The effect of spacing and nitrogen fertilizer levels on some agronomic, physical, and chemical characteristics of two varieties of cigar tobacco were compared over a 3-year period.At each of two nitrogen fertilizer levels, the variety Pennsylvania Broadleaf, irrespective of plant spacing, produced higher yields and returns per acre, more leaves per plant and weight per leaf, but a higher percentage of midrib and yellow trash leaf than the variety Resistant Havana 211. Although the differences between the varieties at each nitrogen level were relatively unaffected by plant spacing, the 20-in. spacing caused a decrease in yield, crop returns, and percentage of yellow leaf and an increase in weight per leaf and percentage of filler leaf from that obtained with the 16-in. spacing. An increase in nitrogen fertilizer from 24 to 60 lb per acre had little effect on Resistant Havana 211 other than to increase the weight per leaf. The additional nitrogen with Pennsylvania Broadleaf, however, increased the yield, crop returns, weight per leaf, and percentage of filler leaf. The variation in rate of nitrogen fertilizer had little effect on grade index, number of leaves per plant, and percentages of nicotine, nornicotine, and total alkaloids in both varieties.The combination of 16-in. spacing with 60 lb of nitrogen was superior to other combinations of 16- or 20-in. spacing with 24 or 60 lb of nitrogen per acre for the production of cigar filler leaf in each of two varieties.
Effect of nitrogen fertilization rates, plant spacing and their interaction on essential oil percentage and total flavonoid content of summer savory (Satureja hortensis L.) plant.
