Response Of Soil Physical And Chemical Properties To Alfalfa Rotations In Northwest Irrigation And Arid Areas

Posted on:2015-04-16

Degree:Doctor

Type:Dissertation

Country:China

Candidate:X Cui

Full Text:PDF

GTID:1223330452460614

Subject:Grassland

Abstract/Summary:

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This research relies on the National Forage special industrial technology system (CARS-35)funding in2010and dry farming areas in Gansu Desert expanded irrigation of alfalfa rotations onsoil physical and chemical properties of the study, through the analysis under different croppingsoil treatment variation of physical and chemical properties, land for cultivation methods in favorof screening raise binds. Meanwhile weights degree rotation mode on soil quality factors,screening suitable for soil quality assessment rotations of evaluation, to provide a theoretical basisand practical support for the regulation of land use and management under different rotations. Themain findings are as follows:1ã€through the study of soil profile0-100cm soil organic carbon and nitrogen changes underdifferent rotation processing found in irrigated areas,"alfalfaâ†’cornâ†’wheatâ†’alfalfaâ†’corn"rotations compared with the five years alfalfa grass, alfalfa five years grassland0-100cm organiccarbon, total nitrogen content of the soil rotation14.49%higher than the average,3.4percent, thefive years alfalfa grass has a significant carbon sink advantage;"wheatâ†’wheatâ†’peaâ†’peasâ†’corn"rotations and continuous cropping with corn than under the rotation mode of organic carbonin0-100cm even higher than the average value of2.4%as compared to the same layer of soilorganic carbon in the rotation mode, respectively,16.9%higher than the continuous croppingpattern,15.6%,6.9%-2.5%,3.7%,-1.1%,0%,6.7%-16.3%-22.5%. In upland areas "alfalfaâ†’cornâ†’fallowâ†’cornâ†’alfalfa" rotations compared with the five years alfalfa grass, organiccarbon content of soil differences within the range of20-100cm significantly (P <0.05), and thefifth in star alfalfa grassland organic carbon in the range of0-30cm higher than the average of9.5%crop rotation patterns.in Soil irrigated area in the "wheatâ†’wheatâ†’peaâ†’peasâ†’corn","cornâ†’cornâ†’cornâ†’cornâ†’corn","cornâ†’alfalfaâ†’wheatâ†’alfalfaâ†’corn","five years alfalfa grass"four farming methods next, in the0-100cm range, organic carbon content than the averagewasteland (CK) were44.57%higher than the soil,41.18%,36.94%,59.77%;63.26%higher thanthe total nitrogen content,51%,75.51%,81.63%; Dry soil area in the "fallowâ†’alfalfaâ†’cornâ†’cornâ†’alfalfa""five years alfalfa grass","wheatâ†’cornâ†’peasâ†’wheatâ†’corn""cornâ†’cornâ†’wheatâ†’cornâ†’corn" cultivation methods,0-100cm soil profile on the organic carbon content of40%higher than the wasteland,49.62%,66.29%,54.81%,79.54%higher than the total nitrogen,81.81%,79.54%,59.09%, which indicates that any kind of way were able to make enhance soilorganic carbon and nitrogen content, years planted alfalfa or alfalfa (legume) and cereal crops forrotation or even better than the grassy rotation.2ã€By studying the structure of the soil profile0-100cm soil aggregates under differentrotation handle discovery, dry sieve under rainfed areas,"alfalfaâ†’cornâ†’fallowâ†’cornâ†’alfalfa"under rotations in the0-20cm soil layer,>0.25quality accumulated mm diameter were higher,"thefive years alfalfa grass","cornâ†’cornâ†’cornâ†’wheatâ†’corn","cornâ†’wheatâ†’wheatâ†’peasâ†’corn" was9.44%,23.28%,16.92%; in20-40cm higher than10.78%, respectively,22.21%,15.19%, indicating that crop rotation "fallowâ†’alfalfaâ†’cornâ†’cornâ†’alfalfa" is treated under thesun in the dry screened cultivation methods with the best aggregate structure. Irrigated areas,"alfalfaâ†’cornâ†’wheatâ†’alfalfaâ†’corn" under rotations in the0-20cm soil layer,>0.25mm particlemass accumulation were higher,"the five years alfalfa grass","cornâ†’cornâ†’cornâ†’cornâ†’corn ","wheatâ†’wheatâ†’peaâ†’peasâ†’corn "was17.43%,14.61%,6.96%;5.41%higher at20-40cmrespectively,15.63%,6.69%, indicating that rotations"alfalfaâ†’cornâ†’wheatâ†’cornâ†’alfalfa "treatment under the sun in the dry screened cultivation methods with the best aggregatestructure.by Wet sieve and dry areas,"alfalfaâ†’cornâ†’fallowâ†’cornâ†’alfalfa" under rotations inthe0-20cm soil layer,>0.25mm particle mass accumulation were higher,"five years alfalfa grass","cornâ†’cornâ†’wheatâ†’cornâ†’corn,"" cornâ†’wheatâ†’peasâ†’wheatâ†’corn,"33.85%,67.62%,60.89%,9.68%higher, respectively, in20-40cm soil,45.43%,10.38%, which Descriptionrotations "alfalfaâ†’fallowâ†’cornâ†’alfalfaâ†’corn" is treated under the sun in the wet filter out thebest way to grow aggregate structure. Irrigated areas, crop rotation model "cornâ†’alfalfaâ†’wheatâ†’alfalfaâ†’corn" in0-20cm soil layer,>0.25mm particle mass accumulation were higher than the"five years alfalfa grass","cornâ†’cornâ†’Cornâ†’Cornâ†’corn "," wheatâ†’wheatâ†’peaâ†’peasâ†’corn"1.94%,107.14%,90.09%; in20-40cm soil, respectively, higher than4.94%,98.82%,78.23%,indicating that rotations" alfalfaâ†’cornâ†’cornâ†’alfalfaâ†’wheat "is the sun in the wet processingunder cultivation methods filter out the best aggregate structure.3ã€Under the rotation and continuous cropping patterns with increasing soil depth,>0.25mmsoil aggregate quality in the dry and wet sieve sieve showed a decreasing trend,0~20cm soillayer, the fractal dimension is less than20~40cm soil layer. Aggregates and the proportion ofeach size fraction, the dry sieve under to>5mm of the highest content of soil aggregates,2~5mm aggregate content followed,0.25~0.5mm minimum aggregate content. Under wet sieve toa particle size of0.25-0.5mm highest content of soil aggregates, other particle aggregates contentdecreases depending on the particle size increases. From the quality point of view, the total massof rotations greater than0.25mm particle size greater than even make way.4ã€By rotation under different processing0-100cm soil profile soil moisture characteristicsfound in upland areas, grasslands and five years alfalfa rotation mode "alfalfaâ†’cornâ†’fallowâ†’cornâ†’alfalfa" than in soil range0-100cm soil moisture significantly different (P <0.05), in the0-40cm range, five years alfalfa grassland soil moisture19.12%higher than the rotation mode; inirrigation, soil moisture five years alfalfa grass higher than the rotation mode "alfalfaâ†’corn wheatâ†’cornâ†’alfalfa"within0-20,20-40,40-60,60-80range, five years alfalfa1.8%higher than therotation mode moisture,9%,13.9%,14.11%this shows that the more perennial alfalfa alfalfarotation mode has a significant role in the catchment soil surface, reflecting strong perennialalfalfa drought resistance.5ã€By studying the correlation between different soil aggregate processing rotation and soilmoisture content was found <0.25mm soil aggregate quality and moisture content showed anegative correlation relationship, the negative correlation between higher next four rotation mode,R2are up to0.6999,0.7318,0.6263and0.8157, cropping pattern negative correlation betweenlow0.476,0.467,0.4555and0.3962respectively.6ã€By0-100cm soil profile soil bulk density characteristics of different crop rotation undertreatment found in upland areas, compared to five years alfalfa grass and crop rotation mode"alfalfaâ†’cornâ†’fallowâ†’cornâ†’alfalfa", soil bulk density in the range of20-60cm significantdifferences (P <0.05), and within the scope of0-80cm five years alfalfa grass soil bulk density washigher than in the same layer rotation mode, in irrigated areas, in0-100cm five years alfalfa soilbulk density within the range is higher than the rotation mode with layers "alfalfaâ†’cornâ†’wheatâ†’alfalfaâ†’corn," and two planting patterns0-40cm range of content weight values significantdifferences (P <0.05).7ã€The research shows that treatment within the next rotation range0-100cm soil bulk densityand soil physical and chemical soil factor correlations found in soil bulk density and soil water content, soil organic matter, the fractal dimension of soil aggregates, organic carbon, total nitrogen,porosity showing highly significant correlation (p<0.01). Soil bulk density was positivelycorrelated with the fractal dimension was, and soil moisture, soil organic matter, organic carbon,total nitrogen, a negative correlation between porosity.8ã€ By rotation of different treatment under the soil profile0-100cm quantitativecharacteristics of soil bacteria found in upland areas, five years alfalfa grass rotations compared tothe number of bacteria,"alfalfaâ†’fallowâ†’cornâ†’alfalfaâ†’corn" in the range of10-100cmsignificant differences (P <0.05), and the next rotation of bacteria in the soil0-100cm mode rangeis higher than the total number of five years alfalfa grass14.1percent. Farming methods "cornâ†’cornâ†’wheatâ†’cornâ†’corn" and "wheatâ†’cornâ†’peasâ†’wheatâ†’corn," compared to the number ofbacteria "legumes grassy" mode up "grassy-grassy" mode15.6%in the number of bacteria under10.98%,17.06%,23.32%,52.8%,28.73%,34.2%,12.82%,14.33%,22.59%, and the number ofbacteria in under two tillage10-50cm soil differences significantly (P <0.05). In irrigated areas,crop rotation"alfalfaâ†’cornâ†’wheatâ†’alfalfaâ†’corn" in the range of0-50cm soil layers, thenumber of bacteria were higher than five years alfalfa grass, and the number of bacteria in therange10-100cm significant difference (P <0.05); rotation mode "wheat peaâ†’peaâ†’wheatâ†’corn"the number of bacteria above the "cornâ†’cornâ†’cornâ†’cornâ†’corn " even as the value, and bothvalues were significantly different (P <0.05). All this indicating that the grassy legume rotationshelp to improve the number of bacteria.9ã€By rotation of different treatment under the soil profile soil fungi0-100cm features foundin upland areas, five years alfalfa grass rotations compared to the number of fungi "alfalfaâ†’fallowâ†’cornâ†’alfalfaâ†’corn" in the range of0-40cm significant differences (P <0.05), and the numberof fungi rotation mode is smaller than five years alfalfa grass23.6%;"wheatâ†’cornâ†’peasâ†’wheatâ†’corn" fungi under rotations within the range of the mean less than0-100cm "cornâ†’cornâ†’cornâ†’wheatâ†’corn "approach10.03%, and within the range of0-40cm soil fungi differencesbetween the two farming methods significantly lower (P <0.05). In irrigated areas, crop rotationmodel "cornâ†’alfalfaâ†’wheatâ†’alfalfaâ†’corn" Compared to five years alfalfa grass cansignificantly reduce the number of fungi, and within the scope of0-100cm soil, fungi weresignificantly different (P <0.05). Within the range of0-70cm soil "cornâ†’cornâ†’cornâ†’cornâ†’cornâ†’" even as the "wheatâ†’wheatâ†’peaâ†’peasâ†’corn" rotation soil fungi significantly different (P<0.05), and the range of0-40cm rotations even make way less than the number of fungi. Inirrigated areas compared to "wheatâ†’wheatâ†’peaâ†’peasâ†’corn" rotations other farming methods,the number of soil fungi reduce the sharpest, All this indicating leguminous plants and grass croprotation can effectively reduce the number of fungi10ã€By rotation under different processing0-100cm soil profile characteristics of soilactinomycetes found in upland areas, put the number of five years alfalfa grassland soilactinomycetes in10-20,20-30,30-40cm respectively, compared with rotation mode "alfalfaâ†’cornâ†’fallowâ†’cornâ†’alfalfa," the number of low19.6%,25.6%,26.7%, and in the0-40cm rangeactinomycetes were significantly different (P <0.05); in the range of0-40cm soil, farming methods"wheatâ†’cornâ†’peasâ†’wheatâ†’corn" actinomycetes greater than farming methods "cornâ†’cornâ†’wheatâ†’cornâ†’corn", and in this context both the number of significant differences (P <0.05).inirrigated areas, crop rotation model "cornâ†’alfalfaâ†’wheatâ†’alfalfaâ†’corn" than five years alfalfagrass is more conducive to the accumulation of actinomycetes, the number of actinomycetesrotation mode than the mean age of five alfalfa grass higher than the average27.95%, the soil in the soil within the range of0-50cm two modes actinomycetes were significantly different (P<0.05); in the soil range20-100cm rotation mode "wheatâ†’wheatâ†’peaâ†’peaâ†’corn"actinomycetes even higher than the number of bacteria as model "cornâ†’cornâ†’cornâ†’cornâ†’corn", and the number of actinomycetes bacteria within10-80cm range of differences in the twomodels was significantly (P <0.05). All this indicating that that the grassy legume rotations thathelp to improve the actinomycetes.11ã€By rotation under different processing0-100cm urease activity in soil profile featuresfound in upland areas, within the range of20-90cm soil, crop rotation mode "alfalfaâ†’cornâ†’fallowâ†’cornâ†’alfalfa" urease activity were higher than fifth instar alfalfa grass, in the range of0-30cm and40-70cm soil urease significant difference between the two (P <0.05); in rotationmode "wheatâ†’cornâ†’peasâ†’wheatâ†’corn",0-10,10-20,20-30cm soil urease activity were higher"cornâ†’cornâ†’wheatâ†’cornâ†’corn" in the same layer of soil88%,126%,140%, and within therange of530-80cm layer of soil urease activity was not significant (P>0.05).In irrigated areas,0-80cm soil rotation mode "alfalfaâ†’cornâ†’wheatâ†’alfalfaâ†’corn" urease activity was higher thanfive years alfalfa grass with soil layer in the range0-100cm urease activity was higher than themean rotation mode five yeras alfalfa grass9.3%; range in10-40cm soil, crop rotation patterns,"wheatâ†’wheatâ†’peaâ†’peaâ†’corn" and even the mode of "cornâ†’cornâ†’cornâ†’cornâ†’corn "urease activity were significantly different (P <0.05), in the range of four0-40cm soil ureaseactivity rotation values were17.4%higher than the value of continuous cropping,52.7%,98.6%,45.7%.All this indicating that the grassy legume crop rotation in favor of urease activity increases.12ã€By rotation under different processing0-100cm soil profile soil catalase activitycharacteristics found in upland areas, within the range of0-90cm soil layer, five years alfalfa grasscatalase activity and "alfalfaâ†’cornâ†’fallowâ†’cornâ†’alfalfa "Soil difference rotation mode wassignificantly (P <0.05), and the activity of the mean rotation mode than five years alfalfa grasshigh16.7%; in rotation mode" wheatâ†’cornâ†’wheatâ†’peasâ†’corn ", the0-80cm soil within thescope of catalase activity were higher than tillage "cornâ†’cornâ†’wheatâ†’cornâ†’corn", and bothwere significantly different activity (P <0.05). In irrigated areas, within the range of0-80cm soilrotation mode "alfalfaâ†’cornâ†’wheatâ†’alfalfaâ†’corn" soil catalase activity were higher than fiveyears alfalfa grass with soil layer, and the difference was significant (P <0.05); continuouscropping pattern "cornâ†’cornâ†’cornâ†’cornâ†’corn" and rotation model "wheatâ†’wheatâ†’peaâ†’peasâ†’corn" compared to the same layer of soil, within a range of40-40cm layer of soil catalaseactivity were significantly different (P <0.05), and the value of the high rotation activity29.17%,respectively, compared even as the value,34.6%,34%,9.5%. All this indicating that the grassylegume crop rotation in favor of an increase in activity over the hydrogen peroxide.13ã€By studying the soil profile0-100cm invertase activity in soil characteristics underdifferent cropping processing found in upland areas, in the0-40cm range, rotation mode "alfalfaâ†’cornâ†’fallowâ†’cornâ†’alfalfa" soil invertase activity higher than five age alfalfa grass, in therange of0-50cm soil significant difference between the two (P <0.05), in the range of crop rotationpatterns within0-100cm invertase activity is higher than the mean age of five alfalfa grass25.9%;range within0-100cm "wheatâ†’cornâ†’peasâ†’wheatâ†’corn "invertase activity mean higher tillage"cornâ†’wheatâ†’cornâ†’cornâ†’corn"30%, and within the scope of both0-30cm soil invertaseactivity were significantly different (P <0.05). In irrigated areas, in the10-50cm range rotations"alfalfaâ†’cornâ†’wheatâ†’alfalfaâ†’corn" invertase activity higher than five years alfalfa grass, andwithin the range of0-40cm soil invertase activity in two significantly different (P <0.05); in the 0-80cm range of continuous cropping pattern " cornâ†’cornâ†’cornâ†’cornâ†’corn" and rotationmodel "wheatâ†’wheatâ†’peaâ†’peaâ†’corn" invertase significant difference (under P <0.05),rotation mode invertase activity even higher than the average of9.1%for the model. All thisindicating that the grassy legume crop rotation help to increase the invertase activity.14ã€In this research, two ecological agricultural areas of eight kinds of crop rotationtreatments, depending on the principal component analysis to obtain: P composite=0.38438P1+0.27953P2+0.19456P3+0.14435P4, mainly based on carbon and nitrogen factor as P1, soiltexture factor as P2ï¼Œ microbial factor as P3, soil moisture factor as P4ï¼Œthis four eight kinds offactor rotation treatments were evaluated and sorted from the advantages of planting pattern todisadvantage as follows:In irrigated areas:"Wheatâ†’Wheatâ†’peaâ†’peasâ†’corn","cornâ†’alfalfaâ†’wheatâ†’alfalfaâ†’corn""Five years alfalfa grass","cornâ†’cornâ†’cornâ†’cornâ†’corn."In the arid areas:"Wheatâ†’Cornâ†’peasâ†’cornâ†’wheat","alfalfaâ†’cornâ†’fallowâ†’cornâ†’alfalfa""Five years alfalfa grass"," cornâ†’cornâ†’cornâ†’wheatâ†’corn"Comprehensive sorting:(irrigated areas),"Wheat Wheatâ†’â†’â†’pea peasâ†’corn"(arid areas),"Wheatâ†’Cornâ†’peaâ†’wheatâ†’corn"(arid areas)"alfalfaâ†’cornâ†’fallowâ†’cornâ†’alfalfa "(irrigated areas)" alfalfaâ†’cornâ†’wheatâ†’alfalfaâ†’corn "(arid areas)," Five years alfalfagrass "(irrigation district)," Five years alfalfa grass "(arid areas)" cornâ†’cornâ†’wheatâ†’cornâ†’corn "(irrigated areas)" cornâ†’cornâ†’cornâ†’cornâ†’corn "...

Keywords/Search Tags:

rotation cropping, continuous cropping, carbon and nitrogen, microbial, moisture, aggregates, bulk density

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