Straw mulching and nitrogen application altered ammonia oxidizers communities and improved soil quality in the alkaline purple soil of southwest China

Songhe Chen,Xiaoling Xiang,Hongliang Ma,Gaoqiong Fan,Yang Yu,Yun Xiao,Rencai Gao,Hongkun Yang,Ting Zheng,Han Li,Xue Zhang

doi:10.1186/s13568-021-01211-x

Abstract

Microbe-mediated ammonia oxidation is a key process in soil nitrogen cycle. However, the effect of maize straw mulching on the ammonia oxidizers in the alkaline purple soil remains largely unknown. A three-year positioning experiment was designed as follows: straw mulching measures as the main-plot treatment and three kinds of nitrogen application as the sub-plot treatment. We found the contents of soil organic carbon (SOC), total nitrogen (TN), available potassium (AK), available nitrogen (AN), available phosphorus (AP), and NH4+-N were increased after straw mulching and nitrogen application in alkaline purple soil, so did the amoA genes abundance of ammonia-oxidizing archaeal (AOA) and bacterial (AOB). Terminal restriction fragment length polymorphism (T-RFLP) analysis revealed that Thaumarchaeote (448-bp T-RF) was dominated the AOA communities, whereas Nitrosospira sp (111-bp T-RF) dominated the AOB communities. The community compositions of both AOA and AOB were altered by straw mulching and nitrogen application in alkaline purple soil, however, the AOB communities was more responsive than AOA communities to the straw mulching and nitrogen application. Further analysis indicated that SOC and AP were the main factors affecting the abundance and community compositions of AOA and AOB in alkaline purple soil. The present study reported that straw mulching and nitrogen strategies differently shape the soil ammonia oxidizers community structure and abundance, which should be considered when evaluating agricultural management strategies regarding their sustainability and soil quality.

Highlights

Nitrification is an important aspect of the soil nitrogen cycle, which helps crops to absorb soil nitrogen and regulate soil nitrogen loss (Liu et al 2019)
The soil organic carbon (SOC) content of straw mulch (S1) treated soil were 18.86 g kg−1, which was significantly higher than that under no straw mulching (S0) treatment of 10.46 g kg−1 (P < 0.05), and the interaction between straw mulching and nitrogen application had no significant effect on the SOC content, while SOC content was significantly increased by nitrogen application compared with no nitrogen application (P < 0.05)
Effects of straw mulching and nitrogen application on soil properties of alkaline purple soil Previous study reported that purple soil had low content of SOC and available phosphorus (AP) (Xiao et al 2016), and most of the phosphorus combined with Ca carbonate in alkaline soil, thereby reducing the availability of phosphorus (Li et al 2011)

Summary

Introduction

Nitrification is an important aspect of the soil nitrogen cycle, which helps crops to absorb soil nitrogen and regulate soil nitrogen loss (Liu et al 2019). The response of AOA and AOB community compositions and abundances for agricultural cultivation management were not consistent (Liu et al 2015). Previous studies have shown that the application of chemical fertilization increases AOB abundance and changes its community composition, but had little influence on AOA in calcareous fluvoaquic soil (Ai et al 2013). Some researchers have demonstrated that organic input has no significant effect on the composition of AOA community in sandy loam (Zhang et al 2019), while Zhalnina et al (2012) found that the addition of organic matter increased AOA abundance and had major influence on the AOA communities in the acidic red soil. The effects of straw returning and chemical N fertilization on soil ammonia oxidizers remain inconsistent; this may be attributed to different soil environments and cultivation measures

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Conclusion