祁连山东段高寒地区土地利用方式对土壤性状的影响

祁连山东段是典型的高寒地区,自然环境脆弱而敏感,探讨该区域土地利用方式对土壤性状的影响有助于高寒地区土地合理利用和生态恢复。在实验区内选取了天然草地(NG)、退耕自然恢复地(NRAC)、坡耕地(SC)和人工草地(SG)4种土地利用方式,研究了不同土地利用方式对土壤物理和化学性状的影响。结果表明,高寒地区不同土地利用方式下土壤理化性状差异显著。不同土地利用方式下土壤含水量表现为:NG>SG>NRAC>SC;土壤容重表现为:NRAC>SG>SC>NG;土壤紧实度表现为:SC>SG>NRAC>NG;总孔隙度为NG>SC>SG>NRAC。在4种土地利用方式中NG有机质含量(116.438 g/kg)显著高于其他土地利用方式(P<0.05);NRAC土壤有机质含量(28.541 g/kg)显著低于其他土地利用方式(P<0.05);全N含量NG最大;SC全P和全K含量最大;NG土壤速效N、P、K含量均最高。研究表明,NG在保持和维护土壤性状方面表现出了较好的效果,SC和SG土壤性状相对较差;退耕4 a的NRAC土壤性状仍然较差,反映出在高寒地区土壤生态系统一旦遭到严重破坏,在自然条件下较难恢复,恢复所需时间也较长。

The effect of different land use patterns on soil properties in alpine areas of eastern Qilian Mountains

The patterns of using land are comprehensive reflection of human being activities on soil,and it is the main reason that provoking the change of global environment and an essential part of the constantly changing global environment as well.Land use patterns have the most profound and direct influence on natural and ecological processes,which including the influence on soil nutrient,soil moisture,soil erosion and land productivity.The present work was performed in the eastern Qilian Mountains,which is characterized by high altitude,important daily temperature variations with sparse air,strong radiation and low temperature.And it belongs to the typical alpine areas characterized by weak and sensitive environment.Therefore,the mainly objectives of this study reported herein was focused on the effect of different land use patterns on soil properties in alpine areas of eastern Qilian Mountains,and so to improve the region′s rational land utilization and ecological restoration.In this research,four land use patterns were selected in the experimental area,which are nature grassland,naturally restored abandoned cropland,slope cropland and sown grassland.The results showed that different patterns of using land in the alpine region leaded to significant difference on soil property.① The following part is the soil moisture content under different land use patterns,the orders are from more to less: nature grassland,sown grassland,naturally restored abandoned cropland,and slope cropland;② As to the soil bulk density,naturally restored abandoned cropland was the highest,followed by sown grassland,the third was slope cropland,and the lowest was nature grassland;③ The soil compaction was in the order of slope cropland > sown grassland >naturally restored abandoned cropland > nature grassland;④ the total porosity of the four pattern used land that can be organized in the order from high to low can be described as follows,nature grassland >sown grassland>naturally restored abandoned cropland >slope cropland.The organic matter content of natural grassland was 116.438 g/kg,significantly higher than the other land use patterns(P<0.05)and that of naturally grass-restored cropland was 28.541 g/kg,which was significantly lower than the other patterns(P<0.05).The natural grassland had the highest total N content and available nutrients of N,P and K,while slope cropland had the maximum contents of total P,K.under different land use patterns.The soil property changes in the study area which indicates that natural grassland had a better function in helping maintain the good soil physical and chemical properties,and also its soil characteristics were distinctly different from those of slope cropland and sown grassland which present the worse soil physical properties and lower nutrients.Restored cropland that had been abandoned 4 years only had soil compaction.Meanwhile,the N content had improved during those days.However,the other properties were still poor.These phenomena show that the soil ecosystem which has been serious damaged is quite difficult to get recovery in alpine areas,and it needs a much longer time to recover.