科尔沁沙地苜蓿草地土壤酶活性的时空变化特征

在科尔沁沙地大田试验条件下,研究了不同种植年限(1~5a)苜蓿草地土壤脲酶和过氧化氢酶活性的时(年限)空(土层)变化特征,旨在探讨种植不同年限苜蓿对土壤生物化学性状的影响,为沙地苜蓿草地管理提供科学依据。结果表明:2种土壤酶活性都随着土层加深而降低,0~20cm土层,土壤酶活性最强,呈现出表聚性。随着种植年限增加,2种土壤酶活性都呈先增后降趋势。在0~70cm土层,土壤过氧化氢酶活性大小顺序为:2a5a4a1a3a;土壤脲酶活性大小顺序为:2a5a3a4a1a原生植被地。2年龄苜蓿草地根际土过氧化氢酶活性显著高于1年龄和3~5年龄(P0.05);2年龄和4~5年龄苜蓿草地非根际土过氧化氢酶活性显著高于1年龄和3年龄(P0.05)。不同种植年限苜蓿草地根际土过氧化氢酶活性均高于非根际土,其中,种植第1年至第3年土壤酶活性差异显著(P0.05)。

Study on the Temporal and Spatial Variation Characteristics of Soil Enzyme Activities in Alfalfa Field with Different Growing Years in Horqin Sandland

A field experiment was conducted to study the seasonal variations of soil enzyme (urease and cat alase) activities in alfalfa field with different growing years (1～5 years) in Horqin sandland,and the objective was to provide a theoretical basis for the alfalfa field management.Results indicated that the two kinds of soil enzyme activities decreased significantly with the increase in soil depth,the most active in the 0～20 cm depth,and showed the surface gathering vertical distribution characters,the two kinds of soil enzyme activities increased at first and then decreased with the increase of growing years.In the 0～70 cm depth,the catalase-enzyme activity was 2 a＞5 a＞4 a＞1 a＞3 a and urea-enzyme activity was 2 a＞5 a＞ 3 a＞4 a＞1 a＞ CK(primary vegetation land).The catalase enzyme activity of rhizosphere soil in 2-yearold alfalfa field was much higher than that in 1-year old and 3～5 year-old alfalfa fields(P＜0.05).The catalase-enzyme activity of non-rhizosphere soil in 2-year-old and 4 ～ 5 year-old alfalfa fields was much higher than that in 1 year-old and 3 year-old alfalfa field (P＜0.05).The catalase-enzyme activity of rhizosphere soil was much higher than that of non-rhizosphere soil in different growing years,and showed significant difference between rhizosphere soil and non-rhizosphere soil from first year to third year of alfalfa growth.