Soil nutrients and plant uptake parameters as related to greenhouse gas emissions

Abstract

Fertilizer and water management practices have short-and long-term effects on soil chemical and physical properties and, in turn, greenhouse gas (GHG) emissions. The goal of this 4-yr field study was to establish the relationships between soil properties, agronomic practices, and GHG (CO 2 and N 2 O) emissions under different fertilizer and water table management practices. There were two fertilizer treatments: inorganic fertilizer (IF) and a mix of solid cattle manure and inorganic fertilizer (SCM), combined with tile drainage(DR) and controlled drainage with subirrigation(CDS). The cropping system was a maize (Zea mays L.)-soybean [Glycine max (L.) Merr.] rotation. Nitrogen in biomass (BMN) and N in grain (GRN) were measured and used to calculate other plant N parameters. Nitrous oxide and CO 2 fluxes were collected weekly, and their respective cumulative emissions were calculated. The results show that soil organic matter (OM), soil total carbon (C), and soil total nitrogen (N) were greater in SCM than IF by 23.7, 35.2, and 24.4%, respectively. Water table management did not significantly affect soil N and C. Increased CO 2 emissions were witnessed under higher soil OM, soil total C, and total N. Plant N uptake parameters were negatively correlated with N 2 O and CO 2 emissions. Higher plant N uptake can reduce environmental pollution by limiting N 2 O and CO 2 emissions. INTRODUCTIONAgriculture is responsible for 10% of the total greenhouse gas (GHG) emissions in Canada (ECCC, 2020). The use of fertilizer for crop production has increased from 57.6 ( 2002) to 87.6 (2016) kg ha −1 in Canada (World Data Atlas, 2020). Greenhouse gas emissions from agricultural soils have also increased with fertilizer use (Rochette et al., 2008), contributing to climate change.

Selected Carbon and Nitrogen Compounds in a Maize Agroecosystem under the Use of Nitrogen Mineral Fertilizer, Farmyard Manure, Urease, and Nitrification Inhibitors

“…Significant correlations were noticed between CO 2 emissions and concentrations of SOC (r = 0.622), TN (r = 0.794), C-HA (r = 0.833), C-H (r = 0.844), NH 4 -N (r = 0.921), and NO 3 -N (r = 0.932) (Table 2). Other authors reported earlier that the availability of N and SOM quality are the key factors to C mineralization in soils [17,34]. Changes in N 2 O emissions significantly depended on the fertilization used.…”

“…Significantly higher contents of SOC (11.28 g kg −1 ) and TN (1.40 g kg −1 ) were found in the soil applied with farmyard manure combined with mineral fertilizer compared to the unfertilized control (Figures 1 and 2), suggesting that organic and mineral fertilization had a beneficial effect on these parameters. Several authors also reported that the SOC levels increase in treatments with farmyard manure [17,30,31] and/or with N inorganic fertilizers [30,32]. This was linked to the amount of additional C and N applied with fertilizers and/or improvements in the crop yields and higher C and N input via rhizodeposition and plant residues [30,33].…”

“…However, it can also increase the production of GHG. Several authors reported [17,30] that carbon dioxide emissions are greater from soils treated with manure compared to inorganic fertilizer, which was attributed to a greater OM availability for microbial respiration in soil. According to previous studies, the soil C/N ratio plays a key role in controlling CO 2 emissions [17], which is consistent with our study.…”

“…Several authors reported [17,30] that carbon dioxide emissions are greater from soils treated with manure compared to inorganic fertilizer, which was attributed to a greater OM availability for microbial respiration in soil. According to previous studies, the soil C/N ratio plays a key role in controlling CO 2 emissions [17], which is consistent with our study. The low SOC/TN ratios in our experiment imply that a prevailing decomposition of OM resulted in significantly higher CO 2 emissions in the treatments characterized by lower values of this parameter (FYM, FYM+UI, FYM+NI, and FYM+UI+NI treatments; Figures 3 and 10; r = −0.963).…”

“…Nitrogen and carbon inputs affect the emissions of CO 2 and N 2 O [17]. Agroecosystems treated with mineral and organic fertilizers, however, have the potential to be not only sources but also sinks of CO 2 [18,19].…”