| Simulation experiment with repacked soil columns,indoor soil-culture,pot experiment,field experiment and field investigation were conducted to study the rule of the leaching lose and the transference of Ca fertilizer in different soil,suggested the indexes of abundance and shortage of available Ca in soil with flue-cured tobacco and optimum content of Ca in tobacco leaf,studied Ca fertilizer rational application effect,and appraised the ability of soil to supply Ca in Fujian tobacco planting area.1.The results of an indoor simulating experiment with repacked soil columns showed that the leaching ratio of exchangeable calcium was different in different soil,and the yellow mud field (16.05%)＞the moist sandy field(12.03%)＞the paddy field(11.22%).The leaching ratio of the calcium fertilizer is 5.45%,8.50%,10.89%respectively in the paddy field,the yellow mud field,the moist sand field.2.Soil culture experiment results showed that the ratio of clench in three soils was in the following order:Paddy field(55.28%)＞Yellow mud field(47.57%)＞Moist sandy field(39.31%) when Ca(NO3)2 was applied in 90 days.Experiment results showed that in the condition of commensurable Ca(NO3)2 application in the paddy field and moist sandy field,the influence of KNO3,KCI and K2SO4 application to exchangeable calcium of soil was in the following order:KNO3＞KCl＞K2SO4:In the condition of commensurable Ca(NO3)2 application in the paddy field and moist sandy field,the influence of K2SO4and MgSO4 application to exchangeable calcium of soil was in the following order: MgSO4＞K2SO4.3.Correlation research of soil exchangeable Ca and fiue-cured tobacco Ca uptake showed that:the content of soil exchangeable Ca(CH3COONH4-A-AS) had good relationship with tobacco-leaf,tobacco-root,tobacco-stem and whole tobacco plant Ca uptake,the correlation coefficient were up to 0.993,0.994,0.985 and 0.995 respectively,being extremely remarkable positive in correlation(r0.01=0.834).4.The result of the pot experiment showed that,after tobacco seedlings were transplanted for 35 days,the number of leaves of Ca1 treatment(370.23mg.kg-1),Ca2 treatment(436.22mg.kg-1) and Ca3 treatment(511.75mg.kg-1) were least(6.0 piece/individual plant);the number of leaves of Ca6 treatment(939.92mg.kg-1) and Ca7 treatment(1142.33mg.kg-1) were most(8.0piece/individual plant);plant height,stem girth and the number of leaves of Ca8 treatment(1540.21mg.kg1) were less than those of Ca7 treatment.Chla,Chlb and nitrate reducetase and Car content of the tobacco leaf of Cal treatment were lowest,attaining the remarkable or extremely remarkable level in contrast with Ca7 treatment.MDA content of flue-cured tobacco leaf of Ca7 treatment reached the lowest value with 4.60nmol.g-1FW,attaining the extremely remarkable level in contrast with Cal treatment and Ca8 treatment.Nitrogen content of tobacco leaf of Ca8 treatment reached the peak value of 2.17%,and nitrogen content of tobacco leaf of other treatments was less 0.18～0.57 percentage points than that of Ca8 treatment.The quantity of phosphorus of tobacco leaf of Cal treatment was maximal(0.26%),and the quantity of phosphorus of tobacco leaf of other treatments was less 0.05～0.07 percentage points than Ca1 treatment.Potassium content of tobacco leaf of Ca6 treatment reached the peak value of 2.02%,and that of other treatments was less 0.09～0.48 percentage points than Ca6 treatment.According to biochemical and physiological index,relative biomass index and absorption of nourishiment of each tobacco treatment in flourishing stage,it might be rational to classify the indexes of abundance and shortage of exchangeable Ca in soil with flue-cured tobacco:it might initially be considered that less than 400mg.kg-1) of soil exchangeable calcium was calcium deficiency(the ratio between the biomass of Cal treatment and the maximal biomass was 52.63%), 400mg.kg-1～700mg.kg-1 was calcium slightly insufficient(the ratio among the biomass of Ca2, Ca3 and Ca4 treatment and the maximal biomass were up to 64.17%,70.74%and 70.10% respectively),700mg.kg-1～1200mg.kg-1 was suitable(the ratio among the biomass of Ca5,Ca6 and Ca7 treatment and the maximal biomass were up to 83.00%,86.07%and 100% separately),more than 1200mg.kg-1 was rich.Considering the content of soil exchangeable calcium and calcium of upper part leaf in flourishing stage,it might initially be considered that calcium content was less than 1.30%for to lack the calcium,1.30%～1.50%for the calcium to be slightly insufficient,1.50%～1.70%for the calcium to be suitable,and was more than 1.70%to be sufficient for the calcium element in the upper part leaf in flourishing stage.5.The field test result indicated that,with the addition of Ca fertilizer applied,growth and develop ment period was delayed when the content of soil exchangeable calcium was higher(827.16 mg.kg-1);the economical character of all treatments is better while the Ca fertilizer application was 0.0kg.hm-2(A treatment),whose plant height,stem girth,the number of effective leaves,the maximal length of leaf and the maximal width of leaf reached the peak value of 107.1cm,10.8cm,18.6 piece/individual plant,81.0cm and 34.8cm respectively in squaring stage of tobacco leaf. yield,output value and the average price of flue-cured tobacco reached the peak value of 3201.15 kg.hm-2,36493.35 yuan.hm-2 and 11.40 yuan.kg-1 respectively while Ca fertilizer application was 0.0kg.hm-2(A treatment).Dolomite power wasn't applied in the soil where the content of exchang -cable calcium was 827.16mg.kg-1.6.By analyzing 2,222 representative soil samples in Fujian tobacco planting area the results indicated that content of soil exchangeable calcium was 42.70mg.kg-1～1820.80mg.kg-1,averaged 522,03mg.kg-1 in Fujian tobacco planting area.The average content of soil exchangeable calcium in Sanming,Nanping and Longyan tobacco planting area were 555.40 mg.kg-1,498.88 mg.kg-1and 489.72 mg.kg-1 respectively.The three great tobacco planting areas all had Ca-deficient soils.The ratio of the Ca-dificient soils were 41.75%,31.59%and 32.05%in Longyan,Nanping,Sanming respectively. |
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