Soil organic carbon dynamics shift by incorporating wheat straw in paddy soil in China.

The objective of this study was to explore the effects of unfertilized control (CK), mineral NPK fertilizer (NPK), NPK plus medium-rate wheat straw (MSNPK), and NPK plus high-rate wheat straw (HSNPK) on soil organic carbon (SOC) fractions and C-cycle enzymes at distinct depths (0-5, 5-10, 10-20, 20-30, and 30-50 cm) in paddy soil. The SOC content at 0-50 cm depth ranged from 8.50 to 21.

A non-chemical weed control strategy, introducing duckweed into the paddy field.

Background: Herbicide resistance in weeds and environmental pollution resulting from excessive application of chemical herbicides keeps increasing. Development of environment-friendly and effective weed management strategies are required for sustainable agricultural production. In this study we investigated the effects of duckweeds (Landoltia punctata (G.

Straw return promoted the simultaneous elimination of sulfamethoxazole and related antibiotic resistance genes in the paddy soil.

Straw return could provide a natural available carbon source for the soil microorganisms, which might affect the environmental behaviours of organic pollutants. In this study, microcosm system was constructed to investigate the effect of rice straw return on the fate of sulfamethoxazole (SMX) and related antibiotic resistance genes (ARGs). The results showed that straw return (1% of soil dry mass) could accelerate the degradation of SMX via co-metabolism.

The effect of integrated rice-frog ecosystem on rice morphological traits and methane emission from paddy fields.

Integrated Rice-frog Ecosystem (IRFE) has the potential to reduce methane (CH) emission and maintain yields from paddy fields. However, the quantitative relationship between rice morphological traits and CH emission remains to be explored. In this study, a 2-year field experiment was conducted to evaluate the effect of IRFE on rice morphological traits and CH emission from paddy fields and the ecological mechanisms.

Effects of long-term integrated agri-aquaculture on the soil fungal community structure and function in vegetable fields.

The diversity and community structure of soil fungi play an important role in crop production and ecosystem balance, especially in paddy-upland vegetable field systems. High-throughput sequencing was used to study changes in the soil fungal community structure and function in paddy-upland vegetable field systems. The results showed that compared with traditional planting, the diversity and community structure of soil fungi were changed by the combination of flooding and drought, the Shannon index increased by 11.

The changes of antioxidant system and intestinal bacteria in earthworms (Metaphire guillelmi) on the enhanced degradation of tetracycline.

Tetracycline (TC) in soil severely imperils food security and ecosystem function. Metaphire guillelmi is a common species in farmland. It could impact the degradation of antibiotics.

Minerals loaded with oxygen nanobubbles mitigate arsenic translocation from paddy soils to rice.

Inhibiting reductive transformation of arsenic (As) in flooded paddy soils is fundamentally important for mitigating As transfer into the food chain. In this study, oxygen-nanobubble-loaded-zeolites (ZON) and -vermiculites (VON) were tested as a novel approach for supplying oxygen to paddy soils to inhibit As influx into rice. The dynamic physio- and bio-chemical variations in the rhizosphere and bulk soil were profiled in a rhizobox experiment.

Rice-duck co-culture integrated different fertilizers reduce P losses and Pb accumulation in subtropical China.

Double pollution with phosphorus (P) losses and potential lead (Pb) accumulation in rice fields could lead to eutrophication and crop toxicity, respectively, and affect people's health. To promote the sustainable and environmentally friendly development of agriculture, we conducted field experiments using a randomized block design to explore P losses, Pb accumulation and any potential association between P and Pb forms in rice-duck (RD) co-culture system and rice monoculture (RM) system combined with different fertilizers applied: the no fertilizer (RD and RM), chemical fertilizer (RDF and RMF), organic fertilizer (RDO and RMO), and a mixture of 70% chemical and 30% organic fertilizers (RDFO and RMFO) treatments with consistent P inputs. The results showed that RDFO had the best advantages in reducing the losses of TP (total phosphorous) (by 6.

Effects of Salinity on Earthworms and the Product During Vermicomposting of Kitchen Wastes.

Population growth and social changes have recently contributed to an exaggerated increase in kitchen wastes in China. Vermicomposting has recently been recognized as an effective and eco-friendly method of organic waste treatment through the combination of earthworms and microbes. However, the influence of salt in kitchen wastes on vermicomposting have been unknown.

Microbial Community Structures and Important Associations Between Soil Nutrients and the Responses of Specific Taxa to Rice-Frog Cultivation.

Rice-frog cultivation is a traditional farming system in China and has been reintroduced as an agricultural practice in China in recent years. The microbial community in paddy rhizospheric soils has attracted much attention because many microorganisms participate in functional processes in soils. In this study, Illumina MiSeq sequencing-based techniques were used to investigate soil microbial communities and functional gene patterns across samples obtained by conventional rice cultivation (CR) and rice-frog cultivation (RF).

Nitrogen leakage in a rice-duck co-culture system with different fertilizer treatments in China.

Nitrogen (N) leakage in paddy fields can cause groundwater pollution. In this study, we conducted a split-plot field experiment over 2 years to compare N leakage in a rice-duck co-culture system and a rice monoculture system with different fertilizer treatments. Four treatments were applied to each field, with consistent N inputs in each fertilizer treatment: no fertilizer (RD and RM, respectively), chemical fertilizer (RDF and RMF, respectively), organic fertilizer (RDO and RMO, respectively), and a mixture of 70% chemical and 30% organic fertilizers (RDFO and RMFO, respectively).

Effects of Integrated Rice-Frog Farming on Paddy Field Greenhouse Gas Emissions.

Integrated rice-frog farming (IRFF), as a mode of ecological farming, is fundamental in realizing sustainable development in agriculture. Yet its production of greenhouse gas (GHG) emissions remains unclear. Here, a randomized plot field experiment was performed to study the GHG emissions for various farming systems during the rice growing season.

Three-Source Partitioning of Methane Emissions from Paddy Soil: Linkage to Methanogenic Community Structure.

Identification of the carbon (C) sources of methane (CH₄) and methanogenic community structures after organic fertilization may provide a better understanding of the mechanism that regulate CH₄ emissions from paddy soils. Based on our previous field study, a pot experiment with isotopic C labelling was designed in this study. The objective was to investigate the main C sources for CH₄ emissions and the key environmental factor with the application of organic fertilizer in paddies.

Comparison of the Abundance and Community Structure of N-Cycling Bacteria in Paddy Rhizosphere Soil under Different Rice Cultivation Patterns.

Eco-agricultural systems aim to reduce the use of chemical fertilizers in order to improve sustainable production and maintain a healthy ecosystem. The aim of this study was to explore the effects of rice-frog farming on the bacterial community and N-cycling microbes in paddy rhizosphere soil. This experiment involved three rice cultivation patterns: Conventionally cultivated rice (CR), green rice-frog farming (GR), and organic rice-frog farming (OR).

The influence of phosphorus on the autotrophic and mixotrophic denitrification.

Autotrophic and mixotrophic denitrification, two approaches of biological denitrification, have drawn more and more attention among the techniques to remove nitrogen from the aquatic environment. This study investigated the influence of phosphorus on the denitrification performance and bacterial community structure in the autotrophic and mixotrophic denitrification reactors. The activity test was applied to evaluate the variation of denitrification activity of autotrophic and mixotrophic sludge before and after phosphorus addition.

Effects of different fertilizers on methane emissions and methanogenic community structures in paddy rhizosphere soil.

Paddy soil accounts for 10% of global atmospheric methane (CH) emissions. Many types of fertilizers may enhance CH emissions, especially organic fertilizer. The aim of this study was to explore the effects of different fertilizers on CH and methanogen patterns in paddy soil.

Variations in nutrient and trace element composition of rice in an organic rice-frog coculture system.

Introducing frogs into paddy fields can control pests and diseases, and organic farming can improve soil fertility and rice growth. The aim of this 2-year field study was compare the yield and elemental composition of rice between an organic farming system including frogs (ORF) and a conventional rice culture system (CR). The grain yields were almost the same in the ORF system and the CR system.

Modeling the impacts of alternative fertilization methods on nitrogen loading in rice production in Shanghai.

Nitrogen (N) loss from paddy fields is an important source of agricultural non-point source pollution that leads to eutrophication of water bodies and degradation of water quality. The impacts of alternative N fertilizer management practices on N loading (N loss through runoff and leaching) from paddy fields in Shanghai were assessed using a process-based biogeochemical model, DNDC. The results indicated that the current fertilization rate in paddy fields of Shanghai (300kgN/ha) exceeds the actual rice demand and has led to substantial N loading of 1142±276kg.

Chemical composition, angiotensin-converting enzyme-inhibitory activity and antioxidant activities of few-flower wild rice (Zizania latifolia Turcz.).

Background: The chemical compositions of the stem and leaf sheath of few-flower wild rice were analysed. In addition, their extracts were evaluated for diphenylpicrylhydrazyl (DPPH) free radical-scavenging activity, ferric-reducing antioxidant power and angiotensin-converting enzyme (ACE)-inhibitory activity, since these are important properties of sources of nutraceuticals or functional foods.

Results: The stems contained more ascorbic acid (0.

Influence of phenanthrene on cadmium toxicity to soil enzymes and microbial growth.

Background: Many contaminated sites contain a variety of toxicants. Risk assessment and the development of soil quality criteria therefore require information on the interaction among toxicants. Interactions between heavy metals are relatively well studied, but little is known about those between heavy metals and polycyclic aromatic hydrocarbons (PAHs).