Optimizing inorganic blended fertilizer application for the maximum grain yield and profitability of bread wheat and food barley in Dawuro Zone, Southwest Ethiopia

2.1 Description of the study area

The field experiment was conducted under rain-fed conduction from July to November in both 2021 and 2022 at the Waka and Kachi trial sites. The detailed description of study areas is presented in Table 1.

2.2 Soil sampling and analysis

Before planting, surface soil samples (0–30 cm depth) were collected from ten randomly chosen points, zigzagging across the Waka and Kachi trial sites using an auger. These samples were then combined into a single composite sample. From this composite, a 1.0 kg subsample was taken, which was subsequently air-dried, crushed, and sieved through a 2 mm mesh to ensure uniformity and preparation for detailed analysis of soil properties. Analysis of selected physicochemical properties of soil samples was carried out at the soil and water analysis laboratory of Horticoop Ethiopia (Horticulture) PLC. The soil texture was determined using the Bouyoucos hydrometer [33]. The soil pH was measured potentiometrically with a digital pH meter in the supernatant suspension of a 1:2:5 soil-to-water ratio [34]. Total nitrogen was determined using the Kjeldahl method by Bremner [35]. Exchangeable calcium (Ca), potassium (K), magnesium (Mg), sulfur (S), phosphorus (P), and boron (B) were determined by the procedures described by Mehlich [36]. The cation exchange capacity (CEC) was determined using the ammonium acetate method by Chapman [37]. The details of the testing site soil results are presented in Table 2.

2.3 Land preparation and field layout

The land for both crops was ploughed three times using oxen before planting. The plowing frequency was adjusted to match local practices and soil conditions, aiming to establish ideal seedbed conditions while reducing soil disturbance and erosion risks. Both crops had their own separate experimental plot, which was 3 m long and 3 m wide, with 0.5 m between experimental units and 1 m between blocks. Each crop had three separate blocks, and each block’s gross dimensions were 31 m long and 3 m wide. Plot sizes were selected to ensure effective detection of treatment effects, taking into account equipment limitations, environmental variability, and adherence to national research standards for fertilizer trials in bread wheat and food barley. The local standard seed rate for both bread wheat and food barley is 100 kg ha⁻¹. Each experimental unit received 90 g seed rate for both crops, which were sown (10 rows per experimental plot) by drilling at a spacing of 0.3 m between rows.

2.4 Experimental material, treatment, design of experiment, and field management

The non-biofortified bread wheat variety Danda’a and the barley variety HB-1307 were used as test crops based on several important considerations. They were selected due to their good adaptation to the environmental and agronomic conditions of the study area. Furthermore, these varieties are popular and widely cultivated in the region, making the study results more relevant and applicable to local farming practices.

The farmer’s utilization rate of 100 kg ha⁻¹ NPSB (18.9% N, 16.44% P, 6.95% S, and 0.1% B) was used as the basis for arranging the treatment for both crops. The treatments for both crops separately included nine NPSB fertilizer levels (0, 25, 50, 75, 100, 125, 150, 175, and 200 kg ha⁻¹). The selection of nine NPSB fertilizer levels was guided by prior research, recommendations from agricultural authorities, the needs of the experimental design, nutrient requirements, practical limitations, and the exploratory nature of the study. This comprehensive approach aimed to encompass a wide range of nutrient application rates for analyzing bread wheat and food barley production. The experiments were set up in a randomized complete block design with three replications. The trial sites varied in slope and soil fertility. To manage this variation, a randomized complete block design with three replications was used in the study. The randomization process of treatments within each block was conducted systematically. Initially, the field was divided into homogeneous blocks, taking into account factors influencing the growth of bread wheat and food barley. Random sequences were then generated for each block to ensure equitable assignment of treatments. Treatments were subsequently allocated to individual plots within each block based on these random sequences. This approach was replicated across multiple plots within each block to enhance the statistical reliability of the study. At planting time, the whole NPSB was administered at the rate specified per plot.

In addition to blended NPSB fertilizer, extra nitrogen was applied to ensure an adequate nitrogen supply and address its lower levels in NPSB. The agricultural office recommended this practice as a standard package for both crops to improve nutrient balance and plant productivity. Nitrogen fertilizer was applied at a rate of 100 kg ha⁻¹ (90 g per experimental plot) in the form of urea two times, splitting 33% at planting and 67% at 35 days after planting for each treatment. The timing and splitting of nitrogen fertilizer applications were synchronized with the growth stages of bread wheat and food barley to maximize nutrient uptake efficiency and minimize losses. Nitrogen is applied early during planting to support initial growth, followed by additional applications timed to coincide with critical growth phases. This strategy ensures consistent and optimal nitrogen levels throughout the growing period, promoting healthy plant development and reducing environmental impact. Such precision is vital for maximizing productivity in bread wheat and food barley crops.

Weeding was done two times (35 and 55 days after planting in bread wheat and 25 and 45 days after planting in food barley) uniformly in each treatment. Weeding schedules were determined based on the growth stage of the crop and the specific weed species present, ensuring interventions were timed to minimize resource competition. Diseases and pests were monitored and protected until the crops were harvested from the field.

2.5 Data collection

Ten randomly selected pre-tagged plants were selected from the central eight rows of each plot, and then data on plant height, spike length, number of kernels per spike, and number of productive tillers per plant were recorded for each plot for bread wheat and food barley and then averaged. The aboveground biomass yield (BY) data were recorded at the physiological maturity of both crops. The entire aboveground biomass plant part (leaves, stems, and seeds) was harvested from the net plot in each experimental plot and sun-dried until a constant weight was reached. Then, the aboveground biomass was weighed at kg per plot using a balance, and then its value (kg per plot) was converted to kg per hectare for analysis. Each crop grain yield (kg per plot) was collected from the net plot area of the experimental unit. After harvest, it was threshed, cleaned, and weighed using a sensitive balance. Also, the grain yield was corrected to a moisture content of 11% using a moisture tester. Then, its value (kg per plot) was converted to kg per hectare for analysis. A thousand seed weights (g) were sampled from each experiment unit of cleaned grain seed and counted using an electronic counter. Then, it was measured using a sensitive balance by correcting the moisture content of the seed to 11%. Harvest index (%) was calculated using the formula HI = weight of grain yield/(Weight of aboveground dry biomass yield) × 100.

2.6 Agronomic data and economic analysis

The analysis of variance (ANOVA) for the traits was performed using SAS statistical software, version 9.4 [41]. Crop characteristics that showed significant differences (p < 0.05) were further tested for mean separation. Each location and season agronomic data were subjected to ANOVA, and the normality test was performed using the Shapiro–Wilk W test. Also, an individual location and season data homogeneity test was performed using Barlett’s test, and then the combined ANOVA was performed after confirming the homogeneity of the error variances. The combined ANOVA was performed using generalized linear model (GLM) procedures for randomized complete block design as follows:

where Y ixjk is the observed value of treatment i in replication k of season x and location j , μ is the grand mean of the treatment, T i is the effect of treatment i, S x is the effect of season x, L j is the effect of location j , TS ix is the interaction effect of treatment i with season x, TL ij is the interaction effect of treatment i with location j, TSL ixj is the interaction effect of treatment i with season x and location j, R k is the effect of replication k , and ɛ ixjk is the error (residual) effect of treatment i in replication k of season x and location j .

To streamline the statistical analysis of the agronomic data, a partial budget analysis was computed for each treatment. This approach consolidates the statistical analysis by evaluating the economic viability and effectiveness of different NPSB fertilizer rates, ensuring that agronomic decisions are both data-driven and cost-effective. According to the CIMMYT procedure [32], farmers would achieve yields 10% lower than the obtained yield in the experiment, and then the mean bread wheat and food barley grain yields were adjusted in the economic analysis by subtracting 10% from the actual yield. Economic evaluations were computed for the total variable cost (TVC), gross field benefit (GFB), net benefit (NB), and marginal rate of return (MRR) ratios using the method described by CIMMYT [32].

The TVC was determined as the sum of all variable costs (the cost of the chemical fertilizer and labor costs for the application of the fertilizer), and the other costs remained constant for each treatment. The cost of NPSB fertilizer was 42.20 ETB kg⁻¹ and the cost of application of NPSB fertilizer (1000.00 ETB ha⁻¹).

The GFB was obtained by multiplying the adjusted total grain yield (kg ha⁻¹) for each treatment by the current open market price of kg per Ethiopian birr (65.00 ETB kg⁻¹) for the wheat bread and (45.00 ETB kg⁻¹) for barley.

The NB was obtained as the difference between the GFB and the TVC.

The MRR% was computed using the formula: MRR ( % ) = ∆ NB ∆ TVC × 100 , where ∆ NB is the change in the NB, and ∆ TVC is the change in the TVC between any pair of treatments.

3.1 Plant height

Plant heights of bread wheat and food barley were significantly (p < 0.01) influenced by the application of NPSB fertilizer (Tables 3 and 4).

The increase in NPSB fertilizer rates corresponded to enhanced growth in both wheat and barley, particularly in terms of plant height. As the NPSB rate increased from 0 to 175 kg ha⁻¹, wheat exhibited a 20.2% increase in height, while barley exhibited a more pronounced increase of 30.7% compared to the unfertilized plot (Table 5). These results indicate that both crops respond positively to higher NPSB rates, with barley showing a greater relative improvement in plant height. This underscores the importance of appropriate NPSB fertilization to optimize plant growth and productivity in these crops. NPSB fertilizer plays a pivotal role in bolstering plant height by enriching the availability of nitrogen (N), phosphorus (P), sulfur (S), and boron (B), crucial nutrients that are fundamental to various physiological processes in plants. By enhancing the availability of these nutrients, NPSB fertilizer promotes vegetative growth in crops such as bread, wheat, and food barley. This enhancement is evident through increased cell division, where new cells are formed, and subsequent cell elongation, which expands tissue and contributes to greater plant height. This study, consistent with the findings of Abera et al. [14], Desta and Almayehu [42], and Usman [43], showed that blended fertilizers significantly increased plant height in wheat and barley. Abera et al. [14] observed improvements due to the synergistic effects of multiple nutrients. Desta and Almayehu [42] reported enhanced nutrient uptake and vegetative growth, while Usman [43] found improvements in height and other agronomic traits. These studies collectively support using blended fertilizers to enhance crop productivity and sustainability.

3.2 Number of productive tillers

The application of NPSB fertilizer had a significant effect on the number of productive tillers per plant for bread wheat and food barley (Tables 3 and 4).

The highest numbers of effective tillers per plant were achieved by the application of 150 kg ha⁻¹ NPSB for wheat and 125 kg ha⁻¹ NPSB for barley, with values of 7.5 and 9.3 tillers per plant, respectively (Table 5). This demonstrates that while both crops benefit from NPSB application to increase the number of effective tillers, wheat requires a higher NPSB rate than barley to reach its optimal tiller production. These findings highlight the importance of adjusting fertilization strategies to meet the specific growth needs of different crops for maximizing productivity.

Increasing the NPSB rate from 0 to 150 kg ha⁻¹ resulted in an 89.9% increase in the number of productive tillers per plant in bread wheat compared to the unfertilized plot. Similarly, as the NPSB rate was increased from 0 to 125 kg ha⁻¹, the number of productive tillers per plant in food barley increased by 130.9% over the unfertilized plot (Table 5). The increased number of productive tillers per plant could be linked to the synergy effect of macro- and micronutrients, which improved nutrient availability in the soil solution for plants as a result of the optimum application of NPSB fertilizer. An increase in the number of productive tillers per plant in response to the blended fertilizer application was also found by Abdisa et al. [44] and Terfa et al. [45] in bread wheat, and by Sigaye et al. [46], Elias et al. [47] and Biramo et al. [48] in food barley. Collectively, these findings underscore the effectiveness of blended fertilizers in enhancing the number of productive tillers, a critical factor for improving crop yield. The increased tiller number translates to more spikes per plant, which can significantly boost grain production. Thus, the strategic application of blended fertilizers is validated as a best practice for optimizing both the quantity and quality of crop yields in bread wheat and food barley.

3.3 Spike length and number of kernels per spike

The ANOVA results showed that the application of NPSP blended fertilizer had a highly (p < 0.01) significant effect on the spike length and number of kernels per spike in wheat and barley (Tables 3 and 4).

The application of 175 kg ha⁻¹ NPSB fertilizer rate resulted in the highest spike length of 7.2 cm in bread wheat (Table 5). This finding indicates that the optimal nutrient supply provided by this specific fertilizer rate effectively promoted the elongation and development of wheat spikes, which are crucial for higher grain production. Similarly, for food barley, the maximum spike length of 7.8 cm was achieved with the application of a 125 kg ha⁻¹ NPSB rate (Table 5). This suggests that food barley may have different nutrient requirements or respond differently to fertilizer rates compared to bread wheat, necessitating a slightly lower application rate for optimal spike growth. Furthermore, the application of a 150 kg ha⁻¹ NPSB fertilizer rate produced the highest number of kernels per spike in both crops, with bread wheat achieving 60.9 kernels and food barley 59.6 kernels per spike (Table 5). This indicates that this specific rate of NPSB fertilizer is particularly effective in enhancing the reproductive development of the plants, leading to a greater number of kernels, which directly translates to higher potential yields. The increased number of kernels per spike at this fertilizer rate highlights the importance of balanced nutrient application for maximizing the yield potential of both bread wheat and food barley.

These findings collectively underscore the critical role of precise fertilizer application rates in optimizing key agronomic traits such as spike length and kernel number per spike. By identifying the optimal NPSB fertilizer rates for each crop, farmers can tailor their fertilizer practices to achieve the best possible outcomes in terms of crop growth and productivity. The data also suggest that while higher rates of NPSB fertilizer generally promote better growth, the specific optimal rate can vary between crops, emphasizing the need for crop-specific fertilizer management strategies. This approach not only enhances crop yields but also ensures efficient use of fertilizers, contributing to sustainable agricultural practices. The significant variation observed among treatments in spike length and number of kernels per spike due to blended fertilizer application aligns with the findings of Usman [43] in bread wheat, as well as Sigaye et al. [46], Malla et al. [49], and Habte and Assefa [50] in food barley. These studies collectively highlight the impact of balanced and well-formulated fertilizer applications on enhancing critical yield components in these crops.

3.4 Biomass yield

The aboveground biomass yield in bread wheat and food barley revealed highly significant (p < 0.01) results among the treatments due to the application of NPSB fertilizer (Tables 3 and 4).

This finding highlights the critical role that nutrient plays in enhancing the overall growth and productivity of these crops. The application of NPSB at varying rates significantly impacted the biomass yield in both bread wheat and food barley. In bread wheat, the highest biomass yield of 29,321 kg ha⁻¹ was achieved with the application of 150 kg ha⁻¹ NPSB, while a slightly lower yield of 28,430 kg ha⁻¹ was obtained with the application of 175 kg ha⁻¹ NPSB (Table 6). In contrast, food barley exhibited a notably higher biomass yield, with the maximum yield reaching 36,256 kg ha⁻¹ when 125 kg ha⁻¹ NPSB was applied (Table 6). This was closely followed by a yield of 35,452 kg ha⁻¹ with the application of 150 kg ha⁻¹ NPSB. This suggests that bread wheat requires a greater nutrient input to achieve its maximum biomass yield, whereas food barley reaches its maximum biomass yield with a somewhat lower rate of NPSB application. The application of a rate of 150 kg ha⁻¹ NPSB fertilizer in bread wheat resulted in a substantial 56.6% increase in biomass yield compared to the unfertilized plot. Similarly, the application of 125 kg ha⁻¹ NPSB fertilizer in food barley led to a 50.3% increase in biomass yield over the unfertilized plot. These findings highlight the significant impact of NPSB fertilizer rates on enhancing biomass production in both crops.

In agronomic terms, aboveground biomass refers to the total mass of the crop’s aerial parts, including stems, leaves, and reproductive structures. Higher biomass yield typically correlates with better crop health and vigor, as well as greater potential for grain yield. Additionally, the observed increase in biomass yield with higher NPSB fertilizer rates suggests that the crops were able to effectively utilize the provided nutrients, leading to improved dry matter production. This finding aligns with several studies that have demonstrated the significant impact of blended fertilizers on enhancing dry biomass yield and dry matter production in bread wheat and food barley. Sigaye et al. [46], Abera et al. [51], Takele and Chimdessa [52], and Alemu et al. [53] have reported similar results, underscoring the effectiveness of balanced nutrient application in improving crop productivity.

3.5 Grain yield

The grain yields of bread wheat and food barley significantly responded to the application of NPSB fertilizer (Tables 3 and 4). This finding underscores the pivotal role of blended nutrient application in influencing crop productivity and overall yield outcomes. The application of a 150 kg ha⁻¹ NPSB rate resulted in the highest grain yield for bread wheat at 5,419 kg ha⁻¹, whereas food barley achieved its maximum grain yield of 4,708 kg ha⁻¹ with a 125 kg ha⁻¹ NPSB rate (Table 6). This indicates that bread wheat benefits from a higher nutrient input to reach its optimal grain yield, while food barley achieves its peak yield with a slightly lower rate of NPSB application. The variation in optimal NPSB rates between the two crops underscores their differing nutrient requirements and responses, emphasizing the need for tailored fertilization strategies to maximize yield potential in each crop.

By increasing the NPSB fertilizer rates, the grain yields of bread wheat and food barley demonstrated a pattern of increase up to the optimal application rate. Beyond this point, however, both crops exhibited diminishing returns or minimal response to further fertilizer application. This phenomenon suggests that there is an optimal level of NPSB fertilizer application where grain yields are maximized. Beyond this optimal rate, additional fertilizer may not provide proportional benefits and could even lead to reduced yields or inefficient nutrient utilization by the crops. This observation underscores the importance of precision nutrient management in agricultural practices, where the application of the right amount of fertilizers tailored to specific crop requirements is crucial for achieving optimal yield outcomes. For example, increasing the NPSB rate from 0 to 150 kg ha⁻¹ resulted in a 125.6% increase in grain yield for bread wheat compared to the unfertilized plot and a 29.3% increase compared to the blanket recommended rate plot. Similarly, increasing the NPSB rate from 0 to 125 kg ha⁻¹ led to a 58.1% increase in grain yield for food barley over the unfertilized plot and a 15.5% increase over the blanket recommended rate plot. These findings highlight the significant yield benefits of optimal NPSB fertilizer application tailored to specific crop requirements.

The observed increase in grain yield in bread wheat and food barley with optimal NPSB fertilizer application is attributed to healthier plant growth due to optimal nutrient levels. The balanced blend of nitrogen, phosphorus, sulfur, and boron enhances nutrient interactions, improving uptake efficiency and overall plant vigor. Enhanced dry matter production, as reflected in traits such as spike length and kernels per spike, indicates efficient nutrient utilization for reproductive growth.

In an earlier study, Jemal et al. [54] concluded that the application of 150 kg ha⁻¹ NPSB in bread wheat resulted in the highest grain yield, increasing it by 78% compared to the unfertilized plot. Similarly, Abdisa et al. [44] reported that the application of 200 kg ha⁻¹ NPSB produced the maximum grain yield in bread wheat, exceeding the yield of the unfertilized plot by 117%. In a related study, Sigaye et al. [46] observed that the application of 0 to 200 kg ha⁻¹ NPSB significantly increased grain yield in food barley, with the maximum yield surpassing that of unfertilized plots by 186%. Additionally, Habte et al. [55] found that the application of 0–125 kg ha⁻¹ NPSB significantly boosted grain yield in food barley by 53% compared to unfertilized plots. Gebreslassie et al. [56] reported that the application of NPSZ at rates of 0–300 kg ha⁻¹ increased grain yield in food barley by 91.5% compared to unfertilized plots. Furthermore, Obsa et al. [57] noted that the application of 0–100 kg ha⁻¹ NPSB tended to increase grain yield in food barley, exceeding the yield of unfertilized plots by 86.5%. Overall, these studies underscore the significant impact of tailored nutrient applications on enhancing grain yield in both bread wheat and food barley. The consistent yield improvements across various studies highlight the importance of optimizing fertilizer use to achieve maximum crop productivity, which is essential for sustainable agricultural practices.

3.6 Thousand seed weight

The bread wheat and food barley of the thousand seed weight revealed highly significant (p < 0.01) results among the treatments due to the application of NPSB fertilizer (Tables 3 and 4). The maximum the thousand seed weight (58.9 g) in bread wheat was produced by the application of a 150 kg ha⁻¹ NPSB fertilizer rate, while the highest the thousand seed weight (61.59 g) in food barley was obtained by the application of a 125 kg ha⁻¹ NPSB fertilizer rate (Table 6). As the NPSB fertilizer rate increased from 0 to 150 kg ha⁻¹, the thousand seed weight in bread wheat had 30.1% advantages over unfertilized plots, while as the NPSB fertilizer rate increased from 0 to 125 kg ha^−1, the thousand seed weight in food barley had 27.3% advantages over unfertilized plots. The increased the thousand seed weight in bread wheat and food barley could be due to the application of the optimum NPSB fertilizer rates, which lead to healthy and vigorous plant growth and result in improved photoassimilation efficiency and dry matter production. This finding is corroborated by earlier research by Usman [43], Biramo et al. [48], Alemu et al. [53], and Tesfaye et al. [58], who found significant variation among treatments and a considerable increase in thousand seed weight in bread wheat and food barley following the application of blended fertilizer. These studies highlight the consistent benefit of blended nutrient application in enhancing seed weight, reflecting improved plant health and nutrient utilization efficiency. These findings emphasize the crucial role of customized fertilizer strategies in optimizing crop productivity and seed quality, thereby supporting sustainable agricultural practices.

3.7 Harvest index

The application of an NPSB fertilizer significantly influenced the harvest index trait in wheat and barley (Tables 3 and 4). The application of a 200 kg ha⁻¹ NPSB rate in bread wheat gave the maximum harvest index (18.8%), while the application of a 150 kg ha⁻¹ NPSB rate in food barley produced the highest harvest index (14.6%) (Table 6). The study observed that an increase in the blended NPSB fertilizer rate leads to an increase in the harvest index. This could be the positive effect of NPSB fertilizer on crop nutrient utilization and photoassimilate movement from vegetative to grain sections of the crop. This conclusion is consistent with Usman [43], Abdisa et al. [44], and Jemal et al. [54] that the application of blended inorganic fertilizer to bread wheat caused the harvest index to significantly increase. Furthermore, Mekonnen and Woldekiros [11] and Biramo et al. [48] reported that blended fertilizer application had a considerable effect on the food barley harvest index.

3.8 Economic performance analysis

The TVCs, GFB, NBs, and MRR are shown in Tables 7 and 8. These metrics provide insights into the economic viability and profitability of the agricultural interventions studied. Total variable costs represent the expenditures incurred in implementing the interventions, including costs related to inputs and labor. Gross field benefit quantifies the total revenue generated from crop production. Net benefits indicate the profitability after deducting TVCs from the GFB. The MRR reflects the efficiency of each additional unit of investment, providing crucial information for decision-making in agricultural management and policy.

The mean performance results clearly demonstrated the significant benefits derived from the application of NPSB blended fertilizer to bread wheat and food barley compared to unfertilized plots, particularly in terms of grain yield and NBs. For bread wheat, the application of NPSB fertilizer at a rate of 150 kg per hectare resulted in the highest NB of 309711.50 Ethiopian Birr (ETB) per hectare, with an impressive MRR of 4096.96% (Table 7). This means that for every ETB spent on the NPSB fertilizer, there was a return of 40.97 ETB, showcasing its cost-effectiveness and profitability. Similarly, for food barley, the optimal rate was slightly lower, at 125 kg per ha, obtaining the highest NB of 184424.00 ETB per ha and an MRR of 2195.39% (Table 8), indicating a substantial return on investment where each ETB invested brought back 21.95 ETB.

These economic indicators collectively offer a comprehensive assessment of the financial performance and sustainability of the interventions evaluated in the study. The partial budget analysis focused on the adjusted mean grain yield of bread wheat and food barley, using TVCs and NBs for each treatment calculation. Variability in the cost of NPSB fertilizer and labor costs influenced the economic assessment, while other expenses remained consistent across treatments for both crops. This approach enabled a precise evaluation of how changes in yield and cost influenced the overall profitability and economic feasibility of different fertilizer treatments in bread wheat and food barley production.

The findings underscore the economic efficiency and agronomic advantages of using NPSB blended fertilizers, which enhance nutrient availability and promote robust plant growth. By increasing grain yield, the fertilizers contribute directly to higher revenue potential, reflected in improved NBs. Smallholder farmers are advised to apply 150 kg ha⁻¹ NPSB blended fertilizer for bread wheat and 125 kg ha⁻¹ for food barley to maximize profitability. These rates have been shown to optimize grain yield and economic returns in the study area and can be effectively utilized in other regions with similar agroecological conditions. Consequently, agricultural policymakers and extension services should promote the use of NPSB fertilizers and provide guidance on the optimal application rates to enhance productivity and profitability in bread wheat and food barley cultivation. Implementing these specific rates will help farmers achieve greater financial benefits and improve overall agricultural productivity.

4.1 Perspective for future study

Combining NPSB fertilizers with other soil fertility practices is a promising area for future research. Integrating these fertilizers with organic amendments, such as incorporating biomass residues, can significantly enhance nutrient availability and soil health. Additionally, implementing crop rotations and conservation tillage alongside NPSB fertilizers can further improve soil structure, boost microbial activity, lower emissions, and enhance water retention. This comprehensive approach not only promotes sustainable farming by reducing dependency on chemical inputs but also increases crop productivity and resilience. By enhancing soil fertility and structure, these practices contribute to more sustainable and climate-resilient agricultural systems, ultimately supporting long-term food security and environmental health.