TY - JOUR

T1 - Drip irrigation improves spring wheat water productivity by reducing leaf area while increasing yield

AU - Yang, Danni

AU - Li, Sien

AU - Wu, Mousong

AU - Yang, Hanbo

AU - Zhang, Wenxin

AU - Chen, Ji

AU - Wang, Chunyu

AU - Huang, Siyu

AU - Zhang, Ruoqing

AU - Zhang, Yunxuan

N1 - CENPERM[2023]

PY - 2023

Y1 - 2023

N2 - To mitigate the climate change-induced water shortage and realize the sustainable development of agriculture, drip irrigation, a more efficient water-saving irrigation method, has been intensively implemented in most arid agricultural regions in the world. However, compared to traditional border irrigation, how drip irrigation affects the biophysical conditions in the cropland and how crops physiologically respond to changes in biophysical conditions in terms of water, heat and carbon exchange remain largely unknown. In view of the above situation, to reveal the mechanism of drip irrigation in improving spring wheat water productivity, paired field experi-ments based on drip irrigation and border irrigation were conducted to extensively monitor water and heat fluxes at a typical spring wheat field (Triticum aestivum L.) in Northwest China during 2017-2020. The results showed that drip irrigation improved yield by 10.3 % and crop water productivity (i.e., yield-to-evapotranspiration-ratio) by 15.6 %, but reduced LAI by 16.9 % in contrast with border irrigation. Under drip irrigation, the lateral development of spring wheat roots was promoted by higher soil temperature combined with frequent dry-wet alternation in the shallow soil layer (0-20 cm), which was the basis for efficient absorption of water and fer-tilizer, as well as efficient formation of photosynthate. Meanwhile, drip irrigation increased net radiation and decreased latent heat flux by inhibiting leaf growth, thereby increased sensible heat, causing a higher soil temperature (+1.10 degrees C) and canopy temperature (+1.11 degrees C). Further analysis proved that soil temperature was the key factor affecting yield formation. Based on the above conditions, the decrease in leaf distribution coef-ficient (-0.030) led to the decrease in evapotranspiration (-5.7 %) and the increase in ear distribution coeffi-cient (+0.029). Therefore, drip irrigation emphasized the role of soil moisture in the soil-plant-atmosphere continuum, enhanced crop activity by increasing field temperature, especially soil temperature, and finally improved yield and water productivity via carbon reallocation. The study revealed the mechanism of drip irri-gation for improving spring wheat yield, and would contribute to improving Earth system models in representing agricultural cropland ecosystems with drip irrigation and predicting the subsequent biophysical and biogeo-chemical feedbacks to climate change.

AB - To mitigate the climate change-induced water shortage and realize the sustainable development of agriculture, drip irrigation, a more efficient water-saving irrigation method, has been intensively implemented in most arid agricultural regions in the world. However, compared to traditional border irrigation, how drip irrigation affects the biophysical conditions in the cropland and how crops physiologically respond to changes in biophysical conditions in terms of water, heat and carbon exchange remain largely unknown. In view of the above situation, to reveal the mechanism of drip irrigation in improving spring wheat water productivity, paired field experi-ments based on drip irrigation and border irrigation were conducted to extensively monitor water and heat fluxes at a typical spring wheat field (Triticum aestivum L.) in Northwest China during 2017-2020. The results showed that drip irrigation improved yield by 10.3 % and crop water productivity (i.e., yield-to-evapotranspiration-ratio) by 15.6 %, but reduced LAI by 16.9 % in contrast with border irrigation. Under drip irrigation, the lateral development of spring wheat roots was promoted by higher soil temperature combined with frequent dry-wet alternation in the shallow soil layer (0-20 cm), which was the basis for efficient absorption of water and fer-tilizer, as well as efficient formation of photosynthate. Meanwhile, drip irrigation increased net radiation and decreased latent heat flux by inhibiting leaf growth, thereby increased sensible heat, causing a higher soil temperature (+1.10 degrees C) and canopy temperature (+1.11 degrees C). Further analysis proved that soil temperature was the key factor affecting yield formation. Based on the above conditions, the decrease in leaf distribution coef-ficient (-0.030) led to the decrease in evapotranspiration (-5.7 %) and the increase in ear distribution coeffi-cient (+0.029). Therefore, drip irrigation emphasized the role of soil moisture in the soil-plant-atmosphere continuum, enhanced crop activity by increasing field temperature, especially soil temperature, and finally improved yield and water productivity via carbon reallocation. The study revealed the mechanism of drip irri-gation for improving spring wheat yield, and would contribute to improving Earth system models in representing agricultural cropland ecosystems with drip irrigation and predicting the subsequent biophysical and biogeo-chemical feedbacks to climate change.

KW - Drip irrigation

KW - Energy balance

KW - Root water uptake

KW - Carbon allocation

KW - Water productivity

KW - CLIMATE-CHANGE IMPACTS

KW - USE EFFICIENCY

KW - WINTER-WHEAT

KW - DEFICIT IRRIGATION

KW - SOIL-MOISTURE

KW - GRAIN-YIELD

KW - ROOT-GROWTH

KW - AGRICULTURE

KW - MANAGEMENT

KW - RATIO

U2 - 10.1016/j.eja.2022.126710

DO - 10.1016/j.eja.2022.126710

M3 - Journal article

VL - 143

JO - European Journal of Agronomy

JF - European Journal of Agronomy

SN - 1161-0301

M1 - 126710

ER -