Advnce Journl of Food Science nd Technology 5(4): 474-481, 2013 ISSN: 2042-4868; e-issn: 2042-4876 Mxwell Scientific Orgniztion, 2013 Sumitted: Decemer 26, 2012 Accepted: Ferury 08, 2013 Pulished: April 15, 2013 Effects of Wter nd Nitrogen Utilized y Mens of Dripping on Growth of Root nd Cnopy nd Mtter Distriution in Spring Whet Jichun Wng, Cuilin Xu, Shn Go, Xiufeng Hn nd Dngwei Jü College of Plnt Science, Trim University, Alr, Xinjing 843300, P.R. Chin Astrct: In order to provide scientific strtegies of wter nd nitrogen regultion, the effects of different mount of wtering nd nitrogen rte y mens of drip irrigtion on root/shoot growth nd mtter distriution in whet were studied y using methods of soil drill smpling nd growth nlysis. The results indicted tht reducing drip irrigtion mounts nd nitrogen rte would cuse root weight decresed, shoot growth reduced nd yield dropped. In wter deficit irrigtion tretments (2400 m 3 /h), root length nd root surfce re incresed in flowering stge, ut rpid declined in milking stge, tht severely hmpered lef growth nd grin grouting. In milking stge, pproprite irrigtion mount (3600 m 3 /h) could mintin higher root weight, root length nd root dimeter tht promoted root/shoot coordinted growing. Nitrogen deficiency significntly reduced dry mtter ccumultion mount of stem in flowering stge nd root length nd root surfce re in milking stge, tht ws not conductive to the extension nd fulfilling of roots functions nd leded to cnopy severely premture ging. High nitrogen supply (ure 450 kg/h) would cuse vigorously growing of shoot nd declining of the growth qulity of spike nd decresing of the economic coefficient. Wter nd nitrogen hd significnt collortive compenstion effects on root/shoot growth nd yield trits nd the effects of regulting wter y nitrogen supply on root trits ws lrger thn on shoot, while regulting nitrogen y wter supply on shoot trits ws lrger thn on root, so in ctul production, it ws necessry to mintin high level of nitrogen supply in flowering stge ut pproprite level of wter supply in milking stge. The drip irrigtion mounts nd nitrogen rte nd yield components indictors in high-yielding drip irrigtion whet field were put forwrd y nlyzing qudrtic polynomil eqution uilt y the dt of wter nd nitrogen two fctors field experiments. Keywords: Compenstion effect, rtio of root to shoot, spring whet, surfce re index of root INTRODUCTION Drip irrigtion in whet field in Xinjing rid re ws wter-sving technique sed on the development of cotton under film drip irrigtion. This technique ws revolution to the irrigtion of close plnting crops, ecuse drip irrigtion could continuously send wter nd nutrient to crop root zone t ny time nd plce nd reduce soil wter lekge nd griculturl wter wste (Skggs et l., 2010), which optimized the fertilizer nd wter supply wy t root zone, improved the reltionship of whet root chrcteristics with fertilizer nd wter using efficiency nd chieved high yield nd wter sving effect (Lio et l., 2008; El-Rhmn, 2009). There were evident influence of wter nd nitrogen on close plnting crops root/shoot growth nd mtter distriution (Li nd Sho, 2000), pproprite mount of nitrogen fertilizer (ure 600 kg/h) could increse totl root weight nd root weight in deep soil lyer nd improve whet drought resistnce. Excessive nitrogen (ure 1500 kg/h) incresed the root weight of top lyer, ut hd little importnce to drought resistnce. Under severe wter stress, it would led to the incresed injury rte to root cell memrne, deteriorted wter reltions in root zone, decresed wter retention cpcity of root nd declined drought resistnce eventully. Under light wter stress, nitrogen ppliction incresed the whet root dry weight, length, vitlity nd ctive sorption re while under severe stress it seriously decresed root volume nd dry weight, which indicted tht nitrogen nutrient, would prtly improve whet drought resistnce to some extent (Zhng nd Zhng, 2001). Drought lso hd significnt influence on crop ssimilte ccumultion nd distriution (Xü et l., 2000). Under drought condition dry mtter weight of whet stem t lter milking stge output more, ut lef nd lef sheth output little. Moderte drought t erly milking-mturtion stge for spring whet could promote the milking progress nd speed nd increse economic yield (Zhng nd Kirhm, 1994). Deficiency y regultion wter t whet seedling stge would reduce nitrogen sorption cpcity, ut fter wter recovery t the medium growth Corresponding Author: Jichun Wng, College of Plnt Science, Trim University, Alr, Xinjing 843300, P.R. Chin, Tel.: 15810731213, 15109075316 474
Tle 1: Assignment of ure (kg/h) nd irrigtion (m 3 /h) volume in different periods of spring whet Tretment Three lef Jointing Booting Flowering Milking Fully milking Dough Irrigtion quot N 0 W l Ure 0 0 0 0 0 0 0 0 Wter 210.1 388.1 350.2 437.7 437.7 357.4 218.8 2400 N 0 W m Ure 0 0 0 0 0 0 0 0 Wter 315.1 582.1 525.2 656.5 656.5 536.2 328.3 3600 N 0 W h Ure 0 0 0 0 0 0 0 0 Wter 420.2 776.2 700.3 875.4 875.4 714.9 437.7 4800 N 225 W l Ure 45 90 0 67.5 22.5 0 0 225 Wter 210.1 388.1 350.2 437.7 437.7 357.4 218.8 2400 N 225 W m Ure 45 90 0 67.5 22.5 0 0 225 Wter 315.1 582.1 525.2 656.5 656.5 536.2 328.3 3600 N 225 W h Ure 45 90 0 67.5 22.5 0 0 225 Wter 420.2 776.2 700.3 875.4 875.4 714.9 437.7 4800 N 450 W l Ure 90 180 0 135 45 0 0 450 Wter 210.1 388.1 350.2 437.7 437.7 357.4 218.8 2400 N 450 W m Ure 90 180 0 135 45 0 0 450 Wter 315.1 582.1 525.2 656.5 656.5 536.2 328.3 3600 N 450 W h Ure 90 180 0 135 45 0 0 450 Wter 420.2 776.2 700.3 875.4 875.4 714.9 437.7 4800 stge, strong compenstion effect of nitrogen sorption ppered (Pndey et l., 2001). The ove studies were crried out in the conventionl irrigtion. Drip irrigtion, due to the chnges in supply wy nd field distriution of wter nd fertilizer, hd significnt difference on the distriution of wter nd nitrogen in field nd whet growth regulting effect with the conventionl one (Zhng nd Lü, 2011). In this reserch, the influence of wter coupled with nitrogen on root nd cnopy growth nd mtter distriution for spring whet y different wter nd nitrogen tretments ws studied under drip irrigtion in the field in order to provide scientific strtegies of wter nd nitrogen regultion for high yield, s well s scientific sis for spring whet irrigtion technique. MATERIALS AND METHODS Test conditions: This test ws conducted t the net room of the experimentl sttion in Trim University in 2011. The test point ws typicl temperte inlnd climte, with the verge nnul temperture 11.2 C, the verge nnul rinfll 45.7 mm, verge nnul evportion cpcity 1988.4 mm nd nnul verge reltive humidity elow 55%. The soil ws sndy lom, with soil ulk density of 0-40 cm ws 1.32 g/cm 3 ; field moisture cpcity ws 23.8% (weight cpcity). The underground wter level ws out 8.0 m. The content of soil orgnic mtter ws 1.025% nd totl nitrogen, lkli hydrolysle nitrogen, ville phosphorus nd ville potssium were 0.685, 49.27, 52 nd 214.1 mg/kg, respectively. Mterils nd design: Tll stlk vriety Xin chun 19 (presented y Shihezi University) ws chosen s tested mteril nd sowed on Mrch 8 th. Ech row ws plnted every 15 cm nd 18 rows were rrnged in ech plot, where one drip irrigtion elt ws lid etween 3 nd 4 line every 6 rows with ptterns of one tue for 6 line. The plnting density ws 5700000 strins/h. 475 The orthogonl experiment with two fctors nd three levels were designed in this study: 3 levels for nitrogen drip irrigtion: No nitrogen (N 0 ) Fertigtion of ure 225 kg/h (N 225 ) Fertigtion of ure 450 kg/h (N 450 ) Three levels for wter irrigtion: Low wter 2400 m 3 /h (W l ) Moderte wter 3600 m 3 /h (W m ) High wter 4800 m 3 /h (W h ) There were 9 tretments in this experiment with 3 replictes for ech tretment, dding up to 27 plots. The re of ech plot ws 13.5 m 2 (2.7 5 m). Rndom lock design ws used. The mount of drip irrigtion ws recorded y wter meter. PVC polyester plte ws used to prevent penetrtion etween plots (Tle 1). Ure of 150 kg/h nd dimmonium phosphte of 120 kg/h s se fertilizers were utilized efore sowing, 900-1500 g 2, 4D-utylte per h ws spryed efore jointing to get rid of weed. Wter nd nitrogen were utilized y drip irrigtion in stges ccording to the requirement lw of whet. Test methods: The growth process of spring whet ws oserved nd plnt height nd lef numer were recorded fter emergency. Representtive 5 plnts were chosen s smples t ech growth period in ech plot. After weighing the fresh orgns, they were put in 105 C ovens for 15 min, then 80 C for 48 h to constnt weight. At mture stge 3 representtive points for smples were chosen nd cut off plnts of 1 m 2 re in ech plot nd threshed for clculting yield nd then weigh dry weight. Soil drilling method for root nd imge processing method were used to study root system chrcteristics t whet flowering (My 18 th ) nd milking period (June 13 th ). The soil drill dimeter ws 4.8 cm, with smple room 15 cm high nd 271.7 cm 3 y volume. Two spots
locted t 7.5 nd 37.5 cm from drip irrigtion elt were selected to drill root smples nd t ech spot 3 drilling (drill intervl 3 cm) ws got side y side perpendiculr to plnt rows in the center of rows, which otined 6 drilling from 2 spots. Ech drilling soil ws lid respectively y 10 cm ech lyer nd 4 lyers were drilled in totl, then finlly the sme lyer of soil smple were mixed. After rinsed y running wter on the 200 sieve mesh, the root smples ws put crefully in glss plte y tweezers, then lck nd white TIF imges were otined y scnning in 300 dpi pixel nd root morphologicl chrcteristics such s root length nd verge dimeter et l were lso clculted y DT- SCAN2.04 imge nlysis softwre (Delt-T Devices Ltd.) (Wng et l., 2011), t lst the root of different lyers were put into the drying oven, where dried t 105 C for hlf n hour then to 65 C dried to constnt weight. Dt nlysis: Root length density (RLD, mm/cm 3 ) ws clculted y the formul L/ (Dπr 2 ) (mong the formul L ws root length, cm; D ws smpling soil depth, cm; r ws soil drill rdius, cm); Root surfce re (RS, cm 2 ) ws clculted y the formul πrl ( R ws root men dimeter, cm; Root Are Index (RAI) equled root surfce re per unit re/ re occupied with soil; rtio of root to shoot could e clculted y dry weight ove ground/dry root weight; Economic coefficient ws got y the rtio etween grin dry weight nd totl dry weight of root nd cnopy. Softwre DPS10.0 nd Duncn multiple comprison method were used in sttisticl nlysis. Microsoft Excel 2003 ws used for mpping. RESULTS AND ANALYSIS Influence on root growth index in different wter nd nitrogen tretments: According to Tle 2, t flowering stge no mtter how much nitrogen ws utilized, root dry weight in high wter tretment reched mximum 0.373-0.395 g/plnt strin, while in low wter tretment root length, root dimeter, root surfce re, root length density nd root surfce re index were ll the lrgest, which were 0.49-1.17, 0.41-0.45, 1.16-2.15, 0.62-1.42 nd 0.95-1.83 times higher thn those of in high wter tretment respectively. During the grin milking stge in moderte wter tretment root length, root surfce re, root length density, root surfce re index reched mximum nd root dry weight showed little difference in moderte wter nd high wter tretments, ut in low wter tretment root dry weight reched minimum which only ws 0.66-0.73 times of high wter tretment. Menwhile, no mtter how much wter ws irrigted t flowering stge, root dry weight nd root surfce re incresed, root length decresed, root dimeter nd root surfce re index chnged little long with nitrogen incresed, ut t milking stge root length, root dimeter, root length density nd root surfce re shrply reduced with nitrogen reduction. Ech index in Adv. J. Food. Sci. Technol., 5(4): 474-481, 2013 476 no nitrogen tretment ws 49-82%, 22.5-65.8%, 43.6-79.0% nd 9.3-39.3% tht of high nitrogen tretment. On the whole, lck of wter or nitrogen cused dry root weight to decrese. Deficiency of nitrogen would esily cuse root length, root dimeter nd root length density decresed. Wter shortge t flowering stge cused root length, root length density incresed, root dimeter grew thinner suffered y light drought nd thicker y severe drought. When wter shortge hppened t milking stge, root length nd root length density firstly incresed nd then decresed while the root dimeter decresed with wter reducing. In ddition, whether t flowering or milking stge, root dry weight in low wter-high nitrogen tretment or in high wter without nitrogen tretment ws higher thn in tretment of low wter without nitrogen, which indicted wter nd nitrogen hd collortive compenstion effect on the root (Li nd Sho, 2000). Root growth chrcteristic vlues in low wter-high nitrogen tretment (regulting wter y fertilizer) were higher thn those of in high wter-low nitrogen tretment (regulting fertilizer y wter) nd the phenomenon reflected tht compenstion effect of nitrogen on low wter inhiiting root growth ws higher thn the effect of wter on low nitrogen inhiition. Anlysis of wter nd nitrogen tretment on root growth index vrition (coefficient of vrition) showed tht (Tle 3), the coefficient of vrition CV% t flowering stge reched mximum y wter tretment. Nmely, t this stge the root growth index ws minly ffected y the influence of wter, mong which root surfce re nd the surfce re index, root length density nd dimeter were sensitive to wter. At this stge wter shortge hd significnt impct on root morphogenesis nd function; wheres, during milking stge root growth index vrition showed to e the mximum cused y nitrogen level chnge. Tht is to sy, t this stge the root trits were minly influenced y nitrogen supply levels. Lck of nitrogen would ccelerte the decline of whet root system nd eventully effect nutrient sorption nd utiliztion t lter stge. Influence on shoot growth index in different wter nd nitrogen tretments: Shortge of wter nd nitrogen could cuse whet oveground orgns growth reduction (Tle 4). Such s, t the flowering stge stems, leves nd spike dry weight in low wter tretment were only 0.69-0.88, 0.40-0.53 nd 0.78-0.79 of high wter tretment nd those index in no nitrogen tretment were only 0.70-0.89, 0.78-0.89 nd 0.77-0.96 of high nitrogen tretment. Growth of shoot orgn ws minly restricted y wter nd nitrogen, ut the chnges of spike weight vried from vegettive orgns under the condition of spike coordinting growth nd ssimilte prior distriution (Zhng et l., 2010). At flowering stge, with nitrogen incresed spike weight incresed, ut excessive nitrogen dripped (in high nitrogen tretment) would led to imlnce etween whet
Tle 2: Chnges of root growth index in different wter nd nitrogen tretments Tretment ----------------------------------- Root dry weight Root length Growing stge Nitrogen Wter (g) (mm) Flowering stge 477 Root length density (mm/cm 3 ) Root dimeter (mm) Root surfce re (mm 2 ) N 0 W l 0.353 8892.5e 0.739c f20637.1 6.336d W m 0.333 4985.1c 0.310 4849.3 3.552 W h 0.373cd 4096.8 0.509 6547.2c 2.919 N 225 W l 0.389cde 7543.2d 0.751c 17799.3e 5.375c W m 0.369c 4189.2 0.322 4238.1 2.985 W h 0.409e 3854.3 0.521 6309.6c 2.746 N 450 W l 0.375cd 7785.7d 0.747c 18278.3e 5.547c W m 0.355 4985.1c 0.318 4983.6 3.552 W h 0.395de 5203.6c 0.517 8456.2d 3.708 Milking stge N 0 W l 0.185 4188.3c 0.471de 6197.7d 2.984c W m 0.196c 5270.5d 0.443d 7333.7e 3.755e W h 0.190 2587.1 0.183 1486.2 1.843 N 225 W l 0.193c 4535.9c 0.386c 5506.4c 3.232d W m 0.209cde 6418.7e 0.558f 11250.5f 4.573f W h 0.208cd 4535.9c 0.497e 7089.0e 3.232d N 450 W l 0.202c 3710.8 0.302 3518.5 2.644 W m 0.223de 6394.2e 0.673g 13518.0g 4.556f W h 0.227e 5312.0d 0.812h 13552.6g 3.785e In ech growing stge, vlues followed y different letters in the sme column re significntly different t p<0.05 Tle 3: Coefficient of vrition (%) of root growth index in different wter nd nitrogen tretments Stge Fctor Root dry weight Root length Root dimeter Root length density Root surfce re Flowering stge Nitrogen 2.90 12.88 0.60 15.01 12.98 Wter 3.56 27.28 33.49 32.07 63.45 Milking stge Nitrogen 6.61 37.96 59.30 42.41 78.09 Wter 3.40 13.52 16.94 13.62 26.14 Tle 4: Chnges of dry weight of shoot orgn in different wter nd nitrogen tretments Tretment ------------------------------------ Cnopy dry Stem dry Lef dry weight Spike dry weight Development stge Nitrogen Wter weight (g) weight (g) (g) (g) Totl (g) Flowering stge N 0 W l 1.364 0.681 0.184 0.499 1.716 W m 1.584c 0.794c 0.362ef 0.429 1.916 W h 1.804d 0.772c 0.397fg 0.634cd 2.177cde N 225 W l 1.565 0.724 0.140 0.702e 1.954c W m 1.816de 0.899d 0.317d 0.600c 2.185de W h 2.067e 0.940de 0.353e 0.774f 2.476fg N 450 W l 1.654c 0.767c 0.235c 0.651cde 2.029cd W m 1.935de 1.005e 0.413gh 0.517 2.290ef W h 2.216f 1.108f 0.448h 0.660de 2.611g Milking stge N 0 W l 1.386 0.387 0.228 0.771 1.571 W m 1.923c 0.468cd 0.362e 1.094 2.119c W h 2.084c 0.495cd 0.441g 1.148 2.275c N 225 W l 1.770 0.425 0.184 1.161 1.963 W m 2.307d 0.514de 0.317d 1.475c 2.516d W h 2.468de 0.550ef 0.397ef 1.522c 2.676de N 450 W l 1.876c 0.463c 0.279c 1.134 2.078c W m 2.413de 0.561ef 0.413g 1.440c 2.636de W h 2.574e 0.604f 0.492h 1.478c 2.801e In ech growing stge, vlues followed y different letters in the sme column re significntly different t p<0.05 vegettive growth nd reproductive growth, which tend to pper unsuccessful trnsformtion to reproductive growth, exuernt growth of stem nd lef, spike orgn growth restricted nd spike weight dropped. While t milking stge, spike weight presented low-high-low tendency with the increse of nitrogen. In other words, too high or too low nitrogen didn t conduce to grin milking. Whether t flowering stge or grin milking stge, spike weight ll decresed in shortge of wter tretment, especilly severe t milking stge. In ddition, shoot growth mount in low wter-high nitrogen tretment nd high wter without nitrogen tretment ws higher thn tht of low wter without nitrogen tretment, which indicted wter increse slowed down the growth inhiition y nutrient stress. Similrly, nutrients increse could lso slow down wter stress inhiition (Sdrs, 2004), ut the phenomenon tht shoot trit vlues in high wter-low nitrogen were higher thn those of high nitrogen-low wter, reflected the former (regulting fertilizer y wter) effect ws igger in the idirectionl compenstion. From the extent of influence on cnopy orgn growth in wter nd nitrogen single fctor experiment (Tle 5), low wter nd less nitrogen gretly ffected the growth of stem nd lef t flowering stge nd ffected lef nd spike weight gretly t milking period, mong which the vrition of lef dry weight ws the iggest in wter tretment t flowering stge nd in nitrogen tretment t milking stge, indicting t
Tle 5: Coefficient of vrition (%) of dry weight of shoot orgn in different wter nd nitrogen tretments Stge Fctor Cnopy dry weight Stem dry weight Lef dry weight Spike dry weight Totl Flowering stge Nitrogen 6.98 13.45 10.21 6.08 6.16 Wter 9.59 9.85 25.76 8.70 8.25 Milking stge Nitrogen 7.29 8.61 22.12 9.39 7.21 Wter 11.18 6.86 8.45 9.70 10.52 Root-shoot rtio 0.3 0.25 0.2 0.15 0.1 0.05 0 c cd cd Flowering stge Milking stge cd cd Fig. 1: Effects of different wter nd nitrogen on the growth of root nd shoot of spring whet Verticl lines indicte the stndrd error; Squre columns with sme colors nd letters re not significntly different t p<0.05 N 0W l N 0W m N 0W h N 225W l N 225W m N 225W h N 450W l N 450W m N 450W h Tretment c d c Root surfce re index 8.00 6.00 4.00 2.00 0.00 e Flowering stge Milking stge de c cd d c c d Fig. 2: Effects of different wter nd nitrogen on the root surfce re index of spring whet Verticl lines indicte the stndrd error; Squre columns with sme colors nd letters re not significntly different t p<0.05 e N 0W l N 0W m N 0W h N 225W l N 225W m N 225W h N 450W l N 450W m N 450W h Tretment cd de flowering stge lef growth ws minly ffected y the influence of soil moisture while t milking stge minly y the influence of soil nitrogen level, which ws ecuse the flowering period ws the mximum period of whet group LAI (Xie et l., 2005) nd t this stge wter stress seriously ffected group LAI nd led to poor growth of shoot (poor growth nd dwrf plnt in ctul whet drought field); milking period ws the period for plnt to trnsfer from vegettive to reproductive development when ssimilte ws sent to spike from vegettive orgns nd lef function grdully wekened nd t this stge deficiency of nitrogen ccelerted lef senescence nd rpid drop of lef dry weight. Generlly speking, the effect of wter fctor on shoot orgn growth ws higher thn the mount of nitrogen for the two fctors. Influence on iomss distriution nd rtio of root to shoot: The rtio of root to shoot represents whet iomss distriution ffected y wter nd nitrogen. From Fig. 1, the rtio t milking stge ws significntly lower thn tht of flowering stge, which ws ecuse the flowering period ws nutrient demnd mximum period for plnt (Jck, 1988) nd high rtio of root to shoot ensured root to sor enough wter nd nutrient; The rtio of low wter no fertilizer tretment (N 0 W l ) ws significntly higher thn other tretments nd even 45% higher thn high wter nd high nitrogen tretment (N 450 W h ), which indicted wter nd nitrogen deficiency cused whet iomss to e trnsported to root nd to promote root growth, so s to enhnce the sorption ility of root to stisfy the moisture nd nutrient demnd, which ws one of ecologicl performnce for whet to dpt the drought rren environment (Wng et l., 2011). No mtter how much nitrogen ws dripped, the rtio of root to shoot y 478 high wter tretment decresed y 25.1-27.2% nd 22.3-46.0% tht of low wter tretment t flowering nd milking stge respectively; The rtio in high nitrogen tretment decresed y 14.1-15.9% nd 3.6-23.7% thn no nitrogen tretment t flowering nd milking stge without considering wter effects. These results showed during mtter distriution, loss of wter contriuted more for iomss to trnsport to root thn nitrogen loss. So, wter regultion ws very importnt. Besides, root growth rte ffected y wter nd nitrogen t milking period ws significntly higher tht of flowering stge, which lso explined the phenomenon tht the shoot speed of growing old ws fster thn root stressed y wter nd nitrogen. Effects of different wter nd nitrogen on the root surfce re index of spring whet: Corresponding with crop Lef Are Index (LAI), root surfce re index is root surfce re per unit re on ehlf of the root uptke function to certin extent (Zhng et l., 2005). In this experiment, different from LAI influenced y wter (Wng et l., 2011), wter stress promoted root re index increse t flowering stge (which in low wter incresed 28.4-56.6% thn in high wter tretment), while t milking period cused root surfce re index decrese (which in low wter reduced 26.6-49.1% thn in high wter tretment). Soil nitrogen nutrition could promote root re index increse nd dely the root function decline, especilly t milking stge with sufficient nitrogen supply the root surfce re ws significntly higher thn tht in low nitrogen tretment. Such s t this period root surfce re index in high nitrogen tretment ws 2.54-3.26 times of no nitrogen tretment nd root kept high sorption function resulting in growing green nd lte mturity, severely lodging t whet lter period (Fig. 2).
Tle 6: Growth nd yield trits of the different tretments Tretment --------------------------- Plnt height Spike length Numer of Grin weight Grins per 1000-grin Grin yield Economic Nitrogen Wter (cm) (cm) spikelet per spike (g) spike weight (g) (kg/hm 2 ) coefficient N 0 W l 81.3f 6.0e 13.7e 0.671e 17.3e 38.9e 3304.1e 0.355cd W m 100.3cd 6.9de 14.7de 0.866d 20.2d 42.9cd 4511.8d 0.348d W h 107.1c 7.3cd 15.6cd 0.930cd 20.3cd 45.2 5053.9c 0.354cd N 225 W l 89.3ef 6.9de 14.9cd 0.952cd 22.7 41.1d 5042.2c 0.397 W m 108.3c 7.8cd 15.9c 1.147 25.5 45.1 6249.9 0.385 W h 115.1 8.2 17.0 1.211 25.6 47.4 6792.0 0.386 N 450 W l 92.0de 7.1cde 15.4cd 0.879d 22.2c 39.4e 4549.0d 0.365c W m 111.1c 8.0c 16.5 1.074cd 25.0 43.3c 5756.7 0.348d W h 117.8 8.3 17.6 1.138 25.1 45.6 6298.8 0.344d In ech growing stge, vlues followed y different letters in the sme column re significntly different t p<0.05 Tle 7: Qudrtic polynomil eqution prmeters Eqution prmeters ---------------------------------------------------------------------------------------------------------------------------- Item c d e f R 2 Yield 6249.9000 874.9000-622.500-332.700-1115.6000 0 0.9974** Plnt height 108.3100 12.8980-5.382-6.130-2.6146 0 0.9871** Grin weight per spike 1.1469 0.1295-0.104-0.066-0.1766 0 0.9917** Economic coefficient 0.3855-0.0050 0 0.006-0.0370 0.0049 0.9927** Spike length 7.7795 0.6241-0.525-0.249-0.3477 0 0.9651** Numer of spikelet 15.9170 1.0508-0.916 0-0.3313-0.0917 0.9488** Grins per spike 25.5370 1.4531-2.422-1.378-2.9341 0 0.9612** 1000-grin weight 45.0950 3.1161-0.214-0.830-2.0063 0 0.9712** Influence on yield trit y wter nd nitrogen: According to the results of whet morphologicl nd yield trits in different wter nd nitrogen tretment listed in Tle 6, wter nd nitrogen supply significntly ffect the plnt height nd yield trits. At the sme level of nitrogen fertiliztion, the less wter ws supplied; the vlue of plnt height, spike length, spikelet numer, 1000-grin weight nd yield ws smller. Nitrogen ppliction esed the wek of plnt height nd yield, ut too much nitrogen supply, yield presented the declined tendency (the verge yield of N 0, N 225 nd N 450 ws 4289.9, 5863.63 nd 5543.9 kg/h); Regrdless of the mount of nitrogen, wter deficit oviously ffected grin weight increse. 1000- grin weight in low wter tretment ws only 86.5% of high wter tretment; nd the numer of grins per spike in different nitrogen conditions chnged gretly. These results indicted tht high nitrogen levels ws importnt ensure for incresing seed-setting rte nd grin numer per spike. Looking from vried economic coefficient, the vlue ws higher in suitle nitrogen nd wter deficit tretment. The might reson ws tht high nitrogen cused very strong vegettive growth nd low nitrogen ws not conducive to individul orgn growth. Both could not resonly regulte nutrient to trnsport to grin, so cusing economic coefficient decresed. The degree of wter deficiency inhiited the vegettive growth nd improved nutrient trnsfer rte to seed correspondingly, so the economic coefficient incresed in certin degree. By two polynomil stepwise regression nlysis on the orthogonl test of two fctors, the simultion eqution y = + X 1 + cx 2 + dx 1 2 + ex 2 2 + fx 1 X 2 ws estlished etween wter (X 1 ), nitrogen (X 2 ) fctors 479 nd root nd shoot growth trits nd yield constitute fctors (y) (Tle 7). Through clculting the extreme for the output eqution, the highest yield mounted to 6249.9 kg/h when irrigtion quntity ws 5177.6 m 3 /h nd fertigtion of ure 287 kg/h. When the mount of wter nd ure for highest yield ws content into estlishing inomil eqution, the dt ws otined s follows: height ws 108.3 cm, spike length 7.8 cm, spikelet numer ws 15.9, spike weight ws 1.15 g, grin numer per spike ws 25.5, 1000-grin weight ws 45.1 g nd economic coefficient ws 0.386. CONCLUSION Soil moisture nd nitrogen level were the most importnt fctors for crop growth. Approprite wter nd nitrogen supply could coordinte plnt vegettive growth nd reproductive growth; promote efficient utiliztion of wter nd nitrogen, improved yield nd qulity (Cmpell et l., 1977). In this experiment, reltionship of root nd shoot growth ws explored y designing different levels of wter nd nitrogen on spring whet nd the results showed s follows: Wter nd nitrogen deficiency cused root weight decresed. With wter decrese root length incresed t flowering stge nd firstly incresed nd then decresed t the milking period. But with nitrogen reduction, root length nd root dimeter were decresed, especilly t milking period. This indicted wter nd nitrogen plyed different roles on root growth. In shortge of wter tretment t flowering stge root system generted lrge numer of rnches nd expnded the root length
to estlish strong root system to meet nutrient needs for seed formtion, ut in lte growth the terminl root (thin root) ppered premture nd cused verge root dimeter incresed. During the milking period, high nitrogen level ws conducive to mintining high root length, slow root senility nd continul growth of shoot orgn. The influence of wter nd nitrogen on whet root production hd concern with growth period. At flowering stge root growth ws gretly ffected y wter while t milking stge gretly ffected y soil nitrogen supply. Wter shortge nd less nitrogen significntly inhiited shoot orgn growth nd cused insufficient growth. At flowering stge minly ffected the growth of stems nd leves nd t milking stge minly on mtter ccumultion of lef nd spike. Too much nitrogen supply cused ssimiltes distriution nd spike weight reduction. In the two fctors, wter hd higher effect on shoot orgn growth thn nitrogen. Wter nd nitrogen hd collortive compenstion effect (Tmki et l., 1999) on shoot growth of spring whet. The drip of nitrogen fertilizer could llevite growth inhiition y wter deficit. Similrly, wter could lso improve growth effect promoted y nitrogen. But the compenstion effect ws different to root nd shoot. The effect of regulting wter y nitrogen ws igger on root nd the effect of regulting nitrogen y wter ws igger on shoot, (wter relieving wekened effect of shoot growth suffered y nitrogen stress >nitrogen inducing inhiition effect of root growth y wter stress). So in the ctul production t the key period of root growth nd function which t flowering stge (Anderson, 1987) proper wter supply (high wter esily cused plnt fell to ground) should e mintined nd nitrogen supply should e pid much ttention to give full ply to the regulting wter y fertilizer effect. At lte period, when physiologicl function ws wekened (t middle nd lte milking stge), soil nutrient supply should e reduced to develop the regulting fertilizer y wter effect y pproprite wter supply. The rtio of root to shoot t flowering stge ws significntly higher thn tht of milking stge. Moderte deficiency of wter nd nitrogen contriuted to improve the rtio, ut the excessive deficiency or high wter nd nitrogen were not conducive for ssimilte trnsporttion to the root nd improvement of the rtio, especilly more prominent t lter stge of spring whet growth. Wter regultion on the rtio of root to shoot ws more ovious etween wter nd nitrogen fctor. At flowering stge wter stress promoted root re index incresed wheres t milking period Adv. J. Food. Sci. Technol., 5(4): 474-481, 2013 480 promoted this index decrese. Becuse t flowering period (of root morphology nd function mximum period) wter deficit stimulted root hydrotropism (Zhng et l., 2002), which performnce root growing thinner, intensified rnches nd extension to the deeper soil lyer nd eventully resulting in root surfce re increses. At lter milking stge, crops root grew old grdully. Due to persistent drought less wter cused plnt senescence, root surfce re index fell shrply nd the plnt premture senility. Nitrogen nutrients minly promoted root re index incresed nd the high nitrogen tretment during milking period still mintined higher root re index, cusing plnt growing green nd lte mturity. Lck of wter nd nitrogen ll cused the decline in output. Wter deficit hd gret effects minly on plnt height, grin weight, spike length nd nitrogen deficiency minly ffected the grin numer per spike nd economic coefficient. In ddition, the high nitrogen levels could cuse decline on the grin weight per spike nd economic coefficient. Through the growth nd yield simultion eqution set up under the influence of wter nd nitrogen y mthemticl nlysis method, wter nd nitrogen ppliction mount under high yield were otined y simultion, which ws 5177.6 m 3 /h nd 287 kg/h with the output of 6249.9 kg/h, plnt height of 108.3 cm, grin numer per spike 25.5, 1000-grin weight of, 45.1 g, economic coefficient of 0.386. ACKNOWLEDGMENT This work ws funded y the Ntionl Nturl Science Foundtion of Chin (30960188, 31260303), the Open Topic of The Key Lortory of Osis Ecogriculture of Xinjing Production nd Construction Group (200803) nd the Specil Fund Project for Scientific nd Technicl Personnel Services in Southern Xinjing (2010GG71). REFERENCES Anderson, E.L., 1987. Corn root growth nd distriution s influenced y tillge nd nitrogen fertiliztion. Agron. J., 79: 544-549. Cmpell, C.A., D.R. Cmeron, W. Nieholiehuk nd H.R. Dvidson, 1977. Effects of fertilize N nd soil moisture on growth, N content nd moisture use y spring whet. Cn. J. Soil Sci., 57: 259-320. El-Rhmn, A.G., 2009. Wter use efficiency of whet under drip irrigtion systems t Al-Mghr Are, North Sini, Egypt. Am-Eurs. J. Agric. Environ. Sci., 5(5): 664-670.
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