Effects of Soil Fertilizers on Growth Indices, Morpho-Physiological Traits and Potassium content of Baurley Tobacco Cultivar

Tobacco with scientific name of (Nicotiana tabacum L.) belongs to Solanaceae family is one of the important industrial crops in the world that plays a critical role in economy of producing countries and its income from various products had a major share of the national income. Tobacco is an annual, short day length and self pollinated crop that its chromosomal number is 2n=48. The yield of plants depends upon several production factors. Among these proper, balanced nutrition plays a significant role. The main purpose of fertilization in tobacco plants not only the quantity but quality should be considered. Now tobacco farmers apply a large amount of fertilizer to improve yields, but these actions not only decrease tobacco leaf quality, but also cause fertilizer pollution. Organic and chemical fertilizers use has played a significant role in increase of crop yield. The use of compost and vermicompost in the soil, generally in order to maintain and increase aggregate stability and fertility of soils for farming and gardening in the past decade has been of particular importance. Increasing soil organic matter stocks and stability by addition of organic amendment offers a good way to substantially improve soil quality and therefore agricultural sustainability. The objective of this study was evaluate the effect of chemical and organic fertilizer on morpho-physiological and yield of tobacco in field conditions.
In order to study the effects of organic and chemical fertilizers on morpho-physiological traits of baurley tobacco cultivar, an experiment was counducted as based on a randomized complete block design with three replications during growing season of 2012-2013 at the research field of Shahrekord University located in 50º 49´ E longitude and 32º21´ N latitude.with sea level of 2116 meter. Treatments included chemical fertilizers based on the tobacco needs and soil test results, compost based on the tobacco needs and soil test results, 50 percent compost 50 percent chemical fertilizer, vermicompost based on the tobacco needs and soil test results, 50 percent vermicompost 50 percent chemical fertilizer and control (no use of fertilizer). Sowing in nursery was done in March 2013 and transplanted to field May 2013. After plowing and disking and leveling by rotary, tobacco seedling were transplanted in main field. In current study the space between rows was 80 cm and between plants on rows was 50 cm. Number row planting in each plots were 6 rows. The area of every plot was 5×4 m2. Traits of specific leaf area, leaf weight ratio, plant height, tips yield, total dry leaf yield and potassium content on leaf of tobacco were evaluated. The data were analyzed by using version 9.1 SAS. Least Significant Difference test was used to compare the means at 1% of significant. Also, the figures were draw by Excel 2010 software.
The results showed the highest specific leaf area and leaf weight ratio in all treatments achieved in the early stages of plant growth, and after that, this values decreased. Maximum specific leaf area and leaf weight ratio in the lastly stages of plant growth, respectively, were obtained from 50 percent compost 50 percent chemical fertilizer treatment and vermicompost treatment. Minimum specific leaf area in the lastly stages of plant growth was obtained from chemical fertilizer and vermicompost treatments. Minimum leaf weight ratio was obtained from chemical fertilizer treatment. Fertilization increased the plant height, tips yield, total dry leaf yield and potassium content on leaf of tobacco. The highest plant height with 162 cm and the tips yield with 216.5 g m-2 were obtained from chemical fertilizer treatment, wich were 2.1 and 4.8 times higher compared to control, respectivly. The highest total dry leaf yield with 350.4 g m-2 obtained from chemical fertilizer treatment and had not difference with compost treatment but showed significant increase with 2.8 and 2.3 times more with control. After that the highest total dry leaf yield, related to vermicompost, 50 percent compost 50 percent chemical fertilizer and 50 percent vermicompost 50 percent chemical fertilizer treatments. Minimum total dry leaf yield with 126.2 g m-2 was obtained from control treatment. Maximum potassium content on leaf was obtained from 50 percent compost 50 percent chemical fertilizer treatment and also chemical fertilizer treatment and control treatment with 2.34 percent had the lowest potassium content on leaf.
Therefore, in order to fulfill the objectives of sustainable agriculture and the adoption of a slight decrease in leaf yield, on condition of increasing the quality of the leaves, compost can be a good alternative to the use of chemical fertilizers in the tobacco fields.