Water-use efficiency as a means of modelling net assimilation in boreal forests

Trees ◽  
2000 ◽  
Vol 15 (2) ◽  
pp. 67-74 ◽  
Author(s):  
A.-S. Morén ◽  
A. Lindroth ◽  
A. Grelle
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Boreal Forests ◽  
Use Efficiency ◽  
Net Assimilation

Comparison of carbon dynamics and water use efficiency following fire and harvesting in Canadian boreal forests

2009 ◽  
Vol 149 (5) ◽  
pp. 783-794 ◽  
Author(s):  
M.S. Mkhabela ◽  
B.D. Amiro ◽  
A.G. Barr ◽  
T.A. Black ◽  
I. Hawthorne ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Boreal Forests ◽  
Carbon Dynamics ◽  
Use Efficiency

The effect of humidity on photosynthesis and water relations of white spruce seedlings during the early establishment phase

1996 ◽  
Vol 26 (6) ◽  
pp. 1015-1021 ◽  
Author(s):  
B.J. Marsden ◽  
V.J. Lieffers ◽  
J.J. Zwiazek
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Absolute Humidity ◽  
White Spruce ◽  
Silvicultural Treatments ◽  
Use Efficiency ◽  
Net Assimilation ◽  
Bare Root ◽  
Establishment Phase ◽  
Treatment Water

Newly transplanted, 3-year-old bare-root white spruce (Piceaglauca (Moench) Voss) seedlings were grown in three levels of absolute humidity difference (AHD), under water-stressed and well-watered conditions in growth chambers. Stomatal conductance to CO2 as well as net assimilation were more than twice as high in the low AHD treatment (6.8 μg H2O•cm−3) as in the high AHD treatment (21.0 μg H2O•cm−3). Transpiration rates were uniform among humidity treatments, but in the low AHD treatment water use efficiency was more than double that of the high AHD treatment. Water use efficiency was greatest in the low AHD conditions, in the water-stressed seedlings, and during the time immediately after planting. There were no differences in the number of new roots produced among humidity treatments, despite the different levels of photosynthesis. In the stress treatment, bud flush of seedlings in the high AHD treatment occurred 3 days later than in the low AHD treatment. A field study on the effects of varying aspen (Populustremuloides Michx.) canopies on humidity levels showed that AHD under partial and full canopies was lower than that of the clearcut. Results suggest that silvicultural treatments that promote higher humidity levels on planting sites should improve white spruce seedling photosynthesis immediately after planting.

Effect of CO2 enrichment on canopy photosynthesis, water use efficiency and early development of tomato and pepper hybrids

2011 ◽  
Vol 59 (3) ◽  
pp. 275-284 ◽  
Author(s):  
S. Bencze ◽  
I. Keresztényi ◽  
B. Varga ◽  
B. Kőszegi ◽  
K. Balla ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Co2 Enrichment ◽  
Total Biomass ◽  
Tomato Plants ◽  
Area Basis ◽  
Rate Of Photosynthesis ◽  
Biomass Components ◽  
Use Efficiency ◽  
Net Assimilation

The effect of CO2 enrichment on the rate of photosynthesis and the water use efficiency (WUE) of young pepper and tomato plants was studied in the phytotron. A CO2 level of 1000 ppm significantly increased the net assimilation rate in the upper foliage, while the increase was even more considerable in the lower layers of the canopy, with values of up to 100%. The 1500 ppm CO2 level caused a further substantial increase in CO2 assimilation and at least doubled (in tomato) or tripled (in pepper) the water use efficiency on a leaf area basis compared to the ambient values. Although the response in terms of photosynthesis and WUE was not variety-specific, there were differences between the pepper hybrids in the biomass components, exceeding 100% for the total biomass at the 1500 ppm CO2 level. In tomato, however, there was no significant variation in the total biomass of the three hybrids investigated in this early phase of development at either CO2 level.

scholarly journals Rising CO2 drives divergence in water use efficiency of evergreen and deciduous plants

2019 ◽  
Vol 5 (12) ◽  
pp. eaax7906 ◽  
Author(s):  
Wuu Kuang Soh ◽  
Charilaos Yiotis ◽  
Michelle Murray ◽  
Andrew Parnell ◽  
Ian J. Wright ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Boreal Forests ◽  
Leaf Mass Per Area ◽  
Mean Annual Temperature ◽  
Evergreen Species ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency ◽  
The Difference ◽  
The Impact

Intrinsic water use efficiency (iWUE), defined as the ratio of photosynthesis to stomatal conductance, is a key variable in plant physiology and ecology. Yet, how rising atmospheric CO2 concentration affects iWUE at broad species and ecosystem scales is poorly understood. In a field-based study of 244 woody angiosperm species across eight biomes over the past 25 years of increasing atmospheric CO2 (~45 ppm), we show that iWUE in evergreen species has increased more rapidly than in deciduous species. Specifically, the difference in iWUE gain between evergreen and deciduous taxa diverges along a mean annual temperature gradient from tropical to boreal forests and follows similar observed trends in leaf functional traits such as leaf mass per area. Synthesis of multiple lines of evidence supports our findings. This study provides timely insights into the impact of Anthropocene climate change on forest ecosystems and will aid the development of next-generation trait-based vegetation models.

Increasing intrinsic water-use efficiency over the past 160 years does not stimulate tree growth in southeastern China

2018 ◽  
Vol 76 (2) ◽  
pp. 115-130 ◽  
Author(s):  
G Guo ◽  
K Fang ◽  
J Li ◽  
HW Linderholm ◽  
D Li ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Tree Growth ◽  
Southeastern China ◽  
The Past ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency

A comparative appraisal of urea super granule application in raised bed and prilled urea application in conventional planting for transplanted boro rice (Oryza sativa)

2016 ◽  
Vol 6 (1) ◽  
pp. 822-832
Author(s):  
Halim Mahmud Bhuyan ◽  
Most. Razina Ferdousi ◽  
Mohammad Toufiq Iqbal ◽  
Ahmed Khairul Hasan
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
N Fertilizer ◽  
Deep Placement ◽  
Prilled Urea ◽  
Planting Methods ◽  
Weed Infestation ◽  
Use Efficiency ◽  
Raised Bed ◽  
Boro Rice

Utilization of urea super granule (USG) with raised bed cultivation system for transplanted boro (winter, irrigated) rice production is a major concern now days. A field experiment was conducted in the chuadanga district of Bangladesh to compare the two cultivation methods: deep placement of USG on raised bed with boro rice, and prilled urea (PU) broadcasting in conventional planting. Results showed that USG in raised bed planting increased grain yields of transplanted boro rice by up to 18.18% over PU in conventional planting. Deep placement of USG in raised bed planting increased the number of panicle m-2, number of grains panicle-1 and 1000-grains weight of boro rice than the PU in conventional planting. Better plant growth was observed by deep placement of USG in raised bed planting compared to PU in conventional planting. Sterility percentage and weed infestation were lower on USG in raised bed planting compared to the PU in conventional planting methods. Forty seven percent irrigation water and application time could be saved by USG in raised bed planting than PU in conventional planting. Deep placement of USG in bed saved N fertilizer consumption over conventional planting. Water use efficiency for grain and biomass production was higher with deep placement of USG in bed planting than the PU broadcasting in conventional planting methods. Similarly, agronomic efficiency of N fertilizer by USG in bed planting was significantly higher than the PU broadcasting in conventional planting. This study concluded that deep placement of USG in raised bed planting for transplanted boro rice is a new approach to achieve fertilizer and water use efficiency as well as higher yield and less water input compared to existing agronomic practices in Bangladesh.

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