**Abstract**

In arid and semiarid ecosystems, low organic matter is an important threat to soil fertility, crop productivity, and economic returns. Sustainable approaches are required to build organic matter in such soils to improve nutrient use efficiency and food security. Therefore, we conducted an experiment on spring maize to test with and without diazotrophic bacteria (BM) (*Azotobacter chroococcum* and *Azospirillum brasilense*) on crop productivity and soil properties when applied with organic (farm yard manure FYM) and inorganic (commercial fertilizer) nitrogen (N) sources (with percentile of 0, 25, 50, 75, and 100%) in 2014. The analysis of the study showed that the application of BM and organic and inorganic N ratio were significant and have a positive effect in crop yield and soil properties. BM with a 50:50 ratio of organic and inorganic N was improved biological yield (kg ha<sup>1</sup> ), grain yield (kg ha<sup>1</sup> ), stover nitrogen (%), and grain nitrogen (%). However, soil organic matter (%) and soil total nitrogen (%) were enhanced with the application of BM with 100% organic source. Soil bulk density (g cm<sup>3</sup> ) was significantly reduced by BM with 100% organic. From overall results, it is concluded that the application of beneficial microbes and organic and inorganic N positively improved maize yield and quality and soil health in Peshawar valley.

**Keywords:** plant growth-promoting bacteria, nitrogen fertilization, soil quality, grain yield

## **1. Introduction**

Maize (*Zea mays* L.) is the third most important cereal crop after wheat and rice, while in the farming system of Khyber Pakhtunkhwa, it ranks third after wheat and rice in its importance [1, 2]. It is an exhaustive and multipurpose cereal crop that provides food for human, feed for animals, and raw material for the industries [3]. It has greater nutritional value as it contains about 72% starch, 10.4% proteins, and 4.5% fats, minerals, and non-cholesterol oil [2, 4].

To mitigate the problem of low yield and contamination in an eco-friendly way is to use effective microorganisms (EM) [5] also known as beneficial

microorganism (BM). Microorganisms economically support the farmer community by improving the soil activities [6] and assimilate accumulation in the final product of the production which in turn maintains the balance of organic and inorganic mechanisms of the soil and plant [7]. Many researches reflected advantageous effects of BM on soil physicochemical status [8, 9]. Beneficial microorganism increases the decomposition rate of organic fertilizer and increases nutrients availability [10]. Beneficial microorganism also promotes soil fertility, crop growth, and yield [11]; also improves soil health, soil quality, yield, and quality [12] of various physiological attributes; and regulates various metabolites and atmospheric nitrogen [13].

**2. Materials and methods**

*DOI: http://dx.doi.org/10.5772/intechopen.92032*

**2.2 Materials and treatments**

organic N was applied 4 weeks before sowing.

*Pre-sowing physicochemical properties of soil (0–0.30 m depth).*

sium (60 kg ha�<sup>1</sup>

**Table 1.**

**167**

**2.3 Experimental design**

The impact of beneficial microbes on enhancing efficiency of organic and inorganic N fertilizers sources was studied on spring maize cropping system in the year of 2014 at Agronomy Research Farm, The University of Agriculture Peshawar, Pakistan. The research area is geographically located at 17°, 35<sup>0</sup> N and 35°, 41<sup>0</sup> W and altitude of 450 m above sea level. The soil of the experimental farm was silt loam, well drained, and fine textured. The experimental site has a semiarid subtropical continental climate with a mean annual rainfall of about 550 mm. The soil is deficient in total N (<0.5%) and AB-DTPA extractable P (<4.0 mg kg�<sup>1</sup> soil) but has adequate AB-DTPA extractable K (>100 mg kg�<sup>1</sup> soil) with a pH of 7.60 and organic matter content <1% (**Table 1**). Rainfall and temperature data were collected from the weather station of Agronomy Research Farm and summarized in **Figure 2**. In addition to rainfall, crop water requirement was fulfilled by supplying

*Enhancing Soil Properties and Maize Yield through Organic and Inorganic Nitrogen…*

The experimental field was irrigated before sowing for weed germination and then plowed with cultivator to prepare a fine seed bed for sowing. The experiment

) were applied at the time of seed bed preparation from the sources

) and potas-

consisted of two factors, i.e., beneficial diazotrophic bacteria (*Azotobacter chroococcum* and *Azospirillum brasilense*) (with BM and without BM) and organic (FYM) and inorganic (urea commercial fertilizer) N ratios (0:100, 25:75, 50:50,

of DAP and SOP. The fertilizer of nitrogen was applied in two equal splits, and

The experiment was conducted at three factorial randomized complete block designs (RCBD) with three replications. The size of plots was 4.2 � 4 m. Row-to-row

**Property Unit Data** Clay % 2.8 Silt % 50 Sand % 47.2 Textural class — Silty loam pH (1:5) — 7.60 EC (1:5) dS m�<sup>1</sup> 0.18 Organic matter % 0.39 Total nitrogen % 0.06 Phosphorus ppm 2.86 Potassium Ppm 120.48 Mineral nitrogen mg kg�<sup>1</sup> 35

75:25 and 100:0). The recommended doses of phosphorus (90 kg ha�<sup>1</sup>

water through surface irrigation according to crop requirement.

**2.1 Experimental site**

Nitrogen significantly improves crop productivity [14]. Fertilizers are usually applied to soil for increasing or maintaining crop yields to meet the increasing demand of food [15, 16]. The application of inorganic fertilizers results in higher soil organic matter (SOM) accumulation and biological activity due to increased plant biomass production and organic matter return to the soil in the form of decaying roots, litter, and crop residues [17, 18]. The addition of SOM enhances soil organic carbon (SOC) content, which is an important indicator of soil quality and crop productivity [19]. Chemical fertilizer applications could also affect soil physical properties directly or indirectly such as aggregate stability, water holding capacity, porosity, infiltration rate, hydraulic conductivity, and bulk density due to increases in SOM and SOC content [20, 21]. In turn, the formation of stable aggregates enhances physical protection of SOM against microbial decomposition [22]. Some fertilizer additions also affect the chemical composition of soil solution which can be responsible for dispersion/flocculation of clay particles and thus affect the soil aggregation stability [21, 23]. We can see the plant and microbial interaction in the retention and improvement of N cycle for better plant growth (**Figure 1**).

The present study aimed to investigate the effect of organic and inorganic nitrogen ratios along with the effect of beneficial diazotrophic bacteria on maize yield and quality and physio-chemical properties of soil.

*Enhancing Soil Properties and Maize Yield through Organic and Inorganic Nitrogen… DOI: http://dx.doi.org/10.5772/intechopen.92032*
