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Northwest A&F University (2022)

Crop Water Use Efficiency Responses of Droughts and the Scale Transformation

于流洋

Titre : Crop Water Use Efficiency Responses of Droughts and the Scale Transformation

Auteur : 于流洋

Grade : Doctoral Dissertation 2022

Université : Northwest A&F University

Résumé partiel
Climate warming leads to frequent droughts,exacerbates water shortages andthreatens food security.Improving crop water use efficiency(WUE)under drought conditions is an important way to alleviate the contradiction of agricultural water use and food security.However,the results of WUE response to drought in the current global multi-point experiments have great heterogeneity due to regional,climate,crop and management factors.At the same time,traditional agricultural WUE usually takes evapotranspiration(ET)rather than the real water consumption,transpiration(T)as a reference.In this study,a global crop WUE database under drought conditions was established by the meta-analysis and mining method,and the heterogeneous sources of crop WUE response to drought were quantified from the perspectives of crop types,drought types,natural and management factors.Taking wheat as an example,the macro-control practices to realize simultaneous increase of yield and WUE under drought conditions were discussed.By quantifying the WUE relationship between leaves and ecosystems,a new method was developed to effectively partition ET and applied to C3 and C4croplands.The main research results are list as follows :(1)A global database of WUE for various crops under drought conditions was established to quantify the variation of WUE between drought and crop types.In total,80 published papers involving 837 observations satisfied our selection criteria for the meta-analysis.Compared with well-watered conditions,crop WUE improved by 1.5%and yield decreased by 25.4%.There is significant residual heterogeneity among different studies(p<0.001).The results revealed that 47%crops WUE increased,while 53%crop WUE decreased under drought stress.Fruit and vegetables,tuber crop,legume and oil crops(except for cereal)showed positive response to drought.C3 crop increased WUE by 4.5%,but C4 crop decreased WUE by 26.7%.Drought intensity,duration and occurrence time were all important factors leading to WUE variation.Short-term drought(<30 days)and drought at vegetative growth stage reduced WUE.The drought intensity responses differed among crop types.The results showed that cotton was recommended as one of the candidate crops for planting in arid areas,while legume crops were not recommended for planting in arid areas without irrigation.

Mots clés : water use efficiency ;drought;meta-analysis ;evapotranspiration partitioning ;scale transformation ;

Présentation (CNKI)

Page publiée le 18 octobre 2022