied was 45 kg/hm~2,the chlorine content and potassium-to-chlorine ratio of tobacco leaves were all within the appropriate range,but there was still a risk of lower chlorine content in tobacco leaves if the amount of chlorine applied to base fertilizer was less than 45 kg/hm~2.There were no significant effects on the growth and development of flue-cured tobacco,the main intrinsic chemical components,the economic and physical properties of tobacco leaves with different amounts of chlorine application.4.There were no significant effects on the agronomic characters,economic characters and physical properties of flue-cured tobacco under the condition of different amount of chlorine and the duration of use in the field of flue-cured tobacco.When the amount of chlorine is 45 kg/hm~2,and 50%chlorine is applied to base fertilizer and top fertilizer respectively,the chlorine content of soil and tobacco leaves is not only increased effectively,the chlorine content of tobacco leaves is 0.54%～0.59%,the ratio of potassium/chlorine is7.44～7.88,Compared with the control,the yield of tobacco increased by 75 kg/hm~2,the output value increased by 3354 yuan/hm2,and the quality of tobacco increased.And when the chlorine level is 75 kg/hm~2,and the base fertilizer is The chlorine content of 140.82mg/kg,tobacco leaves was 0.94%～1.13%,and the content of chlorine in soil was higher than the upper limit of the suitable value,and the quality of tobacco leaves was affected by the application of 50%chlorine in the topdressing.At the same time,it was found that the content of water soluble chlorine in soil of 15 cm～20 cm soil layer was significantly higher than that of 35 cm～40 cm and 55 cm～60 cm,in the treatment of low chlorine content of basal fertilizer during rosette stage.The content of water soluble chlorine in 15 cm～20 cm soil layer was significantly lower than that of 35 cm～40 cm in the 15 cm～40 cm soil layer treated with chlorine fertilizer with high chlorine content.And 55 cm～60 cm,and 50%chlorine application of basal fertilizer and topdressing respectively showed different variation regularity of chlorine content in different soil layers of soil profile.The soil chlorine content in 35 cm～40 cm and 55 cm～60 cm soil layers was significantly higher than that of 15 cm～20 cm,during the prosperous period,indicating that there was a large leaching loss of chlorine in the soil.In conclusion,under the soil climate conditions of Hunan tobacco area,the chlorine dosage of 45 kg/hm~2,and the application of 50%chlorine each of the base fertilizer and topdressing fertilizer had a better effect on the absorption and utilization of flue-cured tobacco and the increase of soil chlorine content.The leaching effect of chlorine in soil is relatively strong,chlorine is all used as base fertilizer,chlorine in soil is easy to be leached,so that the utilization efficiency of chlorine is not high,under the condition that the amount of chlorine is not enough,the available chlorine for tobacco is still relatively small.Tobacco may still be characterized by inadequate chlorine nutrition;The use of part(or 50%)chlorine as topdressing can reduce the risk of chlorine leaching and increase the absorption of chlorine by tobacco to a certain extent.To solve the problem of inadequate chlorine nutrition in tobacco.