Farming System In China Research Articles

Promoting sustainable smallholder farming systems in China

CONTEXTHundreds of millions of smallholder farmers account for 84% of farming households globally. Owing to the limited access to knowledge and resources, smallholder farming systems under sub-optimal management are facing multiple challenges such as adverse environmental impacts and difficulties in meeting growing food demand. Although substantial advanced techniques and practices have been developed, applying these practices on the ground at a large scale remains a great challenge. OBJECTIVESThis study aims to assess the sustainability of typical soil-crop management practices in order to recommend best practice bundles. The study also deploys a farmer survey in order to identify barriers hindering the adoption of sustainable practices and propose ways to overcome these barriers. METHODSTo achieve these aims, we develop a generalizable framework combining technical innovations and social realization pathway for sustainable transformation of smallholder farming systems. We apply this framework in the North China Plain as a case study, propose target-oriented practice bundles and subsequent realization roadmaps from smallholder farmer's perspectives and interests. RESULTS AND CONCLUSIONSOur results show that nitrogen reduction has the greatest positive effect on the overall sustainability of smallholder farming systems (12–14%), followed by formula fertilizer (6–10%) and optimal crop practices (2–4%). Thus, our recommended practice bundles include reducing fertilizer inputs and optimal sowing date and rate. However, our farmer survey shows that the implementation of these recommended practices faces barriers associated with economic costs, labor requirements, and farmer's preferences and acceptance. We suggest ways to overcome these barriers, including multi-stakeholder platforms better connecting smallholders, scientists, government, and industry. SIGNIFICANCEOur framework can be amended to fit different contexts and targets, therefore it can be adopted and tweaked by other regions worldwide dominated by smallholder agriculture to promote sustainable transformation.

Green production of apples delivers environmental and economic benefits in China

Sustainable alternative farming systems are gaining popularity worldwide because of the negative effects of conventional agriculture on global climate change and the environmental degradation caused by intensive use of synthetic inputs. The green farming system in China is an integrated production strategy that focuses on reducing chemical fertilizer use while increasing organic manure inputs. Despite their rapid growth as more sustainable systems over the past decades, green farming systems have not been systematically evaluated to date. We used apple production as a representative case to assess the sustainability of green farming systems. Across major apple-producing regions in China, green farming reduced the application of chemical fertilizer nitrogen (N) by 46.8% (from 412 to 219 kg ha−1) and increased that of manure N by 33.1% (from 171 to 227 kg ha−1) on average compared with conventional systems enhancing N use efficiency by 7.27–20.27% and reducing N losses by 8.92%–11.56%. It also slightly lowered yield by 4.34%–13.8% in four provinces. Soil fertility was improved in green orchards through increases in soil organic matter, total N, and available major nutrients. Our cradle-to-farm-gate life-cycle assessment revealed that green farming helped to mitigate greenhouse gas emissions by an average of 12.6%, potentially contributing to a reduction of 165 239 t CO2 eq annually in major apple-producing areas. In addition, green farming achieved 39.3% higher profitability ($7180 ha−1 year−1) at the farmer level. Our study demonstrates the potential of green production of apples for the development of sustainable agriculture in China. These findings advance our understanding of sustainable alternative farming systems and offer perspectives for the sustainable development of global agriculture.

Characterizing Spatial and Temporal Variations in N2O Emissions from Dairy Manure Management in China Based on IPCC Methodology

The emission factor method (Tier 1) recommended by the Intergovernmental Panel on Climate Change (IPCC) is commonly used to estimate greenhouse gas (GHG) emissions from livestock and poultry farms. However, the estimation accuracy may vary due to practical differences in manure management across China. The objectives of this study were to estimate the direct and indirect nitrous oxide (N2O) emissions from dairy manure management between 1990 and 2021 in China and characterize its spatial and temporal variations following IPCC guideline Tier 2. The N2O emission factor (EF) of dairy cow manure management systems was determined at the national level and regional level as well. The results showed that the national cumulative N2O emission of manure management from 1990 to 2021 was 113.1million tons of CO2 equivalent, ranging from 90.3 to 135.9 million tons with an uncertainty of ±20.2%. The annual EF was 0.021 kg N2O-N (kg N)−1 for total emissions, while it was 0.014 kg N2O-N (kg N)−1 for direct emissions. The proportions of N2O emissions in North China, Northeast China, East China, Central and Southern China, Southwest China and Northwest China were 32.3%, 18.6%, 11.4%, 5.8%, 6.1% and 25.8%, respectively. In addition, N2O emissions varied among farms in different scales. The respective proportions of total N2O emissions from small-scale and large-scale farms were 64.8% and 35.2% in the past three decades. With the improvement in farm management and milk production efficiency, the N2O emissions per unit mass of milk decreased from 0.77 × 10−3 kg to 0.48 × 10−3 kg in 1990–2021. This study may provide important insights into compiling a GHG emission inventory and developing GHG emission reduction strategies for the dairy farming system in China.

Risk assessment of Bacillus cereus in lettuce grown in open-field and greenhouse farming systems in China: A comparative study

Abstract Objectives Bacillus cereus isolates from vegetables can cause diarrheal syndrome food poisoning. Lettuce, the most highly consumed ready-to-eat vegetable, poses a significant risk of B. cereus exposure. Hence, B. cereus monitoring and evaluation during cultivation are essential for preventing foodborne illnesses caused by this food–pathogen combination. However, the impact of different cultivation practices on B. cereus contamination in lettuce currently remains unclear. Furthermore, a validity indicator for the experimental models cannot be effectively validated under field conditions. Materials and Methods Herein, we assessed the risk of B. cereus exposure using lettuce grown under two different cultivation farming systems in China (open-field versus greenhouse) using a quantitative microbial risk assessment model. Tukey’s mean comparison method and kernel density estimation frequency distribution statistics were used for model validation using environmental samples and lettuce. Results The mean concentration of B. cereus in open-field-grown lettuce was significantly higher than that in greenhouse-grown lettuce (P<0.05). No significant differences were observed between measured, formula-calculated, and risk assessment values in environmental samples or lettuce (P>0.05), verifying the accuracy of the risk model. Conclusion Soil solarization, complete manure treatment, usage of mulch films, and irrigation water quality should be considered in agricultural practices to control B. cereus concentrations in lettuce. Overall, we found that B. cereus was more abundant in open-field-grown lettuce, and we provide a risk evaluation framework that can guide farmers and policy-makers to control B. cereus contamination in farm-to-fork lettuce chains in China.

The effects of lotus-fish co-culture on the gut microbiome of Hefang crucian carp (Carassis auratus)

Gut microbiome plays an important role in host's development and reproduction. Lotus-fish co-culture (LFC) is a popular integrated agriculture–aquaculture farming system in China. However, there is still a relative dearth of information on how changes of aquaculture modes will affect the fish gut microbiome. In the present study, metagenomic sequencing was used to compare gut bacteria of the hybrid fish Hefang crucian carp (Carassius cuuieri ♀ × C. auratus var. red ♂) cultured in LFC and intensive pond culture (IPC) systems. The results indicated that aquaculture modes exerted great influences on the fish gut bacterial community. A significantly higher gut bacterial diversity was found in LFC than that in IPC (P < 0.05). The relative abundances of Actinobacteria and Chloroflexi were apparently higher in LFC than those in IPC, whereas Planctomycetota, Firmicutes, and Verrucomicrobia showed opposite patterns. Besides, gut bacterial metabolic potentials involved in energy metabolism, carbohydrate metabolism, amino acid metabolism, environmental information processing, and cellular processes were significantly increased in LFC compared to those in IPC. On the contrary, the bacterial functional potentials related to nucleotide metabolism, DNA mismatch repair, as well as homologous recombination were significantly stimulated in the IPC system. Source‐tracking analysis suggested that fish gut bacterial community in IPC was originated mainly from water sources, whereas the gut bacterial community in LFC was originated from more unknown sources and soil sources. Our results provided new insight into the influence of aquaculture modes on the microbial community diversity and functionality in aquatic animals and highlighted the importance of environment microbiome in reshaping the gut microbes.

Exploring the emergence and changing dynamics of a new integrated rice-crawfish farming system in China

Crop-aquaculture systems are widely adopted around the world as they can provide high protein and energy outputs per unit of land and raise farm incomes, particularly for smallholder farmers. Recently, a new crop-aquaculture system, which combines rice production with crawfish breeding (integrated rice-crawfish farming), has emerged and rapidly expanded in China. However, the spatial extent and temporal dynamics of this integrated farming system largely remain unclear, which prohibits rigorous impact assessments to support its sustainable development. Here we use time series of Landsat satellite data, for the first time, to explore the emergence and the changing dynamics of this rice-crawfish farming system for the period of 2013–2021 in five provinces (805 600 km2) of China, where 90% of the global crawfish are produced. Our analysis reveals that the total area of rice-crawfish farming in these five provinces increased steadily from 0.11 Mha in 2013 to 0.70 Mha in 2019, then sharply contracted by a third in 2020 and rebounded in 2021. Spatially, rice-crawfish system is located primarily in low-elevation plain areas with abundant water resources, where paddy rice cultivation has traditionally dominated agriculture. More concentrated rice-crawfish distribution is observed in Jianghan Plain, and regions around Dongting Lake and Poyang Lake. The spatial distribution of rice-crawfish cultivation experienced considerable expansion towards the east and north from 2013 to 2021, with the largest expansion found in Jiangsu and Anhui after 2018. At the county level, over 6% of counties experienced notable area increases of more than 60 km2 from 2017 and 2019, but 20% of counties have decreased from 2019 to 2021. Among the converted land use types, irrigated cropland is the largest contributor to rice-crawfish expansion with a contribution of 56%, followed by water bodies (25%) and rainfed cropland (13%). The spatial and temporal information provided in this study helps to understand the evolution of rice-crawfish cultivation in China and facilitates more efficient management of land resources under the rapid development of this farming system.

Comparative life cycle assessment of whiteleg shrimp (Penaeus vannamei) cultured in recirculating aquaculture systems (RAS), biofloc technology (BFT) and higher-place ponds (HPP) farming systems in China

Recirculating aquaculture systems (RAS), biofloc technology (BFT), and higher-place ponds (HPP) are considered as alternative technologies in addressing major environmental challenges linked to conventional Whiteleg shrimp farming systems. Global concern about energy consumption and carbon emission in aquaculture industries, especially in countries like China. The application of life cycle assessment (LCA) in shrimp aquaculture, especially in comparing different shrimp production systems, is being used. In our study, surveys on three RAS, three BFT and nine HPP farms have been conducted, and the data inputs were used to establish a cradle to farm-gate LCA by means of software SimaPro 9.3.0.2 and CML-IA methods to evaluate the environmental performance. The methods are well suited to this LCA, as it focuses mainly on energy consumption input, pollution output, and ecological damage. A ton of live weight shrimp production did generate 4424.2, 4657.2, and 4965.6 kg CO2 eq; 21.8, 25.9, 36.2 kg PO4 eq; 38.7, 40.6 and 43.5 kg SO2 eq in RAS, BFT and HPP systems, respectively. Regarding the characterization and normalization results, eleven categories (abiotic depletion, acidification, eutrophication, etc.) were considered. In most impact categories, the results showed that HPP had the highest environmental impact per unit production when compared to RAS and BFT. Acidification potential (AP) and eutrophication potential (EP) were the top two contributing factors to RAS, BFT and HPP. And AP and EP is closely related to the production of electricity. Electricity was identified as primary contributors in all farming processes. Results indicate that BFT and RAS could be used in combination to reduce environmental impacts. In order to improve the environmental performance of these farming systems, feed ingredients substitution; feeding management and effluent treatment are among the suggested measures. In order to enhanced aquaculture LCI databases and support aquaculture LCA research, the life cycle inventory for shrimp farming were established.

Loss of parasitoid diversity in China’s corn agro-ecosystem over a 30-year time period

Globally, insect abundance and diversity are experiencing a rapid decline. Despite important inter-taxa and geographical variability, this can entail an extinction of ecological interactions and a decay of ecosystem functions. In this study, we compared the spatial distribution, abundance and species composition of Trichogramma spp. egg parasitoids (Hymenoptera: Trichogrammatidae) over a 30-year time period in China. During the 1980s and in 2016–2018, egg masses of the Asian corn borer (ACB), Ostrinia furnacalis, were systematically sampled from corn fields across the country. In 2018, five species were identified with Trichogramma ostriniae representing 90% of the species complex. Since the 1980s, two new species have made their appearance while nine (out of 12; i.e., 75%) species disappeared. These include comparative specialists but also generalists such as T. evanescens and T. exiguum. Across sites, species richness (R) and diversity (Shannon-Weiner index) have declined by a respective 25–86% and 56–100% (except for Heilongjiang province) over this time frame. We hypothesize that this is attributed to land use change, pesticide use and plant diversity decline in agro-landscapes. Conversely, no negative impacts were detected of augmentative biological control. Given the drastic reduction in ACB parasitoid richness, agro-ecological measures and diversification strategies should be deployed to restore the ecological resilience of local farming systems. Our work carries major implications for food security and helps to muster support for more nature-friendly, pest-resilient farming systems in China and abroad.

Grassland-based ruminant farming systems in China: Potential, challenges and a way forward

With an increasing demand for high-quality, eco-friendly food products and growing concerns over ecological conservation, the development of ecology-based alternatives for ruminant production in China is urgently needed. This review discusses the capabilities for integrating grassland grazing into existing livestock farming systems to meet the contemporary human needs for high-quality foods and ecologically stable environments. Additionally, this review provides a critical analysis of the challenges and future directions associated with grassland-based ruminant farming systems. Integrating nutritional manipulation with grazing manipulation is critical for improving the productivity of grassland-based ecosystems and natural ecological functions. Biodiversity is the primary determinant of grassland ecosystem functions, while the composition and function of rumen microbiomes determine ruminant production performance. Future studies should focus on the following aspects: 1) how livestock grazing regulates grassland biodiversity and the mechanisms of grassland biodiversity maintenance, offering an important scientific basis for guiding grazing manipulation practices, including grazing intensity, livestock types, and grazing management practices; to 2) characterize the microbial ecology within the rumen of grazing ruminants to offer clarified instruction for the nutritional manipulation of grazing ruminants. Our recommendation includes creating a transdisciplinary system that integrates ecology, animal nutrition, and animal behavior to develop grassland-based ruminant farming systems sustainably, thereby achieving high-quality animal production and environmentally sustainable goals.

Improvement in winter wheat productivity through regulating PSII photochemistry, photosynthesis and chlorophyll fluorescence under deficit irrigation conditions

Deficit irrigation is critical to global food production, particularly in arid and semi-arid regions with low precipitation. Given water shortage has threatened agricultural sustainability under the dry-land farming system in China, there is an urgent need to develop effective water-saving technologies. We carried out a field study under two cultivation techniques: (1) the ridge and furrow cultivation model (R); and (2) the conventional flat farming model (F), and three simulated precipitation levels (1, 275 mm; 2, 200 mm; 3, 125 mm) with two deficit irrigation levels (150 and 75 mm). We demonstrated that under the ridge furrow (R) model, rainfall harvesting planting under 150 mm deficit irrigation combined with 200 mm simulated precipitation can considerably increase net photosynthesis rate (Pn), quantum yield of PSII (ΦPSII), electron transport rate (ETR), performance index of photosynthetic PSII (Fv/Fm′), and transformation energy potential of PSII (Fv/Fo). In addition, during the jointing, anthesis and grain-filling stages, the grain and biomass yield in the R model are 18.9 and 11.1% higher than those in the flat cultivation model, respectively, primarily due to improved soil water contents. The winter wheat fluorescence parameters were significantly positively associated with the photosynthesis, biomass and wheat production. The result suggests that the R cultivation model with irrigation of 150 mm and simulated precipitation of 200 mm is an effective planting method for enhancing Pn, biomass, wheat production, and chlorophyll fluorescence parameters in dry-land farming areas.

Freezing and thawing cycles affect nitrous oxide emissions in rain-fed lucerne (Medicago sativa) grasslands of different ages.

Lucerne (Medicago sativa L.) is a major component of the crops used in dry-land farming systems in China and its management is associated with notable nitrous oxide (N2O) emissions. A high proportion of these emissions is more likely to occur during periods when the soil undergoes freezing and thawing cycles. In this study, the effects of freeze/thaw cycles on N2O emissions and related factors were investigated in lucerne grasslands. The hypothesis was tested whether increased emissions resulted from a disruption of nitrification or denitrification caused by variations in soil temperatures and water contents. Three days (3 × 24 h) were chosen, where conditions represented freezing and thawing cycles. N2O emissions were measured for a fallow control (F) and two grasslands where lucerne had been cultivated for 4 and 11 years. Soil temperature, soil water content, soil microbial biomass carbon (MBC), soil microbial biomass nitrogen (MBN), soil ammonium nitrogen (NH4+-N), and soil nitrate nitrogen (NO3−-N) contents were measured. Moreover, the quantities of soil nitrification and denitrification microbes were assessed. Variations in N2O emissions were strongly affected by freeze/thaw cycles, and emissions of 0.0287 ± 0.0009, 0.0230 ± 0.0019, and 0.3522 ± 0.0029 mg m−2 h−1 were found for fallow, 4-year-old, and 11-year-old grasslands, respectively. Pearson correlation analyses indicated that N2O emissions were significantly correlated with the soil water content, temperature, NH4+-N content, and the number of nitrosobacteria and denitrifying bacteria at a soil depth of 0–100 mm. The numbers of nitrosobacteria and denitrifying bacteria correlated significantly with soil temperature at this soil depth. MBN and soil NH4+-N contents correlated significantly with soil water content at this depth. Principal component analysis highlighted the positive effects of the number of denitrifying bacteria on N2O emissions during the freeze/thaw period. Furthermore, soil temperature and the number of nitrosobacteria at the tested soil depth (0−100 mm) also played a significant role. This shows that soil freeze/thaw cycles strongly impacted both N2O emissions and the diurnal range, and the number of denitrifying bacteria was mainly influenced by soil temperature and soil NH4+-N content. The number of denitrifying bacteria was the dominant variable affecting N2O emissions from lucerne grasslands during the assessed soil freeze/thaw period on the Loess Plateau, China.

Public–private partnership model for intensive maize production in China: A synergistic strategy for food security and ecosystem economic budget

AbstractSmall farms are the mainstay of maize production in China. Its productivity is relatively low despite large farm inputs and the associated environmental footprints. Here, we studied public–private partnership (PPP) model for sustainable intensification of maize production to achieve co‐benefits of food security and environmental sustainability. The PPP model enabled the development of an effective partnership by bringing complementary skills, knowledge, proprietary products and technologies, and resources of public research community and private enterprises to create a new, operational maize farming system in China. We conducted on‐farm research with farmer participation in four major maize‐growing regions spanning temperate to sub‐tropical zones in China for 2 years. The PPP model achieved 78.7% of maize yield potential compared with 61.8% realized in smallholder farm (SHF) (11.0 Mg ha−1 vs. 8.6 Mg ha−1). Overall, environmental externalities of PPP were up to 32.7% lower than that of SHF, depending on the region studied. PPP significantly reduced reactive nitrogen losses by 31.3%–35.5% compared with SHF in both years. There was no significant difference between PPP and SHF for greenhouse gas emission in 2018, but it was significantly lower in PPP (19%) compared to SHF in 2019. Similarly, PPP significantly reduced soil acidification potential (by 10.1%–42.2%) and eutrophication of waterbodies (21.5%) in comparison to SHF. Overall, the net ecosystem economic budget increased 277 USD ha−1 with PPP. The PPP model provides new insights into improving food security and ecosystem and economic budget. As a logical progression to our research, future work should focus on (a) the reasons for the persistence of inter‐regional yield gap in PPP model and (b) to gain a better understanding of socioeconomic drivers critical for successful PPP in different maize‐growing regions.

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.

The current farming system in China is heavily reliant on synthetic fertilizers, which adversely affect soil quality and crop production. Therefore, the aim of this study was to assess the effect of different nitrogen (N) and phosphorous (P) fertilizer application rate on the growth, yield, and yield components of rice cultivars in the Binyang, Beiliu and Liucheng sites of southern China in the early (March to July) and late season (August to December). The study consisted of three fertilization regimes—CK (N0P0); N180P90 (180 kg N + 90 kg P2O5 ha−1) and N90P45 (90 kg N ha−1 + 45 kg P2O5)—conducted at each of three different experimental sites with four cultivars (Baixang 139, Y Liangyou 1, Guiyu 9, and Teyou 582). Results showed that the leaf area index (LAI) was 38.8% found higher in Guiyu 9 compared with Baxiang at reduced fertilization (N90P45). N90P45 resulted higher dry matter production at the heading (9411.2 kg ha−1) and maturity (15319.5 kg ha−1) stages in Teyou 582 at Beiliu. Fertilization (N180P90) had higher effective panicle number (4,158,800 panicle ha−1) and grains panicle−1 (113.84 grains) compared with other treatments. Teyou 582 treated with N90P45 and Y Liangyou 1 treated with N180P90 improved seed setting rate average by 82.91% and 72.17% compared with other treatments at Beiliu in both seasons, respectively. N0P0 and N90P45 increased the thousand-grain weight (TGW) of Y Liangyou 1 at Binyang (27.07 g) and Liucheng (27.84 g) during the early and late seasons, respectively. In Beiliu, the N90P45 treatment (6611.7 kg ha−1) of Teyou 582 increased grain yield compared with other treatments. Overall, our results suggested that reducing N and P at the ratio of 90:45 kg ha−1 in Teyou 582 and Y Liangyou 1 could increase rice grain yield and yield components.

Simulation Study on Coverage Path Planning of Autonomous Tasks in Hilly Farmland Based on Energy Consumption Model

The hilly farmland in China is characterized by small farmland areas and dense farmland distribution, and the working environment is three-dimensional topographic farmland, so the working conditions in the field are relatively complex. In this working environment, the coverage path planning technique of a farmland autonomous task is harder than that of 2D farmland autonomous task. Generally, the path planning problem of 2D farmland is to construct the path cost model to realize the planning of agricultural machinery driving route, while for the path planning problem of three-dimensional terrain farmland in the hilly region, this paper proposes a covering path planning scheme that meets the requirements of autonomous work. Based on the energy consumption model, the scheme searches the optimal driving angle of agricultural machinery, prioritizes solutions to the problem of covering path planning within the scattered fields in the working area, and then searches through the genetic algorithm for the optimal order of traversing the paths of each field to complete the coverage path planning in the working area. On the one hand, the scheme optimizes the planning route in the fields from the angle of optimal energy consumption; on the other hand, through the genetic algorithm, the fields are connected in an orderly manner, which solves the comprehensive problems brought by the unique agricultural environment and farming system in China’s hilly areas to the agricultural machinery operation. The algorithm program is developed according to the research content, and a series of simulation experiments are carried out based on the program using actual farmland data and agricultural machinery parameters. The results show that the planned path obtained at the cost of energy consumption has a total energy consumption of 4771897.17J, which is 17.4% less energy consumption than the optimal path found by the path cost search; the optimization effect is evident.

Allele combinations of maturity genes E1-E4 affect adaptation of soybean to diverse geographic regions and farming systems in China

Appropriate flowering and maturity time are important for soybean production. Four maturity genes E1, E2, E3 and E4 have been molecularly identified and found to play major roles in the control of flowering and maturity of soybean. Here, to further investigate the effect of different allele combinations of E1-E4, we performed Kompetitive Allele Specific PCR (KASP) assays based on single nucleotide polymorphisms (SNPs) at these four E loci, and genotyped E1-E4 genes across 308 Chinese cultivars with a wide range of maturity groups. In total, twenty-one allele combinations for E1-E4 genes were identified across these Chinese cultivars. Various combinations of mutations at four E loci gave rise to the diversity of flowering and maturity time, which were associated with the adaptation of soybean cultivars to diverse geographic regions and farming systems. In particular, the cultivars with mutations at all four E loci reached flowering and maturity very early, and adapted to high-latitude cold regions. The allele combinations e1-as/e2-ns/e3-tr/E4, E1/e2-ns/E3/E4 and E1/E2/E3/E4 played important roles in the Northeast China, Huang-Huai-Hai (HHH) Rivers Valley and South China regions, respectively. Notably, E1 and E2, especially E2, affected flowering and maturity time of soybean significantly. Our study will be beneficial for germplasm evaluation, cultivar improvement and regionalization of cultivation in soybean production.

Comparative analysis of the gut microbiota of grass carp fed with chicken faeces.

The gut microbiota is closely related to health and disease. Grass carp (Ctenopharyngodon idella) is an important food fish in China. We aimed to investigate the effect of a chicken faeces diet on the gut microbiota composition of grass carp reared in an integrated farming system in China. Gut microbiota compositions of grass carps fed chicken faeces, a commercial diet, and grass were compared based on 16S rRNA gene sequencing. The major intestinal phyla in grass carps fed chicken faeces were Firmicutes, Proteobacteria, and Actinobacteria. The untreated chicken faeces diet altered the gut microbiota composition and increased the number of potential pathogens and antibiotic-resistant bacteria in the gut to varying degrees. To reduce the risk of diseases, it is necessary to remove residual antibiotics and antibiotic-resistant bacteria in chicken faeces by fermentation or other techniques, before it can be used as a fish feed for grass carp.

Mitigating Nitrogen Emissions From Dairy Farming Systems in China

Dairy farming intensification results from the increasing demand for dairy products being met by increasing livestock populations, which places huge pressure on resources and the environment due to poor manure management. In this study, we first quantify the nitrogen (N) flows of two typical dairy manure management systems: “Ganqingfen” system and slurry-based system, based on a substance (N) flow analysis method. Second, the effects of ammonia (NH3) abatement technologies on N recycling efficiency (NRE) and N losses are evaluated for the two systems through a scenario analysis. Furthermore, we explore the mitigation potential of integrated crop and dairy production systems using a scenario analysis of a concatenation of mitigation techniques. The results indicate that the ratio of returned manure N in the “Ganqingfen” and slurry-based manure systems are 32% and 34% of feed N, respectively. N losses from manure management are 56.8–59.5% of total N excretion, of which approximately 50% is emitted as NH3. The scenario analysis indicates that implementation of single or combined NH3 abatement measures can reduce NH3 emissions by 2–56%, whereas nitrous oxide emissions (N2O) can increase depending on the specific measures. Total losses can be reduced from 80.4-83.5 kg N·head-1 to 49.2-55.7 kg N·head-1. Regarding integrated crop and dairy production systems, as the level of scenario optimization improves, resource use (e.g. land use and chemical fertilizer use) and N losses (particularly NH3 emissions) are decreased, while the NRE improves. The results of this study provide insights into the N flow and losses of typical dairy manure management systems in China, as well as effective measures towards the sustainable development of integrated crop and livestock production systems.

Thinking on Sustainable Development of the Integrated Rice-Crayfish Farming System in China

The paper introduced specific model of integrated rice-crawfish farming, analyzed its advantages and disadvantages, as well as other relevant problems. Finally, in order...

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). The results showed that RF significantly affected the microbial community composition and richness, which indicated that the rhizospheric microorganisms responded to the introduction of tiger frogs into the paddy fields. Operational taxonomic units (OTUs) from Sandaracinaceae, Anaerolineaceae, Candidatus Nitrososphaera, Candidatus Nitrosotalea, Candidatus Nitrosoarchaeum and some unclassified OTUs from Euryarchaeota and Agaricomycetes were significantly enriched by RF. The abiotic parameters soil organic carbon (SOC), nitrate nitrogen (NO3−-N), and available phosphorus (AP) changed under RF treatment and played essential roles in establishing the soil bacterial, archaeal, and fungal compositions. Correlations between environmental factors and microbial communities were described using network analysis. SOC was strongly correlated with Anaerolineaceae, Methanosaeta, and Scutellinia. NO3−-N showed strong positive correlations with Opitutus, Geobacter, and Methanosaeta. NH4+-N was strongly positively associated with Sideroxydans, and TN was strongly positively correlated with Candidatus Nitrotoga. Compared to conventional CR, RF greatly enriched specific microbial taxa. These taxa may be involved in the decomposition of complex organic matter and the transformation of soil nutrients, thus promoting plant growth by improving nutrient cycling. The unique patterns of microbial taxonomic and functional composition in soil profiles suggested functional redundancy in these paddy soils. RF could significantly affect the bacterial, archaeal, and fungal communities though changing SOC and AP levels.

Does carbon farming provide a cost‐effective option to mitigate GHG emissions? Evidence from China

In this study, we apply a whole farm bioeconomic analysis to explore the changes in land use, farm practices and on‐farm greenhouse gas (GHG) emission under varying levels of agricultural greenhouse gas abatement incentives in the form of a carbon tax for a semi‐arid crop‐livestock farming system in China's Loess Plateau. Our results show that the optimised agricultural enterprises move towards being cropping‐dominated reducing on‐farm emission since livestock perform is the major source of emission. Farmers employ less oats‐based and rapeseed‐based rotations but more dry pea‐based rotations in the optimal enterprise mix. A substantial reduction in on‐farm greenhouse gas emission can be achieved at low cost with a small increase in carbon incentives. Our estimates indicate that crop‐livestock farmers in China's Loess Plateau may reduce their on‐farm GHG emission between 16.6 and 33 per cent with marginal abatement costs &lt;￥100/t CO2e and ￥150/t CO2e in 2015 Chinese Yuan. The analysis implies that reducing greenhouse gas emission in China's semi‐arid crop‐livestock agriculture is potentially a low‐cost option.