PORTUGUESE EXPERIMENTAL SITES

 
In Portugal, several experimental sites were established, being the one in Rio Frio the most relevant one, where the IOP2 (Intensive Observation Period 2) took place in the summer of 2003:
 

RIO FRIO FIELD SITE

Location: the field plot is located near the town of Pinhal Novo, between Lisbon and Setúbal and between the estuaries of Tagus (Tejo) and Sado. Coordinates are 38^o38' N (latitude), 8^o51' W (longitude), 30 m (altitude). The canopy is a cork oak (Quercus suber), with 80 years, distance at plantation: aprox. 10 x 11, density: 76 trees/ha in 2001 and 66 in 2003, average height: 10 to 12 m.

Climate and soil: Mediterranean climate with Atlantic influence. Total precipitation: 750 mm/ year (average 30 years), with maximum in Winter. Average temperature: 16.1^oC, average minimum temperature during January: 5.3^oC,  average maximum temperature during August: 28.9^oC. Other informations in Reis and Zorro (1981) and http://www.meteo.pt. Sandy soil derived from moderately deep sandstone, with some gravel, compact, very low carbon content and available water.

Aerial photos and Maps: maps of scales 1:25000, 1:50000 and 1:100000 are respectively numbers 444 (1971) from IGEOE, 35C (1981) and 35 (1978) from IGP (maps and photos are also available in other supports, both 2D or 3D, see http://www.igoe.pt, for instance).

Field site facilities and long term information (ISA): tower with 20 m (10 platforms, 2 m each), at the center of a fenced area of about 700 m², installed in May 2001, in the frame of WATERUSE project. Precipitation, solar radiation, air temperature and humidity, wind speed and direction recorded at 15 m height (automatic weather station). Components of energy balance, including evapotranspiration, recorded during spring-summer periods (also occasionally during the rainy season) and soil heat flux permanently since May 03. Transpiration according to Granier being recorded since April 2001 in 10 points (4 trees) and from March 2003 in 18 points (10 trees) near the tower. Soil water content (neutron probe) followed during spring-summer periods since 2002. Characterization of soil and stand performed by ISA team.
 

Following the initial visit to the area after the Kick-off meeting, further surveys led to the establishment of this site in the montado area at Rio Frio (60 000 ha), the largest area of cork oak (Quercus suber) in the Lisbon area. A 20 m mast was ordered and installed and a 500 m cable for energy supply (220V) installed by May 2001. The site was chosen to satisfy the project objectives. In particular, the cork oak plantation was chosen because it is representative of a very important land-use system in large areas of Portugal and other Mediterranean countries, the site was relatively flat with an extensive fetch in the predominant wind-direction as is required for micrometeorological measurement systems, and some soil and hydrological information was already available from other surveys.

The density and the size of trees in the area (Rio Frio) were also provided. Soil water content in the root zone (April to August 2002) and soil characterization were completed and provided to the WATERUSE team by ISA. Ground water potential vulnerability (environmental risks - quality changes): data collection from literature and from existing information from IDRHa (former IHERA), INAG and other services (IGM, studies by ANA) was done by IDRHa. The actual density and size of trees were measured in the area under study, in 2001 and 2003 (some trees were removed in 2002, for health reasons). Allometric relationships are difficult to obtain for cork oaks as there is nothing available in the literature because local laws forbid the cutting or severe pruning of cork oaks), so mobile platforms were used. Several independent surveys of parts of the area to estimate leaf area index of both the trees and the distribution of ground-cover vegetation were conducted by Partners 1, 4, 5 and 7, using equipment such as an LAI2000 and a Sunscan.

A last aspect of characterization was related to health conditions of trees. Several specialists were contacted. After visits to the site, observations and analysis,  a report was provided. In conclusion, the identified insects attacking leaves in late Spring were Lymantria díspar and Periclista andrei. The fungus diseases Biscogniauxia mediterrânea and Endothiella gyros, which are the most common problems in Montado stands were not found.

The montado during Winter:

The montado understorey during Winter:

Cistus crispus L.                                                                                                   Briza sp.

Echium plantagineum L.

References:

M. Reis and Zorro 1981. Caracterização climática da região agrícola do Ribatejo e Oeste. Fasc XXXII. O Clima de Portugal, INMG, Lisboa.

ÉVORA FIELD SITE

A valuable complementary set of information on another Montado stand was obtained at a site near Evora, Alentejo. This site on the University farm at Mitra is at 38º32’26” N, 8º00’01” W, 243 m asl, and lies some 150 km southeast of Lisbon. Site topography is slightly undulating with vegetation consisting of a sparse and scattered Q. rotundifolia stand, with 35-45 trees ha^-1, with spots of Quercus suber. The wide and shallow shape of the crowns reflects the traditional pruning performed to increase fruit production and shadow for cattle. The understory consists of a mixture of shrubs and grasses, dominated by Cistus spp., grazed by cattle. The climate is of the Mediterranean type, with hot and dry summers. According to long-term averages (1951-1980), mean annual rainfall is 665 mm (90% of which falls from autumn to early spring) and mean annual open water evaporation is 1760 mm (INMG, 1991). Mean annual air temperature is 15 ºC, ranging from 8.6 ºC in January to 23.1 ºC in August. The soil is a very shallow sandy Cambisol (FAO, 1988) overlying a gneiss rock. Soil water retention capacity is rather low. An automatic weather station was installed on the top of a 25 m high metallic tower giving data on: solar radiation (CM6B, Kipp and Zonen, Delft, The Netherlands), dry and wet bulb temperatures (aspirated psychrometer H301, Vector Instruments, Rhyl, UK), wind velocity (anemometer A100R, Vector Instruments, Rhyl, UK), wind direction (wind vane W200P, Vector Instruments, Rhyl, UK) and gross rainfall (tipping-bucket raingauge recorder ARG100, Environmental Measurements, Gateshead, UK). These data were recorded at 10-minute intervals in a CR10 data-logger (Campbell Scientific, Shepshed, UK). Sapflow density was measured by the Granier method in a sample of 8 Q. rotundifolia trees and of 3 Q. suber trees. Meteorological and sapflow data are available at 10 min intervals. Water vapour fluxes from the ecosystem were monitored by the eddy covariance technique using a three dimensional sonic anemometer (R3A, Gill Instruments, UK) and a krypton fast response hygrometer (Campbell Scientific).
The measurements at this site were conducted largely in the frame of Project INIA-PIDDAC 216/01 with collaboration of the ISA Forestry Department.

ATALAIA FIELD SITE

Peach orchard- already under study in the past, (see Acta Horticulturae, 537, several papers).
This orchard (5 m x 2 m, sandy soil, 50 km east from Lisbon, drip irrigated, ground cover 30%) has an area of about 8 ha and is located near the road, 15 km from Montijo (to the East). Results from a similar orchard in the same area can be found in Acta Horticulturae, 449 (2): 379-384.
The orchard was used during experiments in Summer 2001 and was cut soon after (the measurements made in this site have finished in August 2001, as the orchard has been replaced by a vineyard).These destructive measurements were particularly helpful in achieving aims of the project. These observations were used in WP1, WP2 and WP4. Some of them were also partially included in a Ph D thesis by Paço (2003), completing a set of measurements initiated in 1998, on water use of this orchard (see WP7), in the frame of the project FAIR1-CT95-0030 (concluded in 2000). Further details can be found there and also in first publications submitted.

Paço, M. T. G. A. (2003). Modelação da evapotranspiração em cobertos descontínuos - Programação da rega em pomar de pessegueiro. Ph. D. thesis , Universidade Técnica de Lisboa, Instituto Superior de Agronomia, Lisboa, 225 p.

PALMELA FIELD SITE

VINEYARD at Palmela (Setubal, Portugal). This new experimental site was established with an area of around 300 ha and was excellently situated for eddy covariance studies. The vineyard was irrigated by a drip-irrigation system. Tubes with emitters every 1-meter were fixed at a height of 0.5 m above ground. Training system is bilateral cordon. The distance between rows is 2.8 m, and between plants is 1.2 m. In this vineyard a plot of 3 ha from the variety Syrah was chosen and a sub parcel was considered for irrigation essays. Meteorological variables measured were air temperature and humidity, wind velocity, global and net radiation. Heat flux plates and soil temperature profile measured soil heat flux. Soil moisture was monitored with thetaprobes in the two situations and also TDR probes for the sub parcel. At the installation of soil probes a soil profile description was made. Sap flow was measured by a thermal heat dissipation method (Granier method). Predawn leaf water potential was also monitored during Spring-Summer 2001. This site provided measurements from 1996 onwards (national former projects), and data were used within the frame of the WATERUSE programme to provide data on a regularly distributed vegetation to complement the other vegetations studied. Results were analysed and presented in a Ph D Thesis, (Silvestre, 2003), under the orientation of the WATERUSE project co-ordinator.

Silvestre, J. (2003). Evapotranspiração e Funcionamento Hídrico em Vitis vinifera L. Ph. D. thesis, Universidade Técnica de Lisboa, Instituto Superior de Agronomia, Lisboa, 219 p.

 SAFARA FIELD SITE

OLIVE orchard at Safara (Beja, Portugal). The orchard (4 m x 6.5 m) is irrigated and managed by COTR. It is located near the frontier with Spain and the new Alqueva dam (and future irrigated area), in the driest and warmest area of Portugal. There is a big pressure from users, in order to obtain information about water use and irrigation scheduling and impacts. A standard meteorological station has been installed by COTR during 2001, near the orchard, in the frame of their activities. The trees were selected by ISA for sap flow (transpiration) measurements (possibly under different irrigation conditions) after early Spring 2002. The relevant characterization of soil made by ISA and was ready in early 2002. The first step of transfer of knowledge to COTR was to be linked to the preparation of young engineers for the task of following those measurements. This task has been transferred to colleagues from ESAB/UE (in the same region), who proceeded with extra funding and scientific assistance of ISA, as required.

 CALDAS DAS TAIPAS FIELD SITE

Kiwi orchard at Caldas das Taipas (Guimarães, Portugal). Useful data were also obtained for a new experimental site (set up in collaboration with AGRO 8.1 – Project 288) on Kiwi vine – Var. ‘Hayward’. The plantation distance of 5 x 5 meters (T – bar training system) and irrigated with micro sprinklers. The experimental site is near Guimarães (41º 31’ N, 8º 27’ W). ET was measured with the eddy covariance technique, transpiration (T) was measured by sap flow and the understorey water losses were measured by microlysimeters. Sap flow measurements started at the beginning of the 2002 vegetative cycle. During 2003, ET and Es measurements were used to adjust T estimates, upscaling the sap flow measurements to the stand level.