Atti del XLV Convegno della SocietĂ Italiana di Agronomia
Sassari, 20-22 Settembre 2016
Influence of Planting Density and Pre-Flowering Topping on Tobacco Yield of Seed Oil Eugenio Cozzolino1, Francesco De Lucia2, Patrizia Spigno3, Ida Di Mola4, Visconti Donato4, Luigi Giuseppe Duri4, Mauro Mori4, Massimo Fagnano4 1
CREA-Consiglio per la ricerca in agricoltura e l'analisi dell'economia agraria eugenio.cozzolino@crea.gov.it 2 Dipartimento di Agraria, Ambiente ed Alimenti-UNIMOL; 3ARCA 2010 SocietĂ Cooperativa Arl 4 Dipartimento di Agraria-UNINA
Introduction Tobacco seed oil has a fatty acid composition similar to sunflower seed oil with high content of linoleic acid, which makes it valuable for several uses (del Piano et al., 2014). The tobacco plant can grow in environments with limited water resources (Impagliazzo et al., 2012) and the possibility of its use on marginal agricultural soils for oil production has been recently considered in the pursuit for renewable energy sources, also on account of the demonstrated oil mixability with diesel fuel up to one fourth of the mixture without loss of performance (Srinivas et al., 2013). The aim of our work was to evaluate the oil producing potential of tobacco in a field trial in Campania region. Methods The trial was conducted in the year 2015 in the municipality of Calvi, province of Benevento, a traditional tobacco area, on a neutral silt-clay loam of good fertility. Treatments were combinations of two factors at two levels: planting density (3.6 vs 4.8 plants/m2) and pre-flowering topping (topped vs untopped) and field layout was a complete randomized block design with tree replicates and plots of about 40 m2. After a first harvest, all plants, both topped before flowering and untopped, were topped at 70 cm height to stimulate a regrowth for a second harvest. Plants of the cultivar Solaris (Sunchem Holding) were planted on May 21ston soil previously fertilized with 36 kg/ha NP and 51 kg/ha K and were topdressed with a total 80 kg/ha N in three applications, 18 kg/ha P and 15 kg/ha Ca in one application. The field was irrigated five times with a total water volume of about 1000 m3 per ha. To protect fruit pods against moths four insecticide applications were made. Pre-flowering topping was done on July 3rd at about 60 cm height to allow the formation of 2-3 flowering shoots per plant. The first harvest was carried out on August 6th, cutting the panicles and stratifying them on nonwoven fabric under a plastic covered tunnel to dry. The second harvest, favored by good weather in September, was done on October 10th. Seed and oil yields were determined random sampling 20 plants per plot. Seeds were extracted from the dried pods with the aid of a rubber pestle and separated from pod debris with a steel sieve. On seed samples composite over replicates oil was extracted with a mechanical pressed seed oil concentration was determined. For inferential purposes seed and oil yields were modeled as normally distributed given treatments with means as linear functions of treatments using the R environment (R Core Team, 2016) with the rstan package (Stan Development Team, 2015). Results Plant growth was rather good, despite some adversity, as protracted dry-hot weather and a short hailstorm occurring soon after the first harvest. Percentiles of draws from predictive distribution for treatments and some contrasts are represented in figure 1. Pre-flowering topping had a positive effect on the first harvest yield of seeds, with average increases of 20% and 13% at the lower and higher planting density respectively, but the effect on the second harvest, though still positive at the lower density (+11%) was noticeably negative at the higher density (-20%). Topping effects on oil yield showed a similar pattern, with comparable average increases in the first harvest (+20% and +10% at lower and higher density respectively), but about no increase at the lower density (+3%) and a more marked decrease at the higher
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Atti del XLV Convegno della SocietĂ Italiana di Agronomia
Sassari, 20-22 Settembre 2016
density (-25%). The effect of pre-flowering topping on total yield was positive at the lower density (+12%) and somewhat negative at the higher density (-8%).
Figure 1. Medians and percentiles (1, 2.5, 10, 25, 75, 90, 95, 99) of (1000) draws from predictive distributions for treatment yields of seeds and oil and conditioned first differences between factor levels (topping: topped vs untopped; density: 4.8e+4 vs 3.6e+4 plants/ha).
Increasing planting density increased first harvest yield more for untopped plants (+20% seeds, +22% oil) than for topped ones (+12% seeds, +11% oil), but second harvest yield only for the untopped (+28% seeds, +25% oil), decreasing it for the topped (-7% seeds, -10% oil). Pre-flowering topping conditioned density effects on total yields: with no topping yields increased with density by 23% for seeds and by 22% for oil; with topping yields did not vary much with density. The highest overall yield was obtained with the higher density and no pre-flowering topping, the second highest with the lower density and topping. Conclusions Average seed yields per treatment varied between 2.68 and 3.28 t/ha and oil yields between 0.94 and 1.15 t/ha. Planting density effects on tobacco seed and oil yield were conditioned by pre-flowering topping and vice versa: increasing density from 3.6e+4 to 4.8e+4 plants/ha total yields of two harvests changed little for topped plants, but increased noticeably for untopped plants. References del Piano L. et al. (2014) Valutazione della produzione in seme e del contenuto in olio di nuove costituzioni di Nicotianatabacum L. Atti XLIII Convegno SIA 2014. Impagliazzo et al. (2012) Risposta produttiva del tabacco da olio (N.tabacum L. cv Solaris) a differenti input energetici. Atti XLI Convegno SIA 2012. R Core Team (2016) R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. URL https://www.R-project.org/. Srinivas I.K.et al. (2013)Experimental Analysis of tobacco oil blends with diesel in single cuilinder Ci-Engine. International Journal of Engineering Trends and Technology (UETT) 4 (10): 4535-4539 Stan Development Team (2015). Stan: A C++ Library for Probability and Sampling, Version 2.8.0. URL http://mc-stan.org/.
Attività svolta nell’ambito del progetto PON BioPoliS
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