On the way towards conservation tillage on the activities of soil enzymes related to carbon cycle in a multi-sequence maize-wheat-soybean rotation system

On the way towards conservation tillage on the activities of soil enzymes related to carbon cycle in a multi-sequence maize-wheat-soybean rotation system

Authors: Xiu Dong^1,2, Yan Zhang^1,2, Yuying Shen^1,2*

Affiliations:

¹State key Laboratory of Grassland Agro-ecosystems, Lanzhou University, Lanzhou 730020, PR China

²College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, PR China

Abstract

Designing and developing sustainable cropping systems and reasonable cultivation measures have become the major focuses in the semiarid Loess Plateau region of China. However, long-term conservation tillage practices on the activities of soil enzymes related to carbon cycle in maize-wheat-soybean rotation system are still unclear. This study aimed to investigate the effects of 19 years of conservation tillage practices on the cellobiohydrolase (CBH), β-1,4-glucosidase (BG) and β-1,4-xylosidase (BXYL) activities in the 0-20 cm soil depth under a two-year cycle spring maize (Zea mays L.)-winter wheat (Triticum aestivum L.) -summer soybean (Glycine max L.) rotation cropping system. Treatments included conventional tillage (T), conventional tillage followed by straw mulching (TS), no tillage (NT), and no tillage followed by straw mulching (NTS). We found that conservation tillage practices could increase soil enzyme activities significantly, the highest soil CBH and BG activities were in NTS (1.25 and 5.72 nmol·g^-1·h^-1)， the highest soil BX activities were in TS (2.13 nmol·g^-1·h^-1). Compared to T, no tillage had no effect on soil enzymes activities. The effects of conservation tillage practices on soil enzyme activities varied with soil depth, higher soil enzyme activities were showed in the 0-5 cm than in 5-20 cm soil depths. In addition, our results indicated that the key factors driving the changes in soil enzyme activities were soil microbial biomass carbon and organic carbon. This finding highlighted the importance of conversation tillage practices on maintaining the soil carbon pool in rotation ecosystem.