Effects of plant-derived dissolved organic matter (DOM) on soil CO2 and N2O emissions and soil carbon and nitrogen sequestrations

Abstract

A B S T R A C TDissolved organic matter (DOM) in soils play an essential role in soil physical, chemical and biological processes, but little information is available on the biodegradability of plant-derived DOM and its effect on soil carbon and nitrogen sequestration in field soils. The objectives of this study were to investigate the impacts of crop residue-derived DOM on soil CO 2 and N 2 O emissions, as well as soil carbon and nitrogen sequestration by adding water extracts of maize stalk (i.e., plant-derived DOM) to soils. In this study, wheat was grown in pots under field conditions with treated soils, the soils treatments were: plantderived DOM (PDOM), urea nitrogen (N), PDOM + urea nitrogen (PDOM + N), as well as a control with no additions to soil (CK). Adding plant-derived DOM to soil increased soil CO 2 and N 2 O emissions (P < 0.05). During the wheat growing season, the cumulative CO 2 -C emission from CK, PDOM, N and PDOM + N was 107 AE 1, 157 AE 7, 136 AE 2 and 149 AE 6 g C m À2 , respectively. Meanwhile, the cumulative N 2 O-N emission from CK, PDOM, N and PDOM + N was 188 AE 8, 256 AE 5, 239 AE 10 and 258 AE 7 mg N m À2 , respectively. Compared with N treatment, DOM addition had little effect on soil N sequestration, but it accelerated the decomposition of native soil organic carbon (SOC) and caused a net loss of SOC. The soil C sequestration decreased about 151 AE 67 and 51 AE 45 g C m À2 in PDOM and PDOM + N treatments, respectively. The increased microbial biomass and root biomass were responsible for the greater CO 2 emission in DOMamended soils. Negative correlation between dissolved organic carbon (DOC) content and N 2 O flux suggested that the release of N 2 O was dependent on the supply of DOC. These results indicated that the supply of plant-derived DOM exacerbated soil CO 2 and N 2 O emissions and reduced soil C sequestration. Therefore, agricultural management practices that increase the stability of highly soluble C inputs and/or retard the decomposition of crop residues should be adopted to decrease soil greenhouse gas emission and increase soil C sequestration.2015 Elsevier B.V. All rights reserved.

Vegetation succession influences soil carbon sequestration in coastal alkali-saline soils in southeast China

“…Electrical conductivity (EC) and soil pH were measured in 1:5 (soil:water) suspension after end-over-end shaking for 15 minutes at 25 °C. Total nitrogen (TN) was analyzed by Kjeldahl method 21 . Total phosphorus (TP) was extracted with HF-HNO 3 -HClO 4 and then determined by molybdenum antimony blue colorimetry 22 .…”

Effects of long-term green manure application on the content and structure of dissolved organic matter in red paddy soil

“…Numerous biotic and abiotic factors affect the content and structure of soil DOM, including soil physiochemical properties, climate, crop types and agricultural management practices (Long et al 2015;Shang et al 2015;Smebye et al 2016). The fertilization and crop residue management are the prominent management factors which had profound influences on soil DOM (Qiu et al 2015;Shang et al 2015). The turnover of DOM directly improved soil organic matter content and soil nutrients supply, and increased the aggregate of soil and the capacity of water and nutrients through appropriate tillage practices (Guggenberger and Kaiser 2003).…”

Carbon sequestration and Jerusalem artichoke biomass under nitrogen applications in coastal saline zone in the northern region of Jiangsu, China

“…These soil samples (1-2 kg each) were packed into self-sealing plastic bags for transport and then air-dried and passed through a 0.25-mm sieve for measuring SOC and total N contents. The SOC concentration was determined with the dichromate oxidation method (Walkley and Black, 1934), and total soil N was analyzed by Kjeldahl method (Qiu et al, 2015). Soil bulk density was calculated by dividing the oven-dried soil mass by the volume.…”