Research On The Seasonal Changes Of The Soil Base Cations In Different Artificial Chinese Fir Plantations In The Areas With Different Distances To The Acid Rain Area

With the development of the City industrialization and the increase of the global population,theproblem of acid rain is more and more serious.The phenomenon of acid rain is increasingly serious in ourcountry and China has been the third biggest acid rain area.Acid rain can not only affect the growth of theplants but also cause the soil fertility decline.In this thesis,Shaowu,the typical acid rain city in the south, wasselected as the experiment area.The fixed sample areas of the artificial Chinese fir plantations of differentages(1years old,5years old,10years old,15years old,20years old) were established in the pollution sourcearea,the area close to the pollution source and the area far away from the pollution source.The changes rule ofthe content of the soil exchangesable base cations in different artificial Chinese fir plantation in different areaswas analyzed.The research result laid the theoretical foundation of the sustainable management of the artificialChinese fir plantation in the acid rain area.The reseach showed the following results:With the increase of the distance to the acid rain area, in the same soil layer of the plantations of the sameage and season, on the whole the content of the exchangesable K and Ca decreased, minimum soilexchangeable Na content is the acid area, the maximum exchangesable Mg changesd in the area far from acidarea; with the increase of the soil depth, on the whole the content of the exchangesable K and Ca decreased,the content of the exchangesable Na decreased in spring, winter in the acid area, the maximum exchangesableMg changesd in the soil layer A; With the postponement of the season, in the same soil layer of the plantationsof the same age, the highest contents of the exchangesable K was put off from summer to autumn while1-year-old was advance autumn to summer,10-year-old and15-year-old both appeared at summer, the highestcontents of the exchangesable Na advance autumn to summer, the highest contents of the exchangesable Cawas put off from summer or autumn to winter, the highest contents of the exchangesable Mg was put off fromsummer to autumn while20-year-old advance summer to winter.On the whole,with the increase of the plantation age, in the same soil layer in the same season,the totalcontent of the exchangesable cations of Chinese fir plantations of different ages presented the following trend:the chang increased in the1to10-year-old, the maximum10-year-old fir,and decreased from the10to20-year-old, the maximum10-year-old fir; the soil exchangesable K was1to5-year-old showed an increasingtrend, the maximum5-year-old fir,1to5-year-old showed a decreasing trend,15to20-year-old showed anincreasing trend; the change of the soil exchangesable Na content in spring and winter was similar toexchangesable K;the content of the exchangesable Ca, Mg presented the following trend:1or20-year-oldreached the lowest,the chang increased in the1to10-year-old,10-year-old reached the maximum,anddecreased from the10to20-year-old.