**2.2 Materials and treatments**

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 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, 75:25 and 100:0). The recommended doses of phosphorus (90 kg ha�<sup>1</sup> ) and potassium (60 kg ha�<sup>1</sup> ) were applied at the time of seed bed preparation from the sources of DAP and SOP. The fertilizer of nitrogen was applied in two equal splits, and organic N was applied 4 weeks before sowing.

#### **2.3 Experimental design**


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

#### **Table 1.**

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

**Figure 2.** *Weather data of spring maize growing season from March to June, 2014.*

distances for maize crop were 0.70 m, whereas plant-to-plant distances were 0.20 m. Each plot had six rows. There were 30 plots having treatment combination of two beneficial diazotrophic bacteria and five organic and inorganic source ratios.

### **2.4 Observations recorded**

Biological yield data was recorded by harvesting four central rows in each plot, sundried and weighed by electronic balance whereas harvested central rows were threshed individually through electric thresher and weighed through electronic balance to obtain grain yield and then converted into kg ha�<sup>1</sup> by the following formula: beneficial diazotrophic bacteria as compared to without beneficial microbes. This may be due to diazotrophic bacteria increase the speed of decomposition and mineralization that improve nutrients' availability to the crop and total dry matter production [28]. Similarly, the application of organic and inorganic fertilizers also significantly affects the biological yield, and greater biological yield (12,092 kg ha<sup>1</sup>

*Biological yield and grain yield of spring maize and soil organic matter and soil bulk density as influenced by*

**Grain yield (kg ha<sup>1</sup> )**

Without BM 10,733 b 3662 b 0.87 b 1.19 a With BM 11,708 a 3803 a 1.19 a 1.17 b LSD 602.29 79.52 0.08 0.02

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

0:100 10,961 b 3592 b 0.87 c 1.23 a 25:75 11,401 ab 3793 ab 0.94 bc 1.22 ab 50:50 12,092 a 3907 a 1.02 b 1.19 b 75:25 10,621 b 3684 b 1.10 ab 1.15 c 100:0 11,027 ab 3686 b 1.22 a 1.09 d LSD 952.3 125.7 0.13 0.03

BM R **Figure 3** ns **Figure 4** ns *Mean values of the different categories in each column with different letters discloses significant differences (p* ≤ *0.05) using LSD test.*

**Soil organic matter (%)**

**Bulk density (g cm<sup>3</sup> )**

was achieved with the application of 50:50 N ratio of organic and inorganic fertil-

100% N from inorganic source. It might be due to the reason that nitrogen from organic sources are slow release, while inorganic nitrogen is readily available to plant which may not be available at later stages. The combined application of N from inorganic source (urea) and organic source in a ratio of 75:25 improved grain yield, straw yield, and biological yield, whereas 50:50 N ratio increased uptake of nitrogen [29]. Biological and grain yield was significantly improved with the application of 50% nitrogen from inorganic sources in combination with the application of 25% N from FYM and 25% N from poultry manure [30]. The applications of organic and inorganic N fertilizers significantly enhanced biological yield and grain yield [31, 32]. The application of organic and inorganic nitrogen 50% from urea and 50% from FYM or 50% poultry manure significantly enhanced biological yield,

The graph trend showed that biological yield increased with organic and inorganic nitrogen ratio from 0:100 to 50:50, whereas a decreased trend in biological yield was observed from 50:50 to 100:0 with both beneficial microbes (**Figure 3**). This might be due to the fact that beneficial microbes rapidly decomposed organic matter, provided nutrients, and increased availability of nitrogen from both organic

Beneficial diazotrophic bacteria significantly increased the grain yield (**Table 2**).

microbes as compared to without beneficial microbes. This may be due to the reason that beneficial microbes increase decomposition and mineralization and improve nutrients availability for more total dry matter production [28].

) has been noted with the application of beneficial

izers. Lower biological yield (10,961 kg ha<sup>1</sup>

*beneficial microbes and organic and inorganic ratios.*

**Beneficial microbes**

Interaction

**Table 2.**

Organic and inorganic ratios

**Biological yield (kg ha<sup>1</sup> )**

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

grain yield, and harvest index (%) [28].

and inorganic sources [28].

**169**

Highest grain yield (3803 kg ha<sup>1</sup>

)

) was attained with the application of

$$\text{Grain yield} \left(\text{kg ha}^{-1}\right) = \frac{\text{grain yield in four central rows}}{\text{row} - \text{row distance} \left(\text{m}\right) \times \text{row length } \left(\text{m}\right) \times \text{no.of rows}} \times 10,000 \text{ \textdegree C} \tag{1}$$

Organic matter in soil was determined by the modified method of Nelson and [25]. The nitrogen content in soil, stover, and grains were determined by following Kjeldahl method according to the proposed methodology of Bremner and Mulvaney [26].

#### **2.5 Statistical analysis**

The data recorded was analyzed statistically using analysis of variance techniques appropriate for randomized complete block design. Statistical analysis was done with Statistic-X software. Means were compared using LSD test at 0.05 level of probability, when the F-values was significant [27]. The possible interactions were graphically made using a software of Microsoft Excel 365.
