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Lanzhou University (2021)

Effects of Regulated Deficit Irrigation on Production Performance and Water Utilization of Alfalfa Grassland in the Inland Arid Area of China

刘敏国

Titre : Effects of Regulated Deficit Irrigation on Production Performance and Water Utilization of Alfalfa Grassland in the Inland Arid Area of China

Auteur : 刘敏国

Grade : Doctoral Dissertation 2021

Université : Lanzhou University

Résumé partiel
Drought has become a worldwide problem seriously affecting crop yield and quality,which poses a major challenge to the stability and improvement of agricultural production.The Northwestern China has been facing drought for a long time,and optimizing irrigation strategy and adjusting crop structure are effective ways to improve water use efficiency and agricultural productivity.Compared with traditional grain crops,forage crops have stronger water adaptability,but the lack of water resources still limits forage production.Alfalfa(Medicago sativa L.)is one of the main high-quality forages,and it is of great significance to study the water management and water use characteristics of alfalfa grassland for alfalfa cultivation.Regulated deficit irrigation,aiming at the maximum water productivity,is an important way to balance water input and yield output in arid areas,while application of regulated deficit irrigation in forage still needs further study.A three-year trial(2017-2019)was conducted with two irrigation systems(flood irrigation,FI and subsurface drip irrigation,SDI)and seven irrigation treatments.Irrigation treatments included a full irrigation treatment for the whole growth period(Ifu)and six regulated deficit irrigation(RDI)treatments:slight water deficit for the whole growth period(Isl),moderate water deficit for the whole growth period(Imo),moderate water deficit at the branching and budding stage(Ibb),moderate water deficit at the regrowth stage(Ire),moderate water deficit at the branching stage(Ibr)and moderate water deficit at the budding stage(Ibu).Alfalfa yield and quality,plant height,leaf area index,radiation interception,soil water and evaporation were measured regularly.The effects of regulated deficit irrigation on production performance and growth dynamics of alfalfa under different irrigation systems were analyzed,and the changes of water utilization and movement under different irrigation treatments were simulated.The main results are as follows:1)The yield and quality of alfalfa were significantly affected by the regulated deficit irrigation under two irrigation systems.Irrigation treatment had no significant effect on the dry matter yield of alfalfa in the planting year,but had a significant effect on the yield in the next years.Compared with slight deficit during the whole growth period,moderate deficit irrigation at single growth stage did not lead to a significant decrease in yield.With regulated deficit irrigation treatment,there was a significant quadratic relationship between dry matter yield and plant height,and a significant linear relationship between dry matter yield and leaf area index.Regulated deficit irrigation treatment significantly affected the crude protein content and relative feeding value of alfalfa,which was regulated by alfalfa growth.With regulated deficit irrigation,there was a significant linear relationship between quality indexes and stem leaf ratio,but the R2(coefficient of determination)was low.There was a quadratic relationship between dry matter yield and crude protein content,neutral detergent fiber,acid detergent fiber and relative feeding value.With the increase of dry matter yield,the quality decreased first and then increased.

Mots clés : Inland arid area ;Alfalfa;Irrigation system ;Regulated deficit irrigation ;Production performance ;Water utilization ;

Présentation (CNKI)

Page publiée le 23 octobre 2021