Differential Influence of No-Tillage and Precipitation Pulses on Soil Heterotrophic and Autotrophic Respiration of Summer Maize in the North China Plain

Abstract

It is important to strengthen the studies on the response of soil respiration components to tillage practices and natural precipitation in cropland. Therefore, soil heterotrophic respiration (RH) and autotrophic (RA) respiration were monitored by a root exclusion method in the North China Plain (NCP). The tillage practices included no-tillage (NT) and conventional tillage (CT), and the study periods were the summer maize growth stages in 2018 and 2019. RH, RA, soil water content and temperature were measured continuously for 113 days by an automatic sampling and analysis system. The soil RH values on bright days and rain-affected days were higher under NT in 2018 (14.22 and 15.06 g CO2 m−2 d−1, respectively) than in 2019 (8.25 and 13.30 g CO2 m−2 d−1, respectively). However, the RA values on bright days and rain-affected days were lower under NT in 2018 (4.74 and 4.97 g CO2 m−2 d−1, respectively) than in 2019 (5.67 and 6.93 g CO2 m−2 d−1, respectively). Moreover, NT decreased RH but increased RA compared to CT in 2019. Compared to bright days, the largest increase in both RH and RA after rain pulses was under CT in 2019 (6.75 and 1.80 g CO2 m−2 d−1, respectively). Soil water content and soil temperature were higher in 2018 than in 2019. Moreover, NT increased soil water content and decreased soil temperature on bright days compared to CT in 2019. Furthermore, soil temperature accounted for more variations in RH on bright days and rain-affected days, but soil water content had a greater influence on RA on bright days. However, after precipitation, higher soil water content decreased RA under NT in 2018, while soil water content was positively related to RA under CT in 2019. This study determined the differential response of RH and RA to tillage practices and natural precipitation pulses, and we confirmed that excessively dry soil increases soil carbon loss after rain events in the NCP.

Status of Soil Health Indicators after 18 Years of Systematic Tillage in a Long-Term Experiment

“…In future research, microbial biomass, microbial diversity, and partitioning between autotrophic and heterotrophic respiration would further improve our understanding on the long-term effect of tillage. For example, Du et al [53] found that soil autotrophic respiration is lower in P compared to NT, while heterotrophic respiration is higher in P, but this relation is affected by rainfall (soil moisture changes). All these environmental effects and the different reaction of soil microbes to temperature and moisture changes affect greenhouse gas emissions in the end, but soil microbial respiration provides information on the general activity of microbes.…”

Modeling Soil Water Content and Crop-Growth Metrics in a Wheat Field in the North China Plain Using RZWQM2

“…The soil type is a calcaric Fluvisol, and the texture of the surface soil is silt loam (sand, 12%; silt, 66%; clay, 22%). In the top 20 cm of the soil layer, the mean pH (soil: water, 1:5) was 8.3, total organic content was 12.6 g kg −1 , total N was 0.89 g kg −1 , total P was 2.11 g kg −1 , and total K was 21.4 g kg −1 [30,31].…”

“…The detailed information of the RZWQM2 could refer the study of Ahuja et al [33]. The simulation of SWC used the measured air temperature, air humidity, wind speed, rainfall and soil physical parameters in the module of SWC physical transfer process, and soil nutrients were input into the related nutrients module [30,31,33,34]. The Brooks Corey equation was used to describe the soil moisture characteristic curve, and the Richards equation was used to measured soil water redistribution between soil layers [33,34].…”

A New Non-Inserted and Portable FDR Instrument for Measuring Surface Soil Water Content

“…From mid-July 2020, field comparison testing was conducted at the Shandong Yucheng Agro-ecosystem National Observation and Research Station, Ministry of Science and Technology (36 • 50 N, 116 • 34 E). Detailed environment and cropland management information on this station can be found in previous studies [25][26][27][28]. An ET60 instrument (Insentek Oriental Sense of WisdomTechnology Co. Ltd., Hangzhou, China) was installed as the control instrument after soil punching and grouting [29].…”