Effects of rotation and Bacillus on the changes of continuous cropping soil fungal communities in American ginseng.

The continuous cropping obstacle is the main factor in leading to difficulty in American ginseng replanting. The dormant microbiota in the soil may be the cause of American ginseng disease and eventually caused continuous cropping obstacles, but there are few studies on the dynamic changes of soil microenvironment after American ginseng planting. In this study, we tracked short-term variation in physicochemical properties, enzyme activities, and fungal communities over time-series in soils with continuous cropping obstacle under crop rotation and probiotic Bacillus treatments. Furthermore, we examined the relationships between the important fungal compositions and the soil properties. The results showed that sucrase, cellulase, urease and acid phosphatase activities were significantly increased, while catalase and dehydrogenase were decreased with treatments time. Rotation treatment significantly affected the diversity, dissimilarity degree and species distribution of soil fungal community with continuous cropping obstacle over a short-term. Moreover, beneficial fungal biomarkers such as Cladorrhinum, Oidiodendron, and Mariannaea were accumulated at 48 h under rotation treatments. Almost all fungal biomarkers were negatively correlated with hydrolases and positively correlated with oxidoreductases and acid phosphatase under crop rotation treatments. This study suggested that compared to probiotic Bacillus, crop rotation can significantly affect soil fungal community structure, especially the enrichment of specific potentially beneficial fungal species. Our findings provide a scientific basis for understanding the dynamic changes of fungal communities and soil properties with continuous cropping obstacle of American ginseng in initial stage of soil improvement.

A new Rothamsted long-term field experiment for the twenty-first century: principles and practice.

Agriculture faces potentially competing societal demands to produce food, fiber and fuel while reducing negative environmental impacts and delivering regulating, supporting and cultural ecosystem services. This necessitates a new generation of long-term agricultural field experiments designed to study the behavior of contrasting cropping systems in terms of multiple outcomes. We document the principles and practices of a new long-term experiment of this type at Rothamsted, established at two contrasting sites in 2017 and 2018, and report initial yield data at the crop and system level. The objective of the Large-Scale Rotation Experiment was to establish gradients of system properties and outcomes to improve our fundamental understanding of UK cropping systems. It is composed of four management factors-phased rotations, cultivation (conventional vs reduced tillage), nutrition (additional organic amendment vs standard mineral fertilization) and crop protection (conventional vs smart crop protection). These factors were combined in a balanced design resulting in 24 emergent cropping systems at each site and can be analyzed at the level of the system or component management factors. We observed interactions between management factors and with the environment on crop yields, justifying the systems level, multi-site approach. Reduced tillage resulted in lower wheat yields but the effect varied with rotation, previous-crop and site. Organic amendments significantly increased spring barley yield by 8% on average though the effect again varied with site. The plowed cropping systems tended to produce higher caloric yield overall than systems under reduced tillage. Additional response variables are being monitored to study synergies and trade-offs with outcomes other than yield at the cropping system level. The experiment has been established as a long-term resource for inter-disciplinary research. By documenting the design process, we aim to facilitate the adoption of similar approaches to system-scale agricultural experimentation to inform the transition to more sustainable cropping systems. Supplementary Information: The online version contains supplementary material available at 10.1007/s13593-023-00914-8.

[Soil bacterial communities of different crop rotations and yield of succeeding wheat.] / 不同轮作茬口土壤细菌群落及后茬小麦产量.

Evaluating ecological sustainability and crop productivity of different crop rotation patterns could provide theoretical support for adjusting and optimizing crop planting structure. We set seven treatments with different rotation crops and periods. We used real-time quantitative PCR to determine the abundance of soil bacterial community and 16S rRNA gene amplicon high-throughput sequencing technology to analyze diversity and taxa composition of soil bacterial community. Both soil available nutrients and succeeding wheat yield were measured. The results showed that, compared with the rotation with summer maize, the rotations with summer peanut or soybean in diffe-rent periods reduced soil organic carbon, mineral nitrogen, and available potassium, but significantly increased soil available phosphorus. The 16S rRNA gene copy numbers of soil bacteria in the treatments of rotations with summer peanut or soybean in different periods were significantly decreased, while community richness and diversity were increased. Different rotation crops significantly changed the structure and taxonomic composition of soil bacterial community. Compared with the rotation with summer maize, the rotations with summer soybean in different periods significantly increased the 1000-grain weight and grain yield of succeeding winter wheat. In conclusion, rotations with summer peanut or soybean in different periods could increase soil available phosphorus content and bacterial diversity, and significantly change soil bacterial community structure. In particular, rotation with summer soybean performed best in promoting yield formation of succeeding winter wheat.

Crop management shapes the diversity and activity of DNA and RNA viruses in the rhizosphere.

BACKGROUND: The rhizosphere is a hotspot for microbial activity and contributes to ecosystem services including plant health and biogeochemical cycling. The activity of microbial viruses, and their influence on plant-microbe interactions in the rhizosphere, remains undetermined. Given the impact of viruses on the ecology and evolution of their host communities, determining how soil viruses influence microbiome dynamics is crucial to build a holistic understanding of rhizosphere functions. RESULTS: Here, we aimed to investigate the influence of crop management on the composition and activity of bulk soil, rhizosphere soil, and root viral communities. We combined viromics, metagenomics, and metatranscriptomics on soil samples collected from a 3-year crop rotation field trial of oilseed rape (Brassica napus L.). By recovering 1059 dsDNA viral populations and 16,541 ssRNA bacteriophage populations, we expanded the number of underexplored Leviviricetes genomes by > 5 times. Through detection of viral activity in metatranscriptomes, we uncovered evidence of "Kill-the-Winner" dynamics, implicating soil bacteriophages in driving bacterial community succession. Moreover, we found the activity of viruses increased with proximity to crop roots, and identified that soil viruses may influence plant-microbe interactions through the reprogramming of bacterial host metabolism. We have provided the first evidence of crop rotation-driven impacts on soil microbial communities extending to viruses. To this aim, we present the novel principal of "viral priming," which describes how the consecutive growth of the same crop species primes viral activity in the rhizosphere through local adaptation. CONCLUSIONS: Overall, we reveal unprecedented spatial and temporal diversity in viral community composition and activity across root, rhizosphere soil, and bulk soil compartments. Our work demonstrates that the roles of soil viruses need greater consideration to exploit the rhizosphere microbiome for food security, food safety, and environmental sustainability. Video Abstract.

Effects of planting of two common crops, Allium fistulosum and Brassica napus, on soil properties and microbial communities of ginseng cultivation in northeast China.

BACKGROUND: Long-term cultivation of ginseng can cause severe crop disorders and soil sickness. Crop rotation is an effective agricultural management measure to improve soil sustainability and decrease pathogens. However, the suitable ginseng rotation system and the changes in soil microbial community and soil characteristics under the rotation system need to be further explored. METHODS: To explore suitable ginseng crop rotation systems and improve soil utilization, Allium fistulosum and Brassica napus were planted on ginseng cultivation soil for one year. The effects of the two crops on the chemical properties and enzyme activities of the ginseng cultivation soil were evaluated by chemical analysis. In addition, amplicon sequencing targeting 16 s rDNA genes of bacteria and ITS of fungi has been used to characterize the functional and compositional diversity of microbial communities. RESULTS: The results elucidated that the levels of available phosphorus (AP) and available potassium (AK) in the soil increased significantly after one year of cultivation for both crops and Allium fistulosum cultivation may also have reduced soil salinity. In addition, the effects of the two crops on the activities of key soil enzymes were different. Catalase (CAT), urease (URE), and acid phosphatase (A-PHO) activities were significantly reduced and sucrase (SUC), and laccase (LAC) activities were significantly increased after Allium fistulosum planting. While A-PHO activity was significantly increased and LAC activity was significantly decreased after Brassica napus planting. Allium fistulosum significantly reduced the abundance of soil fungal communities. The cultivation of Allium fistulosum and Brassica napus significantly altered the composition of soil bacterial and fungal communities, where changes in the abundance of dominant microorganisms, such as Ascomycota, and Mortierellomycota, etc., were closely related to soil chemistry and enzyme activity. Moreover, both significantly reduced the abundance of the pathogenic fungus Ilyonectria. CONCLUSIONS: Our study clarified the effects of Allium fistulosum and Brassica napus on the microbial community and physicochemical properties of ginseng cultivated soil and provides a basis for the sustainable application of ginseng cultivation soil and the development of ginseng crop rotation systems.

Impacts of Rotation-Fallow Practices on Bacterial Community Structure in Paddy Fields.

Soil nutrients and microbial community play a central role in determining crop productivity in agroecosystems. However, the relationship between microbial community structure and soil nutrients in various crop rotation-fallow systems remains unclear. Thus, we designed a 3-year crop rotation-fallow field with five cropping systems (one continuous cropping, three rotational cropping, and one fallow system). We conducted a comprehensive analysis by evaluating crop yield, soil physicochemical properties, and overall bacteria composition. Our results showed that rotation-fallow treatments markedly influenced the crop yield and soil physicochemical properties. Proteobacteria, Acidobacteriota, and Chloroflexi were the dominant phyla in all rotation-fallow treatments. pH, available-phosphorus, total nitrogen, and soil organic matter had considerable effects on the soil bacterial community structure in 2019; however, only available-phosphorus had an impact on soil bacterial community in each treatment in 2020. In summary, with the increase of tillage years, different rotational fallow systems can increase paddy yield by promoting soil nutrient uptake and increasing the relative abundances of bacteria in paddy fields. IMPORTANCE Soil nutrients and microbial community play a central role in determining crop productivity. Therefore, elucidating the microbial mechanisms associated with different cropping systems is indispensable for understanding the sustainability of agroecosystem. In the present study, we designed a 3-year field rotation experiment using five cropping systems, including one continuous cropping, three rotational cropping, and one fallow system, to indagate the outcomes of soil microbial community structures in the different tillage systems. Our results showed that the different rotational fallow systems had positive impacts on crop yield, soil physicochemical properties, and bacterial community structure and that available phosphorus might be a key determinant for the limited bacterial community structure in various rotation-fallow systems following a 3-year field experiment. This study suggests that crop rotation-fallow systems play critical roles in improving bacterial community structure.

Scenario analysis using the Daisy model to assess and mitigate nitrate leaching from complex agro-environmental settings in Denmark.

Nitrate (N) leaching from intensively managed cropping systems is of environmental concern and it varies at local scale. To evaluate the performance of agricultural practices at this scale, there is a need to develop comprehensive assessments of N leaching and the N leaching reduction potential of mitigation measures. A model-based analysis was performed to (i) estimate N leaching from Danish cropping systems, representing 20 crop rotations, 3 soil types, 2 climates and 3-4 levels of manure (slurry)-to-fertilizer ratios, but with same available N (according to regulatory N fertilization norms), and (ii) appraise mitigation potential of on-farm measures (i.e. catch crops, early sowing of winter cereals) to reduce N leaching. The analysis was performed using a process-based agro-environmental model (Daisy). Simulated average N leaching over 24 years ranged from 16 to 85 kg N/ha/y for different crop rotations. Rotations with a higher proportion of spring crops were more prone to leaching than rotations having a higher proportion of winter cereals and semi-perennial grass-clover leys. N leaching decreased with increasing soil clay content under all conditions. The effect of two climates (different regions, mainly differing in precipitation) on N leaching was generally similar, with slight variation across rotations. Supplying a part of the available N as manure-N resulted in similar N leaching as mineral fertilizer N alone during the simulation period. Among the mitigation measures, both undersown and autumn sown catch crops were effective. Effectiveness of measures also depended on their place and frequency of occurrence in a rotation. Adopting catch crops during the most leaching-prone years and with higher frequency were effective choices. This analysis provided essential data-driven knowledge on N leaching risk, and potential of leaching reduction options. These results can serve as a supplementary guiding-tool for farmers to plan management practices, and for legislators to design farm-specific regulatory measures.

Environmental consequences of wheat-based crop rotation in potato farming systems in galicia, Spain.

Intensive agricultural farming systems have negative impacts on the ecosystem. Therefore, the use of crop rotation emerges as an opportunity to improve the environmental sustainability of agricultural systems. In the region of Galicia in north-western Spain, potato and wheat are important commodities and essential foods in the diet. Hence, it is interesting to investigate the environmental profile of these crops to improve the understanding of local agrosystems. This study evaluated three agricultural crops managed under a crop rotation system and following a conventional arable farming: the main rotation crop, which is the potato in the first year (cP), followed by a second year of commercial wheat (cW) and autochthonous Galician wheat (GcW) in the third year. The Life Cycle Assessment (LCA) methodology was performed using four types of functional units: in terms of productivity (kg-1); land management (ha-1∙year-1); a financial function (euros €-1 of income from sales) and energetic value (MJ-1). The environmental indicators selected are Climate Change (CC), Particulate Matter (PM), Terrestrial Acidification (TA), Freshwater Eutrophication (FE), Marine Eutrophication (ME), Human Toxicity (HT), Land Use (LU) and Fossil Depletion (FD). The figures show that the GcW has the lowest environmental impact when the functional units refer to land management, financial function and energetic value. However, if analysed in terms of productivity, cP is presented as the best crop due to its comparatively higher yield, reaching a production ratio 10 times higher than wheat. In the specific case of wheat, compared to a previous study in the same region, the environmental impacts are lower when grown in a crop rotation system in contrast to monoculture. This article demonstrates the relevance of using LCA for diverse stakeholders (e.g., farmers, consumers and researchers) to understand the environmental impacts of regional agricultural systems. In addition, it serves as a basis for future work aimed at comparing rotational agricultural systems in this region, integrating economic and social aspects.

Phytoremediation of heavy metals under an oil crop rotation and treatment of biochar from contaminated biomass for safe use.

The disposal of contaminated plants limits the use of phytoremediation. Therefore, the disposal of contaminated sunflower was investigated after determining the phytoremediation of heavy metals under an oil crop rotation of sunflower (Helianthus annuus L)-sesame (Sesamum indicum L.). In the field experiment, the extraction efficiency of sunflower-sesame rotation was 0.07% for lead (Pb); 1.37% for zinc (Zn); 1.10% for copper (Cu); and 6.12% for cadmium (Cd). Contaminated sunflower stems were pyrolyzed at different temperature. The biochar produced at 300 °C was extracted in a two-step process (acid-extraction from biochar and metals precipitation in alkaline condition). At pH = 1, 65.67% of the Cd and much potassium (K) were extracted. After acid-extraction, adjust the pH of filtrate to 10, metals were precipitated and then separated from the K-enriched solution. Therefore, pyrolysis can process contaminated residues, and the biochar extracts can be reutilized as fertilizer to off-site crop production. Thus, an oil crop-rotation system, in addition to creating economic benefits, can be used by local farmers in contaminated soils.

Effect of green garlic/cucumber crop rotation for 3 years on the dynamics of soil properties and cucumber yield in Chinese anthrosol.

BACKGROUND: Long-term drastic anthropic inputs in conventional monoculture systems cause negative plant-soil feedback that will largely affect sustainable cucumber cultivation. The inclusion of multicropping in intensive cropping systems could reduce the detrimental effects of continuous cropping obstacles. The present study investigated the dynamics of soil microbial communities, soil enzyme activities and cucumber yield under plastic tunnel cultivation for three successive growing seasons (2013, 2014 and 2015). RESULT: In the amended crop rotation system, soil pH decreased with increasing number of cropped garlic bulbs. The soil electrical conductivity significantly changed during the entire growth period and increased with increasing number of incorporated garlic bulbs. The level of soil organic matter content increased in the last year (2015). Soil catalase activity was generally induced by the treatments of 10, 15, 20 and 25 garlic bulbs, and soil invertase activity was also enhanced by all the treatments in the last year. Similarly, fungal species richness dramatically increased under these crop rotation systems. In this study, we found the highest cucumber yield under the cropping treatment of 20 garlic bulbs. CONCLUSION: The results indicate that the green garlic/cucumber cropping system is a sustainable and efficient cropping system for cucumber production and can improve the soil environment to a certain extent. © 2019 Society of Chemical Industry.

Phosphorus mining efficiency declines with decreasing soil P concentration and varies across crop species.

High soil P concentrations hinder ecological restoration of biological communities typical for nutrient-poor soils. Phosphorus mining, i.e., growing crops with fertilization other than P, might reduce soil P concentrations. However, crop species have different P-uptake rates and can affect subsequent P removal in crop rotation, both of which may also vary with soil P concentration. In a pot experiment with three soil-P-levels (High-P: 125-155 mg POlsen/kg; Mid-P: 51-70 mg POlsen/kg; Low-P: 6-21 mg POlsen/kg), we measured how much P was removed by five crop species (buckwheat, maize, sunflower, flax, and triticale). Total P removal decreased with soil-P-level and depended upon crop identity. Buckwheat and maize removed most P from High-P and Mid-P soils and triticale removed less P than buckwheat, maize, and sunflower at every soil-P-level. The difference in P removal between crops was, however, almost absent in Low-P soils. Absolute and relative P removal with seeds depended upon crop species and, for maize and triticale, also upon soil-P-level. None of the previously grown crop species significantly affected P removal by the follow-up crop (perennial ryegrass). We can conclude that for maximizing P removal, buckwheat or maize could be grown.

How are arbuscular mycorrhizal associations related to maize growth performance during short-term cover crop rotation?

BACKGROUND: Better cover crop management options aiming to maximize the benefits of arbuscular mycorrhizal fungi (AMF) to subsequent crops are largely unknown. We investigated the impact of cover crop management methods on maize growth performance and assemblages of AMF colonizing maize roots in a field trial. The cover crop treatments comprised Italian ryegrass, wheat, brown mustard and fallow in rotation with maize. RESULTS: The diversity of AMF communities among cover crops used for maize management was significantly influenced by the cover crop and time course. Cover crops did not affect grain yield and aboveground biomass of subsequent maize but affected early growth. A structural equation model indicated that the root colonization, AMF diversity and maize phosphorus uptake had direct strong positive effects on yield performance. CONCLUSION: AMF variables and maize performance were related directly or indirectly to maize grain yield, whereas root colonization had a positive effect on maize performance. AMF may be an essential factor that determines the success of cover crop rotational systems. Encouraging AMF associations can potentially benefit cover cropping systems. Therefore, it is imperative to consider AMF associations and crop phenology when making management decisions. © 2017 Society of Chemical Industry.

Assessment of the Spatial and Temporal Variations of Water Quality for Agricultural Lands with Crop Rotation in China by Using a HYPE Model.

Many water quality models have been successfully used worldwide to predict nutrient losses from anthropogenically impacted catchments, but hydrological and nutrient simulations with limited data are difficult considering the transfer of model parameters and complication of model calibration and validation. This study aims: (i) to assess the performance capabilities of a new and relatively more advantageous model, namely, Hydrological Predictions for the Environment (HYPE), that simulates stream flow and nutrient load in agricultural areas by using a multi-site and multi-objective parameter calibration method and (ii) to investigate the temporal and spatial variations of total nitrogen (TN) and total phosphorous (TP) concentrations and loads with crop rotation by using the model for the first time. A parameter estimation tool (PEST) was used to calibrate parameters. Results show that the parameters related to the effective soil porosity were highly sensitive to hydrological modeling. N balance was largely controlled by soil denitrification processes. P balance was influenced by the sedimentation rate and production/decay of P in rivers and lakes. The model reproduced the temporal and spatial variations of discharge and TN/TP relatively well in both calibration (2006-2008) and validation (2009-2010) periods. Among the obtained data, the lowest Nash-Suttclife efficiency of discharge, daily TN load, and daily TP load were 0.74, 0.51, and 0.54, respectively. The seasonal variations of daily TN concentrations in the entire simulation period were insufficient, indicated that crop rotation changed the timing and amount of N output. Monthly TN and TP simulation yields revealed that nutrient outputs were abundant in summer in terms of the corresponding discharge. The area-weighted TN and TP load annual yields in five years showed that nutrient loads were extremely high along Hong and Ru rivers, especially in agricultural lands.

Biodiesel and electrical power production through vegetable oil extraction and byproducts gasification: modeling of the system.

Aim of this work is to introduce an alternative to the standard biodiesel production chain, presenting an innovative in situ system. It is based on the chemical conversion of vegetable oil from oleaginous crops in synergy with the gasification of the protein cake disposed by the seed press. The syngas from the gasifier is here used to produce electrical power while part of it is converted into methanol. The methanol is finally used to transform the vegetable oil into biodiesel. Through a coupled use of ASPEN PLUS(TM) and MATLAB(TM) codes, a rapeseed, soy and sunflower rotation, with a duration of three year, was simulated considering 15ha of soil. This surface resulted sufficient to feed a 7kWel power plant. Simulation outputs proven the system to be self-sustainable. In addition, economical NPV of the investment is presented. Finally the environmental, economical and social advantages related to this approach are discussed.