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Gansu Agricultural University (2007)

A Study on the Change of Soil Moisture and Efficiency of Yield in Spring Wheat in Different Tillage System in Hexi Oasis Irrigation Area

邓斌;

Titre : A Study on the Change of Soil Moisture and Efficiency of Yield in Spring Wheat in Different Tillage System in Hexi Oasis Irrigation Area

Auteur : 邓斌;

Grade : Master’s Theses 2007

Université : Gansu Agricultural University

Résumé
In this paper, SIRMOD model was used to guide the irrigation of conventional tillage(CONV), fresh raised-bed(FRB), permanent raised-bed(PRB) and zero tillage(ZT) in Hexi Oasis Irrigation Area. Study dynamic water content by Enviroscan. Compare the change of water content in the same layers of four treatments. Soil moisture in the head, middle and end of field after irrigation was measured to analyze irrigation homogeneity, water use efficiency and the influences of yield in different treatment. The result show as following:According to Enviroscan data, during the period from emergence to jointing if soil water content in 0~40cm was 109.34mm plant need irrigated. From jointing to filling when soil water content in 0~60cm was 143.81mm plant need irrigated. If soil water content in 0~80 was 190.52mm plant need irrigated from filling to ripe. The irrigation water volume respectively was 56mm、84mm、112mm. Used SIRMOD to simulate irrigation speed, and used Oddysee to measure irrigation water speed.The plan depth is shallow when the first irrigation, so required fast irrigation. The simulate irrigation speed of PRB is 3.83 m3/s, the simulate irrigation speed of CONV, FRB, ZT more than 42.0%,31.6%,35.0% compared with PRB, but such speeds can’t come true, so replaced with the max speed of channel. Therefore, water volume irrigation is much more than water volume of deficit. When the second irrigation just only PRB could touch simulate speed, after second irrigation all can touch.Soi1 moisture was measured after irrigates the latter 48 hours. Compare irrigation uniformity of different treatments according to soil moisture of different layers, the uniformity of furrow irrigation was better than that of flat irrigation. Irrigation uniformity of PRB was better than that of FRB. The infiltration depth was deeper than depth of the plan. From head to end of the field the infiltration depth became shallower and shallower in board irrigation.When the last wheat was harvested soil moisture became more and more with deep from 0~100cm, but there was not much difference among different treatments. When winter water irrigation comed the change of soil moisture was nearly close in different layers, but water content of PRB was increased quickly. So it didn’t need much more water when irrigation winter. When sowing the surface soil was wetter, which better for emergence. According to water deficit index, the irrigation time was different, so the soil moisture of PRB is higher than other treatment whatever soil moisture of twenty or forty depth when jointing and filling. Dedicate that PRB was more power to gather and keep water. After irrigation the soil moisture was decreasing with time passing, but water consume of PRB is the least, CONV is the most. That’s to say PRB had enough water for plant during the period of growing. PRB could keep water high long time, so need irrigation water not much. But CONV need much more.There was better soil water content in ridge, so wheat grew healthy in PRB tillage, stalks and ears were in longer green stages, LAI、LAD and dry matter of PRB are higher than others, but LAD dedicate greatly for wheat yield and r was 0.935**. Plant of PRB was short but strong, so it wasn′t easy to lodge. Weight of one thousand seeds was heavier comparing PRB with others.PRB were superior to others in wue. Compared to CONV, FRB, ZT, wue of PRB was increased 25.5%, 42%, 40.5%. The water consumption was least, which was 395.33mm. CONV had the most yields, which was 6081.57kg/hm2, but the water consumption also was the most. It was 565.58mm, which was significant compared with others. WUE of CONV was 10.75kg/mm.hm2. WUE and the water consumption of FRB、ZT were very similar. WUE was PRB>CONV>ZT>FRB. Yield was CONV> PRB > FRB > ZT

Mots clés : Water use efficiency; Uniformity of irrigation water; Simulate irrigation; Water-saving irrigation; Permanent raised-bed; Spring wheat;

Présentation (CNKI)

Page publiée le 13 novembre 2017