Nitrogen and phosphorus losses by surface runoff and soil microbial communities in a paddy field with different irrigation and fertilization managements

Abstract

Rice cultivation usually involves high water and fertilizer application rates leading to the nonpoint pollution of surface waters with phosphorus (P) and nitrogen (N). Here, a 10-year field experiment was conducted to investigate N and P losses and their impact factors under different irrigation and fertilization regimes. Results indicated that T2 (Chemical fertilizer of 240 kg N ha−1, 52 kg P ha−1, and 198 kg K ha−1 combined with shallow intermittent irrigation) decreased N loss by 48.9% compared with T1 (Chemical fertilizer of 273 kg N ha−1, 59 kg P ha−1, and 112 kg K ha−1 combined with traditional flooding irrigation). The loss ratio (total N loss loading/amount of applied N) of N was 9.24–15.90%, whereas that of P was 1.13–1.31% in all treatments. Nitrate N (NO3-−N) loss was the major proportion accounting for 88.30–90.65% of dissolved inorganic N loss through surface runoff. Moreover, the N runoff loss was mainly due to high fertilizer input, soil NO3-−N, and ammonium N (NH4+−N) contents. In addition, the N loss was accelerated by Bacteroidetes, Proteobacteria, Planotomycetes, Nitrospirae, Firmicutes bacteria and Ascomycota fungi, but decreased by Chytridiomycota fungi whose contribution to the N transformation process. Furthermore, T2 increased agronomic N use efficiency (AEN) and rice yield by 32.81% and 7.36%, respectively, in comparison with T1. These findings demonstrated that T2 might be an effective approach to ameliorate soil chemical properties, regulate microbial community structure, increase AEN and consequently reduce N losses as well as maintaining rice yields in the present study.

Influence of different irrigation methods on the alfalfa rhizosphere soil fungal communities in an arid region

“…The findings of this study are consistent with those of earlier studies on the soil fungal community structure in arid regions [34,35]. According to Wang and Huang, different irrigation methods significantly affect soil fungal communities in paddy fields [36]. In accordance with this earlier finding, we detected differences in the fungal communities of drip-irrigated and flood-irrigated soils.…”

Integration of phosphate solubilizing bacteria and ponska fertilizer as a soybean fertilization method that is adaptive to climate change

“…The difference in the availability status of nutrients in soils and the nutrient uptake rate in plants affects the growth and development of plant parts such as roots, stems and leaves [30]. Therefore, better root development and growth generally results in better plant shoot growth as well [30]. The results of this study showed a positive correlation of 74 % between the dry weight of the roots and shoots.…”

“…Subsequently, the metabolites are distributed on all plant parts. The difference in the availability status of nutrients in soils and the nutrient uptake rate in plants affects the growth and development of plant parts such as roots, stems and leaves [30]. Therefore, better root development and growth generally results in better plant shoot growth as well [30].…”

“…The level of nutrient availability in the soil and the amount of carbohydrate supply from the top of the plant to the roots affect root growth [34]. Better root development and growth would optimize nutrient absorption so that the plant shoot is filled with nutrients and has declared better plant growth and production [30]. In nutrient-starved soils, plant roots receive a more supply of carbohydrates from the top of the plant than in nutrient-sufficient soil for plants.…”

Nutrient dynamics in water and soil under conventional rice cultivation in the Vietnamese Mekong Delta

“…Furthermore, it has been noted that N loss from rice soils typically occurs through ammonia volatilization and nitrification-denitrification (Shankar et al, 2021), while loss of P was comparatively low due to the enrichment of Ca 2+ , Fe 3+ and Al 3+ oxides which can adsorb P in several mineral forms (Wang et al, 2015;Scalenghe et al, 2014). Several previous studies reported that nutrient migration was lost via surface water (SW) and sub-surface water (SbW) (Peng et al, 2011;Qi et al, 2020;Schröder et al, 2011;Wang and Huang, 2021). Thus, it has been suggested that higher amounts of fertilizer application under conventional rice cultivation and local water management regimes would largely result in increased nutrients in adjacent environments.…”