Effects of inorganic amendments, rice cultivars and cultivation methods on greenhouse gas emissions and rice productivity in a subtropical paddy field

Abstract

With the rapidly increasing demand of rice globally, there is an urgent need to develop management strategies to improve the yields of rice crops, while at the same time minimize the possible adverse climatic impacts arising from greenhouse gas emissions from paddy fields. In this study, we investigated the influence of amendment application (steel slag and sulfate), rice cultivars (super rice cultivar, Qiuyou 6, and common rice cultivar, Hesheng 10), and cultivation methods (hand cultivation, machine cultivation, throwing cultivation) on rice yield, soil properties, as well as CH 4 and N 2 O emissions in a subtropical paddy field in southeast China. When compared to the controls, mean CH 4 emissions were significantly lower in the steel slag amendment and sulfate amendment plots by 66.1% and 23.1%, respectively, but significantly higher in the machine cultivation plots by 26.6% (P<0.05). On the other hand, we observed significantly higher mean N 2 O emissions from the super rice, machine cultivation, and throwing cultivation plots than those from the controls by 133.4%, 45.8%, and 172.2%, respectively (P<0.05). When taking into the account both CH 4 and N 2 O emissions, the total global warming potential per unit yield was significantly lower in the plots amended with steel slag and sulfate than in the controls. Moreover, we found that steel slag application, machine cultivation and throwing cultivation were able to increase crop yield significantly (P<0.05). Our findings suggest that a combination of steel slag application and modernized cultivation methods, in particular throwing cultivation, would be effective in improving crop yields and mitigating greenhouse gas emissions from the subtropical paddy fields.

Effects of Irrigation Regime and Nitrogen Fertilizer Management on CH4, N2O and CO2 Emissions from Saline–Alkaline Paddy Fields in Northeast China

“…In the present study, the total cumulative CH 4 fluxes were encouraged by fertilizer additions; in contrast CH 4 emissions were inhibited in N60 and N150 treatments during the booting stage, in contrast to some reports showing that lower N rates tend to increase CH 4 emissions but higher N rates could potentially inhibit CH 4 emissions [25]. The reason for the difference may be severe soil salinization, lower SOM content and high pH value [53].…”

Azolla incorporation and dual cropping influences CH4 and N2O emissions from flooded paddy ecosystems

“…The carbon sources for CH 4 production in rice paddies can be native soil organic matter, incorporated organic materials such as rice straw and manure, and new carbon substrate from plant growth such as plant debris and root exudates (Nakajima et al 2016;Wang et al 2016). In this experiment, with the exception of the incorporated Azolla in the Azolla amended treatments, the soil had no initial visible plant residues.…”

Quantitative assessment of plant‐available silicon extraction methods in rice paddy soils under different management

“…For example, addition of Si-rich rice residues (e.g., rice husk) to As-contaminated soil improves yield and decreases inorganic As in rice grain, but calcium silicate fertilizer had no effect and this was attributed to differences in the solubility of each Si source over the duration of plant growth (Seyfferth and Fendorf 2012;Teasley et al, 2017). A variety of Si sources with different solubilities have been added to soil including silicate fertilizer (Pereira et al, 2004;Limmer et al, 2018a), silicate slags (Ning et al, 2016, Wang et al, 2016, silica gel (Seyfferth and Fendorf, 2012;Fleck et al, 2013) and rice crop residues (Ma et al, 2014;Seyfferth et al, 2016;Teasley et al, 2017;Limmer et al, 2018a). As plant-available Si becomes increasingly important for rice production, it is critical that estimations of Si plant-availability provide predictions that are independent of soil management.…”