自然生草对冀西北杏园土壤微生物量碳、氮及酶活性的影响

Effects of Natural Grass on Soil Microbial Biomass Carbon,Nitrogen and Enzyme Activities in Apricot Orchards in Northwest Hebei

以杏园野生草种为试材,采用果园自然生草的方法,研究了清耕(CK)、自然生草5年(5a)、自然生草8年(8a)3个处理在不同土层(表层0~20 cm、中层20~40 cm、底层40~60 cm)土壤有机碳(SOC)、全氮(TN)、微生物量碳(SMBC)、微生物量氮(SMBN)及酶活性指标的变化,以期为探索自然生草对冀西北杏园土壤理化性质的影响提供参考依据。结果表明:自然生草显著提高了杏园土壤各土层SOC、TN、SMBC、SMBN含量,同时也提高了土壤中的过氧化氢酶、蔗糖酶、脲酶、纤维素酶及碱性磷酸酶活性。随着生草年限的增加各指标值不断上升,同一土层中各指标表现为自然生草8a>自然生草5a>CK,三者间差异显著;随着土层深度的增加各指标值表现为表层>中层>底层,综合生草年限与土层深度尤以0~20 cm土层自然生草8a处理影响最大,SOC、TN、SMBC、SMBN含量分别较CK增加了62.48%、24.14%、130.33%和76.96%,qMBC与qMBN值分别较CK显著提高了41.86%和42.67%,过氧化氢酶、蔗糖酶、脲酶、纤维素酶及碱性磷酸酶活性分别较CK显著提高了81.82%、82.60%、257.30%、123.91%和134.55%;相关性分析表明微生物量碳、氮与有机碳、全氮及土壤酶之间存在极显著相关关系。由此可见,杏园行间长期自然生草是提高土壤微生物生物量及土壤酶的有效途径,对培肥土壤地力起到极其关键的作用。

The changes of soil organic carbon(SOC),total nitrogen(TN),microbial biomass carbon(SMBC),microbial biomass nitrogen(SMBN)and enzyme activity index in different soil layers(0-20 cm in the surface layer,20-40 cm in the middle layer,and 40-60 cm in the bottom layer)were studied by using the method of natural grass growing in the orchard with the wild grass species in the apricot orchard as the test material,in order to provide reference for exploring the influence of natural grass on the physical and chemical properties of soil in the apricot orchard in northwest Hebei.The results showed that natural grass significantly increased the contents of SOC,TN,SMBC and SMBN in soil layers of apricot orchard,and also increased the activities of catalase,sucrase,urease,cellulase and alkaline phosphatase in soil.With the increase of grass-growing years,the values of various indicators continue to rise.The indicators in the same soil layer were natural grass 8a>natural grass 5a>clear tillage(CK),and the difference between the three was significant.With the increase of soil depth,the index values were as follows,surface layer>middle layer>bottom layer.The comprehensive grass growing years and soil depth,especially the 8-year treatment of natural grass in0-20 cm soil layer,had the greatest impact.The contents of SOC,TN,SMBC and SMBN had increased by 62.48%,24.14%,130.33%and 76.96%respectively compared with clear tillage(CK),and the values of qMBC and qMBN have significantly increased by 41.86%and 42.67%respectively compared with clear tillage(CK).The activities of urease,cellulase and alkaline phosphatase were significantly higher than those of clear tillage(CK)by 81.82%,82.60%,257.30%,123.91%and 134.55%,respectively.Correlation analysis showed that there was a very significant correlation between microbial biomass carbon and nitrogen and organic carbon,total nitrogen and soil enzymes.It could be seen that long-term natural grass growth between rows in apricot orchard was an effective way to improve soil microbial biomass and soil enzymes,and played a key role in enriching soil fertility.