| Tobacco is one of important economic crops in Fujian Province.As the high temperature and rainy climate,the strong desilicification and allitic enrichment,strong eutrophic wastage,strong soil acidity,boron nutritional in soil deficiencies is one of the obstacle factors to affect normal growth and development of tobacco.Currently,there are no study on boron nutrition of the adsorption and leaching conditions,the index abundance of soil solution boron sufficiency and deficiency index of tobacco soil of Fujian,there are still blind in the reasonable application of boron fertilizer.Therefore,indoor soil-culture,simulation experiment with repacked soil columns,the water culture experiment,soil culture experiment and field survey methods were combined to study the absorption rule of boron nutrition in soil of tobacco Fujian and leaching rule,index of abundance and deficiency of tobacco available boron in soil,for the reasonable use of boron in Fujian flue-cured tobacco production to provide reference.This study found that:1.The results of indoor soil-culture show that:(1)Under the same dosage of boron(pure boron 50 mg·kg-1),boron was applied to the soils in the first 5 to 10 days,the content of available boron in soil was increased significantly,The amount increase of available boron in yellow mud field soil was higher than plaster field;When boron was applied 35 days,both the amount of the increased available boron in soil was the minimum value during cultivation perid;After in training 35 days,the amount of the increased available boron in plaster field was more than that in yellow mud field.(2)The application of boron + calcium(pure boron 50 mg·kg-1 + pure calcium 500 mg·kg-1)and boron fertilizer(pure boron 50 mg·kg-1)treatment,the increase in the amount of available boron in soil is different,that was,a fixed rate of absorption was different.Application of boron + calcium treatment field was conducive to boron adsorption and fixed on yellow mud field,was not conducive to boron adsorption and fixed on plaster field.After the application of boron + calcium,the effectiveness of soil available boron mainly accure in the early stage of cultivation.With the cultivation go along,with and without calcium in the two treatments,the differential of the fixed rate of adsorption of boron was no significace level in yellow mud field,but plaster was significant difference.(3)Adding the same amount of calcium in different soil(pure calcium 500 mg·kg-1)had affect the amount increased of available boron in soil.For yellow mud field,the change of the amount increased of available boron in soil and the changes of content available calcium in soil was negatively correlated,the change of the amount increased available boron in plaster field and the changes of content of available calcium in soil have no significant correlation.2.Simulation experiment with repacked soil columns showed that:(1)Boron in the soil is very easy leached.Under the same rate of boron fertilizer(pure boron 50 mg·kg-1)application,at the leaching of the first 10 days,amount of leaching boron in the yellow mud field and plaster field had reached to the total leaching boron loss of 63.29%～70.03%;In the first 25 days of leaching,the cumulative leaching was 91.93%～95.06%of the total leaching loss.(2)Yellow mud field,plaster field at the same rate of calcium + Boron(pure calcium 500 mg·kg-1,pure boron 50 mg·kg-1)treatment fertilizer application.the amount of accumulated volume was not less than leaching of boron fertilizer(pure boron 50 mg·kg-1)treatment.Although the application of calcium increased the points quality of soil boron adsorption,but may be the binding force between the siol crystals and soil boron is weak,and leaching loss was easy due to continuing leaching.(3)Yellow mud field,plaster field of boron fertilizer(pure boron 50 mg·kg-1)application and application of calcium + boron(pure calcium 500 mg·kg-1,pure boron 50 mg·kg-1)treatment,the total amount leaching of boron nutrient in soil and the total leaching of calcium nutrition was positively correlated.3.The results of water culture experiment obtained:When the concentration of boron in nutrient solution was 0 mg·kg-1～0.2 mg·kg-1,the Tobacco seedling leaves was fold,smaller leaves,light color at the early stage,leaf heart was black and rosette,arrest of growth,then top dieback,boron deficiency symptoms of tobacco seedling show obviously;at this time,boron content in leaves of tobacco seedlings was usually less than 25 mg·kg-1 When the concentration of boron in nutrient solution was 0.2mg·kg-1～2.0mg·kg-1,the tobacco seedlings was more vigorous physiological metabolism,growth is normal;this moment boron content in leaves of tobacco seedlings usually was 25 mg·kg-1～65 mg·kg-1.When the concentration of boron in nutrient solution was 2.0 mg·kg-1～50 mg·kg-1,the tobacco seedling growth was inhibited,biomass decline;boron content in leaves of tobacco seedlings at this time usually is 65 mg·kg-1～230 mg·kg-1.When the concentration of boron in nutrient solution was 50 mg·kg-1～400 mg·kg-1,the tobacco leaf appeared yellowish brown spots early,leaf marginal is orange-yellowish and curl downwards,slow growth or no growth,and finally dead,toxic of tobacco boron was serious;then boron content in leaves of tobacco seedlings was general more than 230 mg·kg-1.4.The results of soil culture showed that:When the content of available boron in soil is 0.638 mg·kg-1,tobacco plants like this treatment,in vigorous period,the lowest starch、the highest amino acid and carbon and nitrogen metabolism was more coordination;In mature of tobacco leaf feet(about 70 days after transplanting),when the content of available boron in soil was 0.638 mg·kg-1,tobacco height was the largest and more than 0.87～10.70cm than other treatments,stem circumference was 0.25～0.70cm,tobacco was growing better,when content of available boron in soil was lower than 0.448 mg·kg-1 and 1.215 mg·kg-1～2.252 mg·kg-1,tobacco growth was affected at some extent,when content of available boron in soil was 4.614 mg·kg-1,tobacco growth was affected severely.Roasted tobacco after physiological maturity,when content of available boron in soil was 0.638 mg-kg-1,dry weight of tobacco was the largest,more than the other treatments 2.33%～17.01%,compare with when the content of available boron in soil was 0.015 mg·kg-1 and 1.620 mg·kg-1,difference between the dry weight was significant.According to the growth potential of flue-cured tobacco,physiological and metabolic characteristics of tobacco、accumulation of biomass at the content of available boron in soil each treatment with different level,comprehensive analysis of the situation,initially obtained index of abundance and deficiency of tobacco available boron in soil:when the content of available boron in soil was lower than 0.2 mg·kg-1 is the lack,0.2 mg·kg-1～0.5 mg·kg-1 as a potential lack,between the 0.5 mg·kg-1～1.0 mg·kg-1 is the appropriate;more than 1.0 mg·kg-1～1.5 mg·kg-1 was high,;more than 1.5 mg·kg-1 over.5.From soil samples collected in fujian tobacco planting area:the content of available boron in soil was in the trace～1.22 mg·kg-1 range,with an average of 0.17 mg·kg-1.lower than 0.2 mg·kg-1 of the content of available boron in soil was accounted for 67.08%of soil samples,0.2 mg·kg-1～0.4 mg·kg-1 of the content of available boron in soil was accounted for 25.87%of soil samples,0.4 mg·kg-1～0.6 mg-kg-1 of the content of available boron in soil was accounted for 5.68%,and more than 0.6 mg·kg-1 of soil was accounted for 1.37%.Note that most of Fujian Tobacco boron nutrition in the soil is obviously insufficient,attention should be paid to the application of boron nutrition. |
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