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Northwest A&F University (2018)

Effects of Rainwater-Harvesting Planting with Supplemental Irrigation and Planting Densities on the Growth and Photosynthetic Physiology of Maize in the Semi-Arid Regions

贾倩民;

Titre : Effects of Rainwater-Harvesting Planting with Supplemental Irrigation and Planting Densities on the Growth and Photosynthetic Physiology of Maize in the Semi-Arid Regions

Auteur : 贾倩民;

Grade : Doctoral Dissertation 2018

Université : Northwest A&F University

Résumé partiel
In the semi-arid regions of northwest China,the rainwater-harvesting planting system is being gradually implemented in order to improve soil moisture status and water use efficiency.This study aimed to improve the efficiency of the rainwater-harvesting planting system by investigating the effects of three planting densities(L:52,500 plants ha-1 ;M:75,000 plants ha-1 ;H:97,500 plants ha-1)and four kinds of supplemental irrigation modes(NI:no irrigation ;IV:irrigation at the 11-leaf stage ;IS:irrigation at the silking stage ;and IVS:irrigation at the11-leaf and silking stages)in a semi-arid area(Pengyang County,Ningxia).Through field experiments in two consecutive years(2015-2016),the effects of different supplementary irrigation methods and planting density on farmland soil moisture,water consumption characteristics,maize growth,photosynthetic physiology characteristics,grain yield,and water use efficiency were analysed.The main results are described here in.1.Effects of rainwater-harvesting planting with supplemental irrigation and planting densities on farmland soil moisture and water consumption characteristics(1)The rainwater-harvesting planting with supplemental irrigation led to increased soil water content in the 0-200 cm soil layer after maize silking,especially at the filling stage.At the filling stage,the two-year average soil water content of IV,IS,and IVS treatments increased 7.2%,9.4%,and 13.6%respectively,compared with NI.The effect of planting density on soil water content was small before the 11-leaf stage of maize,while at the silking,filling and maturity stages,soil water content decreased significantly with increasing planting density.The rainwater-harvesting planting with irrigation and planting density mainly affected soil water storage in 0-60 and 60-120 cm soil layers but had little effect in the120-200 cm soil layers.(2)At growth stages before the 11-leaf stage of maize,evapotranspiration and water consumption rate increased with increasing density,and the planting density had less effect with more precipitation.After maize silking,the evapotranspiration and water consumption rate decreased with increasing planting density,especially at the silking to filling stage.At silking to filling stage,average evapotranspiration in both years under medium and high densities was reduced by 9.8%and 20.3%respectively,compared with low density.Supplemental irrigation at the 11-leaf stage mainly increased evapotranspiration and water consumption rate during the 11-leaf to silking stage,whereas irrigation at the silking stage significantly increased evapotranspiration and water consumption rate during the silking to filling stage.From the 11-leaf to silking stage of maize,the two-year average evapotranspiration of IV and IVS treatments increased by 12.3%and 13.5%,compared with NI.From the silking to filling stage,average evapotranspiration increased by 37.6%and54.3%in IS and IVS,respectively,compared to NI.2.Effects of rainwater-harvesting planting with supplemental irrigation and planting densities on maize growth and lodging resistance(1)In 2015 and 2016,supplemental irrigation at the 11-leaf stage increased the root length density and root surface area density in the 0-20 cm soil layer at the silking stage,which was conducive to root growth in the surface soil.However,no irrigation at the 11-leaf stage promoted the extension of the root system to the deep soil.The rainwater-harvesting planting with irrigation can delay the root decay of maize at later growth stages.At the dough stage,compared with NI,the two-year average root length density of 0-100 cm soil layers increased by 28.7%,48.8%,and 55.2%,respectively,and the root surface area density increased by 40.4%,64.9%,and 80.5%,respectively.Compared with no irrigation,supplemental irrigation also significantly increased the leaf area per plant,aboveground dry matter,root weight per plant,and root/shoot ratio at the dough stage,and the increase was higher in IS than in IV.Although the irrigation volume of IVS was twice that of IS,it did not significantly increase the leaf area per plant and aboveground dry matter,but reduced the root/shoot ratio,and increased the plant height and centre of gravity.IVS increased the risk of maize lodging.(2)At the silking and dough stages,the average root length density and root surface area density of the 0-100 cm soil layer under medium and high densities significantly increased compared with low density.However,the root weight per plant and stem diameter under high density was significantly reduced compared with low density,the ear height and ear height coefficient significantly increased,and the root/shoot ratio was significantly reduced relative to the medium density,which increased the maize lodging rate under high density.Under the medium and high densities,the two-year average root lodging rates were4.1 and 10.1 times higher than that under the low density,respectively,and the stem lodging rates were 6.8 and 36.3 times higher,respectively.3.Effect of rainwater-harvesting planting with supplemental irrigation and planting densities on maize leaf and photosynthetic physiology characteristics

Mots clés : Rainwater-harvesting planting; Planting density; Supplemental irrigation; Photosynthetic physiology; Water use efficiency;

Présentation (CNKI)

Page publiée le 5 avril 2019