Synthetic nitrogen coupled with seaweed extract and microbial inoculants improves rice (<em>Oryza sativa</em> L.) production under a dual cropping system

Abstract

The over-reliance on synthetic nitrogen (N) in current farming is a major concern because of its adverse effects on soil quality, the environment, and crop production. Organic fertilizers such as seaweed extract (SE) and microbial inoculants (MI) provide alternatives to chemical fertilizers that could decrease the amount of synthetic N needing to be applied and improve crop growth productivity. This study evaluated the combined effect of SE and MI with reduced N rates on the growth, biomass accumulation, yield, and yield components of an N-efficient rice cultivar (Baixiang 139-A) and N-inefficient rice cultivar (Guiyu 9-B). Field experiments were conducted in the early and late growing seasons at different sites in Guangxi province, China, in 2019. A total of five treatments, such as T1: N 180 + SE 0 + MI 0 (kg ha-1) (control); T2: N 180 + SE 3 + MI 3 (kg ha -1); T3: N 144 + SE 3 + MI 3 (kg ha-1); T4: N 126 + SE 3 + MI 3 (kg ha-1); and T5: N 108 + SE 3 + MI 3 (kg ha-1) were used. The leaf area index (LAI), effective panicle number, grain per spike, grain filling rate, and 1000-grain weight were significantly increased in T2 and T3 compared with the control. T2and T3 enhanced the biomass accumulation and grain yield of rice compared with the control. Furthermore, differences in the growth, yield, and yield components among the different cultivars were significant; however, there were no significant differences among the different locations. T3 increased the LAI, grain filling rate, biomass accumulation, and grain yield of rice by 4.5%, 5.9%, 6.6%, and 5.2%, respectively, compared with the control. Improvements in grain yield were mainly attributed to the enhanced growth and yield components. The correlation analysis also confirmed that LAI, productive tillers, grain filling rate, and biomass accumulation were positively correlated with grain yield. In sum, T3 (N144 + SE 3 + MI 3 (kg ha-1)) could achieve higher grain yield despite a reduction in the usage of chemical N. Generally, this study provides a sustainable nutrient management plan that increases crop production while minimizing costs of chemical N fertilizer application.

Impact of fertilization with reducing in nitrogen and phosphorous application on growth, yield and biomass accumulation of rice (Oryza sativa L.) under a dual cropping system

“…These cultivars require less N and P for their growth and development (Li et al, 2019). Our results are consistent with those of Ali et al (2020), showing that proper N application can increase the number of tillers and LAI of rice and promote its growth but that the excessive application of N fertilizer increases the number of ineffective tillers and reduces the utilization of N (Xie et al, 2021). However, several studies have reported that reducing N and P fertilizer application reduces rice growth traits (Jiang et al, 2021;Murthy et al, 2015) and alters rice flowering days (Ye et al, 2019).…”

“…Our previous study at the same experimental sites was conducted with the same cultivars, which show no significant effect among experimental sites for rice yield. However, their results were significant among the treatments across the experimental sites (Xie et al, 2021).…”

“…During the heading and maturity stages of rice, five representative rice samples were taken from each treatment plot, prepared for preservation, and brought to the laboratory to determine the rice leaf area using the length-width coefficient method (Xie et al, 2021).…”

Manure applications combined with chemical fertilizer improves soil functionality, microbial biomass and rice production in a paddy field

“…Excessive synthetic N fertilization causes significant environmental problems, such as increased greenhouse gas emissions and groundwater contamination, particularly leading to degradation of soil physicochemical and biological properties (Y. Luo et al., 2020; Sarma et al., 2017; Y. Zhang et al., 2019). Moreover, the continued application of chemical fertilizers (CFs) has also increased the soil acidification and compaction of arable soils, thereby suppressing plant growth and production (Iqbal et al., 2019; Ullah et al., 2021; H. Xie et al., 2021). Therefore, this continued reliance on CFs for cereal crop production is not sustainable.…”

Long‐term straw mulching in a no‐till field improves soil functionality and rice yield by increasing soil enzymatic activity and chemical properties in paddy soils

“…Soil organic matter is key for improving crop production because of the role it plays in sustaining and improving soil physical, chemical, and biological properties (Iqbal et al., 2019; Sarker et al., 2018). In the current farming system, over‐reliance on chemical fertilizers is the main reason for the decline in soil health and stagnant rice yields, as chemical fertilizers have negative effects on soil properties, the environment, and crop productivity (Ali, He, et al., 2020; Cai et al., 2018; Iqbal et al., 2020; H. Xie et al., 2021). Ecological concerns over the deterioration in soil health, rice production, and environmental quality in the present farming system could be addressed by encouraging the in‐situ recycling of crop residues and altered tillage practices (Blumfield & Xu, 2003; Saikia et al., 2019; Jing Zhang et al., 2021).…”