| The rotton wheat straw was used to improve soil quality, tobacco leaf growthand quality were concerned on by many tobacco scholars. At present, the researchabout straw appropriate amount, the way to return to fields and their effects on soilimprovement had not been a clear conclusion. Henan were major tobacco producingareas in China. The sustainable development of tobacco had been affected due to soilquality degradation seriously in recent years,,.Based on the research of soil qualityimprovement abroad, field experiments, plot experiments and pot experiments wereconducted to study the effects of rotton wheat straw on soil improvement, tobacco leafgrowth, tobacco yield and quality. The main results as follows:1. The experiments were conducted to study the effects of rotton wheat straw onthe indexes of carbon and nitrogen of soil. The results indicated that the compositionof soil carbon pools were changed by adding of rotten wheat straw, with the TCcontent and the effective carbon content increased significantly; Soil TC content ofeach treatment was decreased at different periods, the changes of contrst were notsignificant, soil TC pre-transformation in0-20cm soil layer was slower at the earlygrowth stage than that at the late growth stage, soil TC pre-transformation in20-40cmsoil layer were stable relatively throughout the growing period; The more strawamount added, the more conducive to maintain a higher level of TC at the late growthstage. The more straw amount added, the higher SMBC content increased, thedifferences among treatments at different stages were correlated significantly.Thechange terends of SMBC in0-20cm soil layer were the same as in20-40cm soil layerbasically,but SMBC in0-20cm soil layer soil layer were higher significantly than in20-40cm soil layer.The effects of rotton wheat straw on soil TN were lesssignificantly than soil TC,. there were no significant differences among treatments.The more straw amount added, the higher SMBN content increased, the differencesamong treatments at different times were correlated significantly. The correlation ofsoil SMBC, SMBN, TN and TC were significant at0.01level respectively aftertransplanting in45,75,90d, the correlation between SMBC and SMBC/SMBN indifferent stages after transplanting were significant, the soil TN and TC weresignificant positive correlation after45d transplanting.2.The experiments were conducted to study the effects of rotton wheat straw on the components of soil active carbon pool. The results indicated that: the more strawamount added, the higher TOC content increased, the differences among treatmentswere correlated significantly. With the growth period of retreat, TOC contents weredeclined. At the early growth stage, the deline speed of TOC in20-40cm soil layerwas faster than in0-20cm soil layer. The decrease of TOC in two soil layers wereconsistent at90days. The effects of rotton wheat straw on EOC were notsignificant,DOC content increased, DOC content of contrst were highest at75days,DOC content of T4were highest at other days, it began to decline after75days. SMQof each treatment were higher than conrest. During the whole growth period, SMQincreased at the beginning and reached maximum at75days, then began to decline.The change extent of SMQ on average in0-20cm soil layer were faster than in20-40cm soil layer. The more straw amount added, the more SMQ in0-20cm soillayer delined, the more SMQ in20-40cm soil layer increased. SMQ in the potexperiments was significantly lower than that in the field experiments. They weredeclined at the whole growth stage,the trend was as same as20-40cm soil layer in thefield experiments. SMQ of each treatment were higher than contral, which indicatedthat rotton wheat straw were conducive to increase TOC accumulation.The results offield tests indclined that, the correlation of TOC and SMBC was significant highly,the correlation of SMBC and SMQ was also significant highly, but the correlation ofTOC and SMQ was not significant. Pot experiment results indclined that thecorrelation of TOC,DOC,SMBC and EOC were perhaps significant highly at differentperiods. the correlation of DOC and EOC was negative significant. The componentsof soil active carbon depended on total carbon storage largely. There were significantor highly significant correlation of SMBC and SMQ at different growth periods.3. The experiments were conducted to study the effects of rotton wheat straw onsoil enzyme activitythe. The results indicated that: soil invertase activity wasimproved significantly, soil invertase activity was increased at the beginning thenbegun to decline. Soil urease activity was reduced. The differents of catalase activityof each treatment was significant, the regularity wasn’t the same in the differentstages. Catalase activity of T3was the hightest in the whole growth periods,itindclined that the suitable rotton wheat straw returning amounts was conducive toenhancing the ability of soil biological oxidation.Soil cellulase activity wassignificantly enhanced, T4was the highest activity.4. The experiments were conducted to study the effects of rotton wheat straw on soil available nutrients. The results indicated that: Soil available nitrogen content wasimproved,which could promote soil nitrogen supply.it was more pronounced in theearly period.Soil available phosphorus content of each treatment were significantlyhigher than CK in45days and90days. Soil available phosphorus content weredeclined with the advance of growth period.Soil available potassium content was increased with the amount of straw, it wasincreased at the beginning, then begun to decline. The effects of rotton wheat straw onsoil available iron content were negative. The effects of rotton wheat straw on soilavailable manganese content were favorable. The effects of T3on soil availablecopper content were the most obvious. The effects of rotton wheat straw on soilavailable zinc content were short-term.5. The experiments were conducted to study the effects of rotton wheat straw onsoil physical properties and pH. The results indicated that:It was narrowed differenttemperature differences of different soil layers. soil temperature could be slightlyimproved when the temperature was decreased, but cooling effect of rotton wheatstraw wasn’t significant when the temperature was high, the surface temperaturecould even be increased. Soil bulk density could be reduced, but the effects on soilbulk density was a certain timeliness.Soil porosity was increased. Soil bulk densitywould be improved significantly in the tobacco growth periods. the effects of rottonwheat straw on pH were significant,soil pH were decreased,but the changes of soil pHwasn’t significant in the tobacco growth periods. Soil water holding capacity could beimproved significantly.Soil had the capacity of reducing water rapidly in the case ofhigh soil moisture,while it could maintain a relatively long period of suitable watercontent in the case of low soil moisture,and reduce evaporation invalid.6. The experiments were conducted to study the effects of rotton wheat straw ontobacco development root. The results indicated that: rotton wheat straw wasconducive to the growth of tobacco, all of the root fresh weight, root dry weight, rootvolume and root vigor were improved significantly. Excessive rotton wheat strawcould hinder the growth of tobacco. Rotton wheat straw was conducive to maintainthe root vigor in the late growth stage and more extensive root absorption area,whichcould improve the tobacco field maturity.7. The experiments were conducted to study the effects of rotton wheat straw ontobacco photosynthetic characteristics and chlorophyll. The results indicated that:Stomatal conductance, transpiration rate and net photosynthetic rateof tobacco leaves were increased significantly in the45days, while the effects of intercellular CO2concentration had not reached significant level. The chlorophyll content wereincreased significantly, so, the photosynthesis of tobacco were promoted. The rate ofchla/b was stable basically in the early growth periods. The degradation speed of chlbwas affected so that tobacco maturity was also affected when tobacco growing intomaturity. Tobacco carotenoids were impacted significantly in different periods,but theeffect degree were different.8. The experiments were conducted to study the effects of rotton wheat straw onthe activity of key enzymes and metabolitesin carbon-nitrogen metabolism of tobacco.The results indicated that: Nitrate reductase activity, invertase activity and amylaseactivity were increased significantly, but the conversion time of tobaccoCarbon-Nitrogen metabolism were not changed, nitrogen metabolism of eachtreatment were transferred into nitrogen metabolism after topping. Starch content oftobacco leaves were reduced, nicotine contents were increased,and total nitrogencontents were not significant.9. The experiments were conducted to study the effects of rotton wheat straw onthe absorption and accumulation of mineral element in tobacco. The results indicatedthat: the accumulation of various mineral elements were increased significantly.Various levels of mineral elements of modulated tobacco could be improved,theperformance of different elements was inconsistent in different parts of tobacco. Withthe addition of rotton wheat straw increased,phosphorus contents of the upper leaveswere gradually improved, the differences of phosphorus contents of the middle leaveswere not significant， phosphorus contentsof the lower leaves were higher thancontrast except T2. Potassium contents of the upper leaves were increased, calciumcontent of the lower leaves and the middle leaves weredecreased;The effects onboron contents of the upper leaf were positive,while the effects on boron contents ofthe middle leaves and the lower leaves were negative.The effects on manganesecontents of the upper leaves and the middle leaves were positive, the effects onmanganese contents of the lower leaves were negative. Copper contents and zinccontents were improved,while magnesium contents and iron contents were reduced.10. The experiments were conducted to study the effects of rotton wheat straw onthe growth, yield and production value of flue-cured tobacco. The results indicatedthat:Tobacco growing periods were prolonged, meanwhile, it existed time differencein different experiment areas. Field experiments indicated that tobacco leaves of CK matured earlier in the early growth periods.Tobacco leaves of T3, T4and T5maturedlater in the early growth periods, focused on mature in the middle growth periods, andthe mature speed of T3, T4and T5was lower than contrast on the upper leavesharvest. Tobacco growth periods of pot experiments were shorter than fieldexperiments,tobacco field growth periods were prolonged significantly, the maturitydegree of T5were not normal, the maternity time was prolonged. The effects of fieldexperiments on plant height were not significant,while the effects of pot experimentswere significant. The effects of overfull rotton wheat straw on tobacco ’s girth werenegative，but the effects on the effective number of leaves of tobacco plants and themaximum leaf area were positive. Dry matter accumulation and dry matteraccumulation amount were promoted,the differences of all of the treatments weresignificant, the peak periods of dry matter accumulation amount were different. Theeffects of rotton wheat straw were conducted to improve the yield and productionvalues of tobacco,the yield of T2were the highest, the production values of T3werethe highest. The yield of the lower were higher than CK except T1;The more of rottonwheat straw amounts,the higher of the yield of the middle. The yield and ratio ofsuperior tobacco were increased significantly, the yield and ratio of inferior and lowtobacco were decreased. All treatments except T1could improve acre yieldsignificantly.11. The experiments were conducted to study the effects of rotton wheat straw onthe quality of flue cured tobacco. The results indicated that:the addition of rottenstraw was beneficial to improve the coordination of routine chemical components intobacco leaves, improve the ratio of two sugar, nitrogen base lifting upper leaf ratio,reduce the content of starch reduced significantly, the changes of total nitrogencontent were not significant.The content of petroleum ether extract of the upper leavescould be improved, but the content of petroleum ether extract of the middle and thelower leaves were decreased.The influence of tobacco total aroma content in differentparts wasn’t consistent.The results in field experiments showed that the processingperformance of T3and T2was better, pot experiments showed that the processingperformance of T3,T4was better.Various groups of neutral aroma componentscontent in different treatments were not consistent completely，and there weredifference in different tobacco part. Applying rotton wheat straw was conductive toimprove the contents of aroma substances, the appropriate amount of rotton wheatstraw for different aroma substances components were different.Sensory qualityof the upper was improved，the main effects were to improve the aroma quantity and thequality of aroma.It was no significant influence on the sensory quality of the middleleaves, to a certain extent, sensory quality of the lower leaf was reduced partly. |
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