滨海盐碱地不同改良年限土壤理化性质的变化特征

为了研究滨海盐碱地改良效果的可持续年限,选择利用“原土直栽绿化综合改良模式”改良的滨海盐碱地为研究对象,采用空间代替时间的方法,通过对不同改良年限滨海盐碱地的土壤容重、总孔隙度、机械组成、全盐含量、有机质、碱解氮和速效磷的分析,研究了滨海盐碱地不同改良年限土壤理化性质的变化特征。结果表明:盐碱地改良后,对土壤物理性质的改良效果随土层深度的增加逐渐减弱,随改良年限的增加,土壤质地无明显变化,0—20 cm土层土壤容重降低,总孔隙度升高,20—40 cm和40—60 cm土层土壤容重先降低后升高,总孔隙度先升高后降低; 3个土层化学性质变化趋势基本一致,随着改良年限的增加,土壤全盐含量先降低后升高,有机质,碱解氮和速效磷含量先升高后降低。总体来说,原土改良模式对滨海盐碱地土壤的改良效果在5年达到最优,11年时土壤的物理化学性质基本上都比未改良的盐碱地好。

Variation Characteristics of Soil Physicochemical Properties of Coastal Saline-alkali Lands with Different Improvement Years

In order to investigate the sustainable years of the comprehensive improvement effects of coastal saline-alkali land,we took the saline-alkali land which was improved in a comprehensive improvement mode and could be planted directly on the original soil as the research object and studied the changes of soil physicohemical properties in different ameliorating years by using space instead of time based on the analysis of soil bulk density,total porosity,mechanical composition,salinity and organic matter,alkali-hydro nitrogen and available phosphorus,of which coastal saline-alkali had been improved in a comprehensive way.The results showed that the improvement effects of this model on soil gradually weakened with the increase of soil depth.With the increase of the recovery years,soil texture did not change significantly,soil bulk density in 0—20 cm soil layer decreased,total porosity increased,while soil bulk densities in 20—40 cm soil layer and 40—60 cm soil layer decreased first and then increased,and total porosities first increased and then decreased.The change trend of the chemical properties of the three soil layers was basically the same.With the increase of the recovery years,soil salinity first decreased and then increased,and the contents of organic matter,alkali-hydro nitrogen and available phosphorus first increased and then decreased.In general,the comprehensive improvement model for the original soil in the coastal saline-alkali land reached the optimal level after 5-year improvement.The physicochemical properties of the soil were basically better than those of the unimproved saline-alkali land in the eleventh year.