Studies On Chlorine Nutrition Of High-quality Flue-cured Tobacco Production In Fujian Province

Field investigation,simulation experiment with repacked soil columns,indoor soil-culture, pot experiment,field experiment and sense appraisal of high grade leaf were conducted to study the rule of migration,accumulation and adsorption of the chlorine-nutrition in different soil and under the different accompanying ions.The indexes of abundance and deficiency of water-soluble chlorine content in soil,and the optimun chlorine content of high quality tobacco leaves,were proposed under Fujian climate and soil conditions.They provided certain scientific basis for chlorine fertilizer reasonable application of flue-cured tobacco.1.The results of simulation experiment with repacked soil columns showed that:(1)Chlorine nutrient was very easily leached from soil,and mainly occurred in the early stage of leaching. Having been leached after 16 days,the amount of chlorine and chlorine fertilizer leaching loss in different soils accounted for the total of 78.01%-84.35%and 95.42%-97.78%respectively;The chlorine leaching rate of different soils in two cases,applying chlorine and not applying chlorine, were for the yellow mud field＞the moist sandy field＞the paddy field,which was correlated with the soil clay content.(2)In different amount of chlorine fertilizer(40mg·kg^-1,100mg·kg^-1and 220 mg·kg^-1)and the same leaching time,the leaching amount of chlorine fertilizer increased with the addition of chlorine fertilizer,but the leaching rate of chlorine fertilizer showed a decreasing tendency,and their leaching rates were 97.57%,88.82%and 88.51%,respectively.(3)Under the same amount of chlorine fertilizer(100mg·kg^-1),to a certain extent,three kinds of accompanying anions,SO₄^2-,NO₃^-,and H₂PO₄^-,promoted chlorine nutrition leaching,but their effect was not so obvious;Accompanying cation inhibited the chlorine fertilizer leaching in soil to a certain extent, and the leaching rate was for K⁺(88.42%)＞Mg²⁺(87.97%)＞Ca²⁺(83.93%),which showed that Ca²⁺applied in soil made the chlorine leaching rate reduce.2.The results of the indoor soil-culture indicated that:(1)Under the same dosage of chlorine fertilizer(100mg·kg^-1),when chlorine fertilizer had been applied on the fifth day,the increased amount of soil water-soluble chlorine was a little more than chlorine charge applied,and the moist sandy field,the paddy field and the yellow mud field increased 6.01mg·kg^-1,11.6mg·kg^-1,3.35 mg·kg^-1respectively;When chlorine fertilizer was applied after 35-45 days,the increasing amount of water-soluble chlorine in yellow clayey field reduced about 7-8mg·kg^-1.(2)Under the same dosage of chlorine fertilizer(100mg·kg^-1),the water-soluble chlorine content of the treatments added NO₃^- and H₂PO₄^- had little difference,and the treatments added SO₄^2-was slightly higher; When chlorine fertilizer applied after 35-45 days,the water-soluble chlorine increased content of the treatments added K⁺ and Mg²⁺in soil reduced 2mg·kg^-1than chlorine charge applied,while the treatments added Ca²⁺reduced 7mg·kg^-1,which showed that the chlorine adsorption amount in soil relatively increased by adding Ca²⁺.(3)The results of the correlation analysis on the indoor soil-culture of different soils,different accompanying anions and accompanying cations,showed that the water-soluble chlorine content all was significantly positive correlated with their corresponding pH,which showed that pH was the important factor that affected soil water-soluble chlorine content.3.Pot experiment results showed that:When the soil water-soluble chlorine content was 33.66 mg·kg^-1(2 treatment),Chla,Chlb,chlorophyll and carotenoid content were relatively higher. When the soil water-soluble chlorine content was more than 33.66mg·kg^-1(2 treatment)or less than 162.07mg·kg^-1(6 treatment),the net photosynthetic rate of flue-cured tobacco leaves obviously declined.Nitrate reductase activity among treatments of the soil water-soluble chlorine content under 162.07mg·kg^-1had little difference;NR activity beyond 239.13mg·kg^-1dramatically reduced,and in the same time the nitrogen metabolism had been hindered.Tobacco plants had luxury characteristics of absorbing chlorine nutrition,namely the chlorine in soil was easily absorbed by tobacco plants and excessively accumulated in tobacco leaves,there was significantly positive correlation between the chloride content of tobacco leaves and the soil water-soluble chlorine content.When the soil water-soluble chloride content was 11.38mg·kg^-1(1 treatment),tobacco plants had no appeared symptoms of chloride deficiency,but their growth had been affected to some degree;When the soil water-soluble chlorine content was beyond 330.42mg·kg^-1,tobacco plants hadn't appeared symptoms of chloride poisoning in earlier stage of tobacco plant growth,but they gradually appeared symptoms from the topping stage to maturity,and the symptoms gradually worsened with the growth process.The detailed performances displayed that:dwarf tobacco plants, leaflet,invisible green leaf color,hypertrophy leaves,new leaves pumping difficultly growing point necrosis,crisp fresh leaves,leaf tips downward curling and shrinkage showing half-fronds, leaf deformity.The biomass of the soil water-soluble chlorine content for 33.66mg·kg^-1(2 treatment)was the largest,and there was very significant difference with other treatments' biomasses.4.Field experiment results showed that:In soil whose water-soluble chlorine content was 19.93mg·kg^-1,when the amount of chlorine fertilizer was 22.5kg·hm^-2(B treatment)and 45.0 kg·hm^-2(C treatment),yield and output value of flue-cured tobacco were 2894.85kg·hm^-2, 2694.90kg·hm^-2and 28312.43yuan·hm^-2,27937.13yuan·hm^-2respectively,but yield and output value had no reached significant difference each other.The smoking result of tobacco leaves of the control treatment was the best,and the result of the amount of chlorine fertilizer for 22.5 kg·hm^-2(B treatment)treatment was also better.5.The sense comments of middle tobacco leaves showed that:When the chlorine content of tobacco leaves was 0.46%-0.66%,the smoking results were best.there were the concentration-faint sent aroma style and a sweet sense,the better quality of aroma,full aroma,middle concentrated zeal,good sweet sense,yet delicate,good taste,but the back-end residual slightly,in other words,it was good in general;The smoking results of tobacco leaves of the chlorine content for 0.75%took second place,strength which was slightly,slightly dry and offensive odor;When the chloride content was beyond 0.99%,all the smoking indexes had significantly decreased.6.Considering the growth condition and the size of biomasses of tobacco plants which were from the pot experiment,the yield and output value of tobacco leaves and the smoking results of tobacco leaf samples in the field test;The soil was preliminary regarded as deficiency when the soil water- soluble chlorine content was under 15mg·kg^-1,latent deficiency when it was15mg·kg^-1 -25mg·kg^-1,suitable when it was 25mg·kg^-1-35mg·kg^-1,sufficient when it was up to 35mg·kg^-1, serious overdose when it was beyond 330mg·kg^-1which resulted in flue-cured tobacco poisoning. It was suitable when the chlorine content of tobacco leaves was between 0.46%-0.66%,and the quality of tobacco leaves was severely affected when it was more than 0.99%.7.Through determining and analyzing the 2555 representative soil samples from Fujian tobacco area,the results showed that:The soil water-soluble chlorine content changed from 0mg·kg^-1to 461.50mg·kg^-1,averaged for 26.30mg·kg^-1in Fujian.From the three major tobaccogrowing areas,the average content of soil water-soluble chlorine was for Longyan(30.95mg·kg^-1)＞Sanming(24.48mg·kg^-1)＞Nanping(22.95mg·kg^-1).The soil in Fujian tobacco areas was in a serious shortage of chlorine,the rate of the soil which had low ability of water-soluble chlorine supply were 72.21%,66.11%,52.88%in Nanping,Sanming,Longyan.