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Article

Exploring the Synergistic Role of Zinc in NPK Fertilization on the Agronomic Performance of Safflower (Carthamus tinctorius)

by
Muhammad Alamgeer
1,2,*,
Hassan Munir
2,*,
Saddam Hussain
3,4,
Sudeep Adhikari
5,
Walid Soufan
6,
Jahangir Ahmed
7,
Maryam Aslam
8 and
Saeed Rauf
9
1
Department of Agronomy, Tropical Research and Education Center, University of Florida, Homestead, FL 33031, USA
2
Department of Agronomy, University of Agriculture Faisalabad, Faisalabad 38000, Pakistan
3
Department of Agricultural and Biological Engineering, Tropical Research and Education Center, University of Florida, Homestead, FL 33031, USA
4
Department of Irrigation and Drainage, University of Agriculture Faisalabad, Faisalabad 38000, Pakistan
5
Plant Breeding Program, Tropical Research and Education Center, University of Florida, Homestead, FL 33031, USA
6
Plant Production Department, College of Food and Agriculture Sciences, King Saud University, Riyadh 11451, Saudi Arabia
7
National Institute of Food Science and Technology, University of Agriculture, Faisalabad 38000, Pakistan
8
Department of Chemistry, Government College Women University Faisalabad, Faisalabad 38000, Pakistan
9
Department of Plant Breeding and Genetics, College of Agriculture, University of Sargodha, Sargodha 40100, Pakistan
*
Authors to whom correspondence should be addressed.
Horticulturae 2024, 10(12), 1243; https://doi.org/10.3390/horticulturae10121243
Submission received: 25 September 2024 / Revised: 13 November 2024 / Accepted: 23 November 2024 / Published: 24 November 2024
(This article belongs to the Section Plant Nutrition)
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Versions Notes

Abstract

:
Safflower is a multipurpose, underutilized annual crop that could be an alternate oilseed crop for normal and marginal lands around the world. Zinc as a nutrient plays a critical role in enzyme activity and nutrient absorption, leading to improved productivity and quality of oilseeds. However, imbalances between NPK and Zn can result in antagonistic interactions, leading to nutrient deficiencies. Therefore, this field experiment at the University of Agriculture, Faisalabad, Pakistan, was conducted to explore the synergistic effects of NPK and Zn on safflower growth, yield, and oil content. Safflower accession (UAF-SAFF-100) was treated with ten different combinations of zinc and NPK having different concentrations, i.e., T0 = control, T1 = NPK at 40:40:40 kg ha−1, T2 = NPK at 50:50:40 kg ha−1, T3 = NPK at 60:60:40 kg ha−1, T4 = NPK at 70:70:40 kg ha−1, T5 = NPK at 80:80:40 kg ha−1, T6 = T1 + zinc at 7.5 kg ha−1, T7 = T2 + zinc at 7.5 kg ha−1, T8 = T3 + zinc at 7.5 kg ha−1, T9 = T4 + zinc at 7.5 kg ha−1, and T10 = T5 + zinc at 7.5 kg ha−1. The results indicated that the application of T9 (NPK @ 70:70:40 kg/ha−1 + zinc @ 7.5 kg/ha−1) showed the most promising results in terms of growth and yield attributes. This treatment significantly improved key metrics such as capitulum diameter, the number of capitula per plant, seed yield, petal yield, and oil content. Thus, this treatment (T9) is proposed as an effective strategy for enhancing safflower growth and productivity, particularly in semi-arid regions. This study underscores the importance of optimizing nutrient management to achieve superior crop performance and suggests that tailored NPK and Zn applications can be a promising approach to maximizing safflower yield and oil quality.

1. Introduction

Pakistan is the third largest importer of edible oil globally, with 92% of its total edible oil consumption being imported [1]. The oilseed industry contributes around 10% to the country’s agricultural output but faces challenges such as rising input costs, climate change, and global warming. In this scenario, exotic and stress-tolerant crops, like safflower, could help bridge the supply–demand gap by offering an alternative source of edible oil and making marginal soils productive [2,3]. The degradation of soil quality has escalated in recent decades, primarily due to climate change and global warming, which have led to a drop in soil nutrient content [4,5]. Safflower (Carthamus tinctorius L.) is an underutilized oilseed that is primarily cultivated for nutritive edible oil, dyes, and pharmaceuticals [6]. It is known to be cultivated on less fertile or marginal lands with water scarcity [7,8]. The crop miraculously tolerates poor soil nutrition right from emergence to maturity [9]. Safflower exhibits high drought resistance, and its cultivation is mostly concentrated in regions with limited water supplies, particularly semi-arid areas [8]. The crop’s ability to withstand drought has been extensively studied, but nutrient management has received less attention.
Major element fertilization plays a significant part in the growth of plants since it enhances plant cell division, ultimately increasing the plant’s biomass and, as a result, the yield. Nitrogen (N), phosphorous (P), and potassium (K) are significant macro-nutrients that contribute to growth, development, and quality enhancement in safflower seeds. Safflower requires nitrogen (N) for canopy formation and potassium (K) for full flowering. However, the level of soil fertility influences whether fertilization is required [10,11]. The increasing nitrogen application improves the chlorophyll index, oil contents, and safflower seed production [12,13]. However, the overuse of N fertilizer resulted in a 50% decreased N recovery that caused numerous environmental consequences and reduced profitability [14,15]. Therefore, the N application should be adjusted considering its environmental impacts and crop yield goals [16]. Similarly, optimum phosphorous level stimulates the enzymes involved in membrane stability, synthesis of biomolecules, and generation of ATPs [17]. The decreased P uptake and utilization in plants results in poor root growth, nutrient uptake, and ATP generation and leads to less crop yield [18]. Oilseeds and pulses have a comparatively high P demand since it is vital for plant metabolism [19], and its deficiency is more critical in oilseeds relative to other nutrients due to their high energy content [20]. Potassium (K) serves as a regulatory nutrient for stomatal opening and closing and expansion/contraction of guard cells [21]. Potassium supplements enhance plants’ root development and young tissue growth [22]. The biological yield and dry biomass of safflower were increased by K application [13,23].
Zinc has a prime nutrient value to plants because of its role in membrane integrity and phytochrome activity and acts as a cofactor of numerous anti-oxidative enzymes [24]. It has been reported that zinc foliar spray boosted safflower seed output [25]. Additionally, micronutrients, such as Zn and Fe, resulted in a rise in leaf area index, hence enhancing light absorption, dry matter accumulation, and yield [26]. They are the integral components of the zinc-finger protein responsible for protein transcription [27]. Zn deficiency causes membrane damage, reduced photosynthesis, IAA production, enzymes, and impedes plant growth and functioning [28]. Previous studies reported that the augmented quality production of agronomic crops was achieved by Zn supplementation with macro-nutrients application [29]. Furthermore, fatty acid quality and oil yield can also be increased with Zn application [30,31].
The combined effect of zinc and NPK on plant growth and yield can exhibit both synergistic and antagonistic interactions, depending on the specific conditions of the soil, the crop species, and the ratios in which these nutrients are applied. When zinc is applied in conjunction with NPK fertilizers, a synergistic effect often occurs, leading to enhanced nutrient uptake, improved root development, and increased overall plant vigor [32]. This is because zinc facilitates the efficient utilization of nitrogen, phosphorus, and potassium by enhancing the activity of enzymes involved in metabolic pathways and supporting the integrity of cellular membranes, which in turn improves nutrient absorption and transport [33,34]. For example, zinc has been shown to increase the efficiency of phosphorus uptake, particularly in soils where phosphorus availability is limited, thus amplifying the beneficial effects of NPK fertilizers. However, the relationship between zinc and NPK is not always straightforward. In some scenarios, an antagonistic interaction can emerge, particularly when the balance between these nutrients is not optimal, and this antagonism can result in zinc deficiency, manifesting as stunted growth, chlorosis, and reduced crop yield, despite the presence of adequate NPK levels [35]. Moreover, high levels of nitrogen can exacerbate zinc deficiency symptoms by promoting rapid vegetative growth, which increases the plant’s demand for zinc beyond what the soil can supply [36]. Optimal fertilization strategies should consider the specific nutrient requirements of the crop, the existing soil nutrient profile, and the potential interactions between zinc and NPK to maximize their positive effects on plant health and productivity [32]. Therefore, the present study aimed to expand the understanding of balanced NPK and Zn application rates for optimal safflower growth, yield, and quality production.

2. Materials and Methods

The experimental field was prepared with two plowings followed by leveling to cultivate the safflower on ridging. Urea, diammonium phosphate (DAP), and sulfate of potash (SOP) were used as sources of primary macro-nutrients, i.e., nitrogen, phosphorus, and potassium, respectively. Zinc sulfate was used as a zinc source. Nitrogen (Urea) was applied in split doses (50% at sowing and 50% at first irrigation), while DAP and zinc were applied at first irrigation (5 weeks after planting). Sulfate of potash (SOP) was applied 8 weeks after planting. A recommended seed rate (20 kg ha−1) of approved safflower accession (UAF-SAFF-100) was used for ridge sowing 45 cm apart with a hand drill. The net plot size was 13.50 m2, having dimensions of 5.0 m × 2.70 m and containing six lines each. Further, plant-to-plant distance (30 cm) was maintained with a thinning operation carried out 20 days after sowing (DAS). Weeds were controlled with hoeing, and flood irrigation was applied at 60 and 90 DAS to enhance the crop growth and yield.

2.1. Experimental Location and Treatments

The field experiment was performed during winter 2022–23 using a randomized complete block design (RCBD) having three replications at the student research area, directorate of farms, the University of Agriculture, Faisalabad, Pakistan, located at 31°26′ latitude and 73°06′ longitude at an elevation of 184 m above mean sea level. For this study, eleven treatments were applied comprising ten different levels of fertilization and a control, as shown in Table 1.

2.2. Soil Properties

The soil samples from the experimental site were collected from 0 to 30 cm depth with the help of a soil auger. Then samples were homogenized and subjected to determine different soil properties. The collected samples were handled with proper protocol and sent to the soil analytical laboratory, Ayub Agricultural Research Institute (AARI), Faisalabad, to determine different soil properties (Table 2).

2.3. Meteorological Data

The meteorological data including the maximum and minimum temperature (°C) and rainfall (mm) of the complete crop growing season was taken from the Agrometeorological bulletin, University of Agriculture, Faisalabad, Pakistan, and given in Figure 1.

2.4. Data Recorded

Growth parameters were taken from randomly selected ten plants from every experimental unit, and an average was taken. Days to stem elongation, flowering, and maturity were counted manually. Plant height was measured from the ground to the tip of the apical meristem using measuring tape at physiological maturity. The diameter of the capitulum was determined using the vernier caliper, whereas the number of branches/plant and capitula/plant were counted manually. A leaf area meter (CI-202, CID Bio-Science, Camas, WA, USA) was used to quantify the leaf area at the vegetative stage of the plant. Five leaves from different plants were taken, and their mean leaf area was calculated. For yield-related parameters, such as seed yield, petal yield, and biological yield, a 1 m2 area was harvested to determine the aforementioned parameters. Further, the petal and capitula were separated from the stem and weighed on electrical balance.
For leaf mineral contents, oven-dried (660 °C for 48 h) samples were grounded and sieved to obtain a 1.25 g composite sample used for digestion with 20 mL H2SO4 (98%) and 4 mL H2O2 (30%). After digestion, the mineral contents were determined using an atomic absorption spectrophotometer (PerkinElmer AAnalyst 400, PerkinElmer, Inc., Waltham, MA, USA) following standard procedures for each mineral element. The digested sample solution was filtered and then diluted appropriately, ensuring that each mineral was analyzed within the calibration range of the spectrophotometer. Calibration standards were prepared to ensure accuracy, and quality control samples were included to verify the precision and reliability of the measurements. The concentration of each mineral was calculated based on the absorbance values using the respective calibration curve. Nitrogen content was determined with the Kjeldahl apparatus, and leaf phosphorous contents were calculated through the colorimetric method following the principles outlined in [46]. A UV-Vis spectrophotometer (Shimadzu UV-1800, Shimadzu Corporation, Kyoto, Japan) was used to measure the phosphorus concentration using the molybdenum blue method. After the color development stage, absorbance was measured at 882 nm, with phosphorus levels quantified by comparing the absorbance to a standard calibration curve.
The soxhlet oil extraction technique used petroleum ether solvent to determine the oil yield. For this, a sample of 2 g dried seed from every treatment was ground, and oil yield/gram of dry matter was calculated following the method described by Roche et al. 2019 [47].

2.5. Statistical Analysis

The collected data were statistically analyzed by Fisher’s analysis of variance technique, and treatment means were compared by least significant difference (LSD) at the 5% probability level [48] using Statistix 10.0 software (Statistix, Tallahassee, FL, USA). Moreover, graphs were plotted using OriginPro–2024 software (Originlab, Northampton, MA, USA). Pearson correlation analysis, scatterplot matrix analysis, and hierarchical clustering were also performed in this software to determine the effect of different treatments and the relationship among different studied traits.

3. Results and Discussion

3.1. Phenological Parameters

The maximum days to stem elongation (62.7 days) were counted from the T10 treatment (T5 + zinc at 7.5 kg ha−1), which were statistically at par with T5 (NPK at 80:80:40 kg ha−1) and T1 (NPK at 40:40:40 kg ha−1), whereas the lowest days to stem elongation (47.8 days) were observed in T3, having NPK at 60:60:40 kg ha−1 (Figure 2a). Moreover, the highest mean number of days to flowering (139 days) and maturity (151 days) were recorded from T10 and T8, respectively, and the minimum days to flowering and maturity were observed in the control (Figure 2b,c). The results declared the positive correlation of soil-applied zinc–NPK combinations on the studied parameters of safflower. The number of days to stem elongation, flowering, and maturity were significantly (p ≤ 0.05) affected by different levels of fertilizers studied in treatment combinations. This could be due to the increased cell division, multiplication, and enlarged cellular growth initiated by optimum NPK and Zn supply during the entire crop growing period. The optimum nitrogen supply enhanced the protein synthesis involved in activating different enzyme functions, boosting photosynthesis [49]. The number of days to maturity observed in this study was between 143 and 150, which was slightly lower than the days to maturity reported by Haghighati (2010) [50] and Rathke et al. 2006 [51]. The number of days to flowering observed in this study was between 131 and 138, which endorsed the results noted by Ashkani et al., 2007 [52], i.e., 133 days. Moreover, the results showed similar days to flowering in safflower, as described by Yeilaghi et al., 2012 [53]. Well-adjusted NPK levels with zinc application optimized the days to maturity and flowering, which strengthened the stalk with more photo-assimilate production and augmented the petal formation associated with increased plant height; consequently, biological yield increased [52,53].

3.2. Growth Parameters

NPK application at 80:80:40 kg ha−1 + zinc (7.5 kg ha−1) resulted in the production of taller plants (190.3 cm), and the shortest height was noted in the control treatment (Figure 2d). Moreover, the leaf area of plants was affected significantly (p ≤ 0.05) by different combinations of nutrients, as depicted in Figure 3a. The maximum mean leaf area (68.3 cm2) was recorded with the application of NPK @ 80:80:40 kg ha−1 + zinc @ 7.5 kg ha−1), which was statistically similar to other treatments, except T1 and the control. Furthermore, the maximum capitulum diameter was also observed in the T9 treatment followed by treatment T10 (Figure 3b). The highest number of branches/plant (8.7) and the highest number of capitula per plant (38.17) were recorded in T9, where NPK @ 70:70:40 kg ha−1 + zinc @ 7.5 kg ha−1 was applied (Figure 3c,d). The lowest outcomes of all aforementioned parameters were found in the control treatment. The plant height ranged from 165 cm to 192 cm, which is in compliance with the range documented by Tuncturk and Yildirim (2004) [54], i.e., 40–210 cm. Furthermore, Strasil and Vorlicek (2002) [55] reported the height of the plant as more than 150 cm, which ultimately advocated this experiment. Siddiqui and Oad (2006) [56] also reported that plant height can be up to 190 cm, which supports the present results. Further, phosphorus supply helps produce energy necessary for plant growth and developmental processes [57]. Similarly, potassium regulated guard cell movement and contributed to safflower growth and development [21].
The experiment results showed that plants had 5–8 branches per plant, which follows the results reported in different studies [58,59,60,61]. These findings were also reported by Malek and Ferri (2014) [62]. Furthermore, increasing nutrient levels significantly enhanced the number of branches per plant. This could be due to the positive role of potassium in cellular turgidity, higher chlorophyll production, and more photo-assimilate synthesis throughout the early plant growth stages. The higher source–sink relation in the continuous supply of zinc and macro-nutrients increased the branch’s production in safflower [63]. The expanded capitula/plant and diameter result from better crop vegetative growth under an optimum supply of essential nutrients [64]. These results align with the previous studies [65,66].
A larger leaf area could be due to the high amount of nitrogen that ensures various developmental processes of the crop. Our findings are supported by the observations of Hiwale et al., 2022 [67], who stated that adequate nitrogen supply augments the crop growth stages and leaf area index. Owing to this, larger leaf areas produced higher photosynthate, and their assimilation subsequently increased plant height. The optimum dose of essential nutrients increased carbohydrate metabolism and plant vegetative growth [68].
In this experiment, the number of capitula per plant was recorded between 21 and 35 capitula per plant. These results are also endorsed by the results presented in similar experiments [69]. Elfadl et al. (2009) [58] also favored the results of the present study, as they reported 24 capitula per plant. Increasing fertilizer rates provided better results on the number of capitula per plant [9,70]. Moreover, Rastgou et al. (2013) [71] reported that optimum fertilization increased the number of capitula per plant by 31%. In contrast, Strasil and Vorlicek (2002) [55] observed that nitrogen fertilization did not affect the number of capitula per plant under rainfed conditions.

3.3. Yield Parameters

The yield and yield components were significantly (p ≤ 0.05) affected by varying nutrient combination levels. The maximum seed yield (2830 kg ha−1) was recorded in T9, followed by T10 (2613 kg ha−1), and the lowest seed yield (1443 kg ha−1) was recorded in the control (Figure 4a). Likewise, the highest petal yield (63.1 kg ha−1) and 1000 grain weight (44.1 g) were recorded, with T9 having NPK @ 70:70:40 kg ha−1 + zinc @ 7.5 kg ha−1, and the lowest grain weight (34 g) and petal yield (30.12 kg ha−1) were observed in the control treatment (Figure 4b,d). Furthermore, the maximum biological yield (10,098 kg ha−1) was recorded in T10 followed by T7, and the lowest biological yield (6610 kg ha−1) was recorded in the control (Figure 4c). The maximum oil yield (875.1 kg ha−1) was recorded in T9, where NPK at 70:70:40 kg ha−1 along with zinc at 7.5 kg ha−1 were applied followed by T10 (830 kg ha−1), and the lowest oil yield (471 kg ha−1) was found in the control treatment (Figure 5c). Grain weight is one of the crucial yield-defining parameters. The 1000 grain weight has a great influence on the seed yield of safflower [72,73]. Also, the dry matter content of the plant is not only dependent on plant height and stem diameter but also on branches and leaves, which increase the number of capitula, presumably resulting in a higher seed output and weightage [74]. This rise in seed weight can be explained by the fact that the rhizosphere was supplied with significant and essential nutrients in ready-made and ample amounts, which boosted the absorption of these nutrients by the roots, ultimately enhancing the total biomass of the plant. This caused increased dry matter production and its translocation to the seeds [75]. Moreover, the effect of NPK on increasing yield is due to potassium (K), which is a cofactor (enzyme activator) for different enzymes, and it helps to maintain electroneutrality in plant cells. The biological yield of the plants increased with an increasing amount of applied fertilizers. Additionally, a study performed by Ismail and Azooz (2005) [76] showed that an increase in shoot length was recorded in safflower with zinc application.
In other experiments, seed yield was substantially increased by zinc application [77,78,79]. These results are also reported in the previous studies [52,58,61,69,80]. Zinc plays an important role in the higher production of biomass [81]. Furthermore, zinc is required for chlorophyll production, pollen function, and germination [34]. The availability of nutrients, particularly nitrogen, possibly allowed the greater accumulation of nutrients, resulting in dry matter accumulation in plant parts during the flowering stage. Dordas and Sioulas (2009) [82] observed that nitrogen fertilization increased dry matter production by 24% until anthesis. Moreover, different concentrations of N and P positively influenced shoot dry matter under controlled conditions [12]. Several studies have shown that a small amount of nutrients, particularly Zn and Mn, can significantly increase the yield of crops [83,84,85,86]. The highest seed yield was observed in the T9 treatment, which may be due to higher photosynthetic activity; more protein and carbohydrate functioning leads to better fertilization at the reproductive phase. This could be the affirmative role of zinc application that positively affects photo-assimilates translocation and pollen tube elongation [87].
Zinc application improved pollination and pollen formation [88]. Similarly, the balanced NPK application increased chlorophyll synthesis, maintained leaf turgidity, and increased water uptake to increase photosynthesis [89]. The higher crop vegetative growth ultimately resulted in higher petal and biological yield. Increased thousand grain weight was owing to a significant increase in growth and yield characteristics under balanced NPK + zinc levels. Balanced fertilization improved the seed weight by enhancing the nutrient uptake throughout the crop growing season [67]. Further, seed weight was also increased with zinc application [88].

3.4. Quality Attributes

The qualitative traits were significantly (p ≤ 0.05) affected by different levels of nutrients. The maximum leaf nitrogen percentage (0.547% w/w) was recorded in T10, where zinc was applied in combination with T5 treatment, and the lowest leaf nitrogen (0.38% w/w) was observed in the control (Figure 5a). Similarly, the maximum leaf phosphorous content (145 mg/kg−1) was found in T10, and that of the lowest (84 mg/kg−1) was in the control (Figure 5b). The recorded increase in quality attributes of safflower could be attributed to the regulatory role of essential nutrients. The combined application of zinc with NPK enhanced the leaf nitrogen and protein contents [49,90]. Further, the optimum utilization of applied nutrients has shown a significant increment in oil yield in oil seed crops [49,91]. These findings explored the synergistic interaction between zinc and NPK levels to optimize the safflower oil and yield attributes, as also reported in soybeans [92]. Zinc application with a balanced supply of NPK facilitates the various enzymatic functions found integral for photosynthesis [87].

3.5. Correlation Analysis and Scatterplot Matrix

Pearson correlation analysis was performed to measure the strength of the relationship among different parameters (Figure 6a). The analysis revealed significant positive relationships among the variables, with most correlations falling in the moderate to strong range (r = 0.36 to 0.96). Notably, variables such as days to stem elongation (DSE) and oil yield (OY), as well as days to flowering (DF) and leaf area (LA), demonstrated the highest correlation (r = 0.96, p < 0.01), indicating a strong interdependence. The overall pattern of positive correlations suggests that these variables are likely capturing related aspects of the data, with little evidence of inverse relationships. These findings provide a robust foundation for further exploration into the interconnected nature of these variables, with implications for understanding the broader dynamics at play in this study.
On the other hand, the correlation matrix (Figure 6b) reveals several significant relationships among the variables. Ellipses represent the strength and direction of correlations, with elongated ellipses indicating stronger correlations and circular ellipses suggesting weaker or no correlations. The matrix highlights strong positive correlations between seed yield (SY), petal yield (PY), and oil yield (OY), as well as between leaf nitrogen percentage (LNP) and leaf phosphorus content (LPC), demonstrating the interrelationship between yield components and nutrient content. Seed yield (SY) is strongly and positively correlated with petal yield (PY) and oil yield (OY), as indicated by the upward trends and tightly fitted ellipses, suggesting that increases in PY and OY are associated with higher SY. Similarly, there is a positive correlation between SY and 1000 grain weight (TGW), though the relationship is slightly weaker. Nutrient content variables, such as leaf nitrogen percentage (LNP) and leaf phosphorus content (LPC), are also strongly positively correlated with each other. There are no evident negative correlations in this matrix.

3.6. Hierarchical Cluster Analysis

The hierarchical cluster analysis (HCA) dendrogram (Figure 7) revealed distinct clusters that highlight relationships among different parameters. Biological yield, seed yield, and oil yield form a closely related cluster at the highest level of similarity. This grouping indicates that these yield-related parameters are strongly correlated, likely due to their direct connection to the overall productivity of the crop.
These variables may be influenced by similar factors, such as nutrient availability or plant growth conditions, making them key indicators of crop performance in response to different fertilizer treatments. Another notable cluster representing plant height, branches per plant, and leaf area are also closely related, which suggests that they are fundamental components of vegetative growth. Their correlation implies that changes in one of these parameters are likely to be reflected in the others, making them important for understanding how fertilizer rates affect the structural development of the crop. Finally, leaf phosphorus content, petal yield, and 1000 grain weight form another cluster, albeit at a lower similarity level. This suggests that while these parameters are related, their connection may be more indirect or influenced by different factors compared to the other clusters. The inclusion of 1000 grain weight in this group might indicate a link between phosphorus nutrition and grain filling, impacting the overall grain quality and yield.

4. Conclusions

This study highlights the critical role of balanced nutrient management, particularly the synergistic application of NPK and zinc, in enhancing the growth and yield of safflower. The results indicate that the treatment combination T9 (NPK @ 70:70:40 kg ha−1 + zinc @ 7.5 kg ha−1), which is the same as T4 but with zinc supplementation, significantly outperformed other treatments, demonstrating its potential as an effective agronomic practice in semi-arid regions. By addressing the challenges of nutrient imbalances, this research contributes valuable insights into optimizing safflower cultivation, suggesting that proper nutrient management can lead to improved agricultural productivity and sustainability. Future studies should explore the long-term effects of these treatments on soil health and crop performance, further establishing safflower as a viable alternative oilseed crop in diverse environments.

Author Contributions

Conceptualization, M.A. (Muhammad Alamgeer) and H.M.; methodology, M.A. (Muhammad Alamgeer) and H.M.; formal analysis, S.A., M.A. (Muhammad Alamgeer) and M.A. (Maryam Aslam); validation, M.A. (Muhammad Alamgeer) and S.H.; investigation, S.H. and S.R.; resources, H.M.; data curation, J.A. and S.A.; writing—original draft preparation, M.A. (Muhammad Alamgeer) and H.M.; writing—review and editing, H.M., S.A., W.S., J.A. and M.A. (Maryam Aslam); visualization, S.H., J.A. and S.R. All authors have read and agreed to the published version of the manuscript.

Funding

This research was supported by institutional funds from the University of Agriculture, Faisalabad, Pakistan.

Data Availability Statement

All data generated or analyzed during this study are included in this article.

Acknowledgments

The authors would like to extend their heartfelt gratitude to the members of Hassan Munir’s lab at the University of Agriculture, Faisalabad, for their invaluable support and assistance throughout this research. We also acknowledge the King Saud University Researchers Supporting Project (RSP2025R390), King Saud University, Riyadh, Saudi Arabia.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Pakistan Bureau of Statistics. Agriculture Statistics. Available online: https://www.pbs.gov.pk/content/agriculture-statistics (accessed on 15 September 2024).
  2. Weiss, E.A. Oilseed Crops, 2nd ed.; Wiley: Hoboken, NJ, USA; Available online: https://www.wiley.com/en-us/Oilseed+Crops%2C+2nd+Edition-p-9780632052592 (accessed on 15 September 2024).
  3. FAO Statistical Yearbook 2013. Available online: https://www.fao.org/4/i3107e/i3107e00.htm (accessed on 15 September 2024).
  4. DE Queiroz, A.F.; Salviano, A.M.; DA Cunha, T.J.; Olszevski, N.; Júnior, V.S.D.S.; Neto, M.B.D.O. Potentialities and limitations of agricultural use in soils of semi-arid region of the state of Bahia. An. Acad. Bras. Ciências 2018, 90, 3373–3387. [Google Scholar] [CrossRef] [PubMed]
  5. Nouraein, M.; Skataric, G.; Spalevic, V.; Dudic, B.; Gregus, M. Short-term effects of tillage intensity and fertilization on sunflower yield, achene quality, and soil physicochemical properties under semi-arid conditions. Appl. Sci. 2019, 9, 5482. [Google Scholar] [CrossRef]
  6. Nosheen, A.; Naz, R.; Tahir, A.T.; Yasmin, H.; Keyani, R.; Mitrevski, B.; Bano, A.; Tong Chin, S.; Marriott, P.J.; Hussain, I. Improvement of safflower oil quality for biodiesel production by integrated application of PGPR under reduced amount of NP fertilizers. PLoS ONE 2018, 13, e0201738. [Google Scholar] [CrossRef] [PubMed]
  7. Yeloojeh, K.A.; Saeidi, G.; Sabzalian, M.R. Drought stress improves the composition of secondary metabolites in safflower flower at the expense of reduction in seed yield and oil content. Ind. Crops Prod. 2020, 154, 112496. [Google Scholar] [CrossRef]
  8. Joshi, S.; Thoday-Kennedy, E.; Daetwyler, H.D.; Hayden, M.; Spangenberg, G.; Kant, S. High-throughput phenotyping to dissect genotypic differences in safflower for drought tolerance. PLoS ONE 2021, 16, e0254908. [Google Scholar] [CrossRef]
  9. Abbadi, J.; Gerendás, J.; Sattelmacher, B. Effects of nitrogen supply on growth, yield and yield components of safflower and sunflower. Plant Soil. 2008, 306, 167–180. [Google Scholar] [CrossRef]
  10. Khalil, N.A.A.; Dagash, Y.M.; Yagoub, S.O. Effect of Sowing Date, Irrigation Intervals and Fertilizers on Safflower (Carthamus tinctorius L.) Yield. Discourse J. Agric. Food Sci. 2013, 1, 97–102. [Google Scholar]
  11. Emongor, V.; Oagile, O.; Phuduhudu, D.; Oarabile, P. Safflower Production. Botswana University of Agriculture and Natural ResourcesI Gaborone, 2017. Available online: http://repository.ruforum.org/system/tdf/Safflower%20Manual_BUAN.compressed.pdf?file=1&type=node&id=36745&force= (accessed on 15 September 2024).
  12. Bonfim-Silva, E.M.; Paludo, J.T.S.; Sousa, J.V.R.; Sousa, H.H.d.F.; da Silva, T.J.A. Development of safflower subjected to nitrogen rates in cerrado soil. Am. J. Plant Sci. 2015, 06, 2136–2143. [Google Scholar] [CrossRef]
  13. Kolanyane, M.O. The Influence of Nitrogen and Phosphorus Nutrition on Growth and Yield Components of Safflower (Carthamus tinctorius L.). Ph.D. Thesis, Botswana University of Agriculture & Natural Resources, Gaborone, Botswana, 2022. Available online: http://researchhub.buan.ac.bw/handle/13049/534 (accessed on 20 August 2024).
  14. Golzarfar, M.; Rad, A.H.S.; Delkhosh, B.; Bitarafan, Z. Safflower (Carthamus tinctorius L.) Response to Different Nitrogen and Phosphorus Fertilizer Rates in Two Planting Seasons. 2012. Available online: https://zemdirbyste-agriculture.lt/99(2)tomas/99_2_tomas_str6.pdf (accessed on 20 August 2024).
  15. Sharifi, R.S.; Namvar, A.; Sharifi, R.S. Grain filling and fatty acid composition of safflower fertilized with integrated nitrogen fertilizer and biofertilizers. Pesqui. Agropecuária Bras. 2017, 52, 236–243. [Google Scholar] [CrossRef]
  16. Liu, D.; Song, C.; Fang, C.; Xin, Z.; Xi, J.; Lu, Y. A recommended nitrogen application strategy for high crop yield and low environmental pollution at a basin scale. Sci. Total Environ. 2021, 792, 148464. [Google Scholar] [CrossRef]
  17. Razaq, M.; Zhang, P.; Shen, H.-L. Salahuddin Influence of nitrogen and phosphorous on the growth and root morphology of Acer mono. PLoS ONE 2017, 12, e0171321. [Google Scholar] [CrossRef] [PubMed]
  18. Aslam, M.M.; Akhtar, K.; Karanja, J.K.; Noor-ul-Ain, N.; Haider, F.U. Understanding the adaptive mechanisms of plant in low phosphorous soil. In Plant Stress Physiology; CABI Books: London, UK, 2020; Available online: https://books.google.com/books?hl=en&lr=&id=ImwtEAAAQBAJ&oi=fnd&pg=PA285&dq=Understanding+the+adaptive+mechanisms+of+plant+in+low+phosphorous+soil.+In+Plant+stress+physiology&ots=AO8htTLSPO&sig=0mZGpY1p9ps5n-Z2RPErpNlsfQo (accessed on 20 August 2024).
  19. Sreekanth, N.; Singh, V.; Tiwari, D.; George, S.G. Effect of nitrogen and phosphorus levels on growth and yield of safflower (Carthamus tinctorius L.). Pharma Innov. J. 2021, 10, 2271–2273. [Google Scholar]
  20. Singh, R.K.; Singh, A.K. Effect of nitrogen, phosphorus and sulphur fertilization on productivity, nutrient-use efficiency and economics of safflower (Carthamus tinctorius) under late-sown condition. Indian J. Agron. 2001, 58, 583–587. [Google Scholar] [CrossRef]
  21. Lazar, T.; Taiz, L.; Zeiger, E. Plant physiology. 3rd edn. Ann. Bot. 2003, 91, 750–751. [Google Scholar] [CrossRef]
  22. Johnson, R.; Vishwakarma, K.; Hossen, M.S.; Kumar, V.; Shackira, A.M.; Puthur, J.T.; Abdi, G.; Sarraf, M.; Hasanuzzaman, M. Potassium in plants: Growth regulation, signaling, and environmental stress tolerance. Plant Physiol. Biochem. 2022, 172, 56–69. [Google Scholar] [CrossRef] [PubMed]
  23. Kikhazaleh, M.; Ramroudi, M.; Galavi, M.; Ghanbari, S.A.; Fanaei, H.R. Effect of potassium on yield and some qualitative and physiological traits of safflower (Carthamus tinctorius L.) under drought stress conditions. J. Plant Nutr. 2023, 46, 2380–2392. [Google Scholar] [CrossRef]
  24. Sein-Echaluce, V.C.; Mulet, J.M.; Barja, M.V.; Peleato, M.L.; Fillat, M.F. Exploring the ability of cyanobacterial ferric uptake regulator (FUR) proteins to increase yeast tolerance to abiotic stresses. In Cyanobacterial Lifestyle and Its Applications in Biotechnology; Elsevier: Amsterdam, The Netherlands, 2022; pp. 179–196. Available online: https://www.sciencedirect.com/science/article/pii/B9780323906340000123 (accessed on 20 August 2024).
  25. Azimi Gandomani, M.; Faraji, H.; Dehdari, A.; Movahhedi Dehnavi, M.; Alinaghizadeh, M. Evaluation of the effect of salinity stress on ion accumulation, quantitative and qualitative yield of spring rapeseed cultivars. Environ. Stress. Crop Sci. 2009, 1, 27–37. [Google Scholar]
  26. Ravi, V.; Khurana, J.P.; Tyagi, A.K.; Khurana, P. An update on chloroplast genomes. Plant Syst. Evol. 2008, 271, 101–122. [Google Scholar] [CrossRef]
  27. Aslam, M.T.; Khan, I.; Chattha, M.U.; Nawaz, M.; Mustafa, A.; Athar, F.; Hassan, M.U.; Kanwal, H.; Shah, A.N. The Biofortification of Zinc in Legumes to Alleviate Zinc Deficiency. In Legumes Biofortification; Springer: Berlin/Heidelberg, Germany, 2023; pp. 327–346. Available online: https://link.springer.com/chapter/10.1007/978-3-031-33957-8_14 (accessed on 20 August 2024).
  28. Aslam, M.T.; Chattha, M.U.; Khan, I.; Haq, M.Z.U.; Mustafa, A.; Athar, F.; Bisma; Nawaz, M.; Shah, A.N.; Mahmood, F.; et al. Scope of Seed Priming in Inducing Biofortification in Plants. In Mineral Biofortification in Crop Plants for Ensuring Food Security; Springer: Berlin/Heidelberg, Germany, 2023; pp. 233–259. Available online: https://link.springer.com/chapter/10.1007/978-981-99-4090-5_11 (accessed on 20 August 2024).
  29. Ghiyasi, M.; Rezaee Danesh, Y.; Amirnia, R.; Najafi, S.; Mulet, J.M.; Porcel, R. Foliar Applications of ZnO and its nanoparticles increase safflower (Carthamus tinctorius L.) growth and yield under water stress. Agronomy 2023, 13, 192. [Google Scholar] [CrossRef]
  30. Rahmani, F.; Sayfzadeh, S.; Jabbari, H.; Valadabadi, S.A.; Masouleh, E.H. Alleviation of Drought Stress Effects on Safflower Yield by Foliar Application of Zinc. Int. J. Plant Prod. 2019, 13, 297–308. [Google Scholar] [CrossRef]
  31. Manvelian, J.; Weisany, W.; Tahir, N.A.R.; Jabbari, H.; Diyanat, M. Physiological and biochemical response of safflower (Carthamus tinctorius L.) cultivars to zinc application under drought stress. Ind. Crops Prod. 2021, 172, 114069. [Google Scholar] [CrossRef]
  32. Shukla, A.K.; Behera, S.K. Zinc Management in Indian Agriculture: Past, Present and Future. 2011. Available online: https://www.cabidigitallibrary.org/doi/full/10.5555/20113337631 (accessed on 15 September 2024).
  33. Fageria, N.K.; Baligar, V.C. Enhancing Nitrogen Use Efficiency in Crop Plants. Adv. Agron. 2005, 88, 97–185. [Google Scholar] [CrossRef]
  34. Cakmak, I. Enrichment of cereal grains with zinc: Agronomic or genetic biofortification? Plant Soil 2018, 302, 1–17. [Google Scholar] [CrossRef]
  35. Alloway, B.J. Soil factors associated with zinc deficiency in crops and humans. Environ. Geochem. Health 2009, 31, 537–548. [Google Scholar] [CrossRef] [PubMed]
  36. Khanda, C.M.; Dixit, L. Effect of zinc and nitrogen fertilization on yield and, nutrient uptake of summer rice (Oryza sativu). Indian J. Agron. 1996, 41, 41_3. [Google Scholar]
  37. Thomas, G.W. Soil pH and Soil Acidity. In SSSA Book Series; Sparks, D.L., Page, A.L., Helmke, P.A., Loeppert, R.H., Soltanpour, P.N., Tabatabai, M.A., Johnston, C.T., Sumner, M.E., Eds.; Soil Science Society of America, American Society of Agronomy: Madison, WI, USA, 2018; pp. 475–490. [Google Scholar] [CrossRef]
  38. Rhoades, J.D. Salinity: Electrical Conductivity and Total Dissolved Solids. In SSSA Book Series; Sparks, D.L., Page, A.L., Helmke, P.A., Loeppert, R.H., Soltanpour, P.N., Tabatabai, M.A., Johnston, C.T., Sumner, M.E., Eds.; Soil Science Society of America, American Society of Agronomy: Madison, WI, USA, 2018; pp. 417–435. [Google Scholar] [CrossRef]
  39. Nelson, D.W.; Sommers, L.E. Total Carbon, Organic Carbon, and Organic Matter. In Agronomy Monographs, 1st ed.; Page, A.L., Ed.; Wiley: Hoboken, NJ, USA, 1982; Volume 9, pp. 539–579. [Google Scholar] [CrossRef]
  40. Keeney, D.R.; Nelson, D.W. Nitrogen—Inorganic Forms. In Agronomy Monographs, 1st ed.; Page, A.L., Ed.; Wiley: Hoboken, NJ, USA, 1982; Volume 9, pp. 643–698. [Google Scholar] [CrossRef]
  41. Olsen, S.R.; Sommers, E.L. Phosphorus soluble in sodium bicarbonate. Methods Soil Anal. Part 1982, 2, 404–430. [Google Scholar]
  42. Knudsen, D.; Peterson, G.A.; Pratt, P.F. Lithium, Sodium, and Potassium. In Agronomy Monographs, 1st ed.; Page, A.L., Ed.; Wiley: Hoboken, NJ, USA, 1982; Volume 9, pp. 225–246. [Google Scholar] [CrossRef]
  43. Lindsay, W.L.; Norvell, W.A. Development of a DTPA Soil Test for Zinc, Iron, Manganese, and Copper. Soil. Sci. Soc. Am. J. 1978, 42, 421–428. [Google Scholar] [CrossRef]
  44. Nachtergaele, F. Soil taxonomy—A basic system of soil classification for making and interpreting soil surveys. Geoderma 2001, 99, 336–337. [Google Scholar] [CrossRef]
  45. Gee, G.W. Particle size analysis. In Methods of Soil Analysis; ASA and SSSA: Madison, WI, USA, 1986. [Google Scholar]
  46. Horwitz, W. Official Methods of Analysis of the Association of Official Analytical Chemists; The Association: Singapore, 1925; Volume 2, Available online: https://books.google.com/books?hl=en&lr=&id=kiRtAAAAMAAJ&oi=fnd&pg=PP26&dq=AOAC+(1996)+Official+Method+of+Analysis+of+the+Association+of+Official+Analytical+Chemists.+AOAC+International,+Arlington.&ots=G-5JxhW56S&sig=Jaooi33vMATsRRBaH_rrpehVvsM (accessed on 20 August 2024).
  47. Roche, J.; Mouloungui, Z.; Cerny, M.; Merah, O. Effect of sowing dates on fatty acids and phytosterols patterns of Carthamus tinctorius L. Appl. Sci. 2019, 9, 2839. [Google Scholar] [CrossRef]
  48. Steel, R.G.D.; Torrie, J.H.; Dickey, D.A. Principles and Procedures of Statistics: A Biometrical Approach; McGraw-Hill: New York, NY, USA, 1997. [Google Scholar]
  49. Liu, Y.; Wei, D. High-efficient CO2-to-protein bioconversion by oleaginous Coccomyxa subellipsoidea using light quality shift and nitrogen supplementation strategy. Chem. Eng. J. 2023, 473, 145166. [Google Scholar] [CrossRef]
  50. Haghighati, A. Study on the effects of nitrogen and phosphorus fertilizers on the yield and oil content of safflower lines in drylands. Res. J. Agron. 2010, 4, 57–62. [Google Scholar] [CrossRef]
  51. Rathke, G.-W.; Behrens, T.; Diepenbrock, W. Integrated nitrogen management strategies to improve seed yield, oil content and nitrogen efficiency of winter oilseed rape (Brassica napus L.): A review. Agric. Ecosyst. Environ. 2006, 117, 80–108. [Google Scholar] [CrossRef]
  52. Ashkani, J.; Pakniyat, H.; Emam, Y.; Assad, M.T.; Bahrani, M.J. The Evaluation and Relationships of some Physiological Traits in Spring Safflower (Carthamus tinctorius L.) under Stress and Non-stress Water Regimes. J. Agric. Sci. Technol. 2007, 9, 267–277. [Google Scholar]
  53. Yeilaghi, H.; Arzani, A.; Ghaderian, M.; Fotovat, R.; Feizi, M.; Pourdad, S.S. Effect of salinity on seed oil content and fatty acid composition of safflower (Carthamus tinctorius L.) genotypes. Food Chem. 2012, 130, 618–625. [Google Scholar] [CrossRef]
  54. Tuncturk, M.; Yildirim, B. Effects of different forms and doses of nitrogen fertilizers on safflower (Carthamus tinctorius L.). Pak. J. Biol. Sci. 2004, 7, 1385–1389. [Google Scholar] [CrossRef]
  55. Strašil, Z.; Vorlíček, Z. The effect of nitrogen fertilization, sowing rates and site on yields and yield components of selected varieties of safflower (Carthamus tinctorius L.). Plant Soil. Environ. 2002, 48, 307–311. [Google Scholar] [CrossRef]
  56. Siddiqui, M.H.; Oad, F.C. Nitrogen Requirement of Safflower (Carthamus tinctorius L.) for Growth and Yield Traits. 2006. Available online: https://www.cabidigitallibrary.org/doi/full/10.5555/20063093528 (accessed on 16 September 2024).
  57. Ma, J.; Chen, T.; Lin, J.; Fu, W.; Feng, B.; Li, G.; Li, H.; Li, J.; Wu, Z.; Tao, L.; et al. Functions of nitrogen, phosphorus and potassium in energy status and their influences on rice growth and development. Rice Sci. 2022, 29, 166–178. [Google Scholar] [CrossRef]
  58. Elfadl, E.; Reinbrecht, C.; Frick, C.; Claupein, W. Optimization of nitrogen rate and seed density for safflower (Carthamus tinctorius L.) production under low-input farming conditions in temperate climate. Field Crops Res. 2009, 114, 2–13. [Google Scholar] [CrossRef]
  59. Emami, T.; Naseri, R.; Falahi, H.; Kazemi, E. Response of Yield, Yield Component and Oil Content of Safflower (cv. Sina) to Planting Date and Plant Spacing on Row in Rainfed Conditions of Western Iran. 2011. Available online: https://www.cabidigitallibrary.org/doi/full/10.5555/20113327040 (accessed on 16 September 2024).
  60. Azari, A.; Khajehpour, M.R. Effects of planting pattern on growth, development, yield components and seed yield of safflower, local variety of Isfahan, Koseh, in spring planting. JWSS-Isfahan Univ. Technol. 2003, 7, 155–167. [Google Scholar]
  61. Santos, R.F.; de Almeida Silva, M. Carthamus tinctorius L.: Uma alternativa de cultivo para o Brasil. Acta Iguazu 2015, 4, 26–35. [Google Scholar]
  62. Malek, H.A.; Ferri, F. Effects of nitrogen and phosphorus fertilizers on safflower yield in dry land conditions. Int. J. Res. Agric. Sci. 2014, 1, 28–33. [Google Scholar]
  63. Kirkby, E.A.; Nikolic, M.; White, P.J.; Xu, G. Mineral nutrition, yield, and source–sink relationships. In Marschner’s Mineral Nutrition of Plants; Elsevier: Amsterdam, The Netherlands, 2023; pp. 131–200. Available online: https://www.sciencedirect.com/science/article/pii/B9780128197738000150 (accessed on 20 August 2024).
  64. Ahmed, M.A.; Rasheed, S.M.; Zeebaree, P.J. Responses of Two Red Cabbage Hybrids to Nano NPK and Zinc Fertilizers (Brassica oleracea L. var. capitata rubra). J. Environ. Sci. Stud. 2023, 6, 1. [Google Scholar] [CrossRef]
  65. Ravi, S.; Jadhav, R.L.; Bhat, S.N.; Shankar, K.A. Response of Iron and Boron on Uptake of Nutrients and Soil Nutrient Status after Harvest of Safflower Crop (Carthamus tinctorius L.) in Kalyan Karnataka, India. Int. J. Plant Soil. Sci. 2023, 35, 24–31. [Google Scholar] [CrossRef]
  66. Mishra, A.; Gupta, H.; Mishra, U.S.; Sirothia, P.; Darwai, P. Interaction Effect of Sulphur and NPK on Growth Parameters and Yield of Mustard. Int. J. Plant Soil. Sci. 2023, 35, 138–144. [Google Scholar] [CrossRef]
  67. Hiwale, S.D.; Chorey, A.B.; Deshmukh, M.R. Balanced crop nutrition to optimized productivity and quality of safflower under rainfed condition. In Advances in Agricultural and Horticultural Sciences; Kosmos Publishers: Harrison, NJ, USA, 2022; p. 125. Available online: https://www.researchgate.net/profile/Tejpal-Dahiya/publication/358899022_Biofloc_Technology_An_emerging_and_innovative_approach_for_sustainable_aquaculture_productivity/links/6253ec66ef0134206669a186/Biofloc-Technology-An-emerging-and-innovative-approach-for-sustainable-aquaculture-productivity.pdf#page=134 (accessed on 20 August 2024).
  68. Sahu, A.; Swaroop, N.; David, A.A.; Thomas, T. Effect of different levels of NPK and Zinc on soil health growth and yield of chickpea (Cicer arietinum L.) var. PUSA 362. Int. J. Curr. Microbiol. Appl. Sci. 2020, 9, 591–597. [Google Scholar] [CrossRef]
  69. Omidi, A.H.; Sharifmogadas, M.R. Evaluation of Iranian safflower cultivars reaction to different sowing dates and plant densities. World Appl. Sci. J. 2010, 8, 953–958. [Google Scholar]
  70. Dordas, C.A.; Sioulas, C. Safflower yield, chlorophyll content, photosynthesis, and water use efficiency response to nitrogen fertilization under rainfed conditions. Ind. Crops Prod. 2008, 27, 75–85. [Google Scholar] [CrossRef]
  71. Rastgou, B.; Ebadi, A.; Vafaie, A.; Moghadam, S.H. The Effects of Nitrogen Fertilizer on Nutrient Uptake, Physiological Traits and Yield Components of Safflower (Carthamus tinctorius L.). 2013. Available online: https://www.cabidigitallibrary.org/doi/full/10.5555/20133186691 (accessed on 16 September 2024).
  72. Mahasi, M.J.; Pathak, R.S.; Wachira, F.N.; Riungu, T.C.; Kinyua, M.G.; Kamundia, J.W. Correlations and Path Coefficient Analysis in Exotic Safflower (Carthamus tinctorious L.) Genotypes Tested in the Arid and Semi Arid Lands (Asals) of Kenya. 2006. Available online: https://www.cabidigitallibrary.org/doi/full/10.5555/20063210358 (accessed on 16 September 2024).
  73. Arslan, B. The Path Analysis of Yield and its Components in Safflower (Carthamus tinctorius L.). J. Biol. Sci. 2007, 7, 668–672. [Google Scholar] [CrossRef]
  74. Koutroubas, S.D.; Papakosta, D.K.; Doitsinis, A. Cultivar and seasonal effects on the contribution of pre-anthesis assimilates to safflower yield. Field Crops Res. 2004, 90, 263–274. [Google Scholar] [CrossRef]
  75. Eryiğit, T.; Yıldırım, B.; Kumlay, A.M.; Sancaktaroğlu, S. The effects of different row distances and nitrogen fertilizer rates on yield and yield components of safflower (Carthamus tinctorious) under micro-climate conditions of Iğdır Plain—Turkey. In Proceedings of the 3rd International Conference on Biological, Chemical & Environmental Sciences (BCES-2015), Kumpur, Malaysia, 21–25 September 2015; pp. 21–22. Available online: https://www.researchgate.net/profile/Tamer-Eryigit/publication/282246178_The_Effects_of_Different_Row_Distances_and_Nitrogen_Fertilizer_Rates_on_Yield_and_Yield_Components_of_Safflower_Carthamus_tinctorious_Under_Micro-Climate_Conditions_of_Igdir_Plain_-Turkey/links/56090dda08aea25fce3b9037/The-Effects-of-Different-Row-Distances-and-Nitrogen-Fertilizer-Rates-on-Yield-and-Yield-Components-of-Safflower-Carthamus-tinctorious-Under-Micro-Climate-Conditions-of-Igdir-Plain-Turkey.pdf (accessed on 16 September 2024).
  76. Ismail, A.M.; Azooz, M. Effect of Zinc Supply on Growth and Some Metabolic Characteristics of Safflower and Sunflower Plants. 2005. Available online: https://www.cabidigitallibrary.org/doi/full/10.5555/20063011881 (accessed on 16 September 2024).
  77. Taha, M.H.; Shalaby, E.A.; Shanan, N.T. IMPROVING SAFFLOWER (Carthamus tinctorius L.) growth and biological activities under saline water irrigation by using iron and zinc foliar applications. J. Plant Prod. 2013, 4, 1219–1234. [Google Scholar] [CrossRef]
  78. Lakzayi, M. Influence of foliar application on safflower yield. Int. J. Multidiscip. Res. Dev. 2015, 2, 336–339. [Google Scholar]
  79. Gülmezoğlu, N.; Aytac, Z. The influences of various zinc applications on seed yield and zinc uptake of Safflower. J. Soil Water 2016, 5, 11–17. Available online: https://agris.fao.org/search/en/providers/122624/records/647461c12d3f560f80a6b6e4 (accessed on 16 September 2024).
  80. Chavoushi, M.; Najafi, F.; Salimi, A.; Angaji, S. Improvement in drought stress tolerance of safflower during vegetative growth by exogenous application of salicylic acid and sodium nitroprusside. Ind. Crops Prod. 2019, 134, 168–176. [Google Scholar] [CrossRef]
  81. Kaya, C.; Higgs, D. Response of tomato (Lycopersicon esculentum L.) cultivars to foliar application of zinc when grown in sand culture at low zinc. Sci. Hortic. 2002, 93, 53–64. [Google Scholar] [CrossRef]
  82. Dordas, C.A.; Sioulas, C. Dry matter and nitrogen accumulation, partitioning, and retranslocation in safflower (Carthamus tinctorius L.) as affected by nitrogen fertilization. Field Crops Res. 2008, 110, 35–43. [Google Scholar] [CrossRef]
  83. Gadallah, M.A.A. Effects of indole-3-acetic acid and zinc on the growth, osmotic potential and soluble carbon and nitrogen components of soybean plants growing under water deficit. J. Arid. Environ. 2000, 44, 451–467. [Google Scholar] [CrossRef]
  84. Hebbern, C.A.; Pedas, P.; Schjoerring, J.K.; Knudsen, L.; Husted, S. Genotypic differences in manganese efficiency: Field experiments with␣winter barley (Hordeum vulgare L.). Plant Soil 2005, 272, 233–244. [Google Scholar] [CrossRef]
  85. Mirzapour, M.H.; Khoshgoftar, A.H. Zinc Application Effects on Yield and Seed Oil Content of Sunflower Grown on a Saline Calcareous Soil. J. Plant Nutr. 2006, 29, 1719–1727. [Google Scholar] [CrossRef]
  86. Sarkar, D.; Mandal, B.; Kundu, M.C. Increasing use efficiency of boron fertilisers by rescheduling the time and methods of application for crops in India. Plant Soil 2007, 301, 77–85. [Google Scholar] [CrossRef]
  87. Safdar, M.E.; Qamar, R.; Javed, A.; Nadeem, M.A.; Javeed, H.M.R.; Farooq, S.; Głowacka, A.; Michałek, S.; Alwahibi, M.S.; Elshikh, M.S.; et al. Combined application of boron and zinc improves seed and oil yields and oil quality of oilseed rape (Brassica napus L.). Agronomy 2023, 13, 2020. [Google Scholar] [CrossRef]
  88. Ullah, A.; Farooq, M.; Nadeem, F.; Rehman, A.; Hussain, M.; Nawaz, A.; Naveed, M. Zinc Application in Combination with Zinc Solubilizing Enterobacter sp. MN17 Improved Productivity, Profitability, Zinc Efficiency, and Quality of Desi Chickpea. J. Soil. Sci. Plant Nutr. 2020, 20, 2133–2144. [Google Scholar] [CrossRef]
  89. Mohammed, B.A.; Khandaker, M.M.; Arshad, A.M.; Nudin, N.F.H.; Majrashi, A.; Mohd, K.S. Effects of foliar NPK application on growth, yield and nutrient content of sweet corn grown on Rengam Series soil. Basrah J. Agric. Sci. 2023, 36, 254–270. [Google Scholar] [CrossRef]
  90. Mahmood, H.N. Foliar and Fertigation Application of NPK Fertilizers Impact on Growth, Seed Yield and Yield Components of Safflower (Carthamus tinctorius L.). Tikrit J. Agric. Sci. 2021, 21, 84–98. [Google Scholar] [CrossRef]
  91. Jaffar, R.A.-A.; Al-Refai, S.I. Response of safflower to (NPK) fertilizer combinations and plants distribution. In IOP Conference Series: Earth and Environmental Science; IOP Publishing: Bristol, UK, 2021; p. 012056. Available online: https://iopscience.iop.org/article/10.1088/1755-1315/923/1/012056/meta (accessed on 20 August 2024).
  92. Bellaloui, N.; Hanks, J.E.; Fisher, D.K.; Mengistu, A. Soybean Seed Composition Is Influenced by Within-Field Variability in Soil Nutrients; Crop Management—Wiley Online Library: Hoboken, NJ, USA, 2009; Available online: https://acsess.onlinelibrary.wiley.com/doi/full/10.1094/CM-2009-1203-01-RS (accessed on 20 August 2024).
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Figure 1. Meteorological observations during crop growing periods.
Figure 1. Meteorological observations during crop growing periods.
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Figure 2. Effect of different treatments on days to stem elongation (a), days to flowering (b), days to maturity (c), and plant height (d). The data are the mean of three replications, and similar letters reflect an insignificant (p ≥ 0.05) difference as determined by the LSD test at a 5% probability level.
Figure 2. Effect of different treatments on days to stem elongation (a), days to flowering (b), days to maturity (c), and plant height (d). The data are the mean of three replications, and similar letters reflect an insignificant (p ≥ 0.05) difference as determined by the LSD test at a 5% probability level.
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Figure 3. Effect of different treatments on leaf area (a), capitulum diameter (b), capitula per plant (c), and branches per plant (d). The data are the mean of three replications, and similar letters reflect an insignificant (p ≥ 0.05) difference as determined by the LSD test at a 5% probability level.
Figure 3. Effect of different treatments on leaf area (a), capitulum diameter (b), capitula per plant (c), and branches per plant (d). The data are the mean of three replications, and similar letters reflect an insignificant (p ≥ 0.05) difference as determined by the LSD test at a 5% probability level.
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Figure 4. Effect of different treatments on seed yield (a), petal yield (b), biological yield (c), and 1000 grain weight (d). The data are the mean of three replications, and similar letters reflect an insignificant (p ≥ 0.05) difference as determined by the LSD test at a 5% probability level.
Figure 4. Effect of different treatments on seed yield (a), petal yield (b), biological yield (c), and 1000 grain weight (d). The data are the mean of three replications, and similar letters reflect an insignificant (p ≥ 0.05) difference as determined by the LSD test at a 5% probability level.
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Figure 5. Effect of different nutrient combinations on (a) leaf nitrogen percentage (% w/w), (b) leaf phosphorus content (mg kg−1), and (c) oil yield (kg ha−1). The data are the mean of three replications, and similar letters reflect an insignificant (p ≥ 0.05) difference as determined by the LSD test at a 5% probability level.
Figure 5. Effect of different nutrient combinations on (a) leaf nitrogen percentage (% w/w), (b) leaf phosphorus content (mg kg−1), and (c) oil yield (kg ha−1). The data are the mean of three replications, and similar letters reflect an insignificant (p ≥ 0.05) difference as determined by the LSD test at a 5% probability level.
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Figure 6. Pearson correlation (a) and scatterplot matrix (b) displaying the correlations among various growth and yield factors such as days to stem elongation (DSE), days to flowering (DF), days to maturity (DM), plant height (PH), leaf area (LA), branches per plant (BPP), capitula per plant (CPP), capitulum diameter (CD), seed yield (SY), petal yield (PY), biological yield (BY), thousand grain weight (TGW), oil yield (OY), leaf nitrogen percentage (NC or LNP), and leaf phosphorus content (PC or LPC) as affected by different experimental treatments.
Figure 6. Pearson correlation (a) and scatterplot matrix (b) displaying the correlations among various growth and yield factors such as days to stem elongation (DSE), days to flowering (DF), days to maturity (DM), plant height (PH), leaf area (LA), branches per plant (BPP), capitula per plant (CPP), capitulum diameter (CD), seed yield (SY), petal yield (PY), biological yield (BY), thousand grain weight (TGW), oil yield (OY), leaf nitrogen percentage (NC or LNP), and leaf phosphorus content (PC or LPC) as affected by different experimental treatments.
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Figure 7. Dendrogram showing the hierarchical clustering of plant traits based on similarity.
Figure 7. Dendrogram showing the hierarchical clustering of plant traits based on similarity.
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Table 1. Details of treatments used in this study.
Table 1. Details of treatments used in this study.
Treatment NumberFertilizer Dose
T0Control (no fertilizer application)
T1NPK at 40:40:40 kg ha−1
T2NPK at 50:50:40 kg ha−1
T3NPK at 60:60:40 kg ha−1
T4NPK at 70:70:40 kg ha−1
T5NPK at 80:80:40 kg ha−1
T6T1 + Zinc at 7.5 kg ha−1
T7T2 + Zinc at 7.5 kg ha−1
T8T3 + Zinc at 7.5 kg ha−1
T9T4 + Zinc at 7.5 kg ha−1
T10T5 + Zinc at 7.5 kg ha−1
Table 2. Soil physiochemical properties.
Table 2. Soil physiochemical properties.
Soil PropertiesResults [Literature Followed for Analysis]
pH7.1 [37]
Electrical Conductivity (dS m−1)1.32 [38]
Organic Matter (%)1.10 [39]
Available Nitrogen (NO3−, mg kg−1)9.84 [40]
Available Phosphorus (mg kg−1)13.4 [41]
Available Potassium (mg kg−1)287 [42]
Zinc (mg kg−1)0.8 [43]
Saturation (%)34 [44]
Sand (% w/w)58 [45]
Silt (% w/w)28 [45]
Clay (% w/w)14 [45]
TextureSandy Loam
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MDPI and ACS Style

Alamgeer, M.; Munir, H.; Hussain, S.; Adhikari, S.; Soufan, W.; Ahmed, J.; Aslam, M.; Rauf, S. Exploring the Synergistic Role of Zinc in NPK Fertilization on the Agronomic Performance of Safflower (Carthamus tinctorius). Horticulturae 2024, 10, 1243. https://doi.org/10.3390/horticulturae10121243

AMA Style

Alamgeer M, Munir H, Hussain S, Adhikari S, Soufan W, Ahmed J, Aslam M, Rauf S. Exploring the Synergistic Role of Zinc in NPK Fertilization on the Agronomic Performance of Safflower (Carthamus tinctorius). Horticulturae. 2024; 10(12):1243. https://doi.org/10.3390/horticulturae10121243

Chicago/Turabian Style

Alamgeer, Muhammad, Hassan Munir, Saddam Hussain, Sudeep Adhikari, Walid Soufan, Jahangir Ahmed, Maryam Aslam, and Saeed Rauf. 2024. "Exploring the Synergistic Role of Zinc in NPK Fertilization on the Agronomic Performance of Safflower (Carthamus tinctorius)" Horticulturae 10, no. 12: 1243. https://doi.org/10.3390/horticulturae10121243

APA Style

Alamgeer, M., Munir, H., Hussain, S., Adhikari, S., Soufan, W., Ahmed, J., Aslam, M., & Rauf, S. (2024). Exploring the Synergistic Role of Zinc in NPK Fertilization on the Agronomic Performance of Safflower (Carthamus tinctorius). Horticulturae, 10(12), 1243. https://doi.org/10.3390/horticulturae10121243

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