Effect of Inoculation with Diazotrophs on Wheat Productivity under Different N-Fertilizer Levels in Sandy Soils

Abstract

Two field experiments were carried out on a sandy soil at Ismailia Agricultural Research Station located at 30º 35´ 41.901˝ N for Latitude and 32º 16´ 45.834˝ E for Longitude, Egypt, during two winter seasons of 2013/14 and 2014/15, to study the effect of inoculation with diazotrophs (Herbaspirillum sp., Azorhizobium caulinodans and Azospirillum brasilense) applied as a single treatment and\or as a mixture treatments under different levels of nitrogen, i.e., zero, 25, 50, 75 and 100 kg N/fed on the growth, yield and some yield components of wheat crop. Obtained results showed that there were significant increases in all wheat vegetative growth characters, yield and some yield components due to inoculation with any tested diaztotrophs. However, using mixture strains followed by Azospirillum brasilense surpassed other inoculated treatments or uninoculated one. Generally, all the inoculated treatments were the superior to in enhancing all wheat growth parameters, wheat yield and its components in the order of mixture> Azospirillum brasilense> Herbaspirillum sp.> Azorhizobium caulinodans> uninoculated.All wheat growth characters yield and its components increased significantly along with increasing N-fertilizer level. Due to the interaction between inoculation and N-fertilizer levels, the splendid results of wheat growth parameters, yield and its components were for wheat plants inoculated with the bacterial mixture inoculum followed by Azospirillum brasilense in combination with 50 kg N/fed, which showed significantly a positive response and gave values nearly similar to or higher than those given by the use of full N-fertilizer level (100 kg N/fed). It is of worth to note that inoculation with diazotrophs having excellent potential to be used with non-legumes not only because of their N 2 -fixing proficiency but also to their ability to acts as PGPR. The triple diazotrophs treatment may be acting as a good practice for sustaining wheat grain yield and reduce the reliance on chemical fertilizers in agriculture, to minimize the environmental pollution and to have safe healthy food.

Dual Inoculation with Azotobacter chroococcum MF135558 and Klebsiella oxytoca MF135559 Enhance the Growth and Yield of Wheat Plant and Reduce N-Fertilizers Usage

“…The pronounce increase in straw's NPK content of wheat plant is also due to the nutrients availability, which lead to the increase in plant height, tillers, leaves and weights. Results are in agreement with those obtained by Iniguez et al (2004) ; Ghazal et al (2011) ;Salim et al (2013) and Desoky and El-sayed (2016).…”

“…The pronounce increase in grain's NPK content of wheat plant is due to the nutrient availability in the rhizosphere as affected by microbial inoculation. Results are in agreement to those obtained by Iniguez et al (2004) ; Abou-Aly and Mady (2009) ; Ghazal et al (2011) ;Salim et al (2013) and Desoky and El-sayed (2016). 20.50 ab 3.040e -g 3.40 f-i 6.41 e-i 1.087 f-i 9.93 a T13 19.04 b-g 3.332 c 4.56 b 7.58 cd 1.300 a 6.99 fg T14 20.04 a-d 3.081 d-g 3.51 ef 8.15 a-c 1.210 bc 9.67 a T15 18.01 g-j 2.753 i 2.85 o 6.36 e-i 0.733 o 6.02 k T16 18.22 f-j 2.817 hi 2.93 no 5.85 g-j 0.918 m 5.68 l T17 17.49 h-j 2.819 hi 3.05 mn 6.10 f-i 0.846 n 7.37 e T18 18.84 d-i 2.991 fg 3.22 j-l 5.10 j 0.805 n 7.02 fg T19 17.39 ij 2.935 gh 3.25 i-l 6.17 f-i 0.920 m 5.53 l T20 18.48 e-j 3.114 d-f 3.75 d 6.49 e-h 1.154 c-e 7.38 e T21 19.63 b-f 2.365 k 3.23 j-l 5.48 ij 1.080 h-j 7.29 ef T22 18.15 f-j 2.794 hi 3.12 lm 6.78 d-g 1.085 g-j 5.40 l T23 18.84 d-i 2.493 jk 3.14 k-m 5.75 h-j 1.008 kl 5.41 l T24 17.20 j 3.104 d-f 4.28 c 5.73 h-j 1.085 g-j 6.26 i-k T25 17.48 h-j 2.527 j 2.81 o 5.47 ij 1.108 e-h 6.17 jk *Means followed by different letter(s) in the column are significantly different Also, data in Table 7 shows the effect of chemical fertilization and bacterial inoculation application of wheat plants on straw NPK content.…”

“…Also, the increase of the yield by increasing the N supply might due to the increase in the dry weight of vegetative organs, which could be considered as a criterion for the photosynthetic efficiency of the plant. Similar observations were reported by (Hussain and Hasnain (2011) ;Saber et al (2012) and Desoky and El-sayed (2016) who noted that using bio-fertilizers improves grain and straw yield.…”

“…In fact, the increase of nutrients content in plant can be explained by an enhancement of the biological N 2 -fixation and/or production of organic acids to solubilize P and K and/or production of certain growth promoting substances, which positively affect root development and consequently their function in the uptake of both water and nutrients. Results are in agreement with those of Iniguez et al (2004) ; Ghazal et al (2011) ; Salim et al (2013) and Desoky and El-sayed (2016). Table 6 show the effect of different Nlevels and / or microbial inoculation on some wheat yield parameters i.e., spike length (cm), spike weight (g), number of grains/spike and weight of 1000 grains (g).…”

“…The pronounced increase in wheat yield parameters is due to N 2 -fixation performance as well as P and K mobilization, phytohormone production and saving the bio-protection against phytopathogens, also the role of nitrogen nutrient in the anabolic plant processes, which has very important function as main constituent of protein, amino acids and many essential compounds in plant system. Similar observations were reported by (Hussain and Hasnain (2011) ;Saber et al (2012) ; Salim et al (2013) and Desoky and El-sayed (2016) who noted that using bio-fertilizers improves wheat yield parameters i.e., spike length (cm), spike weight (g), number of grains/spike and weight of 1000 grains.…”