Effects Of Planting Density And Nitrogen Fertilization Rate On Growth, Yield And Quality Of Flue-cured Tobacco

The field experiment was conducted to study the effects of nitrogen fertilization rate, planting density and its interaction on the growing development, the yield, the quality and the production value of flue-cured tobacco Yunyan87. The results from this study are useful to improve the level of production and tobacco leaf quality in Changde tobacco-growing areas. The main results are as follows:The effects of nitrogen fertilization rate on the growing development, the yield, the quality and the production value of flue-cured tobacco Yunyan87 in 2014. The results showed that the growth rate of tobacco plants increased with certain nitrogen fertilizer and reached resettling stage early. Improving nitrogen fertilizer lengthened growth period and caused the tobacco plants reached lower leaf mature stage and upper leaf mature stage late, it was propitious to development of tobacco plants. Moreover, the economical characters included plant height, stem girth, leaf weight, effective leaves and single plant leaf area index increased markedly when the nitrogen application increased, but the effective leaves and single plant leaf area index decreased when the nitrogen application was 150 kg/ha. It was also found that the contents of nicotine, total chlorine, total sugar, reducing sugar and total nitrogen in the leaves of tobacco were increased with nitrogen supply increased, and the quality of tobacco leaves improved. The yield, price, the highest class leaf proportion and the economic benefit increased with certain nitrogen fertilizer. However, excessive Nitrogenous fertilizer could reduce the quality of tobacco leaves and drive the price down, the economic benefit fell. In summary, this study indicated that the price and economic benefit was highest when the nitrogen rate was 150 kg/ha, the price was 27.1 yuan per kilogram and the economic benefit was 55890 yuan per hectare. The yield was highest (2112.0 kg/ha) when the nitrogen rate was 135kg/ha.The effects of planting density on the growing development, the yield, the quality and the production value of flue-cured tobacco Yunyan87 in 2014. The results showed that the plant height and node length increased and the single plant leaf area index, stem girth and leaf weight decreased with the planting density increased, but the growth period of tobacco plants had not been affected. The contents of total sugar and reducing sugar in the leaves of tobacco were increased and the contents of nicotine, total nitrogen and total potassium in the leaves of tobacco were decreased with the planting density increased. The highest class leaf proportion was decreased and the yield was increased with the planting density increased. In summary, this study indicated that the yield was highest (2198.5 kg/ha) when the planting density was 1.80×10~4 plants per hectare, and the economic benefit was highest (50434.8 yuan per hectare) when the planting density was 1.65×10~4 plants per hectare.The effects of the interaction of planting density and nitrogen fertilization rate on the growing development, the yield, the quality and the production value of flue-cured tobacco Yunyan87 in 2014. The results showed that flue-cured tobacco growth period was mainly affected by nitrogen fertilization rate, and the growth period of tobacco plants had not been affected by planting density. The nitrogen fertilization and clipping height had significant effect on plant height, node length, single plant leaf area index, stem girth and leaf weight of the tobacco plants, had significant effect on the contents of total sugar and reducing sugar in the leaves of tobacco and the contents of nicotine in the lower and middle leaves of tobacco, also had significant effect on the yield, the price and the highest class leaf proportion of tobacco. Both the contents of total sugar and reducing sugar in the upper leaves of tobacco displayed significant interaction between planting density and nitrogen fertilization. The interaction between the planting density and nitrogen fertilization also had significant effect on the contents of reducing sugar and total potassium in the lower and middle leaves of tobacco. Nitrogen fertilization was the dominant factor affecting the plant height, node length, single plant leaf area index, leaf weight, the contents of total chlorine, the contents of total potassium, the contents of total nitrogen, the yield, the price and the highest class leaf proportion of tobacco. Planting density was the dominant factor affecting the stem girth, the highest class leaf proportion and the contents of nicotine, total sugar and reducing sugar in the leaves of tobacco. In summary, this study indicated that the yield was highest (210~4.6 kg/ha) when the planting density was 1.80×10~4 plants per hectare and the nitrogen rate was 150 kg/ha, the economic benefit was highest (52729.7 yuan per hectare) when the planting density was 1.65×10~4 plants per hectare and the nitrogen rate was135kg/ha.From what has been discussed above, nitrogen fertilization rate, planting density and its interaction had significant effect on the growing development, the yield, the quality and the production value of flue-cured tobacco Yunyan87. Reasonable planting density and nitrogen fertilization rate were important measures to improve the quality of flue-cured tobacco, reduce the production cost and improve economic benefit. In order to achieve high production purposes, we must to choose suitable planting density and nitrogen fertilizer according to the different ecological factors.