Methane and nitrous oxide emissions as affected by long-term fertilizer management from double-cropping paddy fields in Southern China

Abstract

SUMMARYThere is limited information about the influences of long-term fertilizer management on methane (CH4) and nitrous oxide (N2O) emissions from double-cropping paddy fields in Southern China. Therefore, the objective of the present study was to characterize the changes of CH4 and N2O related to different fertilizer treatments based on a long-term field experiment. The experiment was initiated in 1986 and consisted of five treatments: unfertilized (CK), mineral fertilizer alone (MF), rice residues plus mineral fertilizer (RF), low manure rate plus mineral fertilizer (M1 + F), and high manure rate plus mineral fertilizer (M2 + F). Investigations were conducted over 2 years, from 2013 to 2014, to examine the CH4 and N2O emissions from paddy field of Southern China. The results indicated that M2 + F plots had the largest CH4 emissions during the early rice and late cropped rice and that MF and RF had larger N2O emissions than CK in both early and late cropped rice. When compared with the control, total N2O emissions in both rice-growing seasons increased in both MF and RF in 2013 and 2014. The global warming potentials (GWP) from paddy fields were ranked as M2 + F > M1 + F > RF > MF > CK. Meanwhile, the results demonstrated that CH4 and N2O emissions were closely associated with the soil redox potential and soil temperature. In summary, the incorporation of rice residues in addition to the use of mineral fertilizer (RF treatment) may be an effective fertilizer management practice for mitigating total GWP per grain yield and maintaining rice grain yield in southern China.

Effects of Long-Term Fertilization Management Practices on Soil Microbial Carbon and Microbial Biomass in Paddy Soil at Various Stages of Rice Growth

“…Soil texture in the tilled layer (0.00-0.20 m) consisted of silt clay loam with 13.71 % sand and 57.73 % silt. The climatic condition of the experimental paddy field, the surface soil (0.00-0.20 m) physicochemical properties at the beginning of this experiment, and the crop rotation systems are described by Tang et al (2016).…”

“…The total amount of N, phosphorus pentoxide (P 2 O 5 ), and potassium oxide (K 2 O) were adjusted to the same level in each fertilization treatment over the whole growth period for early and late rice (Oryza sativa L.). Detailed information about the fertilization management and farming practices is described by Tang et al (2016).…”

Re-assessing nitrous oxide emissions from croplands across Mainland China

“…Accurate and precise prediction of N2O emissions in croplands is difficult since the biotic and abiotic factors influencing N2O emission in field are temporally dynamic and spatially heterogeneous, and influenced by a number of factors related to climate, soil quality, fertilizer application, cropping systems and management practices (Ladha et al, 2016;Tang et al, 2016;Lam et al, 2016;Yue et al, 2017). For instance, N2O emission rates were lower for flooded or paddy rice than upland crops as the anaerobic conditions in wetland soils tend to encourage complete denitrification to N2 (Gerber et al, 2016).…”

Impacts of long-term fertilization on the soil microbial communities in double-cropped paddy fields

“…The fungi/G + bacteria + G − bacteria had a significant, positive correlation with soil total C, total N and grain yield of rice. It might be presumed that microbial community structure was affected by fertilization practices (Yu et al ., 2013; Tang et al ., 2016). The nature of nutrient inputs affects the availability of soil nutrients and substrates as well as the growth of rice plants, affecting the characteristics of microbial habitats in soil (Ai et al ., 2012; Williams et al ., 2013; Li et al ., 2015).…”