Effect of Reducing Chemical Fertilizer on Rice Yield,Output Value,Content of Soil Carbon and Nitrogen after Utilizing the Milk Vetch

A located field experiment was carried out to study the effects of different amount of chemical fertilizer usage on rice yield,economic benefits of rice,soil carbon（C） and total nitrogen（TN） under ploughing back of Chinese milk vetch for 5consecutive years.Six treatments were included in the experiment,they are CK（unfertilized）,CF（100% chemical fertilizer with the amount of N,P2O5,K2 O being150,75,120 kg/hm^2respectively）,A1（22 500 kg/hm^2 Chinese milk vetch and 100%chemical fertilizer）,A2（Chinese milk vetch and 80% nitrogen and potassium fertilizer and 100% phosphate fertilizer）,A3（Chinese milk vetch and 60% nitrogen and potassium fertilizer and 100% phosphate fertilizer）,A4（Chinese milk vetch and 40% nitrogen and potassium fertilizer and 100% phosphate fertilizer）.The results were as follows：application of fertilizer could increase the yield of rice,while Chinese milk vetch combined with fertilizer application had a much more increase effect in rice yield.Under the condition of milk vetch application with 22 500 kg/hm^2,the early rice yield of the treatment A1 was significantly increased by 7.7% compared with that of CF.And the yield of treatment A3 was basically identical to or slight increase in comparison with that of CF.Decreasing amount of fertilizers cloud improve output value of rice in the case of the utilization of Chinese milk vetch.The treatment A1 increased output value of rice by 5.92% in comparison of CF,and treatment A2 was by 4.08% in the next.Treatment A4 showed much better effect in increasing soil organic carbon and total nitrogen in the paddy soil than those of treatments applying mineral fertilizer only.There was a significant reduction on soil organic carbon and TN in treatment A2 in comparison with that of CF.In general,amount of application of milk vetch with 22 500 kg/hm^2 could replace chemical fertilizer partially,it also could improve rice yield,decrease the production cost,and raise the utilization efficiency of nutrients.

Adaptability Comparison of Chinese Milk Vetch (Astragalus sinicus) Varieties for Double-rice Cropping System in Hunan

Five Chinese milk vetch（Astragalus sinicus） varieties were selected to make a comparison in order to screen effective varieties which could suit for the double-rice cropping system of Hunan Province. The results showed that the growth period of Xiangzi 2 is shorter than that of Xiangfei 2, Xiangfei 3 and Yujiangdaye,and is similar to that of Xinyang Chinese milk vetch. The full-bloom stage of Xiangzi 2 is also similar to Xinyang variety and obviously earlier than that of the other three varieties. The fresh grass yield of Xiangzi 2 in full-bloom stage is 23 842.5kg/hm^2, which increases by 39.9% compared with Xinyang variety. Nitrogen content in the fresh grass of Xiangzi 2 is higher than that of the other four varieties. In conclusion, Xiangzi 2 is an extremely early-blossoming and early-maturing Chinese milk vetch variety with moderate fresh grass yield, high nutrient contents, stable characters and wide adaptability. So, Xiangzi 2 is suitable for planting in double-rice cropping region in Hunan Province and other same latitude regions which have similar ecological conditions.

Effects of Rice Combine Harvester Application to Harvest Chinese Milk Vetch Seeds

During the test, the seed yield, Iabor efficiency, harvesting costs and eco-nomic benefits were compared and analyzed between mechanical harvesting tech-noIogy and traditional artificial harvesting technoIogy of Chinese miIk vetch seeds to studied the mechanical harvesting technoIogy and appIication effects. The resuIts showed that mechanical harvesting technoIogy increased the yield of 92.7 kg/hm2, reducing the seeds Ioss. It improved the Iabor efficiency and reduced the harvesting cost. For exampIe, a rice combine harvester was the equal of 18-20 person in the harvest quantity in one day, which directIy reduced the Iabor cost of 2 175-3 000 yuan/hm2 and increased the economic income of 3 307-4 099 yuan/hm2. So it wiI pIay an important roIe in soIving the shortage of Chinese miIk vetch seeds and ac-ceIerating the deveIopment of Chinese miIk vetch green manure crop in south China rice region.

Integration of Growing Milk Vetch in Winter and Reducing Nitrogen Fertilizer Application Can Improve Rice Yield in Double-Rice Cropping System

To study whether integrative fertilization [growing milk vetch in winter and reducing the dose of chemical nitrogen(N) fertilizer] can improve rice yield, and to reveal the underlying regulatory mechanisms for integrative fertilization, a three-year field trial including two treatments, milk vetch-rice-rice(MRR) and winter fallow-rice-rice(FRR), was conducted in 2010, 2011 and 2012.Our results demonstrated that the MRR treatment could significantly improve rice yield compared with the FRR treatment, especially when the application ratio of milk vetch and chemical fertilizer was 1:2.MRR treatment increased the effective panicle number and the spikelet number per panicle.In addition, a higher tillering number, leaf area index, photosynthetic-potential and photosynthetic-potential to grain ratio were observed in MRR treatment, which could provide enough dry matter for yield formation.Moreover, in MRR treatment, we discovered a higher transportation ratio and transformation ratio of dry matter in culm and leaves, and a stronger total sink capacity and spikelet-root bleeding intensity at the heading stage and 15 d after heading.Furthermore, the MRR treatment showed higher total N, phosphorus and potassium uptakes than FRR treatment, which was associated with the higher root dry weight in each soil layers.These results suggest that growing milk vetch in winter can improve rice yield under less chemical N fertilizer application, which is due to the improvement of soil nutrient status and the increased of rice root growth and development.

Substitution of chemical fertilizer by Chinese milk vetch improves the sustainability of yield and accumulation of soil organic carbon in a double-rice cropping system

The double-rice cropping system is a very important intensive cropping system for food security in China. There have been few studies of the sustainability of yield and accumulation of soil organic carbon (SOC) in the double-rice cropping system following a partial substitution of chemical fertilizer by Chinese milk vetch (Mv). We conducted a 10-year (2008–2017) field experiment in Nan County, South-Central China, to examine the double-rice productivity and SOC accumulation in a paddy soil in response to different fertilization levels and Mv application (22.5 Mg ha^–1). Fertilizer and Mv were applied both individually and in combination (sole chemical fertilizers, Mv plus 100, 80, 60, 40, and 0% of the recommended dose of chemical fertilizers, labeled as F100, MF100, MF80, MF60, MF40, and MF0, respectively). It was found that the grain yields of double-rice crop in treatments receiving Mv were reduced when the dose of chemical fertilizer was reduced, while the change in SOC stock displayed a double peak curve. The MF100 produced the highest double-rice yield and SOC stock, with the value higher by 13.5 and 26.8% than that in the F100. However, the grain yields increased in the MF80 (by 8.4% compared to the F100), while the SOC stock only increased by 8.4%. Analogous to the change of grain yield, the sustainable yield index (SYI) of double rice were improved significantly in the MF100 and MF80 compared to the F100, while there was a slight increase in the MF60 and MF40. After a certain amount of Mv input (22.5 Mg ha^–1), the carbon sequestration rate was affected by the nutrient input due to the stimulation of microbial biomass. Compared with the MF0, the MF100 and MF40 resulted in a dramatically higher carbon sequestration rate (with the value higher by 71.6 and 70.1%), whereas the MF80 induced a lower carbon sequestration rate with the value lower by 70.1% compared to the MF0. Based on the above results we suggested that Mv could partially replace chemical fertilizers (e.g., 40–60%) to improve or maintain the productivity and sustainability of the double-rice cropping system in South-Central China.

Application of Chinese milk vetch affects rice yield and soil productivity in a subtropical double-rice cropping system

Green manure can be used as a substitute for chemical fertilizer without reducing rice yield.We studied the responses of soil fertility and rice yield to different combinations of Chinese milk vetch(CMV;Astragalus sinicus L.)and chemical fertilizer in a subtropical double-rice cropping system.Our goal is to reduce chemical fertilizer use and decrease environmental contamination.Compared with the recommended rate of chemical fertilizer(CF),both early-and late-rice yields in the two treatments supplied with 15 and 22.5 Mg CMV ha^-1 plus 60%CF(represented as 60 A and 60 B,respectively)showed no significant differences while the two treatments supplied with 30 and 37.5 Mg CMV ha^-1 plus 60%CF(represented as 60 C and 60 D,respectively)showed significantly higher values.The sustainable yield index(SYI)values in the 60 C and 60 D treatments with double-rice croppong system were significantly higher than those in other treatments(P<0.05).Early-rice yield showed a significant positive relationship with the Chinese milk vetch incorporation rate.The coefficients increased annually from 2009 to 2013 and then decreased in 2014.Soil organic matter increased over time by the end of the experiment in all of the treatment groups.Soil organic matter in 60 A,60 B and 60 C showed no significant difference compared with that in CF,while soil organic matter in 60 D was significantly higher than that in CF.The slopes of soil organic matter and total nitrogen over six years were the highest in 60 C and 60 D.The soil total nitrogen content in 60 A,60 B,60 C and 60 D was higher than that in CF,but the differences were not significant(P>0.05).Therefore,a relatively high Chinese milk vetch incorporation rate(≥30 Mg ha^-1)was more effective in improving the productivity and sustainability of paddy soil.The decreased coefficients of early-rice yield and the Chinese milk vetch incorporation rate in 2014 implied that the benefits of soil fertility and rice yield created by Chinese milk vetch input may decline after five years under a continuously high rate of Chinese milk vetch incorporation.

Management of rice straw with relay cropping of Chinese milk vetch improved double-rice cropping system production in southern China

Improved utilization of rice(Oryza sativa L.)straw and Chinese milk vetch(Astragalus sinicus L.,vetch)has positive effects on rice production.So far,few studies have investigated the productivity of vetch under different residue management practices in double-rice cropping system.The effects of rice straw on the growth and nutrient accumulation of vetch across seven years(2011–2017)and the subsequent effects of rice straw and vetch on two succeeding rice crops in a vetch–rice–rice cropping system,with the vetch established by relay cropping,were examined.The seven-year double-rice experiment consisted of the following treatments:(1)100%chemical fertilizer(F-F100);(2)only vetch without chemical fertilizer(M-Con);(3)80%chemical fertilizer plus vetch plus a low-cutting height(low-retained stubble)with the removal of straw(M-F80);(4)80%chemical fertilizer plus vetch plus a low-cutting height with the retention of straw(M-F80-LR);(5)80%chemical fertilizer plus vetch plus a high-cutting height(high-retained stubble)with the retention of straw(M-F80-HR);and(6)no fertilizer(F-Con).The yields of the two rice crops after vetch were not affected by either the cutting height of stubble with retention of straw or by the management of straw(retention vs.removal)with low-cutting height of stubble.The yields of the two rice crops after vetch were significantly higher for M-F80-HR than for M-F80-LR,but the relative contributions of the high-cutting height and straw retention to the higher rice yield could not be determined in this study.The yield stability of the double-rice grain in M-F80-HR was also increased,as determined by a sustainable yield index.Significant increases in vetch biomass and nutrient uptake were observed in the fertilized treatments during the rice season compared with the unfertilized treatments.In M-F80-HR plots,improvements in the growing environment of the vetch by conserving soil water content were associated with the highest vetch biomass,nutrient uptake,and yield stability of vetch biomass.These increased nutrient inputs partially replaced the demand for chemical fertilizer and stimulated the rice yields.It can be concluded that retaining higher-cutting stubble residues with straw retention could be the best straw management practice for increasing the vetch biomass and nutrient use efficiency,thereby allowing utilization of high-cutting height with retention of straw and vetch to improve the stability of rice productivity in a double-rice cropping system.

Study on Water-Soluble Organic Reducing Substances: II. Organic Reducing Substances Produced from Anaerobic Decomposition of Milk Vetch (Astragalus sinicus L.)

The characteristics of electric charge and molecular weight distribution,oxidation-reduction regimes,e.g.Eh and amounts of organic reducing substances produced by milk vetch during anaerobic decomposition process,were studied by using electrochemical methods.Interaction between soils and organic reducing substances was also observed.The results indicate that the organic reducing substances were mainly the organic compounds with negative and amphoteric charges,which were distributed in two groups at anodic peak potentials of 0.25 and 0.69 volt in differential pulse voltammograms,respectively.Their apparent molecular weights are all less than 700 daltons,in which those active in oxidation-reducion reaction were distributed in the fraction with apparent molecular weight less than 200 daltons.The organic reduction substances can be oxidized by manganese oxides in their interaction with soils.

Production Benefits of Double-Cropping Rice Under Optimized Application of Nitrogen and Potassium Fertilizers Combined with Chinese Milk Vetch and Straw Co-Returning to Fields

In order to explore the technology and effects of reducing nitrogen and potassium fertilizer applications in double-cropping rice,a field plot experiment was conducted to study the effects of optimized application of nitrogen and potassium fertilizers combined with returning Chinese milk vetch and straw to fields on yield,fertilizer utilization efficiency,net photosynthetic rate(Pn),stomatal conductance(Gs),intercellular CO_(2) concentration(Ci),chlorophyll content(SPAD value)and soil physical and chemical properties in late rice harvest period.The results showed that the optimized application of nitrogen and potassium fertilizers combined with the integrated technology of Chinese milk vetch and straw co-returning to the field could enhance the photosynthetic efficiency of double-cropping rice,increase rice yield,and enhance soil biological activity,especially T4 treatment involving the returning of Chinese milk vetch and straw to the field instead of 30%nitrogen fertilizer achieved the highest rice yield,fertilizer use efficiency,net photosynthetic rate and soil biological activity.Compared with the conventional fertilization treatment T2,the total rice yield of T4 treatment increased by 4.1%,among which the early rice and late rice increased by 6.3%and 2.4%,respectively;Pn,Gs and SPAD values of flag leaves at full heading stage significantly increased,and the contents of soil active organic carbon,alkali hydrolyzed nitrogen,available phosphorus and readily available potassium significantly increased.

Advances in Germplasm Resources of Chinese Milk Vetch in China

Chinese milk vetch （Astragalus sinicus L. ） is a conunonly used green manure crop in paddy fields in southern China and it has the effect of fostering fertility and soil. This paper firstly sununarized advances in research of new high quality and yield varieties of germplasm resources of Chinese milk vetch. Then, on the basis of current situation, it came up with recommendations for collection, storage and promotion, as well as application in the current ecological agriculture, including establishing germplasm resource bank and improving germplasm resource evaluation system.

Effects of Winter Planting Milk Vetch on Yield and PartialProductivity of Nitrogen Fertilizer of Machine-transplantedDouble-cropping Rice under Straw Returning to the Field

From 2017 to 2018,the effects of winter planting of milk vetch on yield and partial productivity of nitrogen fertilizer of machine-transplanted double-cropping rice under straw returning were studied in Ningxiang city,Hunan Province.The results showed that the dry matter accumulation,effective panicle,yield and partial productivity of nitrogen fertilizer in the stem,leaf,panicle and aboveground parts of early and late rice treated with winter planting milk vetch and straw returning were signi ficantly higher than those treated with straw returning only.Among them,the effective panicles of early and late rice increased by 2.58%,3.18%(2017)and 5.22%,6.32%(2018),respectively.Yield increased by 11.85%,10.07%(2017)and 12.42%,10.92%(2018),annual partial productivity of nitrogen fertilizer increased by 10.90%(2017)and 11.66%(2018),respectively.In conclusion,winter planting milk vetch under straw returning is beneficial to increase dry matter accumulation,rice yield and partial productivity of nitrogen fertilizer in mechanized double cropping rice.

Effects of Nitrogen Application Rate to Late Rice on Greenhouse Gas Emissions and Soil Carbon Pool During the Growing Season of Winter Chinese Milk vetch

It is of important referential values for the further understanding of the effects of fertilization on greenhouse gas emissions and the effects of winter green manure on soil carbon pool to study the effects of fertilization on the greenhouse gas emissions and soil carbon pool during the growing season of winter Chinese milk vetch in the process of rice cultivation.This study investigated the effects of nitrogen application in late rice season on the yield of the succeeding Chinese milk vetch and greenhouse gas emissions as well as the soil carbon pool characteristics after the winter planting of Chinese milk vetch with the winter idling of no nitrogen application as the control.The results showed that the yield of Chinese milk vetch was the highest under the nitrogen application of 225 kg/hm^2 in the late rice season,reaching up to 18 388.97 kg/hm^2,which was significantly different from other treatments( P <0.05).Nitrogen application in late rice season increased the emissions of N_2 O,CH_4,CO_2 and global warming potential( GWP) in the growing season of Chinese milk vetch.Compared with the winter idling treatment,winter planting of Chinese milk vetch significantly increased the soil organic carbon and soil carbon pool management index.The yield of Chinese milk vetch was significantly positively correlated with N_2O and CH_4 emissions( P < 0.05),while it presented extremely significant positive correlations with CO_2 emissions,GWP,active organic carbon,and carbon pool management index( P < 0.01).Nitrogen application in the late rice season increased the emissions of N_2 O,CH_4,CO_2,and enhanced the greenhouse gas emission potential during the growing season of Chinese milk vetch.Therefore,without reducing the yield of rice,reducing the amount of nitrogen fertilizer in rice could reduce the greenhouse gas emissions in the growing season of succeeding Chinese milk vetch.

Hairy Vetch and Triticale Cover Crops for N Management in Soils

Over-application of fertilizer to cropland adversely affects both environmental and agricultural ecosystems. This study examined whether planting a legume-based winter cover crop mix offsets fertilizer application via natural nitrogen inputs. The influence of the cover crop mixture on available nutrients was also assessed. Hairy vetch (Vicia villosa) and winter triticale (×triticosecale) cover crops were planted in fall and terminated in May. Soil fertility data was collected before and after planting the winter cover crop to determine the effect on fixing nitrogen and soil phosphorus, potassium and organic matter levels. Increases of soil ammonium were observed in plots with cover crop treatments. A triticale-hairy vetch cover crop mix was successful at scavenging P for future crops and appears to hold promise for long-term soil fertility benefits.

Effects of Long-term Return of Milk Vetch(Astragalus sinicus)on Soil Nutrients and Microorganism Communities in Double-rice Cropping Field

[Objectives]This study was conducted to investigate the effects of milk vetch(Astragalus sinicus)on soil nutrients and microorganisms in paddy fields after returning to the field.[Methods]Three treatments,no fertilization,single application of chemical fertilizers and milk vetch return combined with chemical fertilizers,were set up to determine soil nutrient contents and the quantity of microorganisms,respectively.[Results]The return of milk vetch combined with chemical fertilizers could significantly increase the contents of organic matter and total nitrogen in the paddy soil,while the contents of available potassium and available phosphorus decreased.Milk vetch return combined with chemical fertilizers could significantly increase the quantity of soil microorganisms in the paddy field.[Conclusions]The return of milk vetch can be used as a feasible measure to improve soil fertility.

Effects of Returning Straw and Milk Vetch on Rice Growth and Greenhouse Gas Emissions

The effects of different nitrogen application levels on rice yield and greenhouse gas(NO2,CH4)emissions from rice fields under the combined action of straw and milk vetch.Two treatments were set up in the main area of this experiment:R0(no straw returned to the field,0);R1(amount of straw returned to the field under normal conditions,6000 kg·hm^(-2)).Before turning the straw back into the field,use a circular knife to cut the straw into 10~13 cm.And 3 kinds of nitrogen application treatments in the sub-district:N1(no nitrogen application,0),N2(nitrogen application,15 kg·hm^(-2)),N_(3)(nitrogen application,30 kg·hm^(-2)),two-factor cross-combination,and a non-nitrogen control CK,total of 7 treatments.The results showed that in 2017,early rice R1N2 treatment increased the most obvious yield,which was 32.44%higher than CK,and late rice R_(1)N_(1)treatment increased the most significantly,which was 17.91%higher than CK.CH_(4)emission is positively correlated with the straw returned to the field.N_(2)O is the opposite.The N_(2)O emission flux was highest in the treatment of R1N3,and the CH_(4)emission flux was the highest in the treatment of R1N2.

Comparison of Reduplicated Words Translation in We Gather Vetch

叠字在中国古诗中有其特殊的修辞效果和艺术感染力,但是翻译中却很难展现出原诗中叠字的艺术魅力。本篇论文以《采薇》一诗的四个译本比较其中的叠字翻译优劣,并借助其他翻译大家的译作总结出两种叠字的翻译方法。

CH_4 and N_2O emissions from double-rice cropping system as affected by Chinese milk vetch and straw incorporation in southern China

Chinese milk vetch(CMV) and rice straw(RS)were incorporated into soil to substitute for synthetic N fertilizers and to maintain soil fertility. However, little is known about the integrated impacts of CMV and RS incorporation on CH_4 and N_2O emissions in double-rice cropping systems in southern China. A field experiment was conducted to estimate the integrated impacts of CMV and RS incorporation in the early-and late-rice seasons on CH_4 and N_2O emissions. All treatments received uniform N inputs, 6%–37% of which was replaced by CMV and RS crop residue. CMV and/or RS incorporation produced equivalent or slightly more grain yield, while reducing N2 O emissions by 3%–43%. However, both CMV and RS incorporation increased CH_4 emissions. Annual CH_4 emissions ranged from 321 to 614 kg·hm^(–2)from CMV and RS amendment treatments, which were 1.5–2.9 times higher than that from synthetic N. Compared with single synthetic N fertilizer, incorporation of CMV and/or RS increased GWP and yield-scaled GWP by 45%–164% and45%–153%, respectively. Our results demonstrate CMV and RS amendments replacing N fertilizer, maintained stable yield, mitigated N_2O emission, but enhanced CH_4 emission. Further study is needed on crop residue management in double-cropping rice systems.

Co-composting of Chinese milk vetch with rice straw and using the compost as a peat substitute of seeding substrate of vegetables

Chinese milk vetch(Astragalussinicus L.)is an environment-friendly green manure used for rice with low carbon/nitrogen(C/N)ratio and high moisture.To improve the added values of milk vetch,the feasibility of co-composting of milk vetch with rice straw was evaluated.The probability of using the milk vetch-based compost as a peat substitute in seeding substrate of vegetable was further tested.The changes in physicochemical properties during co-composting of milk vetch and rice straw were evaluated,depending on three treatments:(1)milk vetch alone(MV),(2)co-composting of milk vetch and rice straws with 4:1 ration(w/w)(MV+S)and(3)MV+S with the addition of 3%(w/w)microbial inoculation(MV+S+M).The entire composting durations were 15 d,24 d,and 24 d in MV,MV+S,MV+S+M composts.Compare to MV compost,both the MV+S,MV+S+M composts increased the temperature,pH,organic C,total nitrogen(N),total potassium(K)and the germination index(GI)(over 100)during the cooling/mature phase,and decreased total N loss,and generally,the improvements or reductions were greater in the MV+S+M compost than in the MV+S compost.Additionally,the MV+S+M compost was added at a peat substitute rates of 0%,20%,40%,80%and 100%in a pot experiment to testify the utilization of milk vetch-based compost in substrates.The results showed that the substrate with 40%substitute rate increased the cabbage seeding growth,and that the electrical conductivity was the limiting factor of preventing the substitute rate increase.Another pot experiment demonstrated that the substrate with 40%peat substitute increased the cucumber growth as compared to the substrate without compost.In conclusion,the co-composting milk vetch with rice straw was feasible and quick,and microbial inoculation accelerated the composting process and improved the compost quality.The milk vetch-based composts were nutrient-rich and safe,and thus,can replace part of peat in vegetable seeding substrate.

Fungi dominate denitrification when Chinese milk vetch green manure is used in paddy soil

Fungi play an important role in soil nitrous oxide(N_(2)O)emission in many agricultural soil systems.However,the effect of fungi on N_(2)O emission in Chinese milk vetch(CMV)-containing soils has not been examined sufficiently.This study investigated the contribution of bacteria and fungi to soil N_(2)O emission in CMV-amended soils.We compared soils from an experimental field in the Fujian Academy of Agricultural Sciences that had been treated with 30000 kg of CMV per 667 m2 per year with one that was not treated with CMV.We incubated soil using cycloheximide and streptomycin to differentiate fungal and bacterial N_(2)O emissions,respectively.Quantitative PCR(qPCR)was performed to investigate bacterial and fungal abundances in the two agricultural soil ecosystems.The contribution of fungi to soil N_(2)O emission in CMV-amended soils was greater than that in nonCMV-amended paddy soils,with fungi accounting for more than 56%of the emissions in CMVamended soils.Quantitative PCR showed that the ratio of the internal transcribed spacer to 16S rDNA was significantly higher in CMV-amended soils than in non-CMV-amended paddy soils.Furthermore,soil properties,such as pH(P<0.05)and NH_(4)^(+)concentration(P<0.05),significantly and negatively affected N_(2)O emission by fungi in soil,whereas the total organic carbon(P<0.05)and NO3–concentration(P<0.05)showed significant positive effects.Fungi may be important contributors to N_(2)O production in CMV-amended soils,which may create challenges for mitigating N_(2)O production.

不同轮作模式对稻田土壤肥力和微生物群落结构的影响

为了探索不同水稻轮作模式对稻田土壤微生物群落结构的影响,以及与土壤养分供给的关系,本研究采用高通量测序技术对3种不同轮作模式下(水稻-小麦轮作、水稻-紫云英轮作、水稻-休耕)土壤细菌和真菌的群落结构变化进行分析,并进一步探讨了微生物群落结构与土壤养分含量之间的相互关系。结果表明:水稻-紫云英轮作模式能够明显改善稻田土壤的综合肥力,紫云英连续翻压还田后显著提高了土壤中总氮(TN)和有效氮(AN)的含量。土壤微生物群落结构方面,不同种植模式对细菌群落结构的影响大于真菌。水稻-紫云英轮作模式中优势菌群如酸杆菌门(Acidobacteriota)和子囊菌门(Ascomycota)等的富集有助于促进土壤生态系统的养分循环与生态健康。不同种植模式条件下土壤养分的变化如TN、AN、总钾(TK)及速效钾(AK)等可能是导致土壤细菌和真菌群落结构发生变化的主要驱动因素。稻田土壤中细菌群落结构对于土壤养分变化的敏感性要高于真菌。综合来看,水稻-紫云英轮作模式是更加适合水稻生态可持续栽培的种植模式,能够明显改善稻田土壤的综合肥力和土壤微生态环境。