Hojjat Salehzadeh; Manouchehr Gholi pour; Hamid Abbasdokht; Mehdi Baradaran
Abstract
Nitrogen (N) affects adversely the tobacco yield quantity and quality as it increases yield, Chlorine and nicotine contents, but decrease potassium content. This experiment was aimed at optimization of (the balance between) N concentration in leaf, stem and root to increase both yield quantity and quality ...
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Nitrogen (N) affects adversely the tobacco yield quantity and quality as it increases yield, Chlorine and nicotine contents, but decrease potassium content. This experiment was aimed at optimization of (the balance between) N concentration in leaf, stem and root to increase both yield quantity and quality (high potassium, low Chlorine and medium nicotine contents) using artificial neural network. Two field experiments based on complete block design with three replications were conducted in Tirtash and Urmia tobacco research centers. Treatments were factorial arrangement of two N sources (urea and nitrate ammonium) and four application patterns (basal, 2/3 basal and 1/3 after initiation of rapid growth (AIRG), 1/2 basal and 1/2 at AIRG, 1/3 basal and 2/3 at AIRG). The N concentration of leaf, stem and root (model inputs) was measured in 30, 50, 70, 85 and 100 days after transplanting. After harvesting, the quantity of cured leaf and its Cl, K and nicotine content (model outputs) were also determined. The results indicated that a model with one hidden layer and configuration of 15-15-4 is appropriate and there were no significant different between two N sources. The best pattern was use of nitrate ammonium in 2/3 basal and urea 1/3 basal. The average value of optimized N concentration was 3.06, 2.42 and 1.5 percent for leaf, stem and root, respectively. These optimized concentrations can lead to potential increase in quality and quantity of tobacco which should be taken into consideration by breeders and agronomists.
Majid Jafaraghaei; Amir hooshang Jalali
Abstract
To investigate the effect of water treatment and plant density on yield and yield components of two cotton cultivar, a two-year experiment (2006-2007) was carried out in Esfahan Agricultural Research Center. The use of a split plot factorial based on complete block with four replications for study. Two ...
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To investigate the effect of water treatment and plant density on yield and yield components of two cotton cultivar, a two-year experiment (2006-2007) was carried out in Esfahan Agricultural Research Center. The use of a split plot factorial based on complete block with four replications for study. Two irrigation levels 135 (I1) and 180 (I2) mm of cumulative pan evaporation Class A, from flowering stage to the end of growth were assigned as main plots and treatment combination of two varieties of Mehr and Oltan of cotton and plant spacing 12, 15 and 18 cm (respectively, 120.95 and 80 thousand plants ha-1) were assigned made up as subplots. The results showed that both cultivars Mehr and Oltan in the density of 95 thousand plants per hectare in I1 irrigation treatments, respectively, with 2805 and 2745 kg ha-1 of yields produced the highest levels of yield compared to other treatments. In the I2 irrigation treatment and 95 thousand plants ha-1 density, Oltan cultivars producing 2119 kg ha-1, and had lowest yield compared to other treatments. In both cultivars in 95 thousand plants ha-1, between the two treatments of irrigation levels, no significant differences in terms of leaf dry weight. The results showed that irrigation after flowering phase until the end of growth, based on 135 mm evaporation basin A and the density of 95 thousand plants ha-1 can be proposed, for both cultivars studied.
Amir hooshang Jalali; Peyman Jafari
Abstract
To investigate the effect of K fertilizer on yield and yield components of three watermelon cultivars, a two-year study (2007-2008) was conducted in Ardestan Agricultural Research Center (Isfahan province) by using of split plot randomized based on complete block design in three replications. Three watermelon ...
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To investigate the effect of K fertilizer on yield and yield components of three watermelon cultivars, a two-year study (2007-2008) was conducted in Ardestan Agricultural Research Center (Isfahan province) by using of split plot randomized based on complete block design in three replications. Three watermelon cultivars (‘Sugar baby’, ‘Charleston Grey’ and ‘Mahbubi’), were assigned as main plots and four K fertilizer levels (zero, 50, 100, and 150 kg K.ha-1) were assigned as subplots. Two and three times higher than consumption of K fertilizer (100 and 150 kg K.ha-1) in compared to normal conditions (without salinity), led to a 24.8 and 18.5 percent increase in yield of ‘Charlston Gray’ and ‘Sugar Baby’, respectively. The highest fruit yield (39112 kg.ha-1), was obtained using 150 kg K.ha-1 in ‘Charleston Gray’ cultivar. Potassium applications at all levels, increased fruit number in ‘Sugar Baby’ and fruit weight in ‘Charleston Gray’, were considered as the main reason for increasing yield. By increasing of K application, the ratio of Na/K in the leaves from 0.61 to 0.33 and in the stems from 0.81 to 0.4 was decreased. The results indicated that in saline conditions, higher levels of K fertilizers can reduce the deleterious effects of salinity and thus may improve watermelon yield.