Acidification Characteristics And Their Influencing Factors Of Red Paddy Soil Derived From Different Parent Materials

There are many types of red soil parent materials in Jiangxi Province,but few comparative studies on acidification degree of red paddy soil derived from different parent materials,and the effect of soil properties on soil acidification degree is still unknown.At the same time,for a long time,the effect of typical fertilization measures on the acidity improvement of red paddy soil also needs to be verified.Therefore,under the condition of chemical fertilization in Jiangxi province,red paddy soil derived from quaternary red earth,plate shale,red sandstone and granite,and a long-term experimental under the condition of typical fertilization,were adopted as research objects.To clarify the acidification characteristics and influence factor of red paddy soil derived from four parent materials under,verify the improvement effect of long-term typical fertilization on soil acidification.The main results are as follows:(1)In Jiangxi Province,compared with the 1980 s,the p H of red paddy soil derived from four parent materials decreased by 0.47 units averavge,?p H of red sandstone(0.56)and granite(0.54)were the highest,followed by quaternary red earth(0.34)and plate shale(0.32);the BS% decreased by 13.93%,?BS% of granite is the highest(22.53%),plate shale is the lowest(2.66%);the exchangeable acid and exchangeable aluminum increased by 0.43 and 0.20 cmol/kg,respectively.The red sandstone has the highest increment of exchangeable acid and exchangeable aluminum.It indicates that the acidification of red paddy soil is significant in recent 40 years in Jiangxi Province,the degree of acidification of paddy soil derived from red sandstone and granite is relatively higher than that of quaternary red earth and plate shale.(2)Compared with CK treatment,NPK,NPK+GM+S and NPK+GM+M treatment could significantly increase soil p H about 0.38 units;the BS% were significantly increased 7.48%?11.06%,exchangeable acid and exchangeable aluminum were significantly decreased 49.54%?32.41% and 14.89?60%.99%,respectively.Therefore,NPK,NPK+GM+S and NPK+GM+M treatment could improve soil acidification.(3)The results of redundancy analysis showed that soil physical,chemical properties and their interaction could explain 85% of the variation in acidification.Cation exchange capacity(CEC),Available phosorus(AP),sand content,and clay content could explain 59.9%,1.8%,13.2%,and 2.0%(P<0.01)of the variation in the acidification indexes,respectively.However,the soil physico-chemical properties of paddy soil derived from quaternary red earth under the chemical fertilization could explain 61.4% of the variation of acidification index,TP,SOM,AP and AN could explain 28.5%,12.5%,9.8% and 6.6% of the variation(P<0.05),respectively.Therefore,cation exchange capacity,available phosphorus,sand,clay,organic matter,alkali hydrolyzable nitrogen are the main factors affecting the acidity change of red paddy soil.