The Effects of Fe , Mn and Zn Foliar Application on Yield , Ash and Protein Percentage of Forage Sorghum in Climatic Condition of Esfahan

Improving forage yield and quality remains a major concern of the producer. Among the various ways of supplying nutrient to the crops, the efficient utilization of nutrients by the plants is made through foliar application. Foliar application had significant effect on plant height, the number of leaf, the number of tiller, LAI, fresh forage yield, dry leaf yield, dry stem yield, total dry yield, dry leaf weight/dry stem weight ration and ash percentage. Application methods of micronutrients are very important to attain the best absorption. The results of this study demonstrated that, Fe, Zn and Mn had positive effect on yield and quality of forage sorghum. The highest plant height, LAI, Fresh forage yield, dry leaf and stem yield, total dry yield and dry leaf weight/dry stem weight was obtained in Zn+Fe+Mn application. The highest number of tiller was related to combination of Zn and Mn. The maximum ash percentage and appropriate protein percentage also was achieved in application of Zn+Fe+Mn. So, on the basis of the results, it seems that application Zn+Fe+Mn was suitable to gain high forage yield and gain to high quality.


Introduction
Sorghum (Sorghum bicolor (L.) Moench) is a major cereal food crop in many parts of the world (Shahrajabian et al., 2011).It is becoming an increasingly important forage crop in many regions of the world (Kasozi et al., 2005;Carmi et al., 2006).Zink extracts a great influence on basic plant life processes, such as (i) nitrogen metabolism, uptake of nitrogen and protein quality; (ii) photosynthesis-chlorophyll synthesis, carbon anhydrase activity; (iii) resistance to abiotic and biotic stresses protection against oxidative damage (Alloway, 2004;Cakmak, 2008;Potarzychi & Grzebisz, 2009;Tekale et al., 2009).Zink also plays an important role in the production of biomass (Kaya & Higgs, 2002;Cakmak, 2008).Iron plays essential roles in the metabolism of chlorophylls (Bybordu & Mamedov, 2010).Kakade et al. (2009) noted that the application of Fe and Zn give maximum number of flowers, weight and yield of flowers as compared to control.Hebbern et al. (2005), Mirzapor and Khoshgoftar (2006), Chatterjee and Khurana (2007), Fernandes et al. (2007) and Wissuwa et al. (2008) concluded the positive effects of Zn and Fe on yield, yield components and chemical compositions of plant.Magnesium (Mg) is an essential macro-element for plant growth (Trolove et al., 2008).Magnesium deficiency can impair export of photosynthate from leaves (Hermans, 2004), and reduces photosynthetic efficiency (Skinner & Matthews, 1990).Recent studies research had show that a small amount of nutrients, particularly Zn, Fe and Mn applied by foliar spraying increases significantly the yield of crops (Sarkar et al., 2007;Wissuwa et al., 2008;Bybordu & Mamedov, 2010;Sajedi, 2010).It was documented that zinc foliar application is a simple way for making quick correction of plant nutritional status, as reported for wheat (Erenoglu et al., 2002) and maize (Grzebisz et al., 2008).World health organization reported deficiencies of Zn and Fe in human population of developing countries.Shahrajabian et al. (2011) concluded that the number of tillers per plant ranged between 1.889 and 3.444.In their experiment the maximum number of leaves per plant and stem diameter was 11.38 and 21.42 mm, respectively.However, to the best of our knowledge, information regarding application method efficiency of Zn, Fe and Mn on yield and yield components of forage sorghum is not available.Therefore, the purpose of this research is to understand the effects of application of micronutrients as foliar application on forage sorghum.

Materials and Methods
This research was done at Research Farm, Faculty of Agriculture, Islamic Azad University, Khorasgan Branch (Esfahan) (latitude 32 o 40 ' N, longitude 51 o 58 ' E, and 1570 m elevation) in 2010.Soil Texture was silt clay with soil pH of 7.95 at 0-30 cm and 8 at 30-60 cm.EC was 1.9 and 1.6 at 0-30 and 30-60 cm, respectively.A randomized complete block design with four replications were used.Foliar application treatments included control treatment (without using any fertilizer) (T1), Fe (12%) (T4), Zn (10%) (T3), Mn (5%) (T4), Fe+Zn (T5), Fe+Mn (T6), Zn+Mn (T7) and Zn+Fe+Mn (T8).The soil preparation consisted of mouldboard ploughing followed by discing and smoothing with a land leveler.Ditches were prepared separately for each replication.Ditches were prepared separately for each replication.In this experiment, hybrid of forage sorghum, namely, Speed feed was used.Previous crop was barley and harvested on 15th June, and forage sorghum seeds were sown on 20th June with skillful workers.Application of nitrogen fertilizer was done in two stage, (i) 150 kg per ha was used before plantation and (ii) 80 kg N per ha was applied 45 days after plantation.The source of nitrogen fertilizer was urea.According to soil analysis and high amount of P and K, P and K fertilizers were not used.For sorghum, atrazine at 1.3 kg a. i./ha were applied within a day after planting to control post emergence of weeds.Also, weeds were controlled by hoe weeding.The first irrigation was done immediately after sowing and the other irrigation intervals were done according to plant's requirement (10 days).Each experimental plot had six rows, the length and width of each plot was 4 and 3 m, respectively.The distance between rows were 75 cm.Rows number 1, 4, 6 and also upto 50 cm, primer and edge lines were discarded from sampling.Rows number 2 and 3 were used for final sampling.For better irrigation, 2 m distances between main and sub plots and also each plot were designed.For evaluating of forage parameters in one cutting, 10 samples were harvested.After determination of fresh forage yield, plants were divided into separate organs and dried at 60 o C for 96 h in an aerated oven.Ash content determined by incinerating the samples in a muffle furnace at 550 o C for 4 h.Phosphorus estimated by colorimetric method (Badrzadeh et al., 2009).Dry matter yield of crops considered for comparison of yield production of the treatments.The amount of nitrogen calculated by Kjeldahl analysis from dry and ground samples, and then nitrogen will be multiply by 6.25 to determine protein content (Fallah & Tadayyon, 2009).Data were subjected to analysis of variance (ANOVA) using statistical analysis system, followed by Duncan's multiple range test and differences were considered significant at P<0.05 by MSTAT-C software.

Results and Discussion
The results revolved that all experimental characteristics expect of stem diameter, the number of leaf and protein percentage were significantly influenced by fertilizer foliar application.The highest plant height was related to foliar application of Zn+Fe+Mn (T8) (208 cm).This treatment had significant difference with all treatments, expect of Zn+Mn (T7), Fe+Mn (T6) and Fe+Zn foliar application (T5).The lowest plant height was achieved in control treatment (T1) (179 cm) (Table 1).Highest plant height is a good agronomical management to achieve more biomass in forage crops (Shahrajabian et al., 2011).There were no significant differences in number of leaf between foliar application treatments, but the highest number of leas was related to Zn+Fe+Mn foliar application (T8).The highest stem diameter was obtained in Fe foliar application (T2) (2.80 cm), but all differences between treatments were not significant.Application of Zn+Mn (T7) had obtained the highest number of tiller (1.8), but this treatment had no significant difference with T1 and T6.The minimum one also achieved in T8 (1.2).The maximum and the minimum LAI was obtained in Zn+Fe+Mn (T8) (8.06) and control treatment (T1) (6.7), respectively.T8 had significant differences in LAI with T7, T6, T5, T4, T3 and T2 (Table 1).When the economical aim is production of forage crops, suitable leaf area index (LAI) besides high plant height is so important (Shahrajabian et al., 2011).Application of Zn+Mn+Fe foliar application (T8) give the maximum fresh forage yield (125.2 t/ha), and differences between T8 and all other experimental treatments were significant.Shahrajabian et al. (2011) reported that the highest fresh yield in forage sorghum was 138.4 t/ha.Ravi et al. (2010) indicated that combination of Fe and Zn foliar spray recorded the highest yield on safflower.T8 had obtained the highest dry leaf (6.1 t/ha) and dry stem yield (6.0 t/ha).T8 had no significant difference in dry leaf yield and dry stem yield with T3 and T5, respectively.The lowest dry leaf yield and dry stem yield was related to T2 (3.9 t/ha), and T2 (4.3 t/ha), respectively.Toader et al. (2010) also reported that, in the case of an appropriate soil fertilization, the effect of foliar fertilization ensured at maximum parameters of efficiency.The maximum total dry yield was 12.2 t/ha and achieved in Zn+Fe+Mn foliar application (T8) and it had significance difference with T1, T2, T3, T4 and T7 (Table 2).Potarzycki and Grzebisz (2009) reported that yield forming effect of zink fertilizer revealed via improvement of yield structure elements.Thakare et al. (2005) also reported that sorghum can grow well and produce high biomass in addition to grain under dry conditions.The highest and the lowest dry leaf weight/dry stem weight was obtained in application of T8 (1.0%) and T2 (0.78%), respectively.This ratio is one of the main character that revealed the high quality of forage crops (Shahrajabian et al., 2011).T8 and T1 had obtained the highest (13.3%) and the lowest (12.1%) ash percentage, respectively.T8 had no significant differences with T7, T6 and T5, respectively.Yvin and Dufils (2010) and Kumar et al. (2011) concluded that the quality of plants can be influenced directly by foliar application.Shahrajabian et al. (2011) reported that the highest dry forage yield in forage sorghum was 11.12 t/ha.There were no significant differences in protein percentage between treatments, but the maximum one was related to T3 (12.9%)(Table 2).Chemical fertilizes play a dominant role in agricultural development (Machado et al., 2008).Understanding of forage quality content in plants is useful for determining forage plant capacity to achieve higher animal performance (Badrzadeh et al., 2008;Assadi & Khoshnood Yazdi, 2011).Common letters within each column do not differ significantly.

Conclusions
Micronutrients are required by plants in minute quantities, although these are very effective in regulating plant growth as they form a part of the enzyme system and thus regulate plant life (Pathak et al., 2011).Application methods of micronutrients are very important to attain the best absorption.The results of this study demonstrated that, Fe, Zn and Mn had positive effect on yield and quality of forage sorghum.The highest plant height, LAI, Fresh forage yield, dry leaf and stem yield, total dry yield and dry leaf weight/dry stem weight was obtained in Zn+Fe+Mn application.By managing of agronomic practice, quality of forage will be influenced (Dahmardeh et al., 2009).The maximum ash percentage and appropriate protein percentage also was achieved in application of Zn+Fe+Mn.The nutrient value of plant composition and feed quality is necessary for efficient animal production (Asaadi & Khoshnood Yazdi, 2011).So, on the basis of the results, it seems that application Zn+Fe+Mn was suitable to gain high forage yield and gain to high quality.

Table 1 .
Mean comparison for plant height (cm), stem diameter (cm), the number of tiller, LAI, fresh forage yield (t/ha), dry leaf yield (t/ha) and dry stem yield (t/ha)