THE INFLUENCE OF DIFFERENTLY COLOURED PLASTIC FILMS ON THE MICROCLIMATE OF MULCHED PLOTS (*)

In the autumn 1966 the Istituto di Coltivazioni Arboree of the University of Bologna started a combined research on the effects of plastic materials used for mulching and forcing of strawberry culture.

In the present paper, an account is given in the effects of differently coloured plastic films on the microclimate of mulched plots.

In this research, five different treatments (check, mulching with black plastic film 0, 10 mm thick, and with grey, green and clear polyethylene 0, 20 thick) have been layed out with three replication each, at the experimental farm of the University of Bologna on a soil consisting of 40–45 % sand, 30 % loam and 25–30 % clay.

The determination of the soil moisture has been done, according to the Bouyoucos method, at the depth of 10 – 15 cm; at the same depth the soil temperature has been continuously recorded by means of thermographs. The air temperature and humidity have been recorded by sheltered instrument at a level of 20–30 cm above the plots surface.

The date have been recorded since December 20th, 1966 till October 30th, 1967, with the exception of the green and clear mulched plots which have been suppressed at the beginning of July, owing to the great amount of weeds below these plastic films.

Basing on the diagrams supplied by the thermographs, the average daily soil and air temperatures have been calculated according to the conventional rule postulated by Favilli (1) that is averaging the minimum and maximum daily temperatures with those recorded at 8 a.m. and 7 p.m.

All the monthly data have been statistically analized with the aid of the electronic desk computer "Programma 101" - Olivetti.