Abstract:In order to investigate the mechanism of grapefruit disease resistance induced by chitosan(CTS),the experiment used grapefruit leaves as material to study the effects of 1.5%CTS induction for differ-ent time on controlling Penicillium expansum of grapefruit leaves,as well as the expression of resistance genes,using sterile water treatment as control.The results showed that compared with the control,CTS-induced treat-ment significantly reduced the incidence of P.expansum in grapefruit leaves and inhibited the growth of patho-genic bacteria.Fluorescent quantitative PCR analysis showed that CTS increased the expression levels of phe-nylpropane-related genes(CpPAL,CpPPO)and disease course protein genes(CpPR1,CpGLU,CpCHI)sig-nificantly.At the same time,the contents of total phenols,flavonoids and anthocyanins in grapefruit leaves were increased which was positively correlated with the expression of related genes.In conclusion,CTS treat-ment promoted the accumulation of resistant substances by activating the expression of phenylpropane pathway related genes,improved the expression level of disease course protein genes,and enhanced the resistance and defense ability of grapefruit to penicillium.

Abstract:In this experiment,with Shangshu 19 as test material,three treatments including restoring af-ter shading for 40 days with 70％light transmittance at vine-root tuber simultaneous growth stage(restoring treatment),continuous shading with 70％light transmittance from vine-root tuber simultaneous growth stage to harvest time(shading treatment)and no shading during the whole growth period(CK)were set to study their effects on the dry matter mass,the contents of total starch,soluble protein,soluble sugar,reducing sugar and anthocyanin,and the starch composition,swelling potential,solubility and aging value.The results showed that compared to CK,shading treatment reduced the dry matter mass and total starch content of Shangshu 19 root tubers,and increased the contents of amylopectin and soluble protein,and the starch swelling potential and solubility;the soluble protein content increased with the prolongation of shading time.Shading treatment also decreased the starch aging value and contents of reducing sugars,soluble sugars and anthocyanins of root tu-bers.Short-term shading was favorable for the increase of soluble sugar content of Shangshu 19 root tubers.These results could provide data support for sweet potato cultivation in low-light area.

Abstract:In this study,the Sertoli cells(SCs)were isolated from 2-month-old Shannon dairy goats,and the isolation efficiency of three enzyme digestion methods(trypsin digestion,two-step enzyme digestion,and two-step mixed enzyme digestion)were compared.The morphological and molecular biological techniques were used to characterize and evaluate the culture effects.The results showed that the number,viability and proliferation of cells obtained by two-step enzyme digestion and two-step mixed enzyme digestion were signifi-cantly higher than those obtained by pancreatic enzyme digestion.Morphological observation showed that the cells isolated by two-step enzyme digestion method had typical SCs morphology and could be stably passaged to the fifth generation.HE staining showed bipolar corpuscula in the nucleus,and oil red O staining showed lipid droplets with different sizes around the nucleus.Immunofluorescence staining showed that the positive rate of SCs specific protein WT1 and Vimentin antibodies was more than 96％.The ultrastructural observation showed that the cell structure was intact,the organelles were abundant,and the nucleus was irregular in shape,which was consistent with the ultrastructural characteristics of SCs.In conclusion,the two-step enzyme digestion method was simple,low-cost,and could isolate a large number of SCs with good viability and purity,which could be stably cultured in vitro,so it was the best method for isolating SCs from dairy goats,and could pro-vide a good cytological model for the in-depth study of male reproductive function of dairy goats.

Abstract:In order to investigate the function of the WRKY transcription factor family in onion,this study screened and identified a total of 55 AcWRKY gene family members using bioinformatics method based on the whole genome sequence of onion and transcriptomic data of bulb at different developmental stages.Their a-mino acid length ranged from 144 to 683 aa,isoelectric point ranged from 5.11 to 9.65,aliphatic index ranged from 47.14 to 77.24,and all of them were predicted to be hydrophilic proteins.The subcellular localization prediction results showed that the 55 AcWRKY proteins were all localized in nucleus.Phylogenetic analysis showed that the AcWRKY family genes could be divided into three groups of Group Ⅰ,Group Ⅱ and GroupⅢ,and group Ⅱ could be further divided into five subgroups.The WRKY proteins from onion and Arabidopsis were distributed in each group which speculated that the transcription factors from the same group or subgroup might have similar functions.Conserved domain analysis showed that all the AcWRKY proteins had the highly conserved WRKYGQK motif and its characteristic zinc finger structures,and a few members had some amino acid variation in the conserved domain.Gene structure and conserved motif analysis indicated that the number and distribution of exons and motifs were found to be different in different AcWRKY members,and proteins in the same group or subgroup were similar.Analysis results of transcriptome data indicated that the vast majority of AcWRKYs genes were directly or indirectly involved in development and formation of onion bulb.The results of this study could provide reference for further research on the mechanism of AcWRKY gene in onion bulb for-mation.

Abstract:In order to study the adaptability of orchids to dry-hot valley habitat,Bletilla striata,Den-drobium wangliangii,Habenaria aitchisonii and Hemipilia cruclata were selected as the research objects in the field environment of dry-hot valley of Jinsha River,and the chlorophyll fluorescence characteristics were ana-lyzed in wet season(July)and dry season(October).The results were as follows:(1)The maximum photo-synthetic efficiency(Fv/Fm)of the four orchids were all lower than 0.8 in both dry and wet seasons,and were lower in dry season than that in wet season,indicating that the four plants were subjected to drought stress for a long time and the degree of stress was stronger in dry season.(2)The Fv/Fm,the actual photo-synthetic efficiency of PS Ⅱ Y(Ⅱ),electron transport efficiency(ETR)and photochemical quenching coeffi-cient(qP)of B.striata in dry season were significantly lower than those in wet season,while there was no significant difference in the four chlorophyll fluorescence parameters of D.wangliangii and H.aitchisonii be-tween dry and wet seasons,indicating that the photosynthetic apparatus of B.striata in dry season was de-stroyed,the electron transport was blocked,the PS Ⅱ reaction center was damaged,showing photoinhibition,while D.wangliangii and H.aitchisonii had stronger abilities in regulating their own PS Ⅱ reaction center from damage.(3)The non-photochemical quenching coefficient(NPQ)of B.striata and D.wangliangii in dry season was significantly lower than that in wet season,which showed no significant difference between dry and wet seasons in H.aitchisonii and H.cruclata,indicating that the PS Ⅱ reaction center of B.striata and D.wangliangii was damaged,and the heat dissipation capacity and light protection ability were decreased under long-term drought stress in the dry season.(4)The ETR and NPQ of H.cruclata in dry season were signifi-cantly higher than those of the other three plants,Y(Ⅱ)was significantly higher than that of B.striata and H.aitchisonii and slightly higher than that of D.wangliangii,and qP was significantly higher than that of B.striata and slightly higher than that of D.wangliangii and H.aitchisonii,indicating that the performance of plant photosynthetic apparatus in H.cruclata was better than that in the other three orchids.In summary,H.aitchisonii performed the most stable under long-term drought stress in the dry-hot valleys,and H.cruclata per-formed better in drought tolerance.

Abstract:The study was aimed to obtain efficient degradation strains for solid organic wastes from live-stock and poultry breeding.A thermophilic strain BWTGW1.1 was isolated from pig manure sludge compost in Dongguan central slaughter house by dilution coating and high temperature culture methods.The strain was ini-tially identified as Geobacillus galactosidasius through morphological,physiological and biochemical analyses and 16S rRNA gene sequence construction analysis.The ability of salt resistance,high temperature resistance,high temperature protease production and treatment effect on livestock and poultry solid organic wastes of the BWTGW1.1 strain were further studied.The results showed that,in terms of salt tolerance,the BWTGW 1.1 strain grew well under the condition of 1.5％salt concentration,and the OD600 was 1.1 after cultured for 48 hours.In terms of high temperature resistance and high temperature protease production ability,the BWTGW1.1 strain could still survive after cultured for 12 hours at 85 ℃,and could produce hydrolyzed transparent circle after 48 hours at 60 ℃ with hydrolytic circle diameter/colony diameter greater than 2.0.In 116 m3 large verti-cal solid fermenter,BWTGW 1.1 bacterial solution+common bactericide could make the temperature of the pile reach 58 ℃ within 24 hours,which was 13 ℃ higher than that of common bactericide alone,and the high temperature of 60～70 ℃ could last 108 hours,which was only 60 hours in common bactericide treatment.The seed germination index of cucumber in BWTGW1.1 bacterial solution+common bactericide treatment was 86.75％after fermentation for 168 hours,which was 26.24％higher than that in common bactericide treatment.The results indicated that BWTGW 1.1 had potential application value in the compost fermentation process of pig manure sludge and other livestock and poultry solid organic wastes.

Abstract:A two-year field experiment was conducted with the wheat variety Tainong 18 as test material by setting 7 treatments including nitrogen-free control(CK),ordinary urea treatment(CU)and five treat-ments of mixed urea(M,ordinary urea and controlled-release urea at ratio of 7:3)combined with organic fer-tilizer(F).The proportion of organic fertilizer instead of mixed urea was designed as 0,25％,50％,75％and 100％,which were recorded as M100F0,M75F25,M50F50,M25F75 and M0F100,respectively.The effects of dif-ferent fertilization treatments on wheat nitrogen utilization,yield and soil nitrogen supply performance under e-qual nitrogen condition were studied.The results showed that the application of mixed urea combined with or-ganic fertilizer could significantly improve the transformation of soil humic acid components,affect the supply period of soil available nitrogen,promote the growth and nitrogen absorption of wheat,and then improve the nitrogen use efficiency(NUE)and yield of wheat.Under the CU treatment,the content of nitrate nitrogen and ammonium nitrogen in the surface(0～30 cm)soil increased and made wheat grow better at the early stage of winter wheat growth,but the higher leaching amount of nitrate nitrogen and ammonium nitrogen led to the soil available nitrogen content decreased rapidly after that,so the nitrogen use efficiency(NUE)and yield were lower.Compared with CU treatment,the treatments of mixed urea combined with organic fertilizer prolonged the supply period of soil nitrogen,reduced nitrogen leaching and increased soil enzyme activity,promoted the transformation of soil humic acid components,thereby improved wheat dry matter accumulation,NUE and yield.The average NUE of the two years was the highest under M50F50 treatment,and the NUE increased by 1.51％to 21.48％and 8.90％to 22.64％respectively compared with the other fertilization treatments in 2022 and 2023,respectively.In summary,the application of organic fertilizer instead of 50％mixed urea in the ex-periment conditions could improve soil nitrogen supply performance,increase winter wheat yield and NUE,so it was the best organic fertilizer replacement treatment.

Abstract:To construct a hyperspectral accurate estimation model of SPAD value of rice leaves,the ex-periment was conducted with the variety Jingliangyouhuazhan as material,and three fertilization treatments were set.The hyperspectral reflectance and SPAD value data were measured continuously and periodically dur-ing the whole reproductive period.The sensitive information of the spectrum was extracted using vegetation in-dex and continuous wavelet transform(CWT),and then the estimation models of SPAD of rice leaves were es-tablished using traditional linear and nonlinear fittingand the algorithm of back propagation neural network(BPNN),whose estimation effects were compared using the coefficient of determination(R2),root mean square error(RMSE),and relative analysis error(RPD).The results showed that the accuracy of the inverse univariate models for SPAD value constructed with nine commonly used vegetation indices based on the tradi-tional methods(linear function,logarithmic function,exponential function,and quadratic function fitting)were lower(RPD＜1.4).Six parent wavelet functions were selected for CWT,which could effectively improve the correlation between leaf hyperspectral reflectance and SPAD value,and the accuracy of the univariate models constructed using the optimal wavelet coefficients of the parent wavelet functions increased obviously,which could reach the level of rough estimation of SPAD value with RPD between1.523 to 1.581.The accuracy of the SPAD estimation models constructed based on the BPNN algorithm were significantly improved compared with the univariate models with RPD between1.832 to 2.342.Among which,the BPNN models constructed with bior3.3 and gaus4 as parent wavelet functions had better estimation capacity with RPD of 2.342 and 2.178,respectively.However,the BPNN model constructed with gaus4 as the parent wavelet function had the phenomenon of overfitting.In summary,the BPNN model constructed using the first 10 optimum wavelet coef-ficients decomposed by bior3.3 had the highest precision with R2 and RMSE as 0.818 and 1.441,respectively,which could make good prediction of SPAD value of rice leaves.This study proved that CWT could effectively extract the sensitive information of spectral characteristics in rice leaves,and the established bior3.3-BPNN model could be used for the monitoring of rice SPAD value,which could provide references for subsequent rapid and nondestructive monitoring of rice SPAD value throughout the whole growth period,and provide the technical support for real-time monitoring of rice growth and development dynamics.

Abstract:In order to understand the growth and physiological responses of three legume forage grasses(Trifolium repens L.,Medicago sativa L.,Lotus corniculatus L.)to aluminum stress,and to compare their differences in aluminum tolerance,six aluminum concentrations of 100,200,300,500,700 and 1 000 mg·L-1 were set in this study.The seed germination,seedling growth and physiological indexes were measured,the e-valuation indexes of aluminum tolerance were screened out through principal component analysis,and the alu-minum tolerance was evaluated by membership function method.The results showed that low concentration alu-minum stress(100 or 200 mg·L-1)had a certain promoting effect on seedling growth and biomass of T.repens M.sativa and L.corniculatus.As the increase of aluminum concentration,the seed germination and growth in-dicators of the three legume forage grasses significantly decreased,showing the greatest inhibition to root sys-tem.Moreover,as the increase of aluminum concentration,the contents of soluble sugar and proline as well as the activities of peroxidase(POD)and catalase(CAT)in the three legume forages showed the trend of increas-ing first and then decreasing,reaching their maximum values at aluminum concentration of 200 or 300 mg·L-1.The relative root length,relative germination index,relative viability index,relative malondialdehyde content and relative peroxidase activity selected by principal component analysis could be used as evaluation indicators for aluminum tolerance of T.repens,M.sativa and L.corniculatus.The average membership function value of the five indicators calculated by membership function method could be used to identify the aluminum tolerant capacity,and the results showed that T.repens had the strongest aluminum tolerance,followed by M.sativa,and the aluminum tolerance of L.corniculatus was the worst.These results could provide the theoretical basis and certain reference for screening aluminum-tolerant leguminous forage germplasms and breeding new varie-ties in the southwest region of China.

Abstract:To identify candidate genes related to herbicide resistance in maize,this study was conducted by using an association population comprising 234 inbred lines of maize as material.The genome-wide associa-tion analysis(GWAS)was conducted through integrating the genotyping results with 56 000 SNP markers and evaluation data of the traits related to atrazine resistance.The results indicated that a total of 62 quantitative trait nucleotides(QTNs)significantly(P＜0.001)associated with maize resistance to atrazine were identified.Among them,PZE-104041162 and PZE-104041163 were associated with both chlorophyll content and maize injury rate.Through candidate gene analysis,57 candidate genes linked to maize resistance to atrazine were i-dentified;among which,GRMZM2G311465,GRMZM2G017536,GRMZM2 G172826,GRMZM2G129431,GRMZM2G334791,GRMZM2G177878 and GRMZM2G030768 were primarily involved in regulating plant growth and development,immunity,hormonal signaling pathways,and responses to biotic and abiotic stresses.These findings could provide key candidate genes for further exploration of the resistance mechanisms to at-razine in different maize germplasms.

Abstract:The purpose of this study was to explore the effects of organic carbon fertilizer on regulating bacterial community structure in tobacco-growing soil and yield and quality of flue-cured tobacco.The field ex-periment was conducted with four treatments,including CK(conventional fertilization),T1(conventional fer-tilization+75 kg/hm2 organic carbon fertilizer),T2(conventional fertilization+150 kg/hm2 organic carbon fer-tilizer)and T3(conventional fertilization+225 kg/hm2 organic carbon fertilizer).The soil bacterial community structure,relative abundance of dominant bacteria,correlation between relative abundance of major phyla and soil chemical properties,and yield and quality of flue-cured tobacco were investigated and analyzed.The re-sults showed that the application of organic carbon fertilizer resulted in higher values of Shannon index,Ace index and Chao1 index of bacteria in soil compared to CK;moreover,the relative abundance of Acidobacterio-ta and Chloroflexi were significantly increased.There were significant correlations between the relative abun-dance of major phyla and most soil chemical factors,among which,GAL15 had significantly positive correla-tion with available phosphorus and alkali-hydrolyzed nitrogen(P＜0.05),and extremely significantly positive correlation with available potassium,organic matter and total carbon(P＜0.01).Conversely,Bdellovibrio showed significantly negative correlation with available potassium,alkali-hydrolyzed nitrogen and organic mat-ter.The application of organic carbon fertilizer could improve the yield and quality of flue-cured tobacco,and T2 treatment had the best effect,showing the increase of total sugar,reducing sugar and potassium contents in cured tobacco by 9.89％,16.84％and 11.71％respectively,the highest overall score of sensory quality evalu-ation,and the increase ofoutput value of flue-cured tobacco,proportion of high-grade tobacco and average price by 20.01％,13.84％and 3.87％respectively compared with CK.In conclusion,the application of organ-ic carbon fertilizer could improve the soil bacterial community structure and the yield and quality of flue-cured tobacco,and the application of 150 kg/hm2 organic carbon fertilizer had the best effect.

Abstract:In order to solve the problem of stain degradation in cultivation and production process of black fungus(Auricularia auriculata),it is necessary to develop an effective method of fungus rejuvenation to enhance the viability of mycelia.In this experiment,the degraded black fungus strain was used as research ob-ject;the effects of adding six organic nitrogen substances,including corn flour,peptone,spirulina powder,malt extract,beef extract and yeast extract,on the mycelial growth rate,biomass,contents of nutrients and active oxygen,antioxidant enzymes activities of degraded black fungus mycelia in PDA medium were studied.The results showed that compared with PDA medium(CK),adding spirulina powder and malt extract made the mycelia grow faster,the biomass be higher,and the contents of protein and polysaccharide in mycelia in-crease significantly,but reduced the contents of 02·and H2O2 in mycelia significantly except the H202 content in mycelia with the addition of malt extract.The activities of peroxidase(POD),superoxide dismutase(SOD)and catalase(CAT)in mycelia were significantly increased when adding spirulina powder compared with CK.To sum up,the optimal culture medium for rejuvenating the degraded strains of black fungus was PDA culture medium with spirulina powder added.This study could provide technical support and theoretical references for rejuvenating the aging and degraded black fungus strains.

Abstract:In order to understand the differences in leaf color change of different varieties of cigar tobac-co during air-curing,this experiment was conducted taking Dexue 1(D1),Dexue 3(D3),Dexue 5(D5)and Chuanxue 3(C3)as the objects.The change characteristics of moisture content,related enzymes activi-ties,plastid pigment content and polyphenol content in leaves of the four varieties of cigar tobacco during air-curing and their effects on the color and quality of tobacco leaves were studied.The results showed that the comprehensive quality of Dexue 3 leaves was the best that had higher enzymes activities,sufficient degradation of polyphenols and plastid pigments,good color and sufficient aroma components after air-curing,which was followed by Dexue 1 and Chuanxue 3.The leaves of Dexue 1 could be used as wrapper.The comprehensive quality of Dexue 5 leaves was the worst.

Abstract:Wheat quality climatic zoning is of great significance to making full use of regional climatic re-sources and producing high-quality wheat according to local conditions.Shandong Province is a typical region in northern China for growing strong-gluten and medium-gluten wheat varieties for special use.Climatic condi-tions of Shandong Province have changed greatly under the background of climate warming,so the wheat quali-ty zoning results need to be updated.In this study,the agro-climatic indicators for wheat quality zoning were used to comprehensively score the meteorological conditions(temperature,precipitation,and sunshine hour)of 122 meteorological stations in Shandong Province during wheat growth seasons from 1981 to 2020,and the results of agro-climatic zoning of wheat quality in Shandong Province before and after climate warming were ob-tained by ArcGIS interpolation method and the differences were compared.The results showed that whether be-fore and after climate warming,Shandong Province is always a suitable area for strong-gluten wheat and a tran-sition area of strong-and medium-gluten wheat.After climate warming,the suitable area of strong-gluten wheat in Shandong Province was greatly reduced,but the transition area of strong-and medium-gluten wheat was ex-panded,which was mainly in central Shandong and the Jiaodong Peninsula.The increase of ≥0 ℃ thermal time in wheat season and the decrease of daily temperature range in May(flowering-filling stage)were the main reasons for the decrease of overall score in wheat growth seasons.The results of this study would provide a theoretical basis for timely adjusting the suitable area of strong-gluten wheat in Shandong Province and reali-zing the bidirectional adaptation of varieties and ecological areas.

Abstract:On the basis of the existing genetic transformation system,the genetic transformation system was optimized in this study to improve the transformation efficiency and lay a foundation for the subsequent re-search on gene function and molecular breeding of mulberry(Morus alba L.).Firstly,the Agrobacterium-me-diated mulberry genetic transformation system was optimized from five aspects:Agrobacterium rhizogenes spe-cies,explants types,pre-culture time,infection time and co-culture time;then the MaCYP90A-pBI121 plas-mid was constructed and transported into Agrobacterium rhizogenes to induce hairy roots.The results showed that the optimized genetic transformation conditions were as follows:using Agrobacterium LBA9402 with OD600=0.6 to infect the true leaves of sterile mulberry seedlings pre-cultured for 2 d for 10 min,and coculturing for 2 d.In the optimized conditions,the induction rate of hairy roots reached 84.51％.The recombinant plasmid MaCYP90A-pBI121 was transformed into mulberry leaves,and the positive transgenic efficiency was 81.84％after hydomycin resistance screening and PCR identification.qRT-PCR results showed that the expression level of MaCYP90A gene in the positive transgenic hairy roots was 39.97 times higher than that of the blank control.Based on the established mulberry genetic transformation system,this study successfully optimized the system,and the conversion efficiency was 1.8 times higher than that(30.21％)of the system before optimization,which could provide technical supports for the follow-up study of mulberry gene function,analysis of secondary metabolite synthesis pathway and molecular breeding.

Abstract:In this experiment,the effects of pure water(CK)and 2.0 mmol/L sodium nitroprusside(SNP)solution soaking treatments on storage quality,antioxidant enzymes activities and anthocyanin accumu-lation of Sanhua plum fruits were studied using seventy or eighty percent mature fruits as test materials.The re-sults showed that exogenous SNP treatment could significantly delayed the soften of plum fruits,effectively suppressed the decrease of titratable acid,soluble solid and ascorbic acid contents,significantly inhibited the decline of Fv/Fm(PS Ⅱ maximum light energy conversion efficiency)and the accumulation of malondialde-hyde,and improved the activity of peroxidase(POD)and catalase(CAT).Moreover,SNP treatment could significantly increase the expression level of PsCHS and PsANS genes,thus promoted the further accumulation of anthocyanin in postharvest plum.In summary,exogenous SNP treatment could effectively maintain the post-harvest storage quality and antioxidant capacity of Sanhua plum fruits,which could provide the technical basis for storage and preservation of Sanhua plum fruits at room temperature.

Abstract:The aim of this study was to investigate the effects of different maize cultivars and soil fertility on the absorption of mineral element in summer maize and their distribution to grain.Three maize cultivars were selected and sown in high fertility soil(Zhaoyuan of Yantai)and medium fertility soil(Longshan of Ji-nan)to carry out comparative tests.The results showed that high fertility soil had significant promoting effects on growth and yield of maize with the average grain yield and average biomass of the three maize cultivars as 11.4 t/hm2 and 19.1 t/hm2,respectively,which was 23.9%and 28.2%higher than those in medium fertility soil.In the high fertility soil,the requirements of maize grains for phosphorus(P),potassium(K),manga-nese(Mn),copper(Cu)and boron(B)significantly increased,thus significantly increased the absorption of these nutrients by the above-ground plants,which increased significantly by 101.4%,215.8%,162.0%,99.7%and 81.6%,respectively compared with those in medium fertility soil.However,the requirements of grains for nitrogen(N),magnesium(Mg)and zinc(Zn)were relatively stable with an average of 19.7 kg/t,2.2 kg/t and 28.8 g/t,respectively,and the nutrient absorption in the corresponding above-ground plants also increased compared with the medium fertility treatment with an increase of 29.4%、26.1%and 51.1%,respec-tively.The results of the correlation analysis indicated that there was a significant positive correlation between maize yield and grain contents of P(r=0.895∗∗∗),Cu(r=0.830∗∗∗),K(r=0.711∗∗∗),Mn(r=0.765∗∗∗),Mg(r=0.740∗∗∗),Fe(r=0.738∗∗∗)and Zn(r=0.515∗).These results suggested that maize planted in high fertility soil was superior to that in medium fertility soil in yield,biomass,nutrient uptake and mineral element distribution to grain,which might be related to rich soil organic matter and high soil available nutrient contents in high fertility soil.The results could provide important references for high-yield and good-quality cultivation and efficient nutrient management of summer maize.

Abstract:To clarify the distribution characteristics of soil moisture in cotton fields under different plant-ing modes,three planting modes of wheat-cotton intercropping,direct-seeding cotton after wheat harvest,and monoculture cotton were selected in the long-term positioning test in field.The spatial grid method was used to measure the soil moisture in cotton fields during the whole growth period,in order to explore the influence of different planting modes on soil moisture distribution and try to determine the water requirement characteristics of cotton in various growth periods.The results showed that the spatial distribution of soil moisture had a cer-tain spatial heterogeneity,which was specifically manifested in:the determination coefficient of soil moisture semi-variance analysis at different growth stages of cotton under different planting modes were all above 0.92,and the best fitting model was Gaussian model;when the ratio of partial abutment value to abutment value(C/Sill)was above 0.75,the spatial distribution of soil moisture had a strong autocorrelation;the spatial vari-ation range of soil moisture under the three planting modes was larger than the actual sampling interval of 20 cm indicating the spatial variation characteristics of soil moisture.According to the spatial distribution of soil moisture,it was found that the influence of direct-seeding cotton after wheat harvest on soil moisture in cotton fields was mainly concentrated in the 10～50-cm soil layer.In the wheat-cotton intercropping pattern,the soil moisture was obviously affected by the wheat-cotton symbiosis period,and the impact could reach to the 70-cm soil layer due to the roots growing deeper.In summary,the double cropping system of wheat and cotton changed the temporal and spatial distribution of soil moisture in cotton fields,and soil moisture consumption was one of the important factors that determined the spatial differences.In this study,the law of soil moisture movement during the whole growth period of cotton in the double cropping pattern was explored by using the spatial grid method to sample and quantify soil moisture,and using the geostatistics to analyze the spatial het-erogeneity,which could provide theoretical supports for rational use of water resources in cotton fields and in-telligent irrigation in double cropping pattern.

Abstract:In this study,using the soil(0 to 30 cm)with Aralia elata planting for 2,5 and 10 consecu-tive years as test material,the interannual changes of soil enzymes activities and soil microbial biomass carbon and nitrogen and their correlations were analyzed with a view to providing references for growth,cultivation and management of A.elata.The results showed that planting year of A.elata had significant effects on soil enzymes activities.The activity of soil urease and phosphatase showed decreasing trends with the extension of planting years,while that of sucrase showed the opposite trend.As a whole,the activities of urease,phosphatase and sucrose were higher in surface soil compared to deep soil.The contents of soil microbial biomass carbon and ni-trogen mostly showed significantly downward trends with the extension of planting years,and their average con-tents were higher in surface soil compared to deep soil.Under different planting years,soil microbial biomass carbon and nitrogen contents and soil enzymes activities were mostly correlated positively.To sum up,there were obvious differences in soil physical and chemical properties with different planting years of A.elata;the longer the planting year was,the lower the soil urease and phosphatase activities and the microbial carbon and nitrogen contents were;and the soil enzymes activities also had a certain response relationships with the dy-namic change of the microbial carbon and nitrogen contents.

Abstract:In order to study the difference of soil particle size compositions and its correlation with soil biochemical indicators under different continuous cropping years of tobacco,the soil samples of rotation,con-tinuous cropping for 3 years and continuous cropping for 8 years in typical red soil area of Yunnan Province were taken as research objects to determine the particle size compositions,chemical properties and enzyme ac-tivities,and then their correlation analysis and stepwise regression analysis were carried out.The results showed that the proportion of clay in the soil with continuous cropping tobacco for 8 years increased by 19.21％,and that of silt and sand decreased by 21.71％and 14.87％,respectively.With the increase of con-tinuous cropping years,the contents of soil organic matter(OM),total nitrogen(TN),hydrolyzable nitrogen(AN),total phosphorus(TP),available phosphorus(AP),total potassium(TK)and available potassium(AK),the cation exchange capacity(CEC)and the pH value showed decreasing trends,while the activity of urease increased significantly,and the activities of sucrase and catalase decreased.The results of stepwise re-gression analysis showed that the proportion of clay particles had significantly or extremely significantly inhibi-tory effects on soil TN,TP and TK contents and pH value.The proportion of silt particles had significantly or extremely significantly promoting effects on soil OM and AP contents,CEC,and catalase and sucrase activi-ties.Compared with rotation,continuous cropping resulted in an increase of the proportion of clay particles in tobacco-growing red soil and a decrease of soil permeability,thus affected soil nutrient mineralization and en-zymes activities.The results of this study could provide the data support and theoretical basis for continuous cropping soil improvement.