Crop value response of burley tobacco to N application timing and rate*

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1 Interlandi et al. Produzione di Barley a diverse dosi e modalità di concimazione N 51 Crop value response of burley tobacco to N application timing and rate* Giuseppe Interlandi, Maria Grazia Tremola, Romolo Carotenuto, Filippo Piro, Vincenzo Leone, Raffaele Cutolo Summary. The influence on yield and crop value of Burley tobacco (cv B8) of rate and timing of mineral N fertilisation were studied in an experimental layout comprising the combinations of three N rates ( kg/ha) by three schedulesa (AAT, all at transplanting; A40DAT, all at 40 days after transplanting; SPL, 1/3 at transplanting and 2/3 at 40 days after transplanting) by two levels of base organic fertilisation (yes-no). A zero rate N level (N0) was also added as control. The organic fertilisation treatment was applied at soil preparation by broadcasting 500 kg/ha of a commercial fertiliser containing about 14% N, 8% P, 6% K, and 7% organic carbon. Observations were made on cured tobacco yield, leaf value index and some physical leaf properties. Cured leaf yield and crop value increased with organic fertilisation, but the response to mineral N appeared to be dependent both on the organic fertilisation and the N application schedule: without organic the highest yielding schedule was SPL; with organic the highest yield was obtained with A40DAT at the rate of 200 kg/ ha, followed by botha AT and SPL at the rate of 300 kg/ha. In all cases, though, the N0 control gave yields comparable with those achieved with mineral N applications. Leaf value index was adversely affected by organic fertilisation and by A40DAT and SPL, while increasing linearly with AAT. Filling value decreased with organic fertilisation at all leaf positions except the lowest and with AAT and A40DAT in absence of organic. Burning rate was affected by the N treatments mainly in the basal leaves, where it increased from A40DAT to SPL to AAT without organic and in the Key words: Quality; Tobacco; Fertilization reverse G. Interlandi order e with M.G. organic. Tremola, ricercatori, R. Carotenuto, Direttore di sezione, Istituto Sperimentale per il Tabacco, Scafati (SA) F. Piro, Direttore di Sezione, Istituto Sperimentale per l Orticoltura, Pontecagnano (SA) V. Leone e R. Cutolo, CTER, Istituto Sperimentale per il Tabacco, Scafati (SA) *Lavoro presentato al Joint Meeting of Agronomy and Phy- topatology Study Groups Sept./4 Oct. Il Tabacco, 9, 2001: Riassunto. Risposta della produzione di burley a diverse dosi e modalità di somministrazione di azoto. L influenza della concimazione minerale azotata, sullo sviluppo e la produzione di tabacco Burley, è stata studiata in relazione alla dose ed all epoca di somministrazione. IL disegno sperimentale comprendeva la combinazione di tre dosi N ( kg/ha) con tre modalità di somministrazione (AAT, tutto al trapianto; A40DAT, tutto 40 giorni dopo il trapianto; SPL, 1/3 al trapianto e 2/3 40 giorni dopo il trapianto) più un controllo N0, il tutto per due livelli di fertilizzazione organica di fondo (sino). Il trattamento di fertilizzazione organica è stato effettuato alla preparazione del terreno, somministrando 500 kg/ha di un fertilizzante commerciale contenente approssimativamente 14% N, 8% P, 6% K, e 7% carbone organico. I rilievi hanno riguardato il prodotto curato, l indice di valore fogliare e le caratteristiche fisiche della foglia curata. Mentre la produzione di tabacco verde e curato è aumentata con la fertilizzazione organica, la risposta all azoto minerale è stata condizionata sia dalla fertilizzazione organica sia dalla modalità di somministrazione: in assenza di concimazione organica la produzione maggiore si è avuta con il metodo di somministrazione SPL; con la concimazione organica la produzione più alta si è avuta con il metodo di somministrazione A40DAT alla percentuale di 200 kg/ha, seguita da AAT e SPL entrambe alla percentuale di 300 kg/ha. In tutti i casi, tuttavia, il controllo di N0 ha dato una produzione comparabile a quella realizzata con N minerale. L indice di valore fogliare è stato influenzato negativamente dalla concimazione organica e dai metodi A40DAT e SPL, mentre aumentava linearmente con AAT. Per le foglie di tutti i palchi fogliari, ad eccezione delle basali, il potere di riempimento è diminuito con la concimazione organica e con AAT ed A40DAT in assenza di concimazione organica. La combustibilità è stata influenzata dal livello di N principalmente nelle foglie basali, dove è aumentata da A40DAT a SPL ad AT senza concimazione organica e nell ordine inverso con la concimazione. interlandi.p65 51

2 52 Introduction Tobacco quality is a balance of physical and chemical properties, influenced by environmental and agronomic factors. Nitrogen fertilization is a critical factor in cultivation of light tobaccos, because of contrasting effects on yield and quality. Burley tobacco requires good soil fertility to achieve adequate plant development and leaf quality and tolerates relatively high N applications. This aptitude might allow some flexibility in fertilization practice, but the continuing search for optimization could still bring benefits to the industry and the environment. Effects on crop value and on leaf physical quality indicators of combinations of N rates and application schedules are here reported from current trials at the Istituto Sperimentale per il Tabacco, Scafati. Il Tabacco, 9 1/3 at transplanting and 2/3 at 40 days after transplanting) by two levels of base organic fertilization (No organic, Organic). A zero rate N level (N0) was also added as control. The organic fertilization treatment was applied at soil preparation by broadcasting 750 kg/ha of a commercial fertilizer containing about 14% N, 8% P, 6% K, and 7% organic carbon. Tobacco was primed and cured in racks under plastic covered curing barns typical of Italian Burley area. Records were taken about cured tobacco yield, leaf value index, leaf filling value index and burn rate. Leaf value index was obtained as the mean of grade classes weighted by class reference prices. Filling value index was measured with the cylinder method. Burn rate was determined by the point ignition method. Result and discussion Materials and methods Burley tobacco (cv B8) was grown in an experimental layout comprising the combinations of three N rates ( kg/ha) by three application schedules (AAT, all at transplanting; A40DAT, all at 40 days after transplanting; SPL, Table 1. F test probabilities and model adequacy in the ANOVA of Burley yield components in relation to fertilization factors. Source Cured yield (MT/ha) Price index (0-100) The price index was affected by all factors of N fertilization (table 1). The base organic dressing lowered price index at the zero N rate and at all rates in the split application, while rate response was positive only in the all at transplanting application schedule (figure 1). Cured yield and crop value showed significant dependence on the base organic dressing and on the mineral N rate, but not Class A equivalent yield (MT/ha) Organic 0,012 0,813 0,012 N rate 0,159 0,139 0,087 Organic*N rate 0,946 0,214 0,975 N schedule 0,654 0,033 0,811 Organic*N schedule 0,616 0,375 0,388 N rate*n schedule 0,787 0,120 0,442 RSquare Adj 0,48 0,66 0,58 Root Mean Square Error 0,85 1,55 0,49 on the application schedule. Yield increased in the range of N mineral fertilization, but the improvement above the zero rate was significant only for the equivalent yield, which was less affected by the organic base dressing, because of the lower price index (figure 2). Filling value index showed significant interactions among the N fertilization factors and the leaf position, generally with higher values for the interlandi.p65 52

3 Interlandi et al. Produzione di Barley a diverse dosi e modalità di concimazione N 53 Table 2. F test probabilities and model adequacy in the ANOVA of physical properties of Burley cured leaf in relation to fertilization factors. Source Filling power inde x middle and upper leaf positions (Table 2 and figure 3). The organic dressing gave higher filling values for the middle to top leaf positions at lower N rates in the split and delayed application schedules, and lower values for the basal leaf position in the all at one time application schedules. The response to N rate in the split schedule was slightly positive with the base organic dressing and mainly negative without it. A positive response to N rate was showed by the middle to top leaf positions in the all at transplanting schedule. Burn rate, expressed as a negative of the inverse to normalize the distribution, was affected by leaf position, base organic dressing and schedule, but not by N rate (figure 4). Burn rate tended to decrease in intermediate leaf positions, except in the all at transplanting schedule, were the decrease continued to the topmost position. The organic dressing was detrimental for burn rate only at the extreme leaf positions. Crop value response to N fertilization did not -100/Bur n Organic 0,047 0,056 N rate 0,337 0,255 Organic*N rate 0,137 0,398 N schedule 0,471 0,527 Organic*N schedule 0,020 0,125 N rate*n schedule 0,019 0,275 Leaf position 0,004 0,001 Organic*Leaf position 0,002 0,904 N rate*leaf position,989 N schedule*leaf position, , ,854 RSquare Adj 0,36 0,19 Root Mean Square Error 0,89 2,87 dismiss use of 200 to 300 rates, nor of the basal organic dressing for conditions comparable to those of the experiment. Instead, leaf quality was adversely affected by the organic dressing, especially if coupled with absence of mineral fertilization or split and delayed application schedules. The all at transplanting schedule seemed to offer the best trade-off between yield and quality. Bibliografia Akehurst B Tobacco 2 nd ed Longman, London. Atkinson,W.O., and Sims, J.L., Nitrogen composition of burley tobacco II:Influence of nitrogen fertilization, suckering practice and harvest date on yield, value and distribution on dry matter among plant parts. Tob. Sci. 15:63-66, 1971 Giuseppe Interlandi, Filippo Piro, Francesco De Caro, Vincenzo Leone- Influenza della densità di carico e della sezione della capanna di cura sulla qualità del tabacco Burley Il Tabacco, 6, 1988: Romolo Carotenuto, Maria Grazia Tremola Tecniche di produzione del Burley in Campania Il Tabacco,8, 2000: Ayocock M.K. et McKee C.G response of Maryland tobacco cultivars to various rates of nitrogen fertilization Tob. Sci. 23: Castelli F. MiceliF., Piro F., 1990 Effetti delle modalità di raccolta e cura in tabacco (Nicotiana tabacum L.) Burley a differente fertilizzazione azotata e densità di popolamento. Riv. Agr.,24(4): Cavazza L Il problema della conservazione della fertilità del suolo in Italia. Relazione generale di sintesi. Agricoltura e Ambiente Ed agricole 3-33 CuocoloL., Caruso G., Postiglione L Effetti della cultivar, della concimazione azotata e dell epoca di raccolta sulla produzione del tabacco Burley di tipo americano in Italia. Il tabacco Vol. 1(1): Toderi G. Cacchi D. 1973Influenza della concimazione e della successione colturale su sostanza organica, azoto, e sulle rese delle colture. Riv.Agron., VII, interlandi.p65 53

4 54 Il Tabacco, 9 Figure 1. Effect of N fertilization factors on Burley tobacco price index. Figura 2. Effect of N fertilization factors on Burley tobacco yield and crop value. Figure 3. Effect of N fertilization factors and leaf position on filling value index of cured Burley tobacco. interlandi.p65 54

5 Interlandi et al. Produzione di Barley a diverse dosi e modalità di concimazione N 55 Figura 4. Effect of N fertilization factors and leaf position on burn rate index of Burley tobacco. interlandi.p65 55