Atti del XLV Convegno della Società Italiana di Agronomia
Sassari, 20-22 Settembre 2016
Effect of Different Mulching Films on Yield and Quality of Zucchini Grown in Greenhouse Eugenio Cozzolino1, Ida Di Mola2, Vincenzo Leone1, Luigi Giuseppe Duri2, Laura Gioia2, Massimo Fagnano2, Mauro Mori2 1CREA-Consiglio
per la ricerca in agricoltura e l'analisi dell'economia agraria Laboratorio di Caserta eugenio.cozzolino@crea.gov.it 2Dip. di Agraria, Univ. Napoli, IT, ida.dimola@unina.it
Introduction The use of plastic films for soil mulching is an already consolidated practice; it allows 1) to reduce water and pesticide consumption, 2) to contain soil-borne pathogens and weeds, 3) to protect the cultivation area against erosion. But the principal effect of plastic films is to increase the yield and quality of horticultural crops, but also to lengthen the market availability of the products (early or delayed production). In this regard, in the last years, the use of plastic colored photo-selective film is increasing. Still, after the use, the plastic films become “waste” and so they must be disposed in many ways. The plastic waste can be transported to landfills, collected and recycled, or burned in incineration plants to produce energy (Kapanen et al., 2008). The recovered plastics are contaminated by pesticides, soil and biological waste, making the recycling process expensive and time-consuming (Scott, 1999). In order to increase the sustainability of this agricultural practices and to overcome the disposal problems of conventional plastics, films based on biodegradable and renewable agricultural raw materials can nowadays be used to an ever-increasing extent (Malinconico et al., 2002). Methods The research aimed to verify the effect of different mulching films on productive behaviour (quantity and quality) of zucchini grown in greenhouse. The soil of trial was sandy-loam with 1.7% of organic matter, 0.11% of nitrogen and high content in potassium. The trial was carried out at the experimental field Gussone Park of Department of Agriculture (N 40° 48.870’; E 14° 20.821’; 70m asl) in Portici (Naples): The experimental treatments were: - not covered soil: control - biodegradable film with 15 microns thickness (MB15) - low density polyethylene with 15 microns thickness (LDPE) - red polyethylene photo-selective films with 25 microns thickness (RED) The treatments were replicated three times and distributed at randomized blocks. The films were placed manually in the last decade of March 2015 and the transplanting was made on 27 March. The plant density was 1.2 plant per square meter; the harvests were made on alternate days, from 27 April to 19 June 2015 for a total of 23 days. The crop practices were ordinary. The cultivar tested was “Altea”, a Syngenta hybrid; its fruit is light green and mottled, it is harvested with flower at a length of 20-22 cm. At each harvest the number of marketable fruit and their fresh weight were measured; besides, we considered the sums of early eight harvests as “early yield”. In three harvests (early, intermediate, final) the following measurements were also made: dry matter (after oven drying at 50°C until constant weight); Brix degree (Refractometer Atago); texture (Penetrometer BCE with 8 mm probe); color (Colorimeter at reflectance Minolta Chromameter CR200). The data were analyzed with MSTAT software (Crop and Soil Science Department, Michigan State University, Version 2.0).
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Atti del XLV Convegno della Società Italiana di Agronomia
Sassari, 20-22 Settembre 2016
Results The early production (fig. 1a) confirms the capacity of red film to anticipate the productive phase, with a value significantly higher than the other treatments, according with Cozzolino et al. (2014). However, the LDPE and MB15 recuperated during the successive harvests; in fact for the total yield (sum of all harvests) there were not statistical differences among the covered treatments (fig. 1b). For both parameters the control was always statistically different from all other treatments, also because it showed the lowest value of number and average weight of fruits (tab.1). 60
b
a 50
t ha -1
40
30
20
10
0 Control
MB15
Red
Control
LDPE
MB15
Red
LDPE
Figure 1. Effect of different mulching films on early (a) and total yield (b). The vertical bars indicate the standard error.
The zucchini grown on biodegradable film had a higher value of consistence and it was not different from control, while the LDPE showed the lowest value. Probably the MB15 avoided an excessive water soil surplus that had a negative effect on texture. Also regarding the Brix degree, the MB15 reached the highest value and it was different from the control and the LDPE. Finally, in terms of color, the treatment with biodegradable films had a similar behaviour: higher values of brightness and chroma, without statistical differences from Red film. Table 2. Effect of different mulching films on quanti-qualitative parameters of yield.
Treatments
Control Red LDPE MB15 DMS
Number of Fruits n 152 b 199 a 208 a 196 a 14
Fruits average weight g 114.4 b 127.0 a 129.4 a 127.0 a 3.1
Brightness
Chroma
Texture
Brix
% 40.05 b 43.81 a 40.20 b 45.28 a 2.18
27.40 a 27.43 a 23.05 b 29.44 a 2.22
kg cm-2 1.69 ab 1.59 bc 1.54 c 1.72 a 0.11
° 4.42 c 4.77 ab 4.64 b 4.80 a 0.12
Conclusions The effect of mulching on yield, with respect to the soil not covered, was very evident: the total yield of control was about 30% of the average total weight of the covered treatments. Particularly, the red film has confirmed its capacity to anticipate production, while the biodegradable film allows to improve qualitative proprieties of fruits (texture, color and Brix degree). So, the use of the biodegradable film seems to have the best performance and, moreover, it has the advantage to degrade completely in few months, with a notable reduction of economic and environmental costs. References Cozzolino E. et al. 2014. Più qualità e resa nello zucchino con i teli fotoselettivi colorati. Inform. Agr. 8: 49-53. Malinconico M. et al. 2002. Blends of polyvinylalcohol and functionalized polycaprolactone. A study of the melt extrusion and post‐cure of films suitable for protected cultivation J Mater Sci. 37:4973–4978. Scott G. 1999. Polymers and the environment. RSC paperbacks. The Royal Society of Chemistry.
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