Effects of the Autumn Incorporation of Rice Straw and Application of Lime Nitrogen on Methane and Nitrous Oxide Emissions and Rice Growth of a High-Yielding Paddy Field in a Cool-Temperate Region in Japan

Abstract

The effects of autumn plowing and lime nitrogen application on rice straw decomposition, CH4 and N2O emission and rice growth in the following year in a high-yielding rice cultivated paddy field were evaluated for two years. The experimental plots were set up, combining different times of rice straw (750 g m−2) incorporation into the soil by plowing (autumn or the following spring), with and without lime nitrogen application in autumn (5 g-N m−2). Autumn plowing promoted the decomposition of rice straw, but the application of lime nitrogen did not show a consistent trend. The soil pH was high (7.3) at the studied site, and the alkaline effect of lime nitrogen may not have been significant. As with straw decomposition, CH4 emissions were suppressed by autumn plowing, and no effect from the lime nitrogen application was observed. It was also suggested that the straw decomposition period may be shorter and the CH4 emissions may be higher in high-yielding cultivars that require a longer ripening period than in normal cultivars. The effect of both treatments on N2O emission was not clear. Both the autumn plowing of rice straw and lime nitrogen application were effective in promoting rice growth and increasing rice yield.

A seven‐year study on the effects of four tillage modes on soil physicochemical properties, microbial biomass, enzymatic activities, and grain yield in a rice–ratoon rice cropping system

“…However, straw anaerobic decomposition in the deep soil layer before rice transplanting produces reducing substances that inhibit crop root growth (Huang, Ma, et al, 2020; Huang, Pan, et al, 2020). Takakai et al (2021) reported that returning straw to the soil after the rice was harvested in autumn promoted the decomposition of the straw and improved the growth and yield of the second‐year rice. Occasional use of segmented PT (winter plowing + rotary tilling before rice transplanting) has the potential to increase rice yields and maintain soil health in ratoon rice systems (Wang, He, et al, 2020; Wang, Qi, et al, 2020).…”

Nitrogen Budget in a Paddy-Upland Rotation Field with Soybean Cultivation

“…On the other hand, LMC may not inhibit N 2 fixation because of its slow decomposition (mineralization). The lower amount and percentages of N accumulation derived from N 2 fixation than the values shown in Section 2 (Figure 4, [19]) may be due to the fact that the study site was located in a reclaimed land and soil N fertility was high [46]. Therefore, soil N uptake via soybean roots could be high and dependence on symbiotic N 2 fixation could be low.…”