| In this thesis , the effects of acid materials on calcareous soil were studied by using laboratory soil trial and pot experiments trail. The text studied effects of acid materials on pH value in calcareous soil ; studied effects of phosphoric acid (H2SO4 as control) on pH value and micronutrient availability ; studied relation between P and available Fe, Zn in plant; studied effects of acid material on growth of acidophilic plant. The result indicated : (1) phosphoric acid could effectively reduce the pH value in calcareous soil . under condition of the trial, the best acid quantity was 3. 27g , making soil pH value via 8.89 to about 6.0 . (2) in superior soil pH value , it was not practicality , only by lower pH value(5.5) acid solution acidifying in calcareous soil .(3)NH4H2PO4 not only possed better acidification effects ; but also had better buffer capability . NH4H2PO4 could make soil pH value with 8.9 reduce by 2.5 units and persist longer acid condition, only by adding 2.3g NH4H2PO4 average pre 100g calcareous soil .(4) In the condition of the trial , the best dosage of S was 5% of soil weight, making soil pH value with 8.90 reduce to 7.0~7.5 in one month . (5) phosphoric acid and sulfuric acid could reduce dramatically soil pH value , Acidification of phosphoric acid outweighted sulfuric acid at low concentration, however it was opposite at high concentration . (6) the content of available Fe and Mn rised at first and then declined . when phosphoric acid concentration was less than 0.75mol/L,effects of phosphoric acid was more than sulphuric acid on available Fe . when phosphoric acid concentration was more than 0.75mol/L, effects of phosphoric acid was less than sulphuric acid on available Fe; concentration of phosphoric acid and sulphuric acid enhance individually to 2 and 1mol/L, if acid concentration went on rising ,the content of available Fe, Mn would reduce, when phosphoric acid concentration was lower , The antagonism between P and Fe was not showed in soil and plant, but at higher concentration, The antagonism between P and Fe was indicated in soil and stem of peanut. (7) With increasing of acid concentration, the content of available Zn would enhance ,too. The antagonism between P and Zn did not show in soil and plant. (8) With increasing of acid concentration, the content of available Cu was also added but the content of Cu went down dramatically as concentration of sulfuric acid exceeded a higher concentration(1mol/l). effects of phosphoric acid outweighted sulphuric acid on availableCu . (9) From different acid medium trial , we knew that NH4H2PO4 treat was similar to peat treat , completely replacing NH4H2PO4 treat for peat treat , which could reduce cost of planting , enhance benefit . In bud period , leaves manifest different -Fe symptom in different treats .but the symptom would reduce in flower period . From all aspect , treat was the best , and make acidophilic plant grow better . |
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