Francisco José González Minero

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.

Olea europaea Airborne Pollen in Southern Spain

BACKGROUND Olea europaea pollen is one of the most abundant constituent pollens in Seville (southern Spain). It is responsible for many documented cases of pollinosis in the area. OBJECTIVE To contribute to the useful knowledge of Olea europaea for allergists. METHODS The number of Olea europaea pollen grains in the atmosphere was recorded during 8 consecutive years (1987-1994), using a Cour collector. RESULTS The concentration of Olea europaea pollen was as high as 250 to 1015 grains/m3 only during 1 or 2 weeks in April and May. Overall annual production of O. europaea pollen alternated between years. The beginning of the main pollination period was related to the mean temperature of the preceding months (February and March). Pollination occurred when the mean temperature in both months was higher than 14 degrees C; conversely it was delayed when the mean temperature was lower. Main pollination period length depended upon both temperature and rainfall during this period: temperatures higher than 19.5 degrees C and absence of rainfall shortened the main pollination period, while lower temperatures (15 to 18 degrees C) together with rainfall rates above 100 mm lengthened it. CONCLUSIONS Climatic variables such as preceding mean temperature and rainfall impact on pollen anthesis of Olea europaea affect onset and duration of pollination. A consideration of yearly cycles of pollen production as well as these variables should allow pollen forecasting.

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.

Prediction of the beginning of the olive full pollen season in south-west Spain

Given the clinical and agricultural importance of the olive in SW Spain, we have carried out a study to predict the starting date of its full pollen season. The study covers 6 years of meteorological and palynological observations — the latter using a Cour sampler installed in Huelva (SW Spain). The results obtained show that olive full pollination begins when the plant has accumulated 731‡C of daily temperature above 5‡C from the end of its dormant period. The mean duration of this accumulation was 83 days. A positive relationship has been found between mean temperature of the months before the pollen season (February and March) and the date when the season starts (April). From the data available, rainfall registered between 1 September and 31 March (both before pollination), does not affect the starting date of the full pollen season, but can affect total pollen production, particularly in years with prolonged drought.

Aeropalynology ofFraxinus (Ash) in an urban area of southwestern Spain

SummaryThe first observations from Huelva (southwestern Iberian Peninsula) on the phenology of Ash, based on an aeropalynological study over three years, are presented. Sampling was carried out with a Cour trap. The beginning of pollination is related to the moment of the lowest average temperature of the year, usually in January. Flowering occurs earlier if there are exceptionally low average temperatures (<10°C) in November. The amount of rainfall in autumn and winter affects the intensity of pollination.

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.

Study onPlatanus hispanica Miller pollen content in the air of Seville, southern Spain

The work was carried out using a Cour trap that sampled the air of the city for 8 consecutive years (1987–1994). The pollen ofPlatanus hispanica is the fourth most abundant in the air of Seville (a mean of 11.05% of the total pollen collected). The variation throughout the years in the sum of weekly concentrations ofPlatanus hispanica pollen presents a certain biennial rhythm, in which years of high and low collection of pollen alternate. The starting day of the main pollination period (MPP) is negatively related with the mean of the mean temperatures for February (r=0.73,r2=0.53,P=0.0398) and is earlier (at the beginning of March) when the mean temperature for February is high, and vice versa. The pattern of pollen variation inPlatanus hispanica remains constant through the years—pollen appears abruptly in high weekly concentrations (> 150 grains/m3) in March (sporadically at the beginning of April), with a week of maximum pollen emission (WMPE) in which more than 50% of the annual pollen is collected (in 6 of the 8 years), and a main pollination period (MPP) of 2 or 3 weeks (except in 1989 when it was 5 weeks). In every year (except 1989), weekly mean temperatures increased during the MPP, the duration of which depends on mean temperature and mean rainfall: mean temperatures > 16°C and absence of rainfall shorten the MPP, while lower temperatures and presence of rainfall lengthen it. The meteorological conditions most often found during the WMPE are mean temperatures > 15°C and rainfall absent or almost so.

Airborne fungal spores trend over a highly polluted area of south-west Spain using Cour's trap

SummaryThis investigation was aimed at studying the mycoflora present in Huelva (South West Spain), a highly polluted region. The study was carried out using the Cour trap and it is worth pointing out that the chemical treatment performed following the Cour methodology might destroy a certain percentage of spores. We analyzed the presence and biannual changes (10 April 1989 to 8 April 1991) of fungal spores of three genera, seventeen form genera, and four groups lacking taxonomic category, looking at their morphology: ascospores, basidiospores, and unidentified unicellular and multicellular spores. Special attention was given to agriculturally interesting groups. The results obtained were correlated with meteorological parameters (rainfall, minimum temperature and humidity).

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...