[Effects of Microplastics on Soil NO Emission and Nitrogen Transformations from Tropical Agricultural Soils].

A widespread concern had been there regarding soil ecological and environmental problems caused by microplastic pollution in agricultural soils. A controlled laboratory incubation experiment was performed to examine the effects of different types of microplastics on soil properties, NO emissions, and nitrogen （N） transformations in tropical arable soils from a pepper-corn cropping system in Hainan Province. Three treatments were done： soil without microplastics （CK） and soil amended with 5% of polyethylene （PE） or with 5% of polybutylene adipate co-terephthalate （PBAT）.

Molecular-level insight into the effect of fertilization regimes on the chemodiversity of dissolved organic matter in tropical cropland.

Fertilization is a critical agronomic measure for croplands in tropical regions, owing to their low fertility. However, the effects of fertilization on the quantity and chemodiversity of latosolic dissolved organic matter (DOM) in tropical regions remain largely unknown. Therefore, in this study, the variations in latosol DOM concentrations and chemodiversity induced by inorganic fertilization and the co-application of inorganic fertilization with straw return, sheep manure, biochar, and vermicompost fertilizers at a molecular level were systematically investigated using multispectral techniques and ultrahigh-resolution mass spectrometry.

Molecular insights into effects of PBAT microplastics on latosol microbial diversity and DOM chemodiversity.

The impact of biodegradable microplastics on the microbial community and dissolved organic matter (DOM) in latosol has not been well reported. In this study, an incubation experiment at 25 ºC for 120 days using latosol amended with low (5%) and high (10%) concentrations of polybutylene adipate terephthalate (PBAT) microplastics was carried out to explore the impacts of PBAT microplastics on soil microbial communities and DOM chemodiversity, and the intrinsic interactions between their shifts. The main bacterial and fungal phyla in soil, namely Chloroflexi, Actinobacteria, Chytridiomycota, and Rozellomycota showed a nonlinear relationship with PBAT concentration and played a pivotal role in shaping DOM chemodiversity.

Organic substitution stimulates ammonia oxidation-driven NO emissions by distinctively enriching keystone species of ammonia-oxidizing archaea and bacteria in tropical arable soils.

Partial organic substitution (POS) is pivotal in enhancing soil productivity and changing nitrous oxide (NO) emissions by profoundly altering soil nitrogen (N) cycling, where ammonia oxidation is a fundamental core process. However, the regulatory mechanisms of NO production by ammonia oxidizers at the microbial community level under POS regimes remain unclear. This study explored soil ammonia oxidation and related NO production, further building an understanding of the correlations between ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) activity and community structure in tropical arable soils under four-year field management regimes (CK, without fertilizer N; N, with only inorganic N; M1N1, with 1/2 organic N + 1/2 inorganic N; M1N2, with 1/3 organic N + 2/3 inorganic N).

Synergistically mitigating nitric oxide emission by co-applications of biochar and nitrification inhibitor in a tropical agricultural soil.

Agricultural soils are the hotspots of nitric oxide (NO) emissions, which are related to atmospheric pollution and greenhouse effect. Biochar application has been recommended as an important countermeasure, however, its mitigation efficiency is limited as biochar, under certain conditions, can stimulate soil nitrification. Therefore, biochar co-applied with nitrification inhibitor could optimize the mitigation potential of biochar.

Linkages of nitrogen-cycling microbial resistance and resilience to soil nutrient stoichiometry under dry-rewetting cycles with different fertilizations and temperatures in a vegetable field.

Multiple dry-rewetting (DRW) cycles occur in intensively managed vegetable fields due to frequent tillage and irrigation. Soil nitrogen (N) cycling depends on the resistance and resilience of related microbial populations to DRW cycles, which could be closely related to soil nutrient status. However, the linkage of N-cycling microbial resistance and resilience and soil nutrient stoichiometry remains unknown in vegetable field.

Addition of biodegradable microplastics alters the quantity and chemodiversity of dissolved organic matter in latosol.

Dissolved organic matter (DOM) chemodiversity plays an important role in regulating nutrient cycles and contaminant behavior in soil. However, how biodegradable microplastic (MPs) affect the DOM chemodiversity is still unknown, although developing biodegradable plastics are regarded as a promising strategy to minimize the risks of MPs residues in soil. Here, with the common poly (butylene adipate-co-terephthalate) (PBAT) as the model, the molecular effect of biodegradable MPs on soil DOM was explored by adding 0%, 5% and 10% (w/w) of PBAT to tropical latosol, respectively.

Residual effects of four-year amendments of organic material on NO production driven by ammonia-oxidizing archaea and bacteria in a tropical vegetable soil.

Organic material (OM) applied to cropland not only enhances soil fertility but also profoundly affects soil nitrogen cycling. However, little is known about the relative contributions of soil ammonia-oxidizing archaea (AOA) and bacteria (AOB) to nitrous oxide (NO) production during ammonia oxidation in response to the additions of diverse types of OMs in the tropical soil for vegetable production. Herein, the soils were sampled from a tropical vegetable field subjected to 4-year consecutive amendments of straw or manure.

Spatial heterogeneous granulation enhance soil nitrogen supply potential via regulating dissolved organic nitrogen.

Combined application of organic fertilizer (OF) and chemical nitrogen (N) fertilizer (CF) is a common fertilization practice, providing better N supply pattern for crop growth. However, few studies focused on the effect of granulation method of these two fertilizers on N supply to soil. To validate this effect, we mixed the CF (N-(NH)SO) into cow manure powders with maize straw powder at rate of 2% or 8% (dry weight), respectively, in two forms, homogeneous granulation (HG) and spatial heterogeneous granulation (SG), and applied them to soil to investigate their difference in N transformations during an 80-day incubation.

[Impacts of future climate change on spring phenology stages of rubber tree in Hainan, China].

To explore the impacts of future climate change on spring phenology stages (first leaf storey expansion stage, spring flowering stage) of rubber tree in Hainan Island, we established a rubber tree spring phenology simulation model based on the crop clock model and developed a computer software RubberSP. The model simulation accuracy was examined with experimental observed phenology data. Five global climate models (GCMs) from the Coupled Model Intercomparison Project Phase 5 (CMIP5) were integrated using Bayesian Model averaging method (BMA) to predict the impacts of climate change on the spring phenology of rubber tree in 2020-2099 (relative to 1986-2017) under climate scenarios of RCP2.

Combined effects of nitrogen fertilizer and biochar on greenhouse gas emissions and net ecosystem economic budget from a coastal saline rice field in southeastern China.

Biochar amendment has complex impacts on greenhouse gas emissions, crop production and economic benefit. However, few studies have comprehensively investigated the effects of biochar amendment in coastal saline rice fields. Thus, a biochar amendment field experiment was established in a coastal saline rice field in China to estimate the CH and NO emissions, global warming potential (GWP), greenhouse gas intensity (GHGI), and net ecosystem economic budget (NEEB) of the biochar amendment during the rice growing season in 2017.

Overdose fertilization induced ammonia-oxidizing archaea producing nitrous oxide in intensive vegetable fields.

Little is known about the effects of nitrogen (N) fertilization rates on ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) and their differential contribution to nitrous oxide (NO) production, particularly in greenhouse based high N input vegetable soils. Six N treatments (N1, N2, N3, N4, N5 and N6 representing 0, 293, 587, 880, 1173 and 1760 kg N ha yr, respectively) were continuously managed for three years in a typically intensified vegetable field in China. The aerobic incubation experiment involving these field-treated soils was designed to evaluate the relative contributions of AOA and AOB to NO production by using acetylene or 1-octyne as inhibitors.

Nitrification inhibitors mitigated reactive gaseous nitrogen intensity in intensive vegetable soils from China.

Nitrification inhibitors, a promising tool for reducing nitrous oxide (NO) losses and promoting nitrogen use efficiency by slowing nitrification, have gained extensive attention worldwide. However, there have been few attempts to explore the broad responses of multiple reactive gaseous nitrogen emissions of NO, nitric oxide (NO) and ammonia (NH) and vegetable yield to nitrification inhibitor applications across intensive vegetable soils in China. A greenhouse pot experiment with five consecutive vegetable crops was performed to assess the efficacies of two nitrification inhibitors, namely, nitrapyrin and dicyandiamide on reactive gaseous nitrogen emissions, vegetable yield and reactive gaseous nitrogen intensity in four typical vegetable soils representing the intensive vegetable cropping systems across mainland China: an Acrisol from Hunan Province, an Anthrosol from Shanxi Province, a Cambisol from Shandong Province and a Phaeozem from Heilongjiang Province.

[Effects of biochar and nitrification inhibitor incorporation on global warming potential of a vegetable field in Nanjing, China].

The influences of biochar and nitrification inhibitor incorporation on global warming potential (GWP) of a vegetable field were studied using the static chamber and gas chromatography method. Compared with the treatments without biochar addition, the annual GWP of N2O and CH4 and vegetable yield were increased by 8.7%-12.