EFFECT OF NITROXIN AND HUMIC ACID ON YIELD AND YIELD COMPONENTS OF FABA BEAN

Quality and quantity improvement of crops using organic matter and low-cost method in the field is very important. Bio-fertilizer nitroxin and humic acid can increase root and shoot biomass through improved intake of nutrition and they can lead to quality and quantity improvement of product. An experiment was carried out as a completely randomized block design with 4 treatments to study the effect of nitroxin and humic acid on faba bean (Vicia faba L.) traits. Trial treatments included control, nitroxin, humic acid and nitroxin + humic acid. Analysis of variance showed that the effect of combination of nitroxin + humic acid was significant (p< 1%) on some traits such as stem height and yield of faba bean. The highest yield (2,315 kg ha) was obtained under nitroxin + humic acid treatment.


Introduction
Faba bean (Vicia faba L.) is now grown worldwide on 2.56 million ha.The total world production of faba bean is 4.56 million tons (Fouad et al., 2013).China is the most important producer of faba bean in Asia.Cultivation area for faba bean in the world is 2.9 million ha (Turpin et al., 2002) and in Iran, it is 98,920 ha (Khamooshi et al., 2012).Faba bean yield in Iran is 1.2 t ha -1 , which is lower than in Asia (1.7 t ha -1 ).Unfortunately, production rate and yield rate per unit area are not suitable in Iran, and in most cases, yields have no quality due to mismanagement and unsuitable planting substrate.Humic materials are the final product of decomposition of each organic matter in specific conditions by a special microorganism.Some of the characteristics of humic acid are: a) it improves soil structure; b) it contributes in rooting; c) it increases plant growth promoting bacteria in soil and finally reduces toxicity of fertilizers and extra nutrients in soil (Samavat, 2007).Nitroxin is an Azotobacter biological fertilizer which leads to higher quality yields.
An increase of soil nitrate was observed one month after applying green manure to soil in Lithuania (Nedzinskiene et al., 2002).Most agricultural soils lack nitrogen (N) due to an unstable mineral form of nitrogen, so according to results of researches, we can increase stable forms of N and reduce chemical fertilizers by using green manure, which leads to stable cultivation (Cordovil et al., 2007).It has been shown in the past two decades that a wide range of soil bacteria in rhizosphere can improve growth of important crops.Azospirillum and Azotobacter among these bacteria have attracted more attention due to beneficial effects on symbiotic relationships with some crops such as corn, sorghum and wheat (Mishra et al., 1998;Zaied et al., 2003).Meshram and Shende (1982) showed the positive effect of Azotobacter especially with farmyard manure in growth media of crops such as wheat, corn and millet.Eyheraguibel et al. (2008) studied the effect of humic acid on germination of corn seeds and found that humic acid can increase the length of corn seed radicle; it also can increase stem growth.Humic acid promotes the reproductive stage of plant.Farazandeh et al. (2011) studied the effect of humic acid and date of planting on growth of corn seeds.Their results showed that the effect of humic acid is significant on plant height and ear of maize.Akinci et al. (2009) found that humic acid increased the contents of Na and K significantly and the content of Ca and Fe was not significantly increased whereas Cu, Mn and Zn content decreased under humic acid treatment in broad bean.Thus, current research was aimed at increasing faba bean yield using humic acid and nitroxin.

Material and Methods
The trial was done in 2011 as a randomized complete block design with 4 treatments and 3 replications in Shaft city, Guilan province, Iran.Test treatments included nitroxin, humic acid, nitroxin + humic acid and control (no treatment).There are 10 8 Azospirillum and Azotobacter per ml of nitroxin.The bacteria in nitroxin biofertilizer can develop balanced shoots and roots of plant by a growth promoting hormone, like Auxin, and amino acid (Azimzadeh and Azimzadeh, 2013).Nitroxin and humic acid were produced by Mehr Asia Biotechnology Company in Iran.In order to apply various treatments, 2 l of liquid biological fertilizer (nitroxin) was mixed completely with seeds and after inoculation all treated seeds were dried in shadow and finally dried seeds were planted in January.The treated seeds were planted 10−15 cm apart in the row, with rows 60 cm apart.Humic acid was applied in amount of 25g m -2 in granular form.The grains were harvested on May 24.Measured traits included stem height, chlorophyll content (using SPAD chlorophyll meter Opti-Sciences CCM-200), fresh and dry weight of shoots (by oven drying at 105 C for 16 hr), grain yield and fresh and dry weight of root.Data were analyzed by MSTATC and data mean comparisons were done by Tukey's test.

Results and Discussion
According to analysis of variance (Table 1), the effect of treatments was significant on stem height of faba bean (p<0.01).Maximum stem height is achieved by humic acid + nitroxin, in which stem height was approximately 50% higher than control (Table 2).Farazandeh et al. (2011) studied inoculation of corn by Azospirillum brasilense and Azotobacter bacteria with a different amount of manure.They found that plant height was significantly affected by treatments and reported that the effect of humic acid was significant on plant height and ear size.
Table1.Analysis of variance of faba bean experimental traits.According to Table 1, the effect of treatments was significant (p<1%) on chlorophyll.Based on mean comparison (Table 2), maximum amount of chlorophyll was achieved in humic acid treatment.Humic acid leads to chelating of iron, zinc, manganese, copper and their easy absorption.These chelates improve glucose, proteins, vitamins and chlorophyll production.Thus, yield and quality of crops rise (Samavat, 2007).
Based on the results given in Table 1, treatments affected significantly yield of faba bean.According to Table 2, maximum amount of yield was achieved in humic acid + nitroxin treatment.Bozorgi et al. (2011) reported that the highest yield and yield components of faba bean were obtained by treatment with 30 kg/ha of pure nitrogen + nitroxin inoculation.Bakhshaei et al. (2010) studied the effect of biological fertilizer and a different amount of chemical fertilizer on yield of wheat.They revealed that combined use of biological and chemical fertilizers influenced significantly yield characteristics including: grain yield, biological yield and harvest index (p<1%).Organic fertilizers lead to a significant increase in grain yield and biological yield of Ricinus communis (Amin-Ghafoori et al. 2010).According to Table 1, the effect of treatments was significant on fresh and dry weight of root.Mean comparison (Table 2) showed that maximum fresh and dry weight of root is achieved in humic acid + nitroxin treatment.Table 2.The effect of nitroxin and humic acid on stem height, chlorophyll, yield, number of seeds/pod, number of pods and fresh and dry weights of shoots and roots.Hasanabadi et al. (2010) studied the effect of biological and chemical fertilizers on barley morphological characteristics.They found that growth stimulating bacteria can increase the growth and amount of nutrients in grain.This is mostly because of producing plant growth regulators by bacteria which have impact on root growth, water and nutrition absorption from soil.Humic acid indirectly can influence plant growth.Shoots and root are stimulated by humic acid but effects on the root are more obvious.Humic acid increases the absorption of nitrogen, potassium, calcium, magnesium and phosphorus (Sabzevari and Khazaei, 2009).Hajiloo et al. (2010) studied the effect of inoculation of Azospirillum brasilense and Azotobacter combined with different amounts of fertilizers on growth of corn.Dry weight of plant and root was affected significantly under all treatments.Humic acid plays an important role in rooting and generally adding humic acid to soil increases nucleic acids and amino acids and these compounds improve cell multiplying in plant especially in roots.These materials keep the water via bonding to soil minerals and regulate the temperature of rhizosphere; on the other hand, they increase metabolism and permeability of cell wall, which leads to an increase of absorption in roots.Bonding to water molecules reduces evapotranspiration in plant and increases plant resistance to drought.Humic acid can make balance in nutrient absorption.One of the main problems of farmers is the imbalance of nutrients in soil which affects absorption or non-absorption of elements.For example, the absorption of copper decreases when calcium is added to soil.Humic acid application causes reduction of nitrogen and phosphorus application can make balance in improperly fertilized soils.

Conclusion
Results of the present study revealed that most trial traits of faba bean (Vicia faba L.) including stem height, yield and yield components were affected by combined using of bio-fertilizing nitroxin + humic acid.According to results, nitroxin and humic acid are recommended to be used simultaneously in faba bean field of Guilan province.But as a complement, it is better to study effects of different amounts of biological fertilizers on other plant.
Means followed by the same letters in each column are not significantly different at 5% level according to Tukey's test.