Growth, yield and essential oil content of three cultivars of basil grown under different levels of nitrogen in the field

A field experiment was conducted in Southern Italy to investigate the effect of different nitrogen (N) rates (0, 100 or 300 kg ha1) on the number of branchings and leaves per plant, plant height, yield of above-ground fresh biomass, total leaf area, dry weight, leaf-to-stem ratio, leaf essential oil content and the essential oil quality at commercial harvest (full bloom) of the three cultivars of basil (Ocimum basilicum L.): (i) ‘‘Mostruoso mammouth’’ (MM); (ii) ‘‘Genovese profumatissimo’’ (GP); (iii) ‘‘Napoletano a foglia di lattuga’’ (NFL). Nitrogen fertilization up to 300 kg ha1 increased yield of above-ground and leaf fresh biomass, leaf essential oil yield, but it did not affect leaf-to-stem ratio, plant height and the numberof branchings per plant. The increase in essential oil yield induced by N fertilization depended on an increase in both leaf essential oil concentration and leaf biomass. The increase in LAI with increasing N fertilization was due to an increase in leaf number per plant rather than in individual leaf expansion. The cultivar GP was different in morphology from MM and NFL, since it had greater leaf number and plant height, but lower leaf-to stem ratio and LAI. The physiological efficiency of N use (PE) in producing above-ground biomass was not related to N application whereas PE in producing essential oil (PE-oil) tended to increase with increasing levels of N applied.With regard to the effect of the cultivar, GP was less efficient in N use for oil production thanMMand NFL since PE-oil of GP was lower while leaf N and PE-biomass were higher than the other cultivars. NFL was the richest in methyl chavicol but the lowest in linalool, whereas MM and GP contained linalool and eugenol

Effect of increasing nitrogen fertilization rate on yield and quality of Burley tobacco (Nicotiana tabacum L.) grown under stressed and well-watered conditions

Non-optimal levels of N and water cause adverse effects in tobacco, particularly on the quality of cured leaves, which shows nnbalanced chemical properties or generally non-marketable characteristics. This research aimed to study the effects of N fertilisation on leaf yield and quality (mainly smoke injury) of Burley tobacco in both stressed and well-watered conditions. Two water regimes (a rainfed control, RC, irrigated only for seedling establishment and a wellwatered treatment, WW, receiving the full amount of crop evapotranspiration, ETc) and 4 N fertilisation rates (0, 120, 240 and 360 kg ha-IN) were factorially combined in a field experiment carried out in southem Italy in 1994 and 1995. Yield of cured leaves and yield components per plot were determined on the whole plant and per stalk position. Quality of cigarettes and smoke was determined. The RC yielded significantly less than the WW. The yield of cured leaves increased significantly with increasing N fertilisation ti11 the rate of 120 kg ha-', while higher doses than 120 did not produce any substantial changes. As regards quality, the higher number of aspirations per cigarette was recorded in 1995 while the tar content was higher in 1994. Water regimes significantly influenced al1 parameters. For the whole plant, yield in 1994 was lower than 1995 (-30%) although the yield reduction in 1994 was equally distributed among each layer. Nicotine and tar content as well as number of aspirations per cigarette (burning rate) were favourably affected by irrigation. The increase in N fertilisation increased nicotine content while no effect emerged in tar content due to nitrogen

Soil management affects yield components of young olive trees under deficit irrigation

We compared vegetative growth, fruit characteristics and yield components of young olive trees (Olea europaea L. 'Frantoio') grown under either shallow tillage (ST) or permanent grass cover (GC) in a sandy-loam soil over four years. The soil was tilled from the year of planting (2003) until October 2004, when both soil management treatments were established. The ST treatment was kept weed-free by disking (about 0.15 m depth), whereas the GC was obtained by letting the natural flora grow. Trees were fully irrigated until year 3 after planting, when deficit irrigation (about 50% of full) was started for both soil treatments. Trunk cross sectional area (TCSA) of GC trees was 74 and 83% that of ST trees at the end of the 2006 and 2009 growing seasons, respectively. Fruit yield and oil yield of GC trees were 60 and 66% those of ST ones, respectively; however, when expressed on a TCSA basis, they resulted 85 and 94%, respectively. Yield components were differently affected by soil management. The number of fruits of the GC treatment was significantly lower than that of the ST treatment. The oil content in the mesocarp was similar for both treatments. Differences in fruit weight and pulp/pit ratio between treatments were likely due to the crop level rather than soil management practices