Effect of different nutrient management practices on the yield parameters of anthocyanin-rich black wheat (Triticum aestivum L.)

Introduction

Wheat (Triticum aestivum L.) stands as one of humanity's most crucial food crops, serving as a primary source of calories and protein for over one-third of the global population (Charmet, 2011; Guan et al., 2020) [1,2] . However, in the face of rising health consciousness and increasing prevalence of diet-related chronic diseases, there is growing demand for cereal crops that offer not just basic nutrition but also additional health benefits (Cheng et al., 2017; Garg et al., 2022) [3, 4] . This has led to significant interest in specialty wheat varieties, particularly anthocyanin-rich black wheat, which contains elevated levels of bioactive compounds with demonstrated antioxidant, anti-inflammatory, and potentially anti-carcinogenic properties (Abdel-Aal & Hucl, 2003; Francavilla & Joye, 2022; Mikhailova et al., 2023) [5,6,7] . Unlike conventional wheat, black wheat has deep purple grains that contain anthocyanins, the same beneficial pigments found in blueberries and black rice (Ficco et al., 2014; Gamel et al., 2023) [8,9] . This makes it a valuable functional food crop for modern health-conscious consumers (Kumari et al., 2020; Bordoni et al., 2017) [10,11] . Despite its nutritional superiority, black wheat cultivation faces several challenges that limit its widespread adoption. The crop's yield potential under different management systems remains poorly understood, and there is particular uncertainty about its nutrient requirements (Briak & Kebede, 2021; Macholdt et al., 2023) [12,13] . Traditional wheat breeding and agronomic research has focused primarily on yield improvement in conventional varieties, leaving significant gaps in our understanding of how to optimize cultivation practices for this specialty crop (Li et al., 2015; Evans et al., 2022) [14,15] . Moreover, the relationship between nutrient management and anthocyanin production in black wheat is not well-characterized, despite evidence that fertilization strategies can significantly influence phytochemical accumulation in other crops (Böhmdorfer et al., 2018; Liu et al., 2019) [16,17] . Contemporary agricultural systems face the dual challenge of meeting rising food demands while minimizing environmental impacts (Lloyd & Chalabi, 2021) [18] . Conventional wheat production has increasingly relied on synthetic fertilizers, which while effective at boosting yields, have been associated with soil degradation, water pollution, and greenhouse gas emissions. Intensive use of chemical fertilizers can also disrupt soil microbial communities and reduce longterm soil fertility. On the other hand, purely organic approaches using farmyard manure (FYM) or other organic amendments often struggle to provide sufficient nutrients at critical growth stages, potentially limiting yield potential. This dichotomy has led to growing interest in integrated nutrient management (INM) systems that strategically combine organic and inorganic nutrient sources to achieve both high productivity and environmental sustainability. The physiological basis for anthocyanin accumulation in black wheat adds another layer of complexity to nutrient management decisions. Anthocyanin biosynthesis is known to be influenced by multiple factors including nitrogen availability, phosphorus supply, and plant stress status (Abdel-Aal & Hucl, 2003; Ficco et al., 2014) [5,8] . Excessive nitrogen fertilization, while potentially boosting yield, may actually decrease anthocyanin concentration through dilution effects (Liu et al., 2019) [17] . This research advances sustainable farming and nutritional security by promoting anthocyanin-rich black wheat, a health-boosting functional crop. It reveals how integrated nutrient management (INM) blending farmyard manure (FYM) with lower inorganic fertilizer doses matches full chemical yields (49.1-58.0 q ha⁻¹) across two seasons, while boosting soil health. Organic carbon rose to 0.85%, available nitrogen to 200 kg ha⁻¹, and phosphorus to 65 kg ha⁻¹, cutting reliance on synthetics and strengthening ecosystem resilience. These insights deliver practical protocols for growing this specialty crop, supporting climate-smart, nutrition-focused agriculture for farmers, experts, and policymakers (Lloyd & Chalabi, 2021) [18] . This study pursued key objectives such as to evaluate nutrient management effects on growth, yield, grain quality (including anthocyanin levels), and soil health in anthocyanin-rich black wheat; compare organic (FYM), inorganic (NPK), and integrated approaches via growth metrics, yield traits, and physiology; pinpoint optimal fertilizer mixes for high yields and nutrition without eroding soil fertility; and track post-harvest soil changes in pH, organic carbon, and available NPK. This study shows that integrated nutrient management (INM) cuts chemical fertilizer use by 50% in black wheat while maintaining high yields (49-58 q ha⁻¹) and improving soil health (organic carbon, nitrogen, potassium). This offers a sustainable, costeffective approach for growing this nutritious crop (Kumari et al., 2020; Bordoni et al., 2017) [10,11] .

Materials and Methods

Experimental Site

The two-year field trial ran during Rabi seasons 2024-25 and 2025-26 at Crop Research Centre, Shobhit Institute of Engineering & Technology (Deemed-to-be-University), Meerut, Uttar Pradesh (29.01°N, 77.70°E, 237 m MSL). This semi-arid subtropical site in India's northwestern plains receives about 800 mm annual rain with 80% during the July-September monsoon. It features hot summers and cold winters with frost in December-January plus fog. Seasonal rain measured 173.6 mm in 2024-25 and 165 mm in 2025-26. Weekly temperatures ranged from 4.7-23.5°C (min) and 16.2-41.6°C (max). Relative humidity spanned 16.7-92.6%. These conditions supported wheat growth. Soil was sandy loam per USDA classification (54-65% sand, 21-30% silt, 12-15% clay via hydrometer method, Bouyoucos 1965). Initial values before 2024-25 included pH 7.65 (slightly alkaline), EC 0.37 dS m⁻¹ (low), OC 0.24% (low), N 221.92 kg ha⁻¹ (moderate), P 13.9 kg ha⁻¹ (low), and K 135 kg ha⁻¹ (low). After two years, pH dropped to 7.58, OC rose to 0.26%, and S increased to 4.4 kg ha⁻¹. Major nutrients NPK declined, underscoring the need for balanced fertilization. Tests used IARI (2018) STFR protocols on 0-15 cm composite samples collected pre-sowing.

Experimental Design

The field experiment was laid out during the Rabi season of 2024-25 & 2025-26 at the Crop Research Centre (CRC) of Shobhit Institute of Engineering & Technology (Deemed-to-be-University), Meerut, Uttar Pradesh. The study was conducted to evaluate the effects of integrated nutrient management on crop performance under late-sown conditions and timely sown conditions in respective seasons. The experiment comprised 10 treatment combinations, involving different nutrient management strategies, including recommended doses of fertilizers (NPK), altered N:P:K ratios, split nitrogen applications, and the use of farmyard manure (FYM) alone or in combination with inorganic fertilizers. The experiment was laid out in a Randomized Block Design (RBD) with three replications, resulting in a total of 30 experimental plots. Each plot measured 15 m² (3 m × 5 m). A 1.0 m buffer zone was maintained between plots, and 1.5 m wide irrigation channels were provided between blocks to ensure proper water management and avoid treatment interference.

Crop Management

Researchers grew black wheat variety Black 3818 under latesown conditions in 2024-25 (sown December 26, 2024) and normal-sown in 2025-26 (sown November 20, 2025). Broadcasting ensured even seed spread in plots both years. Prior to sowing, fields underwent two cross-ploughings plus leveling for fine tilth. This setup improved soil aeration, moisture holding, and early weed suppression across seasons.Irrigation followed crop needs and key stages in both seasons. It was timed by weather and soil moisture with five applications in 2024-25 and six in 2025-26. Water targeted crown root initiation (CRI), tillering, jointing, heading, and grain filling to boost performance. The extra irrigation in 2025-26 countered lateseason heat stress. Hand weeding at regular intervals kept plots weed-free both years. This cut competition for nutrients, water, and light. Neem-based biopesticides served as preventive pest/disease control per IPM principles. They limited synthetic chemical use and supported sustainability. No major pest or disease issues arose, proving their effectiveness. All practices applied uniformly across plots both years to remove cultural differences and highlight nutrient treatment effects.

Data Collection 2.4.1 Plant Population

To assess the plant population per square meter, a quadrat sampling method was employed at 25 days after sowing (DAS). A 1-meter scale was used to demarcate sampling areas at three randomly selected locations within each experimental plot. Within these marked quadrats, the total number of emerged wheat plants was counted manually. The average of these three counts was then calculated to represent the plant population per square meter for each plot. This method ensured a representative and statistically sound estimation of early plant establishment across treatments.

Growth Parameters

To evaluate nutrient management impacts on crop development, growth traits were measured at 30, 60, 90 DAS, and harvest. Plant height came from meter scale readings on five tagged plants per plot from soil to tallest tiller tip with averages for analysis. Tiller density used 1 m² quadrat counts at three random spots per plot averaged across timings. Dry matter accumulation involved quadrat-sampled above-ground parts air-dried then oven-dried at 70°C to constant weight recorded as g/m² to gauge biomass effects.

Physiological Traits

Leaf Area Index (LAI) measurements occurred at 30, 60, 90 DAS, and harvest with a ceptometer. This optical tool gauges photosynthetically active radiation (PAR) intercepted by the canopy. It compares light above and below to estimate total leaf area. Multiple readings from representative plot spots ensured accuracy and handled variability. The LAI was computed using the standard formula Leaf Area Index (LAI) was used to quantify canopy development and assess the crop's capacity for light interception and photosynthesis. Observations at different growth stages helped evaluate vegetative response under various treatments. Crop Growth Rate (CGR) was calculated to determine the rate of dry matter accumulation per unit area per day (g m⁻² day⁻¹). It was estimated for the intervals 0-30, 31-60, 61-90, and 91-120 DAS using dry matter data. CGR provided insight into biomass production efficiency across growth stages and enabled comparison of treatment performance and resource utilization.

Yield Attributes

Effective tillers per square meter were recorded at harvest using a 1 m² quadrat placed at three random locations in each plot. Only tillers with fully developed spikes were counted, and the average was expressed as effective tillers m⁻², indicating reproductive potential and crop establishment. For spike characteristics, five representative spikes were randomly collected from each plot at harvest. Spike length was measured from base to tip (excluding awns) and averaged in centimeters. The same spikes were used to count spikelets per spike, considering all spikelets irrespective of grain presence, to assess spike structure and fertility. Grains from these spikes were obtained after manual threshing, and the average number of grains per spike was calculated, reflecting reproductive efficiency. The 1000-grain weight was determined by counting and weighing 1000 randomly selected grains from each plot, expressed in grams, indicating grain size, density, and efficiency of grain filling.

Results

Plant Population

Plant population at 25 DAS, an important indicator of crop establishment, showed a positive response to fertilizer application in both seasons (2024-25 and 2025-26). Although differences among treatments were statistically non-significant at the 5% level, clear numerical trends were observed. The control (T 1 ) recorded the lowest plant population (120 and 135 plants m⁻²), while all fertilized treatments performed better. The integrated nutrient treatment T 8 (10 t FYM ha⁻¹ + NPK 40:20:20 kg ha⁻¹) produced the highest plant population (155 and 174 plants m⁻²), followed by T 9 (FYM + NP) and T 5 (nitrogen alone). These results indicate that balanced and integrated nutrient management improved early crop establishment, likely by enhancing seedbed conditions and seedling vigor, even though the differences were not statistically significant.

Number of Tillers per Square Meter

The measurement of plant height across critical growth stages revealed a consistent and statistically significant response to nutrient management over both the 2024-25 and 2025-26 Rabi seasons. The unfertilized control (T

Yield Attributes 3.4.1 Number of Effective Tillers per m²

The number of productive tillers per square meter, which is a key factor determining yield potential, showed a significant and consistent response to nutrient management in both growing seasons. The unfertilized control (T 1 ) consistently gave the lowest number of effective tillers, with 210 and 245 per square meter. All fertilized treatments improved tillering, and the full recommended NPK dose (T 2 ) produced the highest counts, reaching 315 and 365 per square meter. The integrated nutrient management treatment T 8 (FYM + NPK) performed remarkably well, producing 300 and 345 productive tillers per square meter. This result was statistically similar to the full NPK treatment and significantly better than the control. This demonstrates the synergistic benefit of blending organic and inorganic nutrient sources in supporting tiller initiation, survival, and spike-bearing capacity. In contrast, treatments with unbalanced nutrition (T 3 ) or those relying only on organic manure (T 6 , T 7 ) resulted in considerably lower tiller counts, emphasizing the need for a balanced and readily available nutrient supply to optimize this critical yield component.

The control treatment (T 1 ) produced the shortest ears, measuring 8.2 cm and 9.0 cm. In contrast, the application of the full recommended balanced NPK (T 2 ) resulted in the greatest ear elongation, achieving lengths of 11.6 cm and 13.0 cm. The integrated nutrient management treatment T 8 (FYM + NPK) proved highly effective, producing ears measuring 11.0 cm and 12.3 cm, which closely approached the performance of the full NPK treatment. This indicates that the combined nutrient supply from integrated sources effectively supports cell division and elongation within the developing ear. A clear benefit was observed in treatments that included potassium (such as T 2 , T 4 , T 5 , and T 8 ) compared to those without it (e.g., T 3 and T 10 ), highlighting potassium's specific role in ear development.

Additionally, ear lengths were consistently greater across all treatments in the 2025-26 season, which can be attributed to the earlier sowing date that allowed a longer period for spike development under more favorable conditions.

Number of Spikelets per Spike

The number of spikelets per spike, which is a key factor determining potential grain number, showed a significant and positive response to nutrient management in both experimental seasons. The unfertilized control (T 1 ) consistently gave the lowest counts, with 14 and 15 spikelets per spike. The application of the full recommended NPK dose (T 2 ) maximized spikelet formation, resulting in 19 and 21 spikelets per spike. Integrated Nutrient Management, especially treatment T 8 (FYM + NPK), demonstrated strong performance, producing 18 and 20 spikelets per spike, closely matching the results of the full NPK treatment. This indicates that the combined nutrient supply from integrated sources effectively supports floret initiation and differentiation during spike development. Treatments with unbalanced nutrition, such as the potassium-omitted T 3 , or those relying only on organic manure, produced significantly fewer spikelets. Additionally, a consistent increase in spikelet number was observed across all treatments in the 2025-26 season, an advantage linked to the earlier sowing date, which provided more favorable conditions for reproductive meristem development.

Number of Grains per Spike

The number of grains per spike, a direct and critical component of final yield, showed significant and consistent improvement in response to nutrient management strategies during both the 2024-25 and 2025-26 Rabi seasons. The unfertilized control (T 1 ) consistently recorded the lowest grain count, with only 32 and 36 grains per spike. In contrast, the application of the full recommended balanced NPK (T 2 ) resulted in the highest grain number, reaching 48 and 54 grains per spike. The integrated treatment T 8 (FYM + NPK) proved highly effective, producing 44 and 49 grains per spike, which closely approached the performance of the full NPK treatment. This finding highlights the ability of integrated nutrient sources to support successful pollination, fertilization, and grain retention. A clear negative effect was seen in the potassium-deficient treatment (T 3 ), which yielded significantly fewer grains (38 and 42) compared to treatments receiving potassium, emphasizing potassium's essential role in grain development and filling. Moreover, grain number per spike was consistently higher across all treatments in the 2025-26 season, due to the earlier sowing date, which provided a longer grain-filling period under more favorable climatic conditions. [10,11] . [12] . These include a 50% reduction in NPK fertilizer costs (approximately ₹4, 000-₹5, 000 per hectare), the use of farmyard manure that is often available onfarm or at low cost from livestock operations making the system accessible to smallholders improved soil organic matter that enhances water-holding capacity, which is critical in rainfed or partially irrigated systems where moisture stress during grain filling can reduce both yield and anthocyanin accumulation, and stable soil pH that reduces the need for frequent liming or micronutrient corrections, thereby lowering long-term management costs. [5,16,17] . Second, multi-year trials spanning five to ten years are required to assess the long-term sustainability of T

Acknowledgement

AcknowledgementThe author(s) would like to Acknowledge School of Agriculture and Environmental Sciences at Shobhit Institute of Engineering and Technology (Deemed-to-be University), Meerut, India, for their support. FundingThe author(s) received no financial support for the research and publication of this article.

References

1. Charmet G. Wheat domestication: Lessons for the future. C R Biol. 2011;334(3):212-220.
2. Guan J, Garcia DF, Zhou Y, Appels R, Li A, Mao L. The battle to sequence the bread wheat genome: A tale of the three kingdoms. Genomics Proteomics Bioinformatics. 2020;18(3):221-229.
3. Cheng A, Mayes S, Dalle G, Demissew S, Massawe F. Diversifying crops for food and nutrition security -A case of teff. Biol Rev Camb Philos Soc. 2017;92(1):188-198.
4. Garg M, Kaur S, Sharma A, Kumari A, Tiwari V, Sharma S, et al. Rising demand for healthy foods-anthocyanin biofortified colored wheat is a new research trend. Front Nutr. 2022;9:878221.
5. Abdel-Aal ESM, Hucl P. Composition and stability of anthocyanins in blue-grained wheat. J Agric Food Chem. 2003;51(8):2174-2180.
6. Francavilla A, Joye IJ. Anthocyanin content of crackers and bread made with purple and blue wheat varieties. Molecules. 2022;27(21):7180.
7. Mikhailova DV, Shevchenko OG, Golubev DA, Platonova EY, Zemskaya NV, Shoeva OY, et al. Antioxidant properties and geroprotective potential of wheat bran extracts with increased content of anthocyanins. Antioxidants. 2023;12(11):2010.
8. Ficco DB, De Simone V, Colecchia SA, Pecorella I, Platani C, Nigro F, et al. Genetic variability in anthocyanin composition and nutritional properties of blue, purple, and red bread (L Triticum aestivum.) and durum (Triticum turgidum L. ssp. turgidum convar. durum) wheats. J Agric Food Chem. 2014;62(34):8686-8695.
9. Gamel TH, Saeed SMG, Ali R, Abdel-Aal EM. Purple wheat: Food development, anthocyanin stability, and potential health benefits. Foods. 2023;12(7):1358.
10. Kumari A, Sharma S, Sharma N, Chunduri V, Kapoor P, Kaur S, et al. Influence of biofortified colored wheats (purple, blue, black) on physicochemical, antioxidant and sensory characteristics of chapatti (Indian flatbread). Molecules. 2020;25(21):5071.
11. Bordoni A, Danesi F, Di Nunzio M, Taccari A, Valli V. Ancient wheat and health: A legend or the reality? review on KAMUT khorasan wheat. Int J Food Sci Nutr. 2017;68(3):278-286.
12. Briak H, Kebede F. Wheat (Triticum aestivum) adaptability evaluation in a semi-arid region of Central Morocco using APSIM model. Sci Rep. 2021;11(1):23173.
13. Macholdt J, Hadasch S, Macdonald A, Perryman S, Piepho HP, Scott T, et al. Long-term trends in yield variance of temperate managed grassland. Agron Sustain Dev. 2023;43(3):37.
14. Li AL, Geng SF, Zhang LQ, Liu DC, Mao L. Making the bread: Insights from newly synthesized allohexaploid wheat. Mol Plant. 2015;8(6):847-859.
15. Evans CEB, Arunkumar R, Borrill P. Transcription factor retention through multiple polyploidization steps in wheat. G3 (Bethesda). 2022;12(8):jkac147.
16. Böhmdorfer S, Oberlerchner JT, Fuchs C, Rosenau T, Grausgruber H. Profiling and quantification of grain anthocyanins in purple pericarp × blue aleurone wheat crosses by high-performance thin-layer chromatography and densitometry. Plant Methods. 2018;14:29.
17. Liu B, Martre P, Ewert F, Porter JR, Challinor AJ, Müller C, et al. Global wheat production with 1.5 and 2.0°C above pre-industrial warming. Glob Change Biol. 2019;25(4):1428-1444.
18. Lloyd SJ, Chalabi Z. Climate change, hunger and rural health through the lens of farming styles: An agent-based model to assess the potential role of peasant farming. PLoS One. 2021;16(2):e0246788.