ISSN 1746-7659, England, UK Journal of Informaton and Computng Scence Vol. 11, No. 1, 2016, pp. 065-069 Analyss on Responses of Drought Stress on Sol Mosture and Maze Yeld Structure J Xaona, Chen Yunx, Yu Huayou Inner Mongola Nngcheng bureau of meteorology, Chna, Chfeng (Receved September21, 2015, accepted December 11, 2015) Abstract. Takng the drought stress and normal rrgaton felds where plant the same varetes of corn, an experment by drllng sol was conducted to study the effects of drought stress on characterstcs of the sol gravmetrc mosture content, water storage and water consumpton. The result showed that the effect of drought stress enhanced sgnfcantly after the tasselng stage, the sol mosture was markedly lower than that n the normal rrgaton feld. Durng the reproductve perod, the sol water storage of drought stress area was lower than the normal rrgaton feld, and the varaton of the sol water storage n shallow layer was bgger and smaller n the deep layer. Moreover, the drought stress nfluenced on the maze yeld serously, and the ndexes of maze yeld under the drought stress were sgnfcantly lower than the normal water treatment, the hundred gran weght decreased by 23.3%, and the gran yeld fell by 35.6%. Keywords: Drought stress; sol gravmetrc mosture content; Water storage; Water consumpton 1. Introducton Nngcheng county s a sem-ard monsoon clmate zone located n the south of Chfeng cty. Its topography s hgh n west and low n east, and solar-thermal resources s abundant, but lack of natural precptaton, and uneven dstrbuton of tme and space. Under the comprehensve nfluence of clmate, hydrology, geology, sol and topography factors, floods occur occasonally. There are two rvers that across the county from southwest to northeast and form the backbone of rrgaton and dranage, and ts rrgaton condton s better. The county s dvded nto four seasons obvously: Sprng warm up quckly, wnd s far larger and more, ranfall s less, clmate s dry, and sprng drought s frequent. In summer, the condton of hgh temperature, concentrated ranfall, smultaneous ran and heat s favorable for the growth of crops, but sometmes heavy ran causes floodng, and summer drought s frequent n recent years. Autumn s short and fast, temperature drops quckly, enough sunlght s benefcal to mature and harvest of crops, but the change probablty of ran s large n autumn, sometmes the contnuous wet weather occurs. The cold and dry wnter has less ranfall, and a cold wave nvades regularly. In concluson, the weather of county s complex and changeable, dsasters s varous, frequent and large-scale, these serously restrct the economc development, and drought s one of the most serous meteorologcal dsaster. Nngcheng county domnated by agrculture s an mportant commodty gran base n Inner Mongola. In 2015, the crop plantng area of county s 1.59 mllon unt area whch covers corn of 975000 unt area that accounts for about 60% of the cultvated area. Drought reduces the maze yeld by 25% ~ 30%, even lead to rejecton n parts of the regons, s the frst lmtng factor whch nfluence corn growth and yeld n ard and semard regons[1-2]. Rahmat (2007) ndcated that the yeld components and gran yeld were sgnfcantly affected by water supply. Sen (1952) recorded hghest yelds from rrgaton and recommended rrgaton at the tasselng and flowerng stages. For nsuffcent water n Nngcheng, the research on nfluence on the sol mosture change and corn yeld under the drought stress s helpful to fnd a more reasonable rrgaton mode to enhance producton on the bass of reducng approprately rrgaton water, whch mproves fully the effcency of usng water and provdes scentfcally decson-makng serve for feld management. 2. Materals and Methods 2.1 Materals The expermental data s from the observaton data n the whole growth perod of corn n 2015, the corn plantng area s located n a vllage of Nngcheng where annual average temperature s 7.3, annual ranfall s 444.5mm or so, Aprl-September ranfall s 404.1mm. The sol texture s slt, ph value s 8.58 and a weak alkalne, underground water level s about 8m, the volume weght of sol between 10cm and 50cm s 1.37 ~ Publshed by World Academc Press, World Academc Unon
66 J Xaona et.al : Analyss on Responses of Drought Stress on Sol Mosture and Maze Yeld Structure 1.48 g/cm3, feld mosture capacty s 21.1%~28.5%, wltng mosture s 2.6%~5.7%. In 2015, the average temperature s 8.2 hgher than the calendar year 0.9, the annual precptaton s 365.2mm fewer than the calendar year 17.8%. In 2015, maze varety s Jade 4 whch was sowed on Aprl 20 and mature on September 22, the growth perod s 155d. The expermental feld was dvded nto normal rrgaton(ni) and drought stress(ds) feld, whose acreage was 0.11hm2 and 0.1hm2 respectvely. The two felds adopted the horse-drawn plough, seedng rate was 60kg/hm2, sowng depth about 0.06m, spacng 0.5m, plantng dstance 0.37m, and fertlzed dammonum phosphate 375 kg/hm2 before sowng. NI rrgaton mode: the frst rrgaton was completed on June 25 wth 1046.2m3, the second on August 4 wth 900.0m3, and the last on August 21 wth 200.0m3. DS rrgaton mode s wthout rrgaton n the whole growth perod. There are 55 ranfall n the whole growth perod wth 263.5mm. 2.2 Methods Durng the perod of gettng the expermental data, we drlled the sol of two felds to get the weght of sol mosture content of the sample on the eghth day every ten-day, double repeated experment from 10cm to 50cm for a layer of per 10cm were conducted n each secton, each experment repeated 50cm. Sol gravmetrc mosture content was measured by dryng and weghng the sol sample, and calculated the total sol mosture storage( S ) and water consumpton( CW ) [5] further. S 10 w h Among them, w h s the volume weght of sol the sol gravmetrc mosture content and the sol thckness n the -th layer respectvely, 1,2, 5 s the sol layer. CW R I S And R s the precptaton, I s the rrgaton amount, and S s the change of the sol water storage. For the drought stress area, I 0. Moreover, due to the groundwater level s more than 8m, supplemental groundwater s neglected. 3. Results and Analyss As shown n fg. 1a), the sol mosture between 10cm and 20cm change relatvely severe under drought stress, the sol gravmetrc mosture content s lower than that under normal rrgaton 16.9% n the whole growth perod. Due to abundant ran, the change trend of sol mosture content of two felds s close from sowng to seedng stage. In late June, crop enter the jontng stage, and have a gradual ncrease n demand for water, the weght of sol mosture content curve has a downward trend. Especally n July, the weght of sol mosture content declne obvously under drought stress at the begnnng of drought, and begn to be lower than the normal water supply feld. After supplyng water on July 20, the sol mosture content of two felds appear a sgnfcant dfference. a) 10 ~ 20cm sol mosture content b) 30 ~ 50cm sol mosture content Fg.1. Sol gravmetrc mosture content under drought stress As you can see from fg. 1 b), the sol mosture content of 30~50cm change relatvely flat than 10~20cm under drought stress. Wth the growth of crops and duraton of drought stress, the shallow sol s not enough to supply mosture that crop requre for normal growth and development, and root ncrease gradually the use JIC emal for contrbuton: edtor@jc.org.uk
Journal of Informaton and Computng Scence, Vol. 11(2016) No. 1, pp 065-069 67 of deep water, resultng n a bgger declne of the sol mosture content n deep sol layer. The sol gravmetrc mosture content of two felds have a downward trend, and that under drought stress s decreased n large ampltude, especally after tasselng(july 18), the dfference of sol mosture content has an ncreasng gap. The sol gravmetrc mosture content n normal water supply feld between 30cm and 50cm s hgher than that n drought stress feld 33.5%. Drought stress, therefore, s to mprove the utlzaton of deep sol mosture. As showed by fg. 2, the varaton curves of the weght of sol gravmetrc mosture content at two felds are almost unanmous before the mplementaton of water control, and the longtudnal dstrbuton of the sol gravmetrc mosture content under drought stress appears an obvous separaton zone after the mplementaton of water control. It shows that wth the ncrease of demand for water, drought stress effect ncreases sgnfcantly after the mplementaton of water control, the sol mosture decreases gradually, and reaches ts mnmum level n the mature stage. The longtudnal range of the sol mosture content n normal water supply feld s 4.8% or so n the whole growth perod, smoother than that under drought stress for 14.0%. a) drought stress feld b) normal water supply feld Fg.2. Longtudnal dstrbuton of the weght of sol mosture content at each stage of development Fg. 3 shows that summer s a mnmum phase of water storage. Before the mplementaton of water control, the sol water storage n two felds whch has a mnor dfference shows a trend of gradual declne. After pourng the water at jontng stage, the sol water storage mantans hgh level n normal rrgaton feld and that under drought stress contnues to declne. As demand for water of corn growth ncreased, the sol water storage has certan declne, especally fall fast at corn tasselng stage, but the rrgaton quckly replenshes the sol mosture, and ensures the water condton of crop. Due to lack of rrgaton n drought stress feld, sol water storage s fallng, and sgnfcantly lower than that n normal rrgaton treatment. Fg. 3. Varaton of sol water storage and precptaton under drought stress As shown n fg. 4, the sol mosture varaton n shallow(10~20 cm) s bgger, and that n deep(30~50cm) s stable relatvely, t llustrate the crop growth and development manly consume the mosture n shallow sol. The sol mosture under drought stress s better at the seedng stage on account of the precptaton, but enterng the seedlng stage, sol mosture loss speed up, sol water storage declne sgnfcantly. At the jontng stage, abundant ran adds the shallow sol mosture effectvely. wth the ncreasng demand for water JIC emal for subscrpton: publshng@wau.org.uk
68 J Xaona et.al : Analyss on Responses of Drought Stress on Sol Mosture and Maze Yeld Structure of corn germ development, sol mosture runs off faster after the tasselng stage, and reaches the mnmum at the mature stage. Fg. 4. Longtudnal varaton of sol water storage under drought stress and normal water supply Showed n table 1, rrgaton s the man factor affectng the water consumpton at each growth stage of corn, water consumpton under drought stress s sgnfcantly hgher than normal water supply feld, and wth the development of growth perod, the water consumpton at each stage ncrease gradually, and reaches ts peak between the jontng and mlk stage, and starts drop after the mlk stage, t shows that the water requrement of crop growth s up to ts maxmum at the tasselng stage. Affected by precptaton, water s enough n the vegetatve growth stage under drought stress, ts water consumpton ntensty reaches a peak between the jontng and tasselng stage, but decreases sgnfcantly after the water control. Coupled wth the corn growth change from vegetatve to reproductve, the demand for water ncreases, so the water consumpton s hgh always, but s stll sgnfcantly lower than the normal rrgaton treatment because of water control. Table 1 Water consumpton of maze at each growth stage under drought stress (mm) Feld Normal rrgaton Drought stress sowngseedng seedngjontng jontng - tasselng tasselngmlk mlkmature 54.0 148.0 193.2 183.8 150.6 48.5 75.4 114.2 102.4 50.3 As shown n table 2, the maze yeld factors of two felds have sgnfcant dfference, the drought stress affects greatly the external form, yeld components and seed settng rate of corn. The heght, ear length, stem dameter, ear dameter under drought stress s less than normal rrgaton feld 15.8%, 15.0%, 26.5%, 17.7%. The stalk empty rate under drought stress reaches 18.1%, t shows that drought lead to fne and short plants and hgh empty stalk rate, resultng n reduced producton. In addton, by measurng the plant gran weght, hundred gran weght, stem weght of mature corns, drought stress feld shows 18.0%, 23.3%, 11.9% lower level respectvely than the normal water supply. Table 2 Varaton of maze yeld factors under drought stress Feld Normal rrgaton Drought stress heght(cm) ear length(cm) stem dameter(cm) ear dameter(cm) yeld(kg/hm 2 ) 298 29.4 3.4 6.2 16350.0 251 25 2.5 5.1 10525.0 4. Concluson 1) Sol water characterstcs: the varaton on weght of sol mosture content and vertcal dstrbuton of sol mosture shows drought stress effect s sgnfcant after the tasselng stage, sol mosture s lower sgnfcantly than the normal water supply feld. In addton, the low deep sol mosture n the drought stress feld shows the approprate water control can mprove the utlzaton of deep sol water. JIC emal for contrbuton: edtor@jc.org.uk
Journal of Informaton and Computng Scence, Vol. 11(2016) No. 1, pp 065-069 69 2) Sol water storage features: the sol water storage under drought stress s lower sgnfcantly than the normal rrgaton treatment, dfferng by 31.3%. From the vertcal dstrbuton, the varaton n the shallow layer s bgger than that n the deep. It shows that as long as the sutable shallow water, can satsfy the normal growth of crops. So n order to avod waste of water, we do not advocate broad rrgaton. It s best for sprnkler rrgaton or mcro-rrgaton gven certan condtons to optmze truly rrgaton. 3) Maze yeld factors: drought stress caused serous nfluence on corn yeld, resultng n ts producton ndexes of maze are sgnfcantly lower than normal water treatment, the hundred gran weght decrease by 23.3%, and producton by 35.6%. The peak of water consumpton at the jontng-mlk stage llustrate the demand for water of corn s the largest at the reproductve growth stage, so sezng the favorable opportunty for rrgaton s helpful to ncrease producton. 5. References [1] Campos H,etc., 2004. Improvng drought tolerance n maze: a vew from ndustry.feld Crops Res, 90: 19-34. [2] Bu L-D,etc., 2010. Responses of water stress to photosynthetc characterstcs of the maze leaf n the seedng Acta Ecol Sn, 30(5): 1184-1192. [3] Rahmat Ullah Khan, Abdur Rashd, Zulfqar Al and Muhammad Sohal Khan, 2007. Potental for Improvng Crop Yelds Through Better Water Management n Ranfed Regons. Pakstan Journal of Bologcal Scences, 10: 3023-3025. [4] Sen, S., 1952. Wheat and barley. Indan Farmng, 2: 8-11. [5] Ren L-W,etc., 2015. Effects of Drought Stress on Sol Mosture Dynamcs and Water Use Effcency n Corn.Chnese Agrcultural Scence Bulletn, 31(32):142-147 JIC emal for subscrpton: publshng@wau.org.uk