Root distribution and influencing factors of dry-sowing and wet-growing cotton plants under different water conditions.pdf

排灌机械工程学报Journal of Drainage and Irrigation Machinery Engineering2023年10 月第41卷第10 期Oct.2023Vol.41No.10Root distribution and influencing factorsof dry-sowing and wet-growingplants under different water conditionscottonDING Yu-,ZHANG Jianghui-,BAI Yungang*,LIU Hongbo”,ZHENG Ming,ZHAO Jinghua,XIAO Jun?2DINGYu(1.College of Hydraulic and Civil Engineering,Xinjiang Agricultural University,Urumqi,Xinjiang 830052,China;2.Xinjang Acade-my of Water Resources and Hydropower Sciences,Urumqi,Xinjiang 830049,China)Abstract:To study the effect of soil water and salt environment factors on the root growth of cotton un-der different moisture control,three different emergence water volumes(60,105,and 150 m/hm),two different frequencies(high frequency and low frequency)and one double film cover winter irriga-tion control treatment(CK:2 250 m/hm)were set up to analyze the spatial distribution patterns ofsoil water and salt environment and root density in dry sown and wet emerged cotton fields under diffe-rent moisture control conditions.The results show that the soil water content and water infiltration rangegradually become larger with the increase of seedling water quantity,and the larger the seedling waterquantity,the higher the soil water content.With the same seedling water quantity,the soil water con-tent of the high-frequency(HF)treatment becomes obviously larger.The soil conductivity of each treat-ment tends to decrease gradually with the increase of seedling water and drip frequency,among whichthe distribution of soil conductivity of S6 treatment is closest to that of CK.With the increase in soildepth,the soil conductivity tends to increase first and then decrease.Compared with the low-frequency(LF)treatment,the high-frequency treatment shows a significantly deeper soil salt accumulation layer.The root length density(RLD)of cotton gradually increases with the amount of seedling water and thefrequency of dripping.The soil layer of root distribution gradually deepens with the amount of seedlingwater in the vertical direction,and the RLD value in the horizontal direction is significantly greater inthe mulched area than that in the bare area between films.This research can serve as a solid scientificfoundation for the use of dry sowing and wet emergence techniques in cotton fields in southern Xinjiang.Key words:cotton;double film mulching;dry sowing and wet germination;moisture regulation;water and salt distribution;root distributionCLC Number:S275.6 Document Code:A Article No:1674-8530(2023)10-1073-08D0I:10.3969/j.issn.1674-8530.22.0268DING Yu,ZHANG Jianghui,BAI Yungang,et al.Root distribution and influencing factors of dry-sowing and wet-growing cotton plantsunder different water conditions J.Journal of drainage and irrigation machinery engineering(JDIME),2023,41(10):1073-1080.Water scarcity is a major factor limiting the sus-tainable development of agriculture in many arid andsemi-arid regions of the world.Especially in the sou-thern Xinjiang region,where sunshine is strong,Received date:2022-11-07;Accepted date:2023-01-25;Publishing time online:2023-02-27Online publishing:https:/ information:National Key Research and Development Plan(2021YFD1900805);Funded Project of Basic Scientific Research Business ofPublic Welfare Research Institutes in Autonomous Region(KY2022127)First author information:DING Yu(1998),male,master degree candidate(dy98206 ),researching in water-saving irigation tech-nology.Corresponding author information:BAI Yungang(1974),male,professor of engineering(xjbaiyg ),researching in agricultural wa-ter and soil engineering.1074排灌机械工程学报第41卷dryness and rainfall are scarce,and freshwaterresources are severely lacking.With the promotion ofthe three red lines system of water resources manage-ment,the actual rrigated area in Xinjiang is con-trolled by the state to about 5.3x10 hm,but with thecurrent limit of agricultural water saving on arableland,there will be a serious water shortage of 7.3billion cubic meters in 2030,and conventional waterfor winter and spring irrigation cannot be met now.Thekey to sustainable agricultural development in thesouthern Xinjiang region is to develop new water-savingirrigation technologies.The dry sowing and wet emer-gence of double film cover technology does not requirewinter and spring irrigation,and the small amount ofirrigation water greatly improves the utilization rate ofwater resources.The high seedling emergence rate en-sures the yield of cotton fields and achieves the goal ofsaving costs and increasing income 2.WANG et al.3 found that high-frequency irriga-tion had an average impact on soil salt washing,thewater consumption in the field was higher,the range ofsoil transportation was relatively smaller.In contrast,ZHANG et al.4 concluded that high-frequency rriga-tion was effective in reducing soil salt content withinthe wetter as well as increasing cotton yield comparedto low-frequency irrigation.A related study found thatthe growth of cotton roots under sub-membrane drip ir-rigation was concentrated directly below the drip line,and this localized growth was mainly due to the moreabundant soil surface moisture near the drip zone andthe significantly lower soil salinity near the drip zoneby continuous leaching5,At present,research on drysowing and wet germination double-membrane mulchingtechnology in South Xinjiang is not mature,and thesoil water and salt transport in drip-irrigated cottonfields under different water regulations are more com-plex,and there is lttle research related to the root sys-tem as an essential organ between soil and plant inte-raction.Therefore,the cotton variety Yuanmian No.11 was used as the test material to analyze thedifferent moisture treatments on soil water,heat,andsalt environmental factors,as well as root density dis-tribution patterns in dry sowing and wet germinationcotton fields under double film mulching conditions,toimprove the moisture management system suitable forcotton seedling emergence and growth,and to providesome guidance for local agricultural production.1Materials and methods1.1Overview of the test siteThe experiment was studied in the field from Aprilto October 2022 in a cotton field in the Aksu region ofXinjiang,China,in the town of Hailou,ShayaCounty,Northern Tarim Basin(8247E,4113N).The study area is 986 m above sea level,with an ave-rage annual precipitation of only 47.3 mm,a maximumpotential annual evaporation of about 2 000.7 mm,which is 42.3 times more evaporation than precipita-tion,and an average annual temperature of about10.7.T h e s o i l i n t h e c u l t i v a t i o n l a y e r i s m a i n l ysandy loam,with groundwater depth of about 3.8 m,soil pH value of about 7.8,N content of 174 mg/kg,and P content of 142.25 mg/kg.1.2Experimental designThe cotton variety Yuanmian No.11 was selectedas the test crop,and was sowed on April 10,2022,using a planting pattern of 1 film,3 tubes,and 6 rowswith spacings of 66,10 and 46 cm,respectively.Double film mulching of each treatment was conductedusing machinery,for which the width of the film was2.05 m,the plant spacing was 10 cm,and the plantingdensity was 252 000 plants/hm.The experiment was designed using a two-factor,three-level combination scheme with three seedlingwater(SW)levels（6 0,10 5 a n d 150 m/h m）a n dtwo drip frequencies（D F）（l o w f r e q u e n c y a n d h i g hfrequency)（T a b.1),a n d i r r i g a t i o n w a s c a r r i e d o u t a temergence period（EP）a n d s t r o n g s e e d l i n g p e r i o d(SSP),respectively.A total of 7 treatments were setup.The experiment was set up with three low-frequencytreatments（S1:6 0 +2 2 5 m/h m，S2:10 5+225 m/hm,and S3:150+225 m/hm)with dif-fe-rent emergence water volumes,three high-frequencytreatments(S4:60+45+225+150 m/hm,S5:105+45+225+150 m/hm,and S6:150+45+225+150m/hm?)with different emergence water volumes,andone local winter irrigation treatment(CK).The winter第10 期DGYueaRodistiutioandiuencingfacorsfdysowingand weowingoolansuderdife waerondition1075irrigation treatment was irrigated on 20 November 2021with an rrigation quota（IQ)o f 2 2 50 m/h m.Eachtreatment was replicated three times,resulting in atotal of 21 plots,A protection line of 1 m was estab-lished between each plot field,and the area of eachplot was 60 m.The fertilizer level and agronomicmeasures were based on local experience,and the irri-gation water was surface water with a drip rate of 2.1L/h and a drip spacing of 30 cm.Tab.1 2022 seedling irrigation trial programSW/(m3:Treatmentshm-2)S160S2105S3150S460S5105S61501.3Measurement items and methods1.3.1Soil moisture contentSoil moisture content was monitored using a PR2moisture measurement device(Precision TechnologyCo.,Ltd.,U.K.).The instrument was deployed onApril 12,2022,and the PR2 tubing was placed in thewide and narrow rows of the soil crop and between themembranes at depths of 10,20,30,40,60,80 and100 cm,respectively,to monitor soil moisture daily.1.3.2Soil salinity and conductivitySoil samples were taken using a 5 cm diametersoil auger in wide rows,narrow rows(below the driphead),and between the membranes in the same profileat depths of 0-10 cm,10-20 cm,20-30 cm and 30-40 cm,respectively.Soil salinity was characterizedusing a soil-to-water ratio of 1:5 for the electricalconductivity of the soil leachate(ECr:).When thedried soil samples were ground into powder form,18 gwere added to a triangular flask to configure a soil-to-water mass ratio of 1:5.The mixture was shaken for10 min using a shaker and after standing for 15 min,the conductivity of the supernatant was measured usinga conductivity meter typed F3.1.3.3Soil root systemThe spatial layout of the root sampling was desig-ned according to the cotton plant and drip irrigationbelt arrangement(Fig.1).Horizontally 60 cm was di-vided into three positions according to the field layout,0-20 cm for wide row(W),20-40 cm for narrow row(N),and 40-60 cm for inter-film(I).Root samplingwas carried out in selected plots of 20 cm60 cm soilarea and 40 cm soil depth(h),with each plot measu-ring 10 cmx10 cmx10 cm and a total of 48 soil cubescollected.The soil cubes were collected and placed inindividual self-sealing bags and sieved using a nylonDF/IQ/(m3.hm2)(times)EP26021052150460+454105+45225+1504150+45225+150Irigation time/SSP(month-day)225415,5-32254-15,53225415,53225+1504-15,4-205-3,5-11415,4205-3,5-114-15,4-205-3,5-11film sieve(1 mm).The new roots were then separatedfrom the soil particles,cleaned,air-dried,placed inroot trays,and flled with an appropriate amount of wa-ter to disperse the roots.The root system was scannedusing a flatbed image scanner,and the images wereanalyzed using WinRHIZO Pro root analysis software todetermine the total root length.-10-20-30-401zFig.1 Spatial layout of soil root sampling(unit:cm)1.4Data processingThe test data was counted and plotted using Mi-crosoft Excel 2020 and Origin 2016 software.Signifi-cant ANOVA and correlation analysis were performedon the test data using SPSS 25.0,and the dripirrigation tape arrangement and soil root distributionwere mapped using CAD 2016.21Results and analysis2.1Soil moisture spatial distribution characteris-ticsFig.2 showed the distribution of soil water content(SWC)at O-40 cm for each moisture treatment.In thefigure,s represents the distance to the midpoint of widerow.Since the wide rows are generally relatively wide,approximately 40 cm,in order to place the wide andDrip irrigation typeWN2010060 x1010101076排灌机械工程学报第41卷narrow rows between the film placed in a plane,themidpoint of the wide row was used as a reference.It canbe seen from Fig.2a that the drip frequency was thesame,and the soil moisture content gradually increasedwith the increase of the amount of seedling water,showing S1S2S3,S4S5WN.Compared with CK treatment,the soil ECi:s in the narrow row area of S6 treatmentdecreased by 5.9%.The ECr:5 in 0-40 cm soil layerof each treatment decreased significantly due to thelarge drip volume during the seedling stage,and thedifference gradually decreased.The soil ECi:s in thefilm mulching area was lower than that in the non-filmmulching area,and there was no significant difference26.1324.2522.3820.5020.5018.6322.3816.7524.2514.8818.6313.00s/cms/cm(vi)S6(vi)CK29.5029.5029.5020406002040600204060s/cms/cm(v)S5(vi)S635.0032.2529.5029.5026.75015.7524.0018.502125018.5015.7521.2513.00s/cm(vi)CK第10 期DING Yu,et al Ro distriution and ifluencing factors of dy-sowing and wetgroving coto lats under difen water conditons1077in the soil EC s value between the wide row and theTreatmentsS1S2S3S4S5S6CKNote:Different capital letters in the same column indicate significant differences(P0.05);Different lowercase letters in the same column indicate significant differences(PI.Tab.2 Average soil conductivity at seedling stage for each treatmentECep/(S cml)WN62511.1bA49312.6cA57335.1bB4689.0cB52310.6bC39810.9cC53511.5bC4303.1cC51212.2bC3875.6cD46215.5bD3378.5cE36717.5aE35814.5aFEC/(S-cm)EC/(S-cm200300400500-40(b)HFFig.3 Vertical distribution of soil conductivity at the seedling stage by treatmentECssp/(S cm-l)1W7256.9aA400 18.6bB673 9.5aB375 26.6bBC623 18.2aC34150.8bBC6359.3aC3828.1bBC61211.0aC342 10.4bBC562 14.7aD32820.0bC39021.1aE45967.7bAter,showing S1S2S3,S4S5S6.Compared withCK treatment,the ECi:s of 0-20 cm soil layer in highfrequency and large water S6 treatment was signifi-cantly lower.From the vertical distribution of salt in the0-40 cm soil layer during the seedling stage in Fig.3cand Fig.3d,it can be seen that the 0-40 cm soil layerof each treatment remained at a low level due to thelarge drip volume during the seedling stage,and wassignificantly lower than CK treatment,and there wasless variability between treatments.EC/(uS-cm)200 300_400500-10-15-20CK-25-30-35-40Lthe smaller the RLD value.The RLD of S2 and S5treatments were mainly distributed in the 0-25 cm soillayer（Fi g.4b,4e），a n d t h e h o r i z o n t a l d i s t r i b u t i o nrange of RLD increased significantly.The RLD of S3and S6 was mainly distributed in the 0-35 cm soillayer(Fig.4c,4f),and the horizontal RLD value anddistribution range were significantly larger than those ofother treatments.The RLD value of high frequencytreatment was significantly higher and the distributionrange was significantly larger than that of low frequencytreatment.Compared with CK treatment,the RLD dis-tribution of S6 treatment was the most similar,and theRLD values remained at a large level.N39952.2bB38622.6bBC32522.5bCD37128.3bBCD33626.7bBCD30929.5bD499 50.6bA600700200300_4005007-10-15-20-25-30-35-40(c)LF152527.3aB49023.5aBC44845.0aC5228.2aB462 10.4aBC42820.0aC56467.7aAEC/(uS-cm600700CK(d)HF1078排灌机械工程学报第41卷Compared to the CK treatment,the RLD valuesfor the low frequency treatment are significantly smallerand are mainly distributed between wide and narrow-100.400.28300.28-200.23-250.23-300.17-35-40150102030 405060(a)S1-100.49-150.41-2025-30-350.3936-40.0102030405060(d)S4Fig.4 Two-dimensional distribution of RLD in cotton seedlings by treatmentFrom the horizontal distributio