scholarly journals Leaf Phenology Variation within the Canopy and Its Relationship with the Transpiration of Populus tomentosa under Plantation Conditions

Forests ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 603
Author(s):  
Ye Wang ◽  
Guangde Li ◽  
Nan Di ◽  
Brent Clothier ◽  
Jie Duan ◽  
...  
Keyword(s):  
Crop Coefficient ◽  
Populus Tomentosa ◽  
Leaf Phenology ◽  
Leaf Number ◽  
Net Radiation ◽  
Ecological Strategy ◽  
The West ◽  
Tree Transpiration ◽  
Canopy Light Interception ◽  
Light Acquisition

To provide a theoretical basis for developing intensive cultivation practices for Populus tomentosa plantations, the leaf phenology variation within the canopy and its relationship with transpiration of well-watered P. tomentosa tree in a dense plantation were investigated. The variation in canopy light interception, indicated by the ratio between net radiation under (Rn-u) and above (Rn-a) canopy, with leaf development was also studied. During the growing season, the achievement of maximum leaf number tended to be later in higher parts of the canopy. In the lower and middle canopy, the leaf number maximized earlier in the east-facing side than in the west-facing side, but this difference disappeared in the upper canopy. The Rn-u/Rn-a was stable in May, but declined and then varied steadily until late August. Generally, in May, the crop coefficient (Kcb) of the tree reached its highest level and was not correlated with leaf area (LA) in all layers (p > 0.05). However, it increased linearly (p < 0.001) with LA in the layers above a canopy height of 3 m from June to late August, and most of its variation was explained by LA in the 5–7 m layer. After late August, Kcb decreased linearly with decreasing LA in all layers (p < 0.001). Consequently, a temporal ecological strategy seems to be adopted by P. tomentosa leaves in different layers and azimuthal sides for efficient light acquisition. The contribution of the different canopy layers to tree transpiration can vary, with the leaves in the upper and all layers mainly controlling transpiration in summer and in spring and autumn, respectively.

Rheum telianum (Polygonaceae), a new species from Southeastern Anatolia (Turkey)

Phytotaxa ◽  
2020 ◽  
Vol 477 (1) ◽  
pp. 81-89
Author(s):  
AHMET İLÇİM ◽  
FARUK KARAHAN
Keyword(s):  
New Species ◽  
Conservation Status ◽  
Leaf Number ◽  
Eastern Anatolia ◽  
The West ◽  
Basal Leaf ◽  
South Eastern ◽  
West Central ◽  
A New Species ◽  
Shape And Size

Rheum telianum is described as a new species from Kayatepe village (south-eastern Anatolia, Turkey). It is morphologically related to the west-central Asiatic R. ribes and R. rhizostachyum from which can be easily distinguish by its stem surface (slightly verrucose), leaf number, shape, and size (usually 1-basal leaf or rarely with a small one at base, reniform-rotate, 6.5–100 × 4.5–56 cm), achene shape and size (cordate-triangular, 8–15 × 8–16 mm). The distribution, notes on ecology, and conservation status of the new species are also provided.

scholarly journals Winter Wheat Water Productivity Evaluated by the Developed Remote Sensing Evapotranspiration Model in Hebei Plain, China

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Shengwei Zhang ◽  
Hongbin Zhao ◽  
Huimin Lei ◽  
Hongbo Shao ◽  
Tingxi Liu
Keyword(s):  
Winter Wheat ◽  
Agricultural Development ◽  
Water Productivity ◽  
Temporal Variations ◽  
Rapid Decline ◽  
Net Radiation ◽  
Agricultural Water ◽  
The West ◽  
Groundwater Levels ◽  
Hebei Plain

Agricultural water is the main reason for the rapid decline of the NCP groundwater levels. It is of vital importance for the NCP sustainable agricultural development to master the ETa and its CWP. In this paper, the EBEM model was developed according to the theory of energy balance. From 2001 to 2006, the winter wheat ETa and CWP were estimated, and the spatial and temporal variations and their influencing factors were studied in the Hebei Plain. The results indicate that the EBEM model performed well by applying MODIS data to estimate the daily net radiation and ETa. For the daytime net radiation, the relative error between the estimation and the measurement amounted to 8.2% and the SEE was 0.82 MJ m−2/day. The average ETa deviation between the estimates and the measures amounted to 0.86 mm daily, and the SEE was 1.2 mm. The spatial variations indicated that the major distribution of ETa ranged from 350 to 450 mm, which trended downward within the study area from west to east. In the study period, the winter wheat CWP was mainly distributed between 0.29 and 1.67 kg/m3. In space, the CWP was higher in the west than in the east.

scholarly journals Coordination of physiological and structural traits in Amazon forest trees

2012 ◽  
Vol 9 (2) ◽  
pp. 775-801 ◽  
Author(s):  
S. Patiño ◽  
N. M. Fyllas ◽  
T. R. Baker ◽  
R. Paiva ◽  
C. A. Quesada ◽  
...  
Keyword(s):  
Soil Fertility ◽  
Shade Tolerance ◽  
Individual Species ◽  
Maximum Height ◽  
Amazon Forest ◽  
Ecological Strategy ◽  
Construction Costs ◽  
Leaf Economic Spectrum ◽  
Structural Traits ◽  
Light Acquisition

Abstract. Many plant traits covary in a non-random manner reflecting interdependencies associated with "ecological strategy" dimensions. To understand how plants integrate their structural and physiological investments, data on leaf and leaflet size and the ratio of leaf area to sapwood area (ΦLS) obtained for 1020 individual trees (encompassing 661 species) located in 52 tropical forest plots across the Amazon Basin were incorporated into an analysis utilising existing data on species maximum height (Hmax), seed size, leaf mass per unit area (MA), foliar nutrients and δ13C, and branch xylem density (ρx). Utilising a common principal components approach allowing eigenvalues to vary between two soil fertility dependent species groups, five taxonomically controlled trait dimensions were identified. The first involves primarily cations, foliar carbon and MA and is associated with differences in foliar construction costs. The second relates to some components of the classic "leaf economic spectrum", but with increased individual leaf areas and a higher ΦLS newly identified components for tropical tree species. The third relates primarily to increasing Hmax and hence variations in light acquisition strategy involving greater MA, reductions in ΦLS and less negative δ13C. Although these first three dimensions were more important for species from high fertility sites the final two dimensions were more important for low fertility species and were associated with variations linked to reproductive and shade tolerance strategies. Environmental conditions influenced structural traits with ρx of individual species decreasing with increased soil fertility and higher temperatures. This soil fertility response appears to be synchronised with increases in foliar nutrient concentrations and reductions in foliar [C]. Leaf and leaflet area and ΦLS were less responsive to the environment than ρx. Thus, although genetically determined foliar traits such as those associated with leaf construction costs coordinate independently of structural characteristics such as maximum height, others such as the classical "leaf economic spectrum" covary with structural traits such as leaf size and ΦLS. Coordinated structural and physiological adaptions are also associated with light acquisition/shade tolerance strategies with several traits such as MA and [C] being significant components of more than one ecological strategy dimension. This is argued to be a consequence of a range of different potential underlying causes for any observed variation in such "ambiguous" traits. Environmental effects on structural and physiological characteristics are also coordinated but in a different way to the gamut of linkages associated with genotypic differences.

scholarly journals Transpiration and Water Use of an Irrigated Traditional Olive Grove with Sap-Flow Observations and the FAO56 Dual Crop Coefficient Approach

Water ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 2466
Author(s):  
Àngela Puig-Sirera ◽  
Giovanni Rallo ◽  
Paula Paredes ◽  
Teresa A. Paço ◽  
Mario Minacapilli ◽  
...  
Keyword(s):  
Water Balance ◽  
Water Use ◽  
Sap Flow ◽  
Crop Coefficient ◽  
Irrigation Scheduling ◽  
Soil Evaporation ◽  
Olive Grove ◽  
Crop Evapotranspiration ◽  
Tree Transpiration ◽  
Mean Square Errors

The SIMDualKc model was applied to evaluate the crop water use and the crop coefficient (Kc) of an irrigated olive grove (Olea europaea L.) located in Sicily, Italy, using experimental data collected from two crop seasons. The model applies the FAO56 dual Kc approach to compute the actual crop evapotranspiration (ETc act) and its components, i.e., the actual tree transpiration (Tc act), obtained through the basal crop coefficient (Kcb), and soil evaporation according to an evaporation coefficient (Ke). Model calibration was performed by minimizing the difference between the predicted Tc act and the observed daily tree transpiration measured with sap flow instrumentation (TSF field) acquired in 2009. The validation was performed using the independent data set of sap flow measurements from 2011. The calibrated Kcb was equal to 0.30 for the initial and non-growing season stages, 0.42 for the mid-season, and 0.37 for the end season. For both seasons, the goodness-of-fit indicators relative to comparing TSF field with the simulated Tc act resulted in root mean square errors (RMSE) lower than 0.27 mm d−1 and a slope of the linear regression close to 1.0 (0.94 ≤ b0 ≤ 1.00). The olive grove water balance simulated with SIMDualKc produced a ratio between soil evaporation (Es) and ETc act that averaged 39%. The ratio between actual (ETc act) and potential crop evapotranspiration (ETc) varied from 84% to about 99% in the mid-season, indicating that the values of ETc act are close to ETc, i.e., the adopted deficit irrigation led to limited water stress. The results confirm the suitability of the SIMDualKc model to apply the FAO56 dual Kc approach to tree crops, thus assessing the water use of olives and supporting the development of appropriate irrigation management tools that are usable by farmers. A different way to estimate Kcb is based on the approach suggested in 2009 by Allen and Pereira (A&P), which involves the measured fraction of ground covered (shaded) by the crop and the height of the trees. Its application to the studied grove produced the mid-season Kcb values ranging from 0.40–0.45 and end-season Kcb values ranging from 0.35–0.40. The comparison between the A&P-computed Tc act A&P and TSF field shows RMSE values ranging from 0.27 to 0.43 mm d−1, which demonstrates the adequacy of the latter approach for parameterizing water balance models and for irrigation scheduling decision making.

Enumeration and Identification of Asbestos Fibres in Water

1974 ◽  
Vol 32 ◽  
pp. 526-527 ◽  
Author(s):  
O. Mudroch ◽  
J. R. Kramer
Keyword(s):  
Water Supply ◽  
Water Samples ◽  
Drainage Basin ◽  
Lake Superior ◽  
Research Work ◽  
List Type ◽  
The West ◽  
Asbestos Fibre ◽  
Amphibole Asbestos

Approximately 60,000 tons per day of waste from taconite mining, tailing, are added to the west arm of Lake Superior at Silver Bay. Tailings contain nearly the same amount of quartz and amphibole asbestos, cummingtonite and actinolite in fibrous form. Cummingtonite fibres from 0.01μm in length have been found in the water supply for Minnesota municipalities.The purpose of the research work was to develop a method for asbestos fibre counts and identification in water and apply it for the enumeration of fibres in water samples collected(a) at various stations in Lake Superior at two depth: lm and at the bottom.(b) from various rivers in Lake Superior Drainage Basin.

The fight to save Uganda’s White Rhino

1964 ◽  
Vol 2 (01) ◽  
pp. 6-12
Keyword(s):  
The West ◽  
West Nile ◽  
White Rhino

In the West Nile District of Uganda lives a population of white rhino—those relies of a past age, cumbrous, gentle creatures despite their huge bulk—which estimates only 10 years ago, put at 500. But poachers live in the area, too, and official counts showed that white rhino were being reduced alarmingly. By 1959, they were believed to be diminished to 300.

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