Predicting maize and soybean crops dry biomass through rhizobacteria microorganisms activity on foliar bio-fertilizer in an arid agro-climate: A multiple linear regression analysis

After previously showing rhizobacteria Pseudomonas fluorescence and foliar bio-fertilizer mixture as a suitable practice in improving maize and soybean crops development and dry biomass, this study thus embark on predicting the above-mentioned plants dry biomass feature through their yield and growth parameters by assessing P. fluorescence activities on foliar bio-fertilizer in an arid agro-climate. For this purpose, several scripts and functions from our previous computational statistic pipeline, developed in R programming environment were partially used for statistical survey. Several multiple linear regression models have been achieved aimed at understanding the links between maize and soybean crops (i) dry biomass, (ii) yield and (iii) growth features as well as highlights the synergic roles of rhizobacteria microorganisms and foliar bio-fertilizer on that relationship. Findings, revealed as expected, a significant difference in term of crops development between plants from seeds without treatment and those from seeds under (i) rhizobacteria, (ii) rhizobacteri + foliar bio-fertilizer mixture and (iii) foliar biofertilizer treatments (p<0.05). Also, yield parameters exhibited a substantial variability reacting to rhizobacteria microorganism as well as to rhizobacteria microorganism + foliar bio-fertilizer mixture as opposed to growth features. Hence, the present results clearly showed significant difference between rhizobacteria microorganism and foliar bio-fertilizer activities impacting both maize and soybean crops yield and growth features (p<0.05). Indeed, findings suggested a selective impact of rhizobacteria microorganisms (P. fluorescence) on processed plants yield features. The same findings exhibited P. fluorescence and foliar bio-fertilizer mixture, as adjusting the synergy between both processed crops growth and yield parameters by improving dry biomass feature (p= 0.17). Finally, this study emphasized rhizobacteria microorganism’s activities on foliar bio-fertilizer in an arid agro-climate low fertile soil as a weighty promoter improving maize and soybean crops dry biomass by normalizing the relationship concerning growth and yield features.


INTRODUCTION
Soil composition is generally conditioned by many factors such as vegetation, climate (agro-climate) and environmental factors as well as by microorganism including bacteria, fungi and variety of insects and worms alongside protozoa activities on the earth.Continued interactions between these features enable guaranteeing and maintaining long term soil productiveness.Plant development is strongly correlated with soil nutriment availability.So, for constant growth, plants need several macro-elements such as nitrogen (N), phosphorous (P), potassium (K), calcium (Ca), magnesium (Mg) and sulfur (S).Also, deficiency of these inorganic chemical elements in soil intended for agricultural practices compel farmers to use chemical fertilizers that have been recovered over time to be potential environmental and water pollutants.Thus, cultivable soil composition dynamism strongly depend on farmers practices, due to the use of pesticides as well as fertilizers.For optimal plant growth, the soil must be capable of storing the above-mentioned nutrients and transporting them to the root surface for endorsement by plant.However, findings suggest that, one of the most important factors in the generation of high yields from cereal cultivars is nitrogen (N) fertilizer; hence, farmers keep applying high amounts of the fertilizers which is very expensive and make the environment perilous especially when used discriminately.In addition, more than 50% of the applied nitrogen (N) fertilizers are somehow lost through different processes which is not limited to cash loss by the farmers.N is lost through different mechanisms including ammonia volatilization, denitrification and leaching losses, causing environmental pollution problems (Choudhury and Kennedy, 2005).Crop scientists all over the world are facing this alarming situation and are trying to overcome this condition by exploring alternative sources which is cost effective and save the environment.Bio-fertilizer, an alternative source of N-fertilizer, especially plant growth promoting Rhizobacteria (PGPR) affects plant growth by producing and releasing secondary metabolites, facilitating the availability and uptake of certain nutrients from the root environment and inhibiting plant pathogenic organisms in the rhizosphere (Kumar et al., 2008).It is noteworthy to emphasize that PGPR are free living bacteria, isolated from the rhizosphere, which when applied to seeds or crops, enhance the growth of the plant or reduce the damage from soil borne plant pathogens.Plant growth promoting Rhizobacteria can on the one hand form a symbiotic relationship with the plants and on the other hand, freely live in the soil though are found near or even the roots of plants.Generally, the impact of rhizobacteria on plant growth and health may be classified as neutral, deleterious or beneficial.Beneficial free living bacteria referred to as plant growth promoting rhizobacteria are found in the rhizosphere of the roots of many different plants.Among the means available to achieve sustainability in agriculture production, bio-fertilizers plays an important and key role because it processes many desirable soil properties and exerts beneficial effect on the physical, chemical and biological characteristics of the soil.Based on this, bio-fertilizers because of its vital role in maintaining long term soil fertility could be requested for many agricultural soils (Khosro and Yousef, 2012;Biari et al., 2008).It has been fully sustained that intensive use of mineral fertilizers can cause problems as the flow of these fertilizers into rivers, lakes and streams constitutes a source of pollution (van Keulen andBreman, 1990, Umesha et al., 2014).It is therefore appropriate to find alternative solutions at the overuse of chemical fertilizers.Bio-fertilizer are found to positively contribute to soil fertility, resulting in an increase in crop yield without causing any environmental, water or soil pollution hazards (Umesha et al, 2014).Research work has already been undertaken on the potential effect of bio-fertilizers on crop yields.Hernandez et al. (2010) claimed that inoculation of maize seed with rhizobacteria in combination with a dose of 120 kg N ha -1 results in an increase of around 25% of returns compared to those obtained with the same dose of nitrogen but without inoculation with microorganisms.Also, the combination of rhizobacteria raised with a dose of 120 kg N ha -1 can increase over 60% the maize yields in comparison with those obtained in plots without nitrogen application or inoculation of bacteria (Hernandez et al. 2010).From the previous studies and others, a positive interaction between Pseudomonas fluorescence and foliar biofertilizer promoting rice (Oryza sativa L.), maize (Zea mays L.) and soybean (Glycine max L.) crops growth and yield was suspected, as well as enhancing the resistance against pathogens (Ahemad and Khan, 2011;Adolphe et al, 2012;Munees et al. 2013;Pérez-Montaño et al, 2014;Diarrassouba et al, 2015).Also, recent findings suggested that the combined use of Pseudomonas fluorescence biofertilizer as plant growth-promoting rhizobacteria (PGPR) and inorganic nitrogen fertilizer has been found promising not only in maintaining and sustaining high productivity but in providing stability to rice crop (Oryza sativa L.) production and minimizing the cost of inputs and environmental pollution (Nehal, 2015).Consequently, integrated use of PGPR Pseudomonas along with inorganic and organic nutrient sources provides a sustainable agricultural ecosystem.From the results and observations, it was necessary to evaluate via a computational bio-statistical survey, the interaction *Corresponding author.E-mail: dgnoel7@gmail.com,noel.dago@upgc.edu.ci.Tel: (+39) 3381426596 or (+225) 48397811.
Author(s) agree that this article remain permanently open access under the terms of the Creative Commons Attribution License 4.0 International License between rhizobacteria microorganisms (P.fluorescence) and foliar bio-fertilizer in promoting maize (Zea mays.L.) and soybean (G.max) growth and yield (development) as well as dry biomass features interaction in an arid agroclimate characterized by arid and low fertile soil.

MATERIALS AND METHODS
Maize (Zea mays L.) and soybean (G.max) plants features like growth, yield and dry bio-mass data used in the present study were recycled from previous works (Diarrassouba et al., 2015;Dago et al, 2016).Briefly, the study was conducted on farm in the Department of Korhogo (north of Côte d'Ivoire).The experimental site is located between an average altitude of 392 m between -5° 34  North.The climate in this area is characterized by two types of Sudanese seasons: a dry season, from November to April, punctuated by the Harmattan characterized a dry wind from the Sahel, and a rainy season from May to October.The climate of this area is the maritime sub-equatorial with the temperatures that range between 24 and 33°C and the annual precipitation varies between 1100mm and 1600 mm.It is also noteworthy to emphasize that the soil in this region is arid which would explain the strong erosions of the latter during the rainy season.

Maize and soybean seeds material and experimental design
Maize and soybean seed varieties used in this experimentation are available at the Centre National de Recherche Agronomique (CNRA of Côte d'Ivoire).The experimental design consisted of a block of 4 treatments and 4 replications.The two blocks corresponding to each variety of maize of soybean plants were divided into 16 basic plots corresponding to the four different treatments (T0, T1, T2 and T3).The space between the ridges was 75 cm between rows and 40 cm between bunches with 2 plants per hill after thinning.The various treatments have covered each elementary plot of 4 m × 4 m (16 m²).Each elementary plot contained 4 lines of 4 m long.The four treatments were as follows: T0: plots planted without P. fluorescence and without foliar fertilizer (pots planted in soil standard condition); T1: subdivision sown with the seed inoculated with P. fluorescence only; T2: land sown with the seed inoculated with P. fluorescence and foliar bio-fertilizer and T3: subdivision sown with foliar fertilizer only.Moreover, a regular weeding (once a month) was made for the maintenance of the plot.The present experimental design has been performed in the raining season when no watering was made on the analyzed maize and soybean plants outside the rain.In total, 20 samples in each considered experimental site for each processed treatment and replicate with regards to both maize and soybean crops yield and growth as well as dry biomass features were handled for the different statistical surveys.

Preparation of inoculums and seed inoculation
Rizofos Liq Maize bio-fertilizer manufacture requires the strain of bacterium P. fluorescence specifically selected for its phosphorus solubilizing ability.If stored under the recommended conditions (cool below 25°C), the product contains 1×109 CFU/ml in manufacturing.The inoculums were prepared from 500 ml Rizofos Liq Maize Premax-R + 200 ml of Premax-R for 100 kg of maize seed.The needed amount of Premax-R was put in a container and then the required amount of Rizofos Liq Maize was added.It was Dago et al. 837 mixed until a homogeneous mixture was obtained before inoculation of the required amount of seed.This is followed by planting of seeds, and making holes about 3 cm deep, in which two inoculated seed of maize are deposited.The same experimental protocol was applied to soybean with the only difference being that the inoculums were prepared from Rizo Liq Top inoculant or bio-fertilizer for soybean culture, containing nitrogen-fixing bacteria (Bradyrhizobium sp).If stored under the recommended conditions (cool place less than 25°C), this product contains 1 × 1010UFC/ml.Inoculums were prepared from 50 ml Rizo-Liq Top + 20 ml Premax R; Soybean inoculant bacterial protector and adhesive for 10 kg of soybean seeds.

Foliar bio-fertilizer
Foliar bio-fertilizer composition enables high potential crops to aid plant growth in critical development stages (flowering, fertilization) without penalizing the latter"s metabolism.It acts as a pump for the plant and allows the best use of fertilizers conventional and soil mineral reserves.Foliar bio-fertilizer composition (g/L) is as follows: 140 g N; 70 g P2O5; 70g K2O and trace elements.Nitrogen (N) total 14%; Phosphoric acid (P2O5) 7%; K2O 7%; B 0.4 g / L; Mo 0.04 g/L; Cu 0.2 g/L; Zn 0.6 g/L; Mn 0.2 g/L and Fe 0.6 g/L.Foliar biofertilizer doses are as follows; (i) soybeans; 2 applications (3 L.ha -1 ) at the beginning of the run and at the last visible leaf stage (ii) maize; 8 L.ha -1 at 5-10 leaf stage.

Growth and production measured parameters
During this study, growth and yield as well as dry biomass parameters were measured and calculated respectively, on each maize (Z.mays L.) and soybean (G.max) plants in the two considered experimental sites for each treatment (T0, T1, T2 and T3 treatments).

Growth parameters
Five features were evaluated during the growth phase (i) height of the plant, (ii) number of leaves, (iii) length of leaves, (iv) width of the leaves and (v) the diameter of the collar which has been measured using an electronic sliding caliper.The growth parameters were evaluated using centimeter as scale of measurement (cm).The height of the plants have been measured from the ground level to the end of the longest petiole.The number of leaves per plant was counted weekly.

Yield or production parameters
Five features were evaluated during the production phase (i) length of the ears and/or pods for (Z.mays L.) and soybean (G.max) plants respectively (ii) width of the ears for maize plant, (iii) geometric diameter of the ears for maize plants (iv) number of seed per ear or spike and/or pods for maize and soybean plants respectively and (v) number of ear (maize) and pods (soybean) per plant.Length, width and the geometric diameter parameters have been measured by using an electronic caliper using a centimeter as scale of measurement (cm).

Dry biomass
For estimation of dry biomass, the fresh weight of the vegetative material for both maize and soybean separately were first determined and next the material was dried using an oven-dried for 48 h (at a temperature of 60°C: time and temperature required for a constant dry weight).The weights were measured using a precision balance 10 -4 g (Toledo).Dry biomass was calculated using the following formula:

Data normalization process
Data for the present experiment were statistically analyzed based on several scripts from R statistical package (R Core Team, 2014).Maize and soybean growth and yield parameters, because of their heterogeneity, were submitted to normalization by scaling between 0 and 1, since in statistics, normalization refers to the creation of shifted and scaled versions of statistics, where the intention is that these normalized values allow the comparison of corresponding normalized values for different datasets in a way that eliminates the effects of certain gross influences, as in an anomaly time series (Dodge, 2003).

Computational Pipeline content for statistical analysis
The present study developed computational statistical pipeline (computational pipeline) analyzing the relationship between (Z.mays L.) and soybean (G.max) plants growth and yield as well as dry biomass parameters based on several R version 3.4.3.Details as regards that computational statistical pipeline is reported in supplementary material chapter (Appendix).

Impact of rhizobacteria microorganism and foliar biofertilizer on maize (Z. mays. L.) and Soybean (G. max) plants development
Maize (Z.mays.L.) and soybean (G.max) seeds inoculated by P. fluorescence, P. fluorescence + Foliar bio-fertilizer mixture and foliar bio-fertilizer, exhibited different behavior in terms of cereals growth and yield features data distribution, when compared to T 0 treatment (seeds without P. fluorescence and foliar bio-fertilizer treatment and/or in soil standard condition) (Figure 1).Ratio value between growth and yield parameters under T 0 treatment resulted to around 0.97.The same ratio value concerning T 1 , T 2 and T 3 treatments were 0.76, 0.97 and 0.91 respectively (Table 1).So, a substantial difference has been observed between analyzed cereals growth and yield parameters for all processed treatments (Figure 1, Table 1).Moreover, T 0 (soil standard condition) and T 2 treatments resulting in P. fluorescence + foliar biofertilizer mixture, exhibited the same ratio value by comparing processed plants growth and yield data.This finding evoked normalization as well as a synergic impact of P. fluorescence + foliar biofertilizer mixture with regards both maize and soybean plants growth and yield features (Table 1 and Figure 1).Additionally, maize (Z.mays L.) and soybean (Glycine max) seeds under rhizobacteria microorganisms (p=2.574e-09) and rhizobacteria microorganism + Foliar bio-fertilizer mixture (p= 0.07) treatments, exhibited a positive impact by processing cereal yield parameters as opposed to the same seeds under foliar biofertilizer treatment (p = 0.6), when treatment T 0 and/or experimental site soil standard condition was considered as reference.Also, cereal seeds under T 1 , T 2 and T 3 treatments induced a high dynamism for both maize and soybean crops yield parameters as opposed to their growth features (Figure 1).2).Indeed, processed parameters clustered disregarding rhizobacteria microorganisms (P.fluorescence), foliar bio-fertilizer as well as P. fluorescence + Foliar bio-fertilizer mixture treatments.However, findings suggested high variability of maize and soybean plants yield parameters with respect to growth features.In the same tendency, rhizobacteria microorganisms (P.fluorescens) treatment and rhizobacteria microorganisms (P.fluorescens) + Foliar biofertilizer mixture referred as T 2 treatment were recorded as inducing high variability in processed plants yield parameters (p<0.05) as opposed to T 0 and T 3 treatments (Figure 2).Also, the present result suggested a relative positive effect of both (i) P. fluorescence + Foliar bio-fertilizer mixture and (ii) rhizobacteria microorganism (P.fluorescence) treatment on maize (Zea mays L.) and soybean (Glycine max) plants growth parameters (Figure 2) as opposed to both T 0 and T 3 treatments.Further, findings exhibited no substantial difference between T 0 and T 3 treatments with regard to maize (Zea mays L.) and soybean (Glycine max) growth and yield parameters (Figure 2).Taking together, the present survey suggested a selective difference between (i) processed plants from seeds inoculated with P. fluorescens as well as with P. fluorescens + Foliar bio-fertilizer mixture referred as T 1 and T 2 treatments respectively and (ii) those from seeds in experimental site soil standard condition and with foliar bio-fertilizer inoculation denoted as T 0 and T 3 treatments respectively.

max) yield and growth features data dispersion
Findings suggested that one component (PC1) do not sufficiently explain the present process data dispersion (Figure 3).Data dispersion evidence has been highlighted by introducing and/or combining two principal component factors referred to as PC1 and PC2 (Figure 3).Furthermore, test of the hypothesis that 2 factors are sufficient (degrees of freedom for the model is 13) based on 22 observations, displayed a Chi Square value = 30.42with an associated p value = 0.004.Also, the root mean square of the residuals of this model is 0.1 (p<0.05).Moreover, data distribution source became strongly evident by introducing a third component (PC3).Indeed, test of the hypothesis evaluating 3 factors and explaining processed data dispersion (degrees of freedom for the model is 7) based on 22 observations, exhibited a Chi Square value = 29.16 with an associated p value =0.0001.The root mean square of the residual associate to this model is 0.06 (p<0.05).These results suggested 3 component factors as strongly efficient in discriminating maize and soybean growth and yield features data dispersion source with respect to the other considered systems (Figure 3).Thus, Figure 3 clearly showed T 1 referred to yield and growth parameters of maize and soybean plants from seeds inoculated by P. fluorescence and T 2 referred to yield and growth features of maize and soybean plants from seeds under P. fluorescence and foliar bio-fertilizer mixture treatments as potential sources of presently analyzed data variability.Also, merging the present result (Figure 3) with the previous one (Figure 2); it seem obvious to deduce both maize (Zea mays.L.) and soybean (Glycine max) cereal plants yield attributes as significantly influenced by P. fluorescence as well as by P. Fluorescence microorganism activities on foliar bio-fertilizer (P.Fluorescence + Foliar bio-fertilizer mixture).

R fitting curve weighing rhizobacteria microorganism activities on foliar bio-fertilizer assessing the relationship between both maize and soybean plants yield features
Here, the performance of maize (Z.mays L) and soybean (G.max) yield parameters for seeds under rhizobactera microorganism"s (P.Fluorescence) and rhizobactera microorganism + Foliar bio-fertilizer treatments was assessed assuming plants from T 0 treatment as reference.Processed maize (Z.mays L.) and soybean (G.max) plants yield parameters from maize and soybean seeds inoculated by rhizobacteria microorganisms (P.fluorescence), exhibited a heterogeneous behavior as opposed to those from seeds inoculated by rhizobacteria microorganisms (P.fluorescence) + Foliar bio-fertilizer mixture and foliar bio-fertilizer when experimental site soil standard condition was assumed as reference and/or benchmark.Interestingly, this analysis showed seeds inoculated by rhizobacteria microorganisms + Foliar bio-fertilizer mixture, as improving and normalizing maize (Z.mays L.) and soybean (G.max) cereal plants yield parameters as opposed to plants from seeds inoculated by rhizobacteria microorganisms only (Figure 4).Overall, these findings suggested the implication of rhizobateria microorganisms (P.fluorescence) activity on foliar bio-fertilizer in the normalization procedure of both maize (Z.mays L.) and soybean (G.max) crops yield parameters improving plants development performances in an arid agro-climate low fertile soil.

ANOVAs and multiple linear regression survey linking T 0 , T 1 , and T 2 and T 3 treatments by handling maize and soybean plants yield features data
Results concerning the present analysis of variance, displayed 0.11 as residual standard error, on 18 degrees of freedom with a multiple R-squared value =0.52 (R 2 = 0.52) and adjusted R-squared = 0.4452.Fisher test, associated to this variance analysis exhibited F-statistic = 6.618 on 3 and 18 Degree of Freedom (DF) with p=0.00, indicating that the null hypothesis that the yield parameter variables concerning maize and soybean plants from seeds inoculated by rhizobacteria microorganisms referred as T 1 treatment (YP.T 1 ), and rhizobacteria microorganisms + Foliar bio-fertilizer mixture yield denoted T 2 treatment (YP.T 2 ) and foliar bio-fertilizer (YP.T 3 ), collectively were not influenced by previous maize (Z.mays.L.) and soybean (G.max) seeds treatment should be clearly rejected.Results (Table 2) also showed cereal plants yield parameter from seeds under T 1 (p-value=0.91)and T 2 (p-value= 0.34) treatments, as not significantly controlling for yield parameter variable of the cereal plants from cereal seeds  under T 3 treatment (p = 0.00).However, the same analysis exhibited processed maize and soybean plants yield parameter from seeds inoculated by foliar bio-fertilizer as controlling both maize and soybean cereal plants yield parameter under T 1 and T 2 treatments (p=0.00).Also, results of the partial analysis of variance have been reported as follows: F = 0.55 with p = 0.47.Thus, the null hypothesis (β 1 = 0) at the 5% level of significance cannot be rejected.It seems that the variables YP.T 1 (p=0.46)and YP.T 2 (p=0.12)do not contribute significant information to maize (Z. mays.L.) and soybean (G.max) treated seeds, once yield parameter variable from seeds under T 3 treatment (YP.T 3 ) has been taken into consideration.In other words, both maize (Z.mays L.) and soybean (G.max) seeds treated by rhizobacteria microorganism + Foliar bio-fertilizer mixture and rhizobacteria microorganism exhibited a contrast behavior among themselves and also with respect to seeds without inoculation plus seeds under foliar bio-fertilizer treatment.Altogether, these surveys are in agreement with the previous results (Figures 2 and 3).

Relationship between maize and soybean dry biomass and both yield and growth features evaluating P. fluorescence activity on foliar bio-fertilizer
Here, several multiple linear regression surveys aimed at understanding the relationship between maize (Z.mays L.) and soybean (G.E3), proposed foliar bio-fertilizer as having a relatively high influence on growth parameters with respect to yield attributes.Also, considering equation (E 4 ) as the resultant of both equations (E 2 ) and (E 3 ), we can suppose (i) rhizobacteria microorganisms and (ii) foliar bio-fertilizer treatment as influencing processed plants yield and growth parameters respectively.Next, the relationship between maize and soybean plants dry biomass, yield and growth parameters was analyzed by merging all processed treatments.Results of the developed multiple linear regression model was as follow; (E 5 ): Dry Biomass=2.19*Yieldparameter -4.04*Growth parameter + 63.28.This survey hypothesized a positive effect of yield parameters on analyzed plants dry biomass attribute as opposed to growth parameter.Also, equation E 5 suspected a potential drop of maize and soybean plants dry biomass by a strong upturn of cereal growth parameters (p=0.17).Collectively, these analysis suggested high fluctuation as regards analyzed plants dry biomass parameters for each considered treatments (Figure 5) and exhibited the combination between rhizobacteria microorganisms and foliar bio-fertilizer as a suitable practice normalizing the relationship among considered plants yield and growth features data by improving their dry biomass component, since high dry biomass value were recorded for processed plants from seeds inoculated by P. fluorescence + Foliar bio-fertilizer mixture (Table 3 and Figure 5).

Relationship between maize and soybean dry biomass features for seeds under P. fluorescence and foliar bio-fertilizer treatment by processing variable number of principal components
We performed a relationship analysis between considered plants dry bio-mass components was performed aimed at assessing rhizobacteria microorganism"s activity on foliar bio-fertilizer through a principal component analysis by processing a variable number of principal component (Figure 6).As expected, the present analysis suggested 2 factors and/or components (Component 1 and 2) as enough for explaining the variability as well as the difference ratio among presently processed cereal plants dry biomass parameters (Figures 5 and 6).So, this analysis revealed Components 3 and 4 as unable to explain dry biomass data dispersion (Figure 6).Considering both Components 1 and 2 of Figure 6, our results suspected a high difference and/or an opposed behavior between both maize (Z.mays L) and soybean (G.max) plants dry biomass parameters for seeds under T 0 (plants from seeds without treatment) and T 3 (plants from seed inoculated by foliar bio-fertilizer) treatments (Figure 6).This result is in agreement with previous results reported in Table 3.Also, principal components 1 and 2 exhibited a relative difference in terms of data distribution with regards to dry biomass parameter referred to in both T 1 (maize and soybean seeds inoculated by P. fluorescence microorganisms) and T 2 (maize and soybean seeds under rhizobacteria microorganism + Foliar bio-fertilizer mixture inoculation) treatments (Figure 6).However, considering soil standard condition as benchmark, the present findings supported the high normalization aptitude of rhizobacteria microorganism + Foliar bio-fertilizer mixture treatment,   on maize (Z.mays L) and soybean (Glycine max) growth and yield features data as opposed to T 1 and T 3 treatments (Figure 6).Combining this result with those of Tables 3, we can suggest rhizobacterium microorganism"s activities on leaf bio-fertilizer, as being responsible for the adjustment of the synergy between growth and yield parameters, while improving the dry bio-mass features.

DISCUSSION
The inoculation of plant growth promotor rhizobacteria P. fluorescence in cereal plant may increase number of panicles, number of grains panicle, percentage of filled grains because of enhancement of plant biomass, root elongation, uptake of NPK and ultimately increase all characters without deteriorating soil health.Subsequently, they act as potential bio-fertilizers and antagonistic agents to save synthetic chemical fertilizers and pesticides, respectively and become an ecofriendly alternative in upcoming days (Khorshidi et al., 2011;Kumar and Dangar, 2013).This study examined the interaction between Rhizobacteria microorganism (P.fluorescence) and foliar bio-fertilizer with the purpose to highlight their influences and/or interference on maize and soybean crops performance in an arid agro-climate low fertile soil.The study revealed a consistent normalization effect of P. fluorescence + Foliar biofertilizer mixture on both processed maize and soybean growth and yield attributes.Also our findings showed that rhizobacteria microorganism improved cereal production (Khorshidi et al., 2011) unlike foliar bio-fertilizer, which would appear to have an impact on the considered plants growth process.Indeed, several studies showed that the interaction effect of rhizobacterium and different soil macronutrients (P, N) levels significantly influenced cereals plants yield feature data (Hossein et al., 2015).Then, the high performance of rizhobacteria microorganism (P.fluorescence) + Foliar bio-fertilizer mixture in presently considered agricultural practice can be attributed to the interaction effect between the latter"s increasing soil macronutrient.This finding is in agreement with Alam et al. (2008) who reported that cereal plants yield attributes increased as the levels of macronutrients (P, N) increased.Further, findings showed significant variation between both maize and soybean plants yield and growth attributes for seeds inoculated with rhizobacteria microorganism alone as well as foliar biofertilizer.However, results suggested a high instability in processed plants yield features data as opposed to growth attributes (p-value<0.05)(Diarrassouba et al., 2015;Noel et al., 2016).In addition, our findings showed a high susceptibility of maize and soybean cereal plants yield parameters by replying to rhizobacteria microorganisms (P.fluorescence) + Foliar bio-fertilizer mixture as well as rhizobacteria microorganisms (P.fluorescence) stimulus.These results suspected rhizobacteria microorganism activities in arid soil as improving maize and soybean crops yield attributes.In the other words, our findings linked the performance of processed plants yield attribute to the rhizobacteria microorganism"s activities on foliar bio-fertilizer.Indeed, Hernandez et al. (2010) showed that inoculation of maize cereal seed with rhizobacteria in combination with nitrogen (N), enabled increase in maize yield attribute in comparison with those obtained with the same dose of nitrogen but without inoculation with microorganisms.Also, our finding suspected plants yield parameters from seeds inoculated with rhizobacteria microorganism (P.fluorescence) + Foliar bio-fertilizer mixture and rhizobacteria microorganisms alone as a source of data variability, suggesting the consistent impact of the former"s and the latter"s on that plants yield attributes.Therefore, we showed both maize and soybean plants yield attributes as significantly influenced by P. fluorescence microorganism as well as by P. fluorescence microorganisms activities on foliar biofertilizer.Several studies suggested a significant variation of the effects of different levels of soil macronutrient on cereal yield parameters (Hossein et al. 2015).Based on these evidences and others (Hernandez et al, 2010), the interaction between rhizobacteria microorganism and foliar bio-fertilizer as increasing soil macronutrients can be suggested, allowing the correct development of cereal plants.Shaharoona et al. (2006) showed the efficiency of Pseudomonas increasing significantly maize plant growth and production when adequate quantity of nitrate has been provided.Previous studies showed that rhizobacteria improve maize productivity increasing the absorption of nitrate, phosphate, potassium, zinc, manganese, copper and iron (Biari et al., 2008).Our findings via an R fitting curve survey highlighted the strong normalization effect of rhizobacteria microorganism and foliar bio-fertilizer mixture on yield attributes of both analyzed maize and soybean plants.The same analysis suggested a high instability of rhizobacteria microorganism"s vis-à-vis of analyzed plants yield parameter as opposed to both (i) rhizobacteria microorganisms and foliar bio-fertilizer mixture and (ii) foliar bio-fertilizer treatments when soil standard condition referred as T 0 treatment was assumed as benchmark.Also, performed ANOVA analysis showed that, maize and soybean plants from seeds inoculated with P. fluorescens + Foliar bio-fertilizer mixture and rhizobacteria microorganism exhibited a contrast behavior among themselves as well as with respect to plants from seeds without inoculation and with seeds inoculated with foliar bio-fertilizer in term of processed plants yield attributes.Interestingly, our developed multiple linear regression analysis suggested a selective effect of rhizobacteria microorganism and foliar bio-fertilizer on maize and soybean plants yield and growth attributes respectively.The same survey evoked a high fluctuation as regards analyzed plants dry biomass parameters for each considered seeds treatments and exhibited the combination between rhizobacteria microorganisms and foliar bio-fertilizer as a suitable practice in normalizing the relationship among considered plants yield and growth feature data (Dago et al., 2015) by improving dry biomass component, since high dry biomass value were recorded for plants from seeds inoculated by P. fluorescence + Foliar bio-fertilizer mixture.Also, findings referring to above mentioned developed multiple regression survey, linked presently analyzed cereals plants dry biomass attribute with yield component.Principal component analysis based on multiple component factors enhanced normalization and synergic aptitude of rhizobacteria activity on foliar bio-fertilizer on both maize and soybean plants yield and growth attributes.Lack of knowledge with regards to chemical composition of considered experimental earth site represented a limit to the present work, since chemical characterization of the former could help to clearly understand the interaction between rhizobacteria microorganisms (P.fluorescence) and foliar bio-fertilizer in improving maize (Z.mays.L.) and soybean (G.max) growth and yield features.

Conclusion
This study assessed the interaction relationship between rhizobacteria microorganism (P.fluorescence) and foliar bio-fertilizer improving maize and soybean crops dry biomass by processing a computational statistical survey.Findings exhibited rhizobacteria microorganisms (P.fluorescence) and foliar bio-fertilizer as influencing both processed plants yield and growth attributes respectively.Rhizobacteria microorganism"s activities on foliar biofertilizer was suspected to trigger the high proportion of dry bio-mass by normalizing the synergic relationship among analyzed maize (Z.mays.L.) and soybean (G.max) plants growth and yield parameters.

Figure 1 .
Figure 1.Box plot multivariate survey by weighting maize and soybean development dynamism under T0, T1, T2 and T3 treatments.(YP and GP acronyms were referred to growth and yield parameters respectively).
Dry biomass = [(Fresh weight of leaves) × (Dry weight of the leaf sample) / (Fresh weight of the leaf sample)] + [(Fresh weight rods) x (Dry weight of the sample rod ) / (Wet weight of the sample rods)].

Figure 3 .
Figure 3. Principal component analysis weighing processed maize (Z.mays L.) and soybean (G.max) plants growth and yield parameters data dispersion source.

Figure 4 .
Figure 4. R fitting curve analyzing maize (Z.mays.L.) and soybean (G.max) yield performances by processing P. fluorescence microorganism"s activities on foliar bio-fertilizer.

Figure 5 .
Figure 5. PCA graph assessing maize and soybean plants dry biomass features data dispersion evaluating P. fluorescence activities on foliar biofertilizer in an arid and low fertile soil.

Figure 6 .
Figure 6.Relationship between both maize (Z.mays L) and soybean (G.max) dry biomass parameters through 4 principal components by assessing P. fluorescence activity on foliar biofertilizer.

Table 1 .
Descriptive statistic and variance ratio test estimation between both maize (Zea mays L.) and soybean (G.max) cereal crops yield and growth features.

Effect of rhizobacteria microorganism on maize (Z. mays L.) and Soybean (G. max) plants growth and yield parameters relationship
Cluster dendrogram graph based on Euclidian distance of Pearson correlation survey showed two distinct groups and/or tendencies (Figure Taking everything into consideration, the present results confirmed the normalization effect of rhizobacteria microorganisms + Foliar bio-fertilizer mixture on processed plants yield and growth features.

Table 2 .
Analysis of variance (ANOVA) table, linking T0 treatment with T1, and T2 and T3 treatments by processing cereals yield features.
max) plants dry bio-mass together with both yield and growth parameters were performed.

Table 3 .
Summary of processed maize and soybean plants dry biomass data features by processing T0, T1, T2 and T3 treatments.

statistic parameter Dry biomass treatment T0 Dry biomass treatment T1 Dry biomass treatment T2 Dry biomass treatment T3
The p was calculated by performing a Student exact test assuming mean value of dry biomass of both maize and soybean plants of plants in experimental site soil standard condition as benchmark value. *