山东寿光不同种植年限设施土壤的酸化与盐渍化

Acidification and salinization in greenhouse soil of different cultivating years from Shouguang City,Shandong

以山东寿光不同种植年限设施菜地为对象,研究并分析了土壤的酸化与盐渍化状况,结果表明:设施菜地土壤pH值平均为6.86,全盐含量为2.47g.kg-1,与露天菜地、自然土相比有较明显的酸化与盐渍化现象;设施菜地在连续种植0-12.7a间,土壤pH值随种植年限增加而降低,12.7a后则出现随种植年限增加而升高的现象,土壤全盐含量则表现出与pH值相反的变化趋势,其发生变化的转折年限约为8.4a;设施土壤中的Na+,Mg2+,Cl-,SO24-含量随种植年限的变化均表现出与土壤全盐量相同的趋势,且与种植年限的相关性均达到显著水平,这4种离子含量的变化可能是导致土壤全盐量随种植年限变化的重要原因;从土壤盐分离子组成来看,设施菜地土壤主要以SO42-、Cl-、Ca2+为主,分别占全盐量的62.4%、10.6%、9.3%,设施菜地中SO24-、Cl-、Mg2+、Na+含量与全盐量均呈极显著相关,其中相关性程度最大的为SO24-(r=0.9291)和Mg2+(r=0.7224)。设施菜地中SO24-含量与pH值变化存在极显著相关(r=-0.5508),其大量累积可能是造成调查区域设施土壤酸化的重要原因。

The acidification and salinization in greenhouse soil of different cultivating years of Shouguang City in Shandong province were studied.The results showed that the pH and total salts in greenhouse soil were 6.86 and 2.47g·kg^-1,respectively,and the significant acidification and salinizaion were found in greenhouse soil compared with open vegetable soil and natural soil;In two planting periods of 1-12.7a and 12.7-15a of greenhouse soil,the trends of pH values were observed to decrease gradually and then it increased again,but the opposite changing trend with pH was observed for the total salts and the turning point was 8.4a.With the increasing of cultivating years the contents of Na^＋,Mg^2＋,Cl^-,SO4^2- showed（P〈0.05）to increase gradually and then it had decreasing trends and it had similar trends with the changing trend of the total salts,the change in Na^＋,Mg^2＋,Cl^-,SO4^2- contents brought about the change for the total salts with the increasing of cultivating years.Studies on salt ions in greenhouse soil indicated that a large part of total salts was accounted by SO4^2-、Cl^-、Ca^2＋,the proportions were 62.4%、10.6%、9.3%,respectively.The very significantly correlations were obtained between SO4^2-、Cl^-、Mg^2＋、Na ^＋ and total salts,However,it was most to SO2-4（r=0.9291）and Mg^2＋（r=0.7224）among these correlations;The correlation between SO4^2- and pH was very remarkable,and a large accumulation of SO4^2- was one of the important reasons for the acidification in greenhouse soil.