渭北旱塬不同年限撂荒地土壤酶活性及其化学计量变化特征OACSTPCD

[Objective]This study aims to explore the variations and drivers of soil nutrient and extracellular enzyme activities and their stoichiometric characteristics under the abandoned land in the dry area of Northern Weihe River Basin in order to provide a theoretical basis for the improvement and management of abandoned land in this region.[Methods]Soil nutrients and enzyme activities associated with carbon(C),nitrogen(N),and phosphorus(P)cycles in the lands with different abandoned years(5 years,10 years,20 years,25 years and 33 years)in dry area of Northern Weihe River Basin were measured.Subsequently,The changes and driver factors of them and their stoichiometry were determined by One-way ANOVA,enzyme stoichio-metric model,and principal coordinate analysis(PCoA).[Results]With the increase of abandoned years,the activities of C-acquiring enzymes and N-acquiring enzymes decreased,but the activity of P-acquiring enzymes significantly increased.The changes of soil C,N and P contents showed the opposite trend compared with enzyme activities.Moreover,the C-limitation of soil microorganisms alleviated but P-limitation increased with the increase of abandoned years.Further,the results of PCoA fitting environmental factor analysis showed that soil dissolved organic carbon,total phosphorus,available nitrogen and available phos-phorus were the key factors driving the change of enzyme activity and its econometric ratio.[Conclusion]Abandonment has a significant improvement on soil nutrient,but P-limited will be aggravated with increas-ing of abandoned years(more than 20 years).Therefore,appropriate phosphate fertilizer should be applied to a long-term abandoned land to improve its soil condition.