【作者】 焦庆先；

【导师】 周连仁；

【作者基本信息】 东北农业大学 ， 土壤学， 2011， 硕士

【摘要】 我国东北地区土壤盐碱化现象十分严重,严重阻碍了农业生产的发展,由于本区盐碱土以苏打碱土为主,治理难度较大。本试验以松嫩平原大庆地区苏打草甸碱土为研究对象,采用完全随机区组设计,利用建筑工地表层(0～20cm)肥沃土壤在不同碱化程度的土壤上分别采用四种不同厚度建筑黑土进行直接覆盖处理,即2cm、4cm、6cm和8cm,并分别设置对照处理(不覆盖),同时进行牧草补播。对牧草生长状况(牧草高度、总盖度、总产量)、土壤物理性质(土壤容重、自然含水量)、土壤化学性质(pH、土壤电导率、阳离子交换量、交换性钠离子、碱化度、总碱度、有机质、土壤速效养分)进行测定。通过对牧草生长状况和土壤理化性质的对比,评价不同覆盖厚度对苏打草甸碱土植被的恢复效果,筛选出适宜不同碱化程度土壤的覆盖厚度,为牧草提供一个淡化的萌发表层,实现珍贵黑土资源利用最大化,苏打草甸碱土绿色覆盖率最大化的整体目标。试验结果表明:不同厚度覆盖处理,都能改善土壤理化性状,地面植被状况都有不同程度的改善。随着覆盖厚度的增加修复效果越明显。当覆盖厚度为6cm和8cm时,从土壤化学性质方面来看无论在重度碱化土壤还是在中度碱化土壤上,土壤pH都能下降到8.5以下;土壤碱化度急剧下降,下降幅度达80%以上;CO32+离子的测定结果为0,总碱度也随之大幅下降;土壤阳离子交换量和土壤有机质都有一定程度的提高。从牧草生长状况来看,在同一种碱化程度土壤上以覆盖厚度为6cm和8cm最佳,从景观上看二者无明显差异;在不同碱化程度土壤上,整体看是中度碱化土壤上牧草长势较好,但随着覆盖厚度的增加在两种碱化程度土壤上牧草生长状况差距越来越小,统计分析表明当覆盖厚度为8cm时,二者无显著差异。黑土覆盖厚度是决定一切变化的主导因素。通过回归分析表明:在两种碱化程度土壤上牧草的各项生长指标都与覆盖厚度显著正向关联,符合三次曲线变化规律,即在黑土覆盖厚度较低时(本试验的2cm和4cm),牧草生长状况不良,并且变化幅度较小,当覆盖厚度增加到一定值时(本试验的6cm和8cm),牧草的生长状况有一个突越式的变化,并且之后变化趋于平稳。土壤碱化度与覆盖厚度呈极显著线性负相关。覆盖厚度与土壤pH、电导率呈二次曲线极显著负相关,与土壤有机质呈线性极显著正相关。本试验宗旨是寻找一个适宜的覆盖临界厚度,结合牧草恢复状况和土壤理化性质变化状况,在中度碱化土壤上黑土覆盖厚度不应低于6cm,在重度碱化土壤上覆盖厚度不应低于8cm。更多还原

【Abstract】 At present, the phenomenon of soil salinization in the northeast of China is very serious, and seriously hindered the development of agricultural production. Due to soda soil as main alkaline soil in the area, it is difficult to be managed. A study was performed on alkaline soda meadow soil in Daqing region of the Songnen Plain. Randomized blocks design was adopted. The surface （0 20cm） soil in the construction site was directly used to cover on the soil of different alkalify degree with four different cover thickness, namely 2cm、4cm、6cm and 8cm respectively. The control treatments （no cover） was set, meanwhile reseed forage. Through the determination of grass growing status （forage height, total covering, output）, soil physical properties （soil bulk density, natural water content）, soil chemical properties （pH, soil conductivity, CEC, exchangeable sodiumions, ESP, total alkalinity, organic matter, soil available nutrients）. Through comparing of grass growing status and the soil physical and chemical properties, effect of different cover thickness on vegetation restoration of alkaline soda meadow soil was evaluated, and the suitable cover thickness at different alkalify degree would be selected, which would provide a desalination surface for grass germination, and realize the integral goal of maximizing the use of precious soil resources and maximization of green coverage on alkaline soda meadow soil.Test results showed that: different thickness cover processing could improve soil physical properties and ground vegetation status by different degree. With the increase of covering thickness, the repairing effect became more apparent. When cover thickness was 6cm or 8cm, for soil chemical properties, no matter in severe alkalify soil or in moderate alkalify soil, soil pH descended to 8.5 following; soil ESP fell sharply by 80%; CO₃²⁺determined was 0; total alkalinity also dropped accordingly; soil CEC and soil organic matter had a certain degree of improvement. For grass growing situation, on the same kind of alkalify degree soil, the cover thickness of 6cm and 8cm was the best, and there was no obvious landscape difference between the two treatment; Overall, for different alkalify degree soil, forage crop on moderate alkalify soil was better, but with the increase of covering thickness in these two alkalify degree soil, the grass growing status was more similar each other, and statistical analysis showed that when cover thickness was 8cm, there was no significant differences between the two alkalify degree soils.Covering thickness of black soil was the dominant factors for anything changing. Regression analysis showed that: on two alkalify degree soil, the growth of forage index was significantly positive correlation with covering thickness, and regression equation accorded with changing rule of cubic curve. Namely soil cover thickness was lower （2cm and 4cm in the test）, grass growth situation was bad, and change little. When cover thickness increases to a certain value （6cm and 8cm in the test）, grass growing status had a big change, and after that change, trend of grass growing leveled off. Soil ESP and cover thickness was significantly linear negatively correlated. Cover thickness and soil pH, conductivity fitted quadratic curves, and were very significant negative correlation, and with soil organic matter was linear and very significant positive correlation.This experiment aim was to find a suitable and critical covering thickness. Considering forage recovering status and the changing state of soil physical and chemical properties, black soil covering thickness should be no less than 6cm on moderate alkalify, and no less than 8cm on severe alkalify soil.更多还原