Response of Barley to Nitrogen Fertilizer Sources, Sulphur Application, Inoculation with Mycorrhizae and Phosphate Slubilizing Bacteria in Salt Affected Soil

INTRODUCTION

Barley (Hordeum vulgare, L.) is grown as a commercial crop in one hundred countries around the world and it assumes the fourth rank in total cereal production in the world after wheat, rice and maize (FAO, 2004). Barley is considered as one of the most important cereal crops in Egypt. It is the major food source in many North African countries, because it tolerates the adverse environments compared to other cereal crops (Hayes et al., 2003). Nitrogen is the most important factor affecting crop morphology (Amanullah et al., 2008), increased grains yield with increasing nitrogen level (Singh and Uttam, 2000).

Plant growth is enhanced through conversion of nutritionally important elements as nitrogen and phosphorus by biological processes as nitrogen fixation and solubilization of rock phosphate (Mohammadi and Sohrabi, 2012).

Sulphur is considered as soil amendment. Oxidation of sulphur to H₂SO₄ is beneficial in alkaline soil to reduce pH, supply SO^-₄ to plants, makes phosphorus and micronutrients more available in reclaim soils (Lindemann et al.,1991). Ghani et al. (1997) reported that microbial population in soil is not a limiting factor in elemental sulphur oxidation. Now days, biofertilizers inoculation is considered to limit the use of mineral fertilizers and supports an effective tool for desert development under less polluted environment, decreasing production costs, maximizing crop yield due to providing them with an available nutritive clement (Metin et al., 2012). Soil micro- organisms bind soil particles into stable aggregates, which improve soil structure and reduce erosion potential (Shetty et al., 1994).

Biofertilizer can be used as fertilizer or as soil amendment, depending on its effect on the plant nutrition.Hence, a fertilizer is a source of quickly available nutrients that have a direct and short-term effect on plant growth, while a soil amendment can influence plant growth indirectly by improving the physical and biological properties of the soil (Angelova et al., 2013).

A- Mycorrihzal fungi have been shown to promote plant growth and salinity tolerance by many researchers. They promote salinity tolerance by utilizing various mechanisms, such as enhancing nutrient uptake, producing plant growth hormones, improving rhizospheric and soil conditions, improvement in photosynthetic activity or water use efficiency, accumulation of compatible solutes, and production of higher antioxidant enzymes. As a result, AM fungi are considered suitable for bioamelioration of saline soils (Asghari et al. 2005, Hajiboland et al., 2010, Manchanda and Garg 2011, and Evelin et al., 2012 and 2013).

The present investigation was carried out to study the effect of sulphur application rates, nitrogen sources and biofertilizers inoculation on growth, grains yield and its components of barley crop.

MATERIALS AND METHODS

Two filed experiments were carried out at the Experimental Farm, Faculty of Agriculture (Saba Basha), Alexandria University, Alexandria, Egypt, during 2013/2014 and 2014/2015 growing seasons to study effect of sulphur application rates, nitrogen fertilizer sources and biofertilizers inoculation on growth, grain yield and components, besides grain chemical contents of six- rows barley cv. Giza 123. A split- split plot design with three replicates were used in both seasons. Three sulphur application rates (0, 200 and 400 kg/ha) were randomly assigned in the main plots, three nitrogen sources, i.e. urea (46% N), ammonium nitrate (33.5% N) and ammonium sulphate (20.6% N) were allocated in sub-plots and three biofertilizers treatments (uninoculation, mycorrhizae and phosphorein at 400 g/ha.) were randomly distributed in sub-sub plots. Barley was sown on 4^th and 8^th December in two growing seasons, respectively, after maize planting. Seeding rate was (70 kg/ha.) and plot size was 10.5 m² (1/400 fed.) with 3.5 m length and 3 m width. Sulphur applied during seed bed preparation, nitrogen fertilizer at 144 kg/ha., were applied in two equal doses before the first and second irrigations.

Phosphorene (Bacillus megtherium phosphbacterium) was performed by coating barely grains with each product individually using a sticking substance (Arabic gum 5%) just before sowing. A- mycorrhizal fungi (Glomus macrocaripum) was obtained from Plant Production Department, Faculty of Agriculture (Saba Basha), Alexandria Uinversity at the rate of 250 spores was mixed with grain. Recommended cultural practices for barley production were conducted Soil physical and analyses were carried out in the two growing seasons and showed in Table (1).

Table (1). Physical and chemical properties of experimental soil in 2013/2014 and 2014/2015 seasons.

At harvest, one square meter was randomly taken in each sub- sub plot to determine number of spikes/m², ten random spikes were chosen in each sub-sub plot to calculate number of grains/spike and thousand kernel weight (g) was determined as an average of three samples.  Biological and grain yield by harvesting all plants in each sub-sub and converted to tons/ha., harvest index besids protein N, P and K grain content were determined.

Protein percentage was determined by estimating the total nitrogen in the grains and multiplied by 6.25 to obtain the protein percentage according to grains protein percentage to AOAC (1990). NPK percentages were determined in the dry grains. Their dry weights were determined following drying in a drying chamber to a constant weight at 75^oC for 72 hour according to Tandon (1995). After dryness, the plant samples were milled and stored for analysis as reported. However, 0.5g of the grains powder was wet-digested with H₂SO₄–H₂O₂ mixture according to (Lowther, 1980) and the following determinations were carried out in the digested solution to determine NPK. Total nitrogen was determined in digested plant material colorimetrically by Nessler`s method (Chapman andPratt, 1978). Phosphorus was determined by the Vanadomolyate yellow method as given by Jackson (1973) and the intensity of colour developed was read in spectrophotometer at 405nm. Potassium was determined according to the method described by method Jackson (1973) using Beckman Flame photometer.

Collected data were statistically analyzed using Co stat (2005) statiscal program, and treatment mean were compared using the least significand differences method (L.S.D) at 5% probability level as described by Gomez and Gomez (1984). 

RESULTS AND DISCUSSION

A-   Yield and yield attributes:

Data presented in Table (2) showed that studied yield components, i.e. spikes number and weight/m², number of spikelets and grains/spike and 1000- grain weight were, significantly, affected by sulphur application levels, nitrogen fertilizer sources and biofertilizer inoculation in the two studied seasons.

Increasing sulphur application from zero to 400 kg/ha., significantly increased the previous traits by 23.11% for number of spikes/m², 26.66 % for spikes weight/m², 17.90% for number of spikelets/spike, 14.48% for number of grains/spike and 7.21% for 1000- kernel weight as an average of the seasons, respectively. These increases in the studied yield components in barley crop might be reffered to the favorable effect of sulphur for decreeing soil pH and increasing phosphorus and micronutrients availability to plant (Lindemenn et al., 1991). 

Results also, demonstrated that nitrogen application as ammonium sulphate produced the highest number of spikes/m² (394.14 and 388.96), heaviest spikes weight/m² (279.19 and 269.50g), highest number of spikelets/spike (51.74 and 52.51), highest number of grains/spike (38.66 and 39.70) and heaviest 1000- grain weight (46.46 and 49.55g) in the first and second growing seasons, respectively.

Concerning biofertilization treatments, results in Table (2) revealed that inoculated barley grains with mycorrhizae or phosphorein significantly increased all the studied yield attributes in the two seasons compared to uninoculated grains.

Barley grains inoculated with phosphorein biofertilizer showed the highest number of spikes/m² (402.20), spikes weight/m² (284.82g), number of spikelets/spike (52.96), number of grains/spikes (40.24) and 1000- grains weight (48.12g) as an average of the two seasons. These increase could be due to the stimulation effect of micro- organisms that produce plant pgytohormons as IAA, Gas and SKs, which promote plant growth cell division, hence encouraging photosynthesis and assimilates accumulation (El- Khawas, 1990 and Hussein and Radwan 2001).

Concerning sulphur appliacation levels X N sources interaction effect, results in Table (3) showed that applied 400 kg S/ha to barley fertilized by ammonium sulphate shoed the highest number of spikes/m² (418.66) in the second season, weight of spikes/m² (335.17 and 300.77g), number of spikelets/spike (57.88 and 58.66) and number of grains/spike (42.0 and 43.44) in the first and second seasons, respectively.

Results presented in Table (3) indicated that biological, straw and grain yield besides harvest index were significantly affected with the three studied factors, where applied 400 kg S/ha produced the highest biological yield (18.03 and 17.87 ton/ha) straw yield (11.03 and 10.83 ton/ha), grain yield (6.97 and 7.03 ton/ha) and harvest index (38.51 and 39.19%) in the first and second seasons, respectively.

Data in Table (3) also, revealed that using ammonium sulphate as nitrogen source gave the highest values(17.24 and 16.99 ton/ha), (10.30 and 9.98 ton/ha), (6.99 and 6.78ton/ha) and (40.11 and 39.70%) for the respective traits in the two seasons, respectively. Also, inoculated barley grains with phosphorein showed the highest values (17.46 and 17.19 ton/ha), (10.61 and 10.52 ton/ha), (6.84 and 6.66 ton/ha) and (38.93 and 38.44%) for the previous characters in the two successive seasons.

On the other side, applied 400 kg S/ha combined with ammonium sulphate fertilization showed the highest biological, straw and grain yields besides H.I in the two seasons Table (4). However, sulphur application at 400 kg/ha inoculated grains with phosphorein produced the highest straw yield (12.02 ton/ha) in the first season, biological yield (19.99 and 19.77 ton/ha), grain yield (7.96 and 8.05 ton/ha) and H.I. (39.66 and 40.66%) in the first and second seasons, respectively. as reported in Table (5).

With respect to nitrogen sources X biofertilizers inoculation effect, results presented in Table (10) indicated that phosphorein inoculation combined with fertilization with ammonium sulphate produced that highest straw yield (10.81 ton/ha) in the first season, biological yield (18.72 and 18.78 ton/ha), grain yield (7.90 and 7.92 ton/ha) and harvest index (42.21 and 42.18%) in the two successive seasons, respectively..

Regarding three factors interaction effect, results presented in Table (7) showed that the highest straw yield in the first season (12.68 ton/ha), biological yield (21.77 and 21.78 ton/ha), grain yield (9.09 and 9.16 ton/ha) and HI (41.53 and 42.05%) in the first and second seasons, respectively. resulted from using 400 kg S/ha, ammonium sulphate as N source application to inoculated barley grains with phosphorein.

Table (2). Effect of sulphur application level, nitrogen fertilizer source and biofertilizers on barley yield components during 2013/2014 and 2014/2015 seasons.

Means at the same column followed by the same letter are statistically equaled according to L.S.D. at 0.05 value, ns: not significant and *: significant difference at 0.05 level of probability.

Table (3). Effect of sulphur application level, nitrogen fertilizer source and biofertilizers on barley yield during 2013/2014 and 2014/2015 seasons.

Means at the same column followed by the same letter are statistically equaled according to L.S.D. at 0.05 value, ns: not significant and  *: significant difference at 0.05 level of probability.

Table (4). The interaction between sulphur application levels and nitrogen fertilizer sources for biological yield, straw yield, grain yield (ton/ha) and harvest index (%) during 2013/2014 and 2014/2015 seasons.

Table (5). Effect of sulphur application level and biofertilizers on biological yield, straw yield, grain yield (ton/ha) and harvest index (%) during 2013/2014 and 2014/2015 seasons.

Table (6). Interaction between nitrogen fertilizer sources and biofertilizers for biological yield, straw yield, grain yield (ton/ha.) and harvest index (%) during 2013/2014 and 2014/2015 seasons.

Table (7). The interaction effect among sulphur application levels, nitrogen sources and biofertilizers inoculation for biological yield, straw yield, grain yield (ton/ha) and harvest index (%) during 2013/2014 and 2014/2015 seasons.

B- Chemical composition of grains:

Data in Table (8) illustrated the three studied factors effect on crude protein, nitrogen, phosphorus and potassium content of grain in the two seasons. Increasing sulphur application up to 400 kg/ha produced the highest protein (9.03 and 7.27 %), nitrogen (1.44 and 1.163 %), phosphorus (0.273 and 0.299 %) and potassium (0.550 and 0.616 %) content in the first and second seasons, respectively.

Also, barely fertilized with ammonium sulphate produced the highest mean values of the studied traits (9.27 and 7.23 %) for protein (1.485 and 1.157 %) phosphorus, (0.266 and 0.285 %) and potassium (0.550 and 0.616 %) content in the two successive seasons, respectively.

Inoculation with phosphorein gave the highest protein content (9.14 and 7.27 %) nitrogen (1.433 and 1.163 %) and potassium (0.540 and 0.619 %) in the first and second seasons, respectively. However, mycorrhizae inoculation produced the highest phosphorus content (0.273 and 0.287 %) in the first and second seasons, respectively.

Concerning the three factors of interaction, results presented in Table (8) revealed that there were significant interactions among the traits under this study.

The previous results pointed out that interaction among the three studied factors had significant interaction for the yield, yield components and grain chemical composition.   

Plant responses are deeply affected by the proportion of mineral N sources (Andrews et al., 2013). While NH⁺₄ as sole nutrient can induce toxicity symptoms, its co-provision with NO₃⁻ generally promotes a synergistic effect leading to growth enhancement (Britto andKronzucker, 2002). It is noteworthy that NH⁺₄  tolerance was related to high root N metabolism sus- tained by high GS activities (Cruz et al., 2006), which in maize appear to be associated with the capacity to cope with the C skeleton demands (Schortemeyer et al., 1997).

Table (8). Effect of sulphur application level, nitrogen fertilizer source and biofertilizers on protein in grains %, N, P and K percentage during 2013/2014 and 2014/2015 seasons.

Means at the same column followed by the same letter are statistically equaled according to L.S.D. at 0.05 value., ns : not significant and  *: significant difference at 0.05 level of probability.

Conclusion

In conclusion, applying 400 kg S/fed., and ammonium sulphate as nitrogen fertilizer source to inoculated barley grains of Giza 123 cultivar with phosphorein produced the highest grains yield, yield attributes and grains quality studied traits under Alexandria Governorate conditions.