Carmen Tomas

Forecasting olive crop production based on ten consecutive years of monitoring airborne pollen in Andalusia (southern Spain)

This work describes a predictive model for the harvest of olives destined for olive oil, using olive groves in the province of Seville (southern Spain). The study was carried out between 1987 and 1996, monitoring airborne olive pollen with a Cour trap, and using agronomic data (size of harvest expressed in kg/ha) and meteorological observations (rainfall before and after olive pollination, days of rainfall during harvesting, and maximum temperatures during pollination). The data were subjected to simple and multiple regression analysis. Eight equations were obtained, enabling the olive harvest to be forecast with a high degree of reliability: five equations for use at the beginning of July (the end of flowering, and six months before fruit picking), another two at the end of November (immediately before picking), and the remaining one at the end of January, once picking was over.

Forecasting olive (Olea europaea) crop production by monitoring airborne pollen

Forecasting harvests of olives destined for the production of olive oil can be based on counts of airborne olive pollen, and meteorological and agronomic observations. This study was carried out during six consecutive years (1990–1995) in the Campiña Alta (an olive-producing region in the province of Córdoba, south-west Spain). Olive pollen totals are the annual sum of the concentrations recorded for the periods that the filters of a Cour trap were exposed. The meteorological data are the values of accumulated rainfall between 1 September and the following 15 April (a date prior to the beginning of olive flowering). The agronomic data are the forecast and actual productions for the province of Córdoba, supplied by the Board of Agriculture of the Andalusian government, and the actual production of the Campiña Alta, supplied at the end of harvest by private olive-growing co-operatives. The data were combined, and four mathematical equations were obtained to forecast the crop 6 months in advance, with varying degrees of reliability. The reliability was very high for an appropriate agricultural area. The most accurate equation isY=−1.90×104+2.35X+53.94 (which forecasts the production of the Campiña Alta), whereY is the olive production (MT),X the olive pollen count,Z the rainfall prior to flowering, anda, b andc are constants. The least accurate equation is that relating olive pollen concentrations with olive production in the province of Córdoba.

Airborne grass (Poaceae) pollen in southern Spain. Results of a 10‐year study (1987–96)

This work reports an exhaustive study of the aerobiology of the Gramineae in Seville, Spain, which is typical of coastal Mediterranean areas. Sampling was done with a Cour trap installed on the roof terrace of the School of Pharmacy, Seville, from 1987 to 1996, both inclusive. The climatic pattern of that period was characterized by two exceptionally wet years (1989 and 1996), between which were 5 consecutive years of drought (1990–5). This typieally Mediterranean climate affects grass aerobiology. The annual amounts of total grass pollen are low, never exceeding 25(X) grains/m3. The start, length, and intensity of the pollen season are significantly correlated with preseasonal meteorologic factors (precipitation and temperature), but intraseasonal meteorologic conditions have no effect on the three variables. The relationships are stated by three equations that, while further years of observations are anticipated, can be considered models to forecast the characteristics of the pollen season: the starting date depends on the mean temperatures of January and February, and the length and intensity of the season depend on the rainfall between the beginning of January and the starting date of the season. For the study period, the weekly concentrations (pollen curves) throughout the year showed no typical pattern of variation over the years, so that it was impossible to make mid‐ and long‐term forecasts of the variation in weekly concentration. The most noteworthy aspects of grass pollen curves are a long pollen season, which starts in February or March and lasts until September or October; peaks of higher concentration (>1(K) grains/m3) in May and June, associated with increases in temperature and absence of precipitation; and other peaks in the summer months that may be as high as the spring peaks.

Study of the pollen emissions of Urticaceae, Plantaginaceae and Poaceae at five sites in western Spain

A comparative study is presented of the pollen emissions of Urticaceae, Plantaginaceae and Poaceae, collected during 1995 with Hirst samplers (Burkard or Lanzoni) at five sites in western Spain: two Mediterranean sites located in the south (Huelva and Seville) and three Atlantic sites in the north (Orense, Vigo and Santiago). The annual pollen of Poaceae and Plantaginaceae collected in the Atlantic cities was found to be twice that in the Mediterranean sites, and the total amount of Urticaceae was higher at sites with an urban environment and subject to sea influence (Vigo, Huelva and Seville). At all the sites, the start of the main pollination periods (MPP) took place in the following order: Urticaceae, Plantaginaceae and Poaceae. It was also observed that the MPP of these three pollen types began earlier in Huelva and Seville, where the mean temperatures necessary for the beginning of pollen emissions are recorded very early. Regarding the variation in pollen concentrations throughout the year, Urticaceae presented peaks of maximum concentration in March (Huelva, Seville, Vigo and Orense) and June (Santiago); Plantaginaceae in March (south) and June (north); and Poaceae in May (south) and June–July (north). At northern sites, pollen emissions of Urticaceae and Plantaginaceae continued throughout the summer, while in the south they decreased considerably from May onwards. From the allergenic point of view, the indices of reactivity described for Urticaceae and Poaceae were exceeded more often at northern sites, in particular at Vigo. The meteorological conditions associated with periods of highest pollen emission of these three herbaceous types are a rise in mean temperature, light or absent rainfall, and abundant sunshine. The statistical correlations between pollen emissions and meteorological factors were not well-defined, either for the stations or for all the taxa, although they were clearer for the Atlantic cities and for Urticaceae.

A comparative study of atmospheric pollen concentrations collected with Burkard and Cour samplers, Seville (Spain), 1992–1994

A comparative study has been carried out of the relative efficiency of a Burkard sampler and Cour trap, by taking samples from the air of Seville (SW Spain) for two consecutive years (July 1992 to July 1994). The devices were subjected to identical conditions of installation. 16 specific pollen types were studied either because of their high presence in the regional atmosphere or because of their allergenicity. With both methods, the variations in weekly concentrations throughout the year were analysed. Then the data from the two traps was compared in order to compare the efficiency of the two methods. The Burkard sampler collects 1.42 times more total pollen than the Cour trap. Certain pollen types are found more frequently in the Burkard trap (Casuarina, Mercurialis, Olea, Platanus, Rumex and Urticaceae); some are approximately equal in the two traps (Amaranthaceae/Chenopodiaceae, Cupressaceae, Fraxinus, Pinaceae, Plantago, Poaceae and Quercus); and others are found more frequently in the Cour trap (Art...

A study on non‐arboreal pollen collected during ten consecutive years in the air of the SW Spain

A Cour trap was used to sample the air of the city of Seville continuously from 1987 to 1996, both inclusive. The most important climatological feature of the period was a prolonged drought, which began in 1990 and reached its severest moment in 1995 after six consecutive years without exceeding the mean annual precipitation for the city. The study was conducted on the 16 pollen types that appeared in amounts greater than 0.05% of the total pollen collected in the ten‐year period: Poaceae, Urticaceae, Plantago Chenopodiaceae‐Amaranthaceae, Asteroideae, Rumex, Mercurialis Brassicaceae, Helianthus Lactucoideae, Typha Cyperaceae, Echium Apiaceae, Artemisia and Leguminoseae. The aspects examined were the possible effect of the drought on the variation, over the years, in the annual total pollen concentrations; the relationship between the non‐arboreal vegetation of the region and the quantitative composition of the pollen spectrum; and the description of the pollen curves (the variation, through the year, in ...

The pollen spectrum of trees and shrubs in SW Spain (1987–1996)

A Cour trap was used to sample the air of Seville of continuously from 1987 to 1996. The most important climatological feature recorded during that period was the drought that began in 1990 and which was at its most severe in the first half of 1995. The behaviour of a total of 20 pollen types was studied: those exceeding 0.01% of the total pollen collected during the ten‐year period. These were Quercus, Olea Cupressaceae, Platanus Myrtaceae, Pinaceae, Palmae, Moraceae, Fraxinus Ericaceae, Citrus, Pistacia, Acer, Casuarina Salicaceae, Ulmus, Alnus, Castanea Cistaceae, and Viburnum. The following aspects are described and analysed: the spectrum of tree and shrub types identified in the air, and their possible significance for allergies; the relationship between the woody vegetation of the region and the composition of the pollen spectrum in quantitative terms; and the possible effect of the drought on annual variations total pollen concentrations. A detailed study of olive pollen, aimed at finding applicati...

Airborne pollen concentration in Seville (Spain), 1993–1996. First results obtained with Hirst’s method

The data presented constitute the longest historical series of results obtained in Seville with a Hirst-type sampler, and are a further contribution to earlier aerobiological studies carried out in the city with a Cour trap. This work supplies an updated pollen calendar of the city, together with pollen counts and other aerobiological parameters for the 14 most important types in the 4-year period of sampling. These werePlatanus hispanica, Olea europaea, Quercus, Cupressaceae, Poaceae, Urticaceae, Moraceae, Chenopodiaceae/ Amaranthaceae,Plantago, Pinaceae,Rumex, Myrtaceae, Compositae, andCasuarina.

Aeropalinología de Huelva. Resultados de dos años de estudio (1995-96)

El trabajo se ha realizado con un captador Lanzoni situado en la azoica del ayuntamiento de Huelva, en el centro de la ciudad. En total se han identificado 37 tipos polinicos diferentes en 1995 y 40 en 1996. Los mas abundantes son: Urticaceae, Cupressaceae, Quercus, Olea europaea, Poaceae y Amarathaceae/Chenopodiaceae . En menor cantidad, se recogen tipos entomofilos ( Acacia , Compositae, Cruciferae, Echium, Labiatae, Cistus , etc.) y polen marcador ( Betula y Cannabis ). Los meses de mayor recogida de polen total fueron abril en 1995 y mayo en 1996.