Effects of rice straw mulching on N2O emissions and maize productivity in a rain-fed upland

Abstract

In the hilly areas of southern China, uplands and paddies are located adjacent to each other. Using rice straw as mulch for upland soil may improve crop production and partially replace chemical fertilizers, which may mitigate NO emissions. A field experiment was conducted to investigate the potential of rice straw mulching for mitigating NO emissions and increasing crop production. The treatments included no mulching (CK), 5000 kg ha of straw mulching (SM5), and 10,000 kg ha of straw mulching (SM10). Moreover, all the treatments received equivalent amounts of nitrogen, phosphorus, and potassium from chemical fertilizers plus rice straw. Relative to CK, cumulative NO emissions decreased by 23.1 and 33.5% with SM5 and SM10, respectively. Significant positive correlations were observed between NO fluxes and soil water-filled pore space (WPFS) (r = 0.495, P< 0.05) and between seasonal cumulative NO fluxes and the chemical N fertilization rate (r = 0.814, P< 0.05). These findings indicate that soil WPFS was the key environmental factor in NO emissions and that the substitution of chemical nitrogen fertilizer with rice straw was the main driver of NO mitigation. Relative to CK, the maize yield increased by 16.5 and 29.6% with SM5 and SM10, respectively, which can be attributed primarily to the increases in soil moisture. The chemical fertilizer input could be decreased and NO emissions could be mitigated through straw mulching, while achieving improved crop yield. This management strategy has great potential, and this study provides an important reference for low-carbon agriculture.

Greater promotion of DNRA rates and nrfA gene transcriptional activity by straw incorporation in alkaline than in acidic paddy soils

“…In addition, crop residues such as straw incorporation are widely applied in paddy soil fields to improve soil quality and fertility in China. It has been suggested that straw returning in paddy soil can remarkably enhance soil organic carbon stock and has distinct effects on greenhouse emission and soil microbial community through altering soil physical condition and soil C/N (Yan et al, 2013;Lu et al, 2015;Wang et al, 2018a;Wu et al, 2018;Yao et al, 2018). However, the influence of straw returning on DNRA process is rarely estimated.…”

Enhancing Sustainable Agriculture in China: A Meta-Analysis of the Impact of Straw and Manure on Crop Yield and Soil Fertility

“…In terms of the difference between SOC and TN, the high C/N of straw could be one major reason. When straw is added to soil, microorganisms use up available nitrogen to decompose the straw, temporarily slowing the short-term increase in TN [51]. This shows that the improvement effect of straw return on different indicators is influenced by their characteristics.…”

“…However, the SOC will decrease rapidly once the continuous straw return stops due to the introduction of numerous labile carbon compounds and the acceleration of "priming effects" [41]. In a rain-fed upland, the practice of long-term rice straw return was used to increase maize productivity; although compared with the control, straw return significantly increased maize yield, a year-on-year comparison within the straw return group showed a decline over the years [51]. Jiang et al and Wang et al found that straw return significantly increased crop yield after continuous return for 5 years [54,55].…”

“…Compared with other forms, straw mulching has shown superiority in reducing water evaporation and increasing soil moisture, thereby enhancing crop yield and water use efficiency [50]. Furthermore, straw mulching has been observed to lower soil temperature, which is beneficial for ensuring crop growth and soil moisture during the high temperatures of the summer [51]. In contrast to mulching, straw incorporation increases the contact area between straw and soil microorganisms when the straw is buried at the soil layer of 0-20 cm, which accelerates the decomposition rate of straw [7].…”

Elevated tropospheric ozone and crop production: potential negative effects and plant defense mechanisms

“…Nitrous oxide production can be mitigated using mulches (e.g., rice straw) and by minimizing fertilizer requirements in the soil. It is evident that soil water-filled pore spaces play an important role in N 2 O emissions in the field; therefore, altering nitrogenous fertilizer with mulch can contribute to N 2 O mitigation ( Wu et al., 2018 ). Intercultural operations, such as mulching, can also reduce O 3 -induced losses.…”