The effects of the depth of fertilization on losses of nitrogen and phosphorus and soil fertility in the red paddy soil of China.
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ABSTRACT:
SUBMITTER: Hou K
PROVIDER: S-EPMC8139273 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description: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.
| S-EPMC8274659 | biostudies-literature
Project description:Appropriate fertilizer application is an important management practice to improve soil fertility and quality in the red soil regions of China. In the present study, we examined the effects of five fertilization treatments [these were: no fertilizer (CK), rice straw return (SR), chemical fertilizer (NPK), organic manure (OM) and green manure (GM)] on soil pH, soil organic carbon (SOC), total nitrogen (TN), C/N ratio and available nutrients (AN, AP and AK) contents in the plowed layer (0-20 cm) of paddy soil from 1998 to 2009 in Jiangxi Province, southern China. Results showed that the soil pH was the lowest with an average of 5.33 units in CK and was significantly higher in NPK (5.89 units) and OM (5.63 units) treatments (P<0.05). The application of fertilizers have remarkably improved SOC and TN values compared with the CK, Specifically, the OM treatment resulted in the highest SOC and TN concentrations (72.5% and 51.2% higher than CK) and NPK treatment increased the SOC and TN contents by 22.0% and 17.8% compared with CK. The average amounts of C/N ratio ranged from 9.66 to 10.98 in different treatments, and reached the highest in OM treatment (P<0.05). During the experimental period, the average AN and AP contents were highest in OM treatment (about 1.6 and 29.6 times of that in the CK, respectively) and second highest in NPK treatment (about 1.2 and 20.3 times of that in the CK). Unlike AN and AP, the highest value of AK content was observed in NPK treatments with 38.10 mg·kg(-1). Thus, these indicated that organic manure should be recommended to improve soil fertility in this region and K fertilizer should be simultaneously applied considering the soil K contents. Considering the long-term fertilizer efficiency, our results also suggest that annual straw returning application could improve soil fertility in this trial region.
| S-EPMC3460972 | biostudies-literature
Project description:Surface runoff is one of the predominant routes for agricultural nitrogen (N) and phosphorus (P) losses, yet their characteristics and corresponding control measures are not fully understood. In 2019 and 2020, field-scale plot experiments were performed at Dongjiang Basin in South China to investigate the characteristics of N and P runoff losses from paddy and maize cropping systems. The results showed that N and P losses from maize fields via surface runoff (27.85 and 1.24 kg ha-1 year-1) were significantly higher than those from paddy fields (15.37 and 0.8 kg ha-1 year-1). The main forms of N losses were nitrate ( NO3- -N) and ammonium ( NH4+ -N) in paddy and maize fields, respectively, whereas particulate P form predominated in surface runoff losses from both the paddy and maize fields. Considerable proportions of agricultural N and P (71-83% of the total runoff loss) were lost during basal fertilization and first topdressing application. Moreover, frequent rainfall events following fertilizer application triggered N and P losses from the monitored fields. About 26.22 and 37.48% of N fertilizer was recovered from grains and straw of paddy and maize, respectively, whereas only 12.35 and 19.51% of P fertilizer were recovered during the crop harvesting stage. Surface runoff was one of the dominant liquid pathways in N loss, whereas most of P loss (introduced from fertilizers without crops utilization) was fixed in the soil. Principal component analysis (PCA) proved that the primary sources of N and P losses were fertilizers rather than N and P in the soil. The current results suggest controlled management relating to fertilization, irrigation, and tillage strategies are effective measures for reducing N and P losses, thereby controlling agricultural non-point source pollution. It is hoped that this study will provide comprehensive field-based inputs on characteristics of N and P runoff losses and formulate appropriate control strategies to protect aquatic environments from eutrophication.
| S-EPMC8384078 | biostudies-literature
Project description:Soil microbes provide important ecosystem services. Though the effects of changes in nutrient availability due to fertilization on the soil microbial communities in the topsoil (tilled layer, 0-20 cm) have been extensively explored, the effects on communities and their associations with soil nutrients in the subsoil (below 20 cm) which is rarely impacted by tillage are still unclear. 16S rRNA gene amplicon sequencing was used to investigate bacterial and archaeal communities in a Pup-Calric-Entisol soil treated for 32 years with chemical fertilizer (CF) and CF combined with farmyard manure (CFM), and to reveal links between soil properties and specific bacterial and archaeal taxa in both the top- and subsoil. The results showed that both CF and CFM treatments increased soil organic carbon (SOC), soil moisture (MO) and total nitrogen (TN) while decreased the nitrate_N content through the profile. Fertilizer applications also increased Olsen phosphorus (OP) content in most soil layers. Microbial communities in the topsoil were significantly different from those in subsoil. Compared to the CF treatment, taxa such as Nitrososphaera, Nitrospira, and several members of Acidobacteria in topsoil and Subdivision 3 genera incertae sedis, Leptolinea, and Bellilinea in subsoil were substantially more abundant in CFM. A co-occurrence based network analysis demonstrated that SOC and OP were the most important soil parameters that positively correlated with specific bacterial and archaeal taxa in topsoil and subsoil, respectively. Hydrogenophaga was identified as the keystone genus in the topsoil, while genera Phenylobacterium and Steroidobacter were identified as the keystone taxa in subsoil. The taxa identified above are involved in the decomposition of complex organic compounds and soil carbon, nitrogen, and phosphorus transformations. This study revealed that the spatial variability of soil properties due to long-term fertilization strongly shapes the bacterial and archaeal community composition and their interactions at both high and low taxonomic levels across the whole soil profile.
| S-EPMC5559540 | biostudies-literature
Project description:The application of iron powder stimulated the growth of iron-reducing bacteria as a respiratory substrate and enhanced their nitrogen (N)-fixing activity in flooded paddy soils. High N fertilization (urea) in the flooded paddy soils has caused adverse environmental impacts such as ammonia (NH3) volatilization, nitrous oxide (N2O) emissions, and nitrate (NO3-) leaching. This study aims to investigate the effects of N fertilization rates in combination with an iron amendment on rice yields and N losses from flooded paddy fields. We performed a 2-year field plot experiment with traditional rice-wheat rotation in China's Yangtze River Delta. The investigation consisted of seven treatments, including 100%, 80%, 60%, and 0% of the conventional N (urea and commercial organic manure) fertilization rate, and 80%, 60%, and 0% of the conventional N with the iron powder (≥99% purity) amendment. The rice yields decreased with a reduction in the conventional N fertilization rate, whereas they were comparable after the iron application under the 80% and 60% conventional N rate. The critical N losses, including NH3 volatilization, N2O emissions, and NO3- and NH4+ leaching, generally decreased with a reduction in the conventional N fertilization rate. These N losses were significantly greater after the iron amendment compared with the non-amended treatments under the 80% and 60% conventional N fertilization rate in the first rice-growing season. However, it was comparable between the iron-amended and the non-amended treatments in the second season. Furthermore, NO3- leaching was the most significant N loss throughout the two rice seasons, followed by NH3 volatilization. The iron amendment significantly increased soil Fe2+ content compared with the non-amended treatments irrespective of N fertilization, suggesting the reduction of amended iron by iron-reducing bacteria and their simultaneous N fixation. A combination of the iron application with 60-80% of the conventional N fertilization rate could maintain rice yields similar to the conventional N fertilization rate while reducing the critical N losses in the flooded paddy field tested in this study. Our study leads to the establishment of novel and practical rice cultivation, which is a step towards the development of green agriculture.
| S-EPMC9318169 | biostudies-literature
Project description:The contents and properties of soil organic phosphorus (Po) largely drive ecosystem productivity with increasing development of natural soil. We hypothesized that soil Po would initially increase with paddy management and then would persist under steady-state conditions. We analyzed soils from a 2000-year chronosequence of a rice-wheat rotation and an adjacent non-paddy 700-year chronosequence in Bay of Hangzhou (China) for their Po composition using solution 31P-NMR after NaOH-EDTA extraction. Land reclamation promoted Po accumulation in both paddy and non-paddy topsoils (depths ≤ 18 cm) until steady-state equilibria were reached within 200 years of land use. Greater Po concentrations were found, however, in the non-paddy subsoils than in those under paddy management. Apparently, the formation of a dense paddy plough pan hindered long-term Po accumulation in the paddy subsoil. The surface soils showed higher proportions of orthophosphate diesters under paddy than under non-paddy management, likely reflecting suppressed decomposition of crop residues despite elevated microbial P compounds stocks under anaerobic paddy-rice management. Intriguingly, the composition of Po was remarkably stable after 194-years of paddy management and 144-years of non-paddy management, suggesting novel steady-state equilibria of P dynamics had been reached in these man-made ecosystems after less than two centuries.
| S-EPMC5589726 | biostudies-literature
Project description:Plants and soil interactions greatly affect ecosystems processes and properties. Ecological stoichiometry is an effective means to explore the C, N, P correlation between plants and soil and the relationship between plant growth and nutrient supply. Serious soil erosion on China's Loess Plateau has further barrenness the soil. Fertilization solves the problem of ecosystem degradation by improving soil fertility and regulating the ecological stoichiometric between soil and plants. No fertilization (CK), nitrogen fertilization (N), phosphorus fertilization (P) and N and P combined fertilization (NP) treatments were set in an alfalfa grassland. Organic carbon (C), nitrogen (N) and phosphorus (P) nutrients and their stoichiometry were measured in shoot and soil. P and NP fertilization increased shoot C concentration (3.12%, 0.91%), and all fertilization decreased shoot N concentration (6.96%). The variation of shoot C and N concentrations resulted in a greater increase in shoot C:N under the fertilization treatment than that under CK (8.24%). Most fertilization treatments increased shoot P concentration (4.63%) at each cut, which induced a decrease of shoot C:P. Shoot N:P of most treatments were greater than 23, but it was lower under N and NP fertilization than that under CK. Fertilization only increased soil C in 2014, but had no effect on soil N. Soil P content was significantly higher under P fertilization in 2014 (34.53%), and all fertilization in the second cut of 2015 (124.32%). Shoot and soil C:P and N:P having the opposite changes to shoot and soil P, respectively. Our results suggest that the change of P after fertilization largely drove the changes of stoichiometric. The growth of alfalfa in the Loess Plateau was severely restricted by P. It is an effective method to increase the biomass of alfalfa by increasing the addition of N or NP fertilizer to alleviate P limitation.
| S-EPMC8298445 | biostudies-literature
Project description:Food production in China results in large losses of nitrogen (N) and phosphorus (P) to the environment. Our objective is to identify hotspots for N and P losses to the environment from food production in China at the county scale. To do this, we used the NUFER (Nutrient flows in Food chains, Environment and Resources use) model. Between 1990 and 2012, the hotspot area expanded by a factor of 3 for N, and 24 for P. In 2012 most hotspots were found in the North China Plain. Hotspots covered less than 10% of the Chinese land area, but contributed by more than half to N and P losses to the environment. Direct discharge of animal manure to rivers was an important cause of N and P losses. Food production was found to be more intensive in hotspots than in other counties. Synthetic fertilizer use and animal numbers in hotspots were a factor of 4-5 higher than in other counties in 2012. Also the number of people working in food production and the incomes of farmers are higher in hotspots than in other counties. This study concludes with suggestions for region-specific pollution control technologies for food production in China.
| S-EPMC5956281 | biostudies-literature
Project description:We studied microbial communities in two paddy soils, which did not receive nitrogen fertilization and were distinguished by the soil properties. The two microbial communities differed in the relative abundance of gram-negative bacteria and total microbial biomass. Variability in microbial communities between the two fields was related to the levels of phosphorus and soil moisture. Redundancy analysis for individual soils showed that the bacterial community dynamics in the high-yield soil were significantly correlated with total carbon, moisture, available potassium, and pH, and those in the low-yield cores were shaped by pH, and nitrogen factors. Biolog Eco-plate data showed a more active microbial community in the high yield soil. The variations of enzymatic activities in the two soils were significantly explained by total nitrogen, total potassium, and moisture. The enzymatic variability in the low-yield soil was significantly explained by potassium, available nitrogen, pH, and total carbon, and that in the high-yield soil was partially explained by potassium and moisture. We found the relative abundances of Gram-negative bacteria and Actinomycetes partially explained the spatial and temporal variations of soil enzymatic activities, respectively. The high-yield soil microbes are probably more active to modulate soil fertility for rice production.
| S-EPMC4740891 | biostudies-other
Project description:Increased inorganic nitrogen (N) and phosphorus (P) additions expected in the future will endanger the biodiversity and stability of agricultural ecosystems. In this context, a long-term fertilizer experiment (37 years) was set up in the black soil of northeast China. We examined interaction impacts of elevated fertilizer and host selection processes on arbuscular mycorrhizal fungi (AMF) communities in wheat rhizosphere soil using the Illumina MiSeq platform. The soil samples were subjected to five fertilization regimes: no fertilizer (CK) and low N (N1), low N plus low P (N1P1), high N (N2), and high N plus high P (N2P2) fertilizer. Long-term fertilization resulted in a significant shift in rhizosphere soil nutrient concentrations. The N fertilization (N1 and N2) did not significantly change rhizosphere AMF species diversity, but N plus P fertilization (N1P1 and N2P2) decreased it compared with CK. Non-metric multidimensional scaling showed that the rhizosphere AMF communities in CK, N1, N2, N1P1 and N2P2 treatments were distinct from each other. The AMF communities were predominantly composed of Glomeraceae, accounting for 30.0-39.1% of the sequences, and the relative abundance of family Glomeraceae was more abundance in fertilized soils, while family Paraglomeraceae were increased in N1 and N2 compared with CK. Analysis shown that AMF diversity was directly affected by soil C:P ratio but indirectly affected by plant under long-term fertilization. Overall, the results indicated that long-term N and P fertilization regimes changed rhizosphere AMF diversity and community composition, and rhizosphere AMF diversity was both affected by soil C:P ratio and plant.
| S-EPMC7506078 | biostudies-literature