IMPROVING COTTON PRODUCTIVITY AND FIBER QUALITY THROUGH IMPLEMENTATION OF REDUCED TILLAGE AND BALANCED NUTRITION UNDER ARID CLIMATE

INTRODUCTION

Cotton (Gossypium hirsutum L.) is a significant commercial crop as it holds substantial economic value for the global textile industry (Khan et al., 2020). The highest production of cotton is attained in subtropical and seasonally dry areas in both the northern and southern hemisphere, however most of the production takes place towards north of equator (Khan et al., 2025). In recent decades the of cotton is also expanded to the arid or semi warm agro-ecological regions of several countries  including Pakistan, India, China, the United States, and Brazil (Bange et al., 2016). Cotton is very important for economy while its production is compromised every year due to poor soil fertility, deficiency in organic matter content (OMC), insect pest infestation and drought conditions due to climate change effect (Fareed et al., 2025; Hussain et al., 2025). The disturbance in soil and water dominate the production losses while the other factors involve mono cropping, conventional tillage practices, loss of macronutrient and over use of agrochemicals. The average cotton yield in Pakistan is approximately 700 kg ha^-1 which is at least 15-20% less as compared to the top producing countries (Farooq et al., 2018).

 The aforementioned productivity losses are also contributed by tillage practices which disturb soil structure, and contribute to the loss of nutrients and soil organic carbon. The extended use of traditional tillage methods can further degrade soil quality and increase the need for synthetic fertilizers (Boincean and Dent, 2019). Apart from the above challenge nutrients also serve as limiting factor in cotton production (Ghaffar et al., 2020; Ahmad et al., 2021). The nutritional requirements of cotton are specific as a balanced and adequate supply of nutrients across the entire growth phase serve a vital role for optimal vegetative growth, fiber quality improvement, and stress tolerance under adverse environmental conditions (Ahmad et al., 2022; Ahmed et al., 2023). The role of macronutrients in cotton is very specific as the supply of nitrogen (N) in cotton significantly influences cotton growth by improving the chlorophyll content and vegetative growth of crop (Manzoor et al., 2022; Usman et al., 2025). In addition phosphorus (P) deficiency reduce the  dry matter and total biomass of cotton followed by lower regulation of carotenoids and total soluble proteins (TSP) (Venkatachalam et al., 2017). The lower availability of P reduces the seed development and cotton seed yield. The other limiting nutrient for cotton is potassium (P) whose deficiency decrease the process of photosynthesis, protein synthesis and enhanced carbohydrates metabolism by activating the enzymes (Kapoor et al., 2020; Akhtar et al., 2023).

 The problem of water scarcity and excessive tillage can be addressed by incorporating crop residues (Ahmad et al., 2024) and promotion of conservation tillage systems, especially reduced tillage which enhance the retention of more than 30% moisture (Li et al.,  2024). Additionally, the issue of nutrient losses and nutrient deficiency can be decreased by the application of synthetic fertilizers. Although tillage and nutrient application have been widely studied as a separate factor while a limited information is available on the combined effect of conservation tillage with balanced NPK fertilizer.

 The available data document that the combined influence of tillage systems and nutrient application on cotton have been evaluated in prior studies, for instance the combined effect of reduced tillage with N application (Usman et al., 2014), similarly the influence of tillage with K application and conservation tillage with organic amendments (Ahmad et al., 2022). The previous studies have evaluated the influence of tillage coupled with individual nutrient management, however, the available information still remains limited regarding the response of cotton yield and fiber quality to a combination of reduced versus conventional tillage across a balanced range of NPK under the arid conditions of Dera Ismail Khan. Therefore, the present study was conducted to assess the efficiency of reduced tillage in comparison with conventional tillage and to evaluate balanced NPK combination under different tillage system for improving cotton yield and fiber quality under arid climate.

MATERIALS AND METHODS

Experimental site, soil and weather conditions: The current research was conducted on Agricultural Research Institute, Ratta Kulachi, Dera Ismail Khan (31.52884° N, 70.54715° E). The sample of soil was collected from 0-30 cm layer to characterize the key physicochemical parameters including SOM (Walkley & Black, 1934), pH and EC (soil: water), total soil N (Bremner & Mulvaney, 1982), P and K (Soltanpour, 1985), cation exchange capacity (ICARDA) and soil texture (Bouyoucos, 1951) (Table 1).

Table 1. Soil physicochemical and biological characteristics of the experimental site

OMC= organic matter content, N=nitrogen, P=phosphorus, K=potassium, CEC=cation exchange capacity, EC= electrical conductivity, %= percentage, mg kg^-1= milligram per kilogram, meq c kg^-1= milliequivalent charge per kilogram

This trial was conducted in arid region where annual rainfall ranged from 179 mm to 350 mm and faces extended hot summer periods. The climatic conditions in second year of experiment were favorable for the production of cotton which improved the production in second year (Fig 1)

Fig. 1. Meteorological data including both daily maximum and minimum temperatures and rainfall during both growing years

(Source: Weather Observatory Agricultural Research Institute, Ratta Kulachi, Dera Ismail Khan)

 Experimental design and Treatments: The current experiment was conducted for two consecutive years (2023 and 2024) by applying randomized complete block design (RCBD) with split-plot arrangement and three replications of each treatment having a net sub plot size of 10 m × 3 m. The main plots were tillage systems (a) reduced tillage (b) conventional tillage. The subplots were nutrient management treatments,  (i) NPK₁ (0:0:0), (ii) NPK₂ (200:0:0), (iii) NPK₃ (0:120:0), (iv) NPK₄ (0:0:150), (v) NPK₅ (200:120:0), (vi) NPK₆ (200:0:150), (vii) NPK₇ (0:120:150), (viii) NPK₈ (200:120:150) and (ix) NPK₉ (250:170:200 kg ha^-1). The aforementioned treatments were applied during both the experimentation seasons.

Crop Husbandry: At first, seedbed was prepared for the cultivation of cotton with separate sub plots were prepared to compare the land preparation systems (conventional vs reduced tillage). In plots of reduced tillage, two cycles of tillage operations were performed whereas in conventional tillage plots four cycles of tillage operations were performed including disk plow, tiller and two cycles of rotavator (Fig. 2). The basal dose fertilizers including urea, triple superphosphate (TSP) and potassium sulfate (K₂SO₄) were applied at the time of land preparation. The fertilizers were applied with a hand drill which was positioned slightly in front of the seed rows at the time of sowing. The remaining split doses of N were applied to all the treatments at the specific growth stage as per the prescribed doses. Additionally, fertilizer treatments were carried out in both years according to the stated NPK rates (kg ha^-1) for each treatment. After application of fertilizer cotton seed (variety Bt-FH-333; Dated: April 12, 2023 and April 14, 2024) were sown using a seed drill. The process of thinning was done 20-30 days after seedling emergence to maintain the desired plant population, while irrigation was applied as per the requirement of crop. The irrigation was applied after every 5-7 days to adequately moisten crop root zone (each irrigation at the depth of 75-100 mm), however total 13-14 irrigation were applied. The agronomic practices such as weed control was carried out by spraying pendimethalin and S-metolachlor, however whitefly and jassids were controlled by spraying imidacloprid followed by pink bollworm was controlled by bifenthrin as per labelled doses. The picking of cotton bolls was carried out manually (Dated: October 20, 2023 and October 25, 2024).

Fig. 2. Pictorial representation of field experiment. “a” and “b” are depicting reduced tillage plots while “c” and “d” are showing conventional tillage plots. 

Data Collection: Data parameters involved morphological, yield and fiber quality of grown cotton during both the experimentation years.  The morphological parameters included sympodial and monopodial branches were counted manually 85-90 DAS by tagging six plants in sub plot of each treatment prior to first picking. Furthermore the data was collected from tagged and mean of two plants was considered as a single replicate which further statistically analyzed. Afterwards plant height (cm) was measured at 115 DAS or at physiological maturity by using a measuring scale from the same tagged plants. The productive bolls were counted manually at the time maturity around 120 DAS. Boll weight (g) was measured on weighing balance in laboratory by picking the fully opened and healthy bolls. Afterwards lint was separated from the seed cotton and weight of 100 cotton seed (g) was measured through the digital weighing balance in the laboratory. Seed cotton yield (kg ha^-1) was estimated on the basis of obtained yield from the net plot area. Additionally, fiber quality attributes including fiber length (mm), fiber strength (µg inch^-1), fiber uniformity (%), micronaire value (g tex^-1) were analyzed using 20 g lint sample from each treatment. The fiber quality of cotton was evaluated through computerized High-Volume Instrument (HV, USTER, 900A) available at fiber testing laboratory of Central Cotton Research Institute (CCRI), Multan Pakistan. The ginning outturn was estimated by collecting 300 g of seed from each treatment followed by ginning and calculation through the equation 1.

Economic analysis: Economic analysis was also performed by taking local market prices of all the major inputs and outputs prevailing during the 2023 and 2024 which further converted to current date US dollar (USD) by using the equation 2 & 3. The cost of cultivation was calculated by including expenditures on land rent, land preparation, seed, fertilizer, pesticide, labor, irrigation, cultural practices and harvesting. Gross income was estimated by cotton seed yield and market sale price, while net return was calculated by subtracting the total production cost from gross income. After that benefit cost ration (BCR) was calculated for both of the conducted experiments.

Statistical analysis: The recorded data were subjected to three-way analysis of variance (ANOVA) using the statistical software (Statistix 8.1). In addition the Pearson’s correlation coefficient were calculated through the means of measured variables through the mix matrix correlation calculation on OriginPro V. 2025. The correlation was performed to evaluate the relationship among plant growth, yield and fiber quality attributes. The experiment was conducted as per RCBD with split-plot arrangement where factor A (tillage operations) was assigned as main plot and factor B (fertilizer doses) served as a subplot with three replications of each randomized treatment. The current trial was conducted on the same location for two consecutive years and year was included in the statistical analysis as a fixed factor. The means of treatments were compared using Tuckey’s honestly significant difference (HSD) test at p≤0.05 by following the procedure described by Steel et al. (1997).

RESULTS

Growth and Yield Attributes of Cotton: The effect of three-way interaction of TS×NPK×Year significantly influenced the sympodial branches plant^-1 and plant height (cm) of cotton (Table 2). The statistical analysis revealed that NPK (200:120:150) dose resulted in the maximum sympodial branches (57.7 and 59.2 sympodial branches plant^-1) during 2023 and 2024 under reduced tillage. Similarly, NPK (200:120:150) outperformed under conventional tillage (59.9 and 51.9 sympodial branches plant^-1) during 2023 and 2024 under conventional tillage. The influence of interactive effect of TS×NPK×Year was found significant on plant height during both years of the experiment. Therefore, maximum plant height (151.5 cm) was attained by the application of NPK (200:120:150 kg ha^-1) in 2024 under reduced tillage and 150.1 cm taller plants were observed under conventional tillage in 2023 as compared to minimum plant height under control (Table 2).

The effect of all the studied factors significantly influenced the number of bolls (plant^-1), boll weight (g) and 100 seed weight (g). The maximum number of bolls plant^-1 (59.7 bolls in 2023 and 60.7 bolls in 2024) resulted by balanced NPK (200:120:150 kg ha^-1) under the reduced tillage condition. While the maximum bolls plant^-1 (60.0) under conventional tillage was also produced by same treatment in 2024. The maximum boll weight (4.00 g) attained by (NPK (200:120:150 kg ha^-1) under reduced tillage during both 2023 and 2024 as compared to the control. The highest boll weight (3.97 g) was observed in the same treatment under conventional tillage in 2023, while the boll weight in 2024 was statistically at par. The 100-cotton seed weight (10.89 and 10.29 g) was also found maximum under the application of balanced NPK (200:120:150 kg ha^-1) during both of year in reduced tillage treatment. Similarly, results were attained under the conventional tillage which showed that maximum seed weight (10.89 and 10.32g) was observed with non-significant influence during both the years 2023 and 2024 (Table 3).

 Table 2. Effect of different tillage systems and fertilizer application rates on plant height (cm) and sympodial branches plant^-1 of cotton

TS₁ = Reduced tillage; TS₂= Conventional tillage; NPK₁ = 0:0:0; NPK₂ = 200:0:0; NPK₃ = 0:120:0; NPK₄ = 0:0:150; NPK₅ =200:120:0; NPK₆ =200:0:150; NPK₇ =0:120:150; NPK₈ =200:120:150; NPK₉ =250:170:200 kg ha^-1.

Table 3. Effect of different tillage systems and fertilizer application rates on number of bolls plant^-1, mean boll weight and 100 cotton seeds weight of the cotton crop.

TS₁ = Reduced tillage; TS₂= Conventional tillage; NPK₁ = 0:0:0; NPK₂ = 200:0:0; NPK₃ = 0:120:0; NPK₄ = 0:0:150; NPK₅ =200:120:0; NPK₆ =200:0:150; NPK₇ =0:120:150; NPK₈ =200:120:150; NPK₉ = 250:170:200 kg ha^-1. Means with similar letters and having no letters are not significantly different at 0.05 probability level.

Table 4. Effect of different tillage systems and fertilizer application rates on seed cotton yield, ginning outturn and fiber length of the cotton crop

TS₁ = Reduced tillage; TS₂= Conventional tillage; NPK₁ = 0:0:0; NPK₂ = 200:0:0; NPK₃ = 0:120:0; NPK₄ = 0:0:150; NPK₅ =200:120:0; NPK₆ =200:0:150; NPK₇ =0:120:150; NPK₈ =200:120:150; NPK₉ = 250:170:200 kg ha^-1. Means sharing dissimilar letters are different significantly at 0.05 probability level.

Fiber Quality Attributes: The effect of individual NPK significantly influenced fiber strength (g tex^-1), micronaire (µg inch^-1), fiber uniformity (%) and fiber length (cm). The effect of TS on fiber strength resulted maximum strength by reduced tillage (30.4 g tex^-1 and 31.5 g tex^-1) during both the years 2023 and 2024 under the application of balanced NPK (200:120:150 kg ha^-1) followed by the highest fertilizer dose of NPK (250:170:200 kg ha^-1) in both seasons. The results revealed that micronaire (µg inch^-1) was lower under the NPK (200:120:0, 200:120:150, and 250:170:200 kg ha^-1) while micronaire values were higher under (0:120:150 kg ha^-1). Fiber uniformity increased with increasing nutrient inputs which was maximum 83.7% during 2023 while it reduced to 74.5% in 2024 by the application of NPK (250:170:200 kg ha^-1). The balanced NPK outperformed with a maximum fiber length in both of the years and under both tillage systems. Therefore, highest fiber length (39.5 mm in 2024 and 37.5 mm in 2023) was produced under the combination reduced tillage and the cotton from conventional tillage produced maximum fiber length (39.1 mm in 2024 and 37.1 mm in 2023) (Table 5).

Economic analysis: Substantial variations in total income, total expenditure, net benefits, and benefit-cost ratios across different tillage and nutritional regimes of NPK were observed in the economic analysis (Table 6). The reduced tillage system at NPK (200:120:150 kg ha^-1) showed the maximum economic returns of US $: 1003.18 ha^-1 with the BCR of 2.3, while achieving 2803 kg ha^-1 seed cotton yield during the present study. Contrastingly the conventional tillage system resulted lower yield and economic retunes 11-14% as compared to reduced tillage with NPK (200-120-150 kg ha^-1).

Table 5. Effect of different tillage systems and fertilizer application rates on fiber strength (g tex^-1), micronaire (µg inch^-1), fiber uniformity (%) and fiber length (cm) of the cotton crop

Table 6. Effect of tillage practices and NPK levels on cotton economics (means of 2023 & 2024). 

TS₁ = Reduced tillage; TS₂= Conventional tillage; NPK₁ = 0:0:0; NPK₂ = 200:0:0; NPK₃ = 0:120:0; NPK₄ = 0:0:150; NPK₅ =200:120:0; NPK₆ =200:0:150; NPK₇ =0:120:150; NPK₈ =200:120:150; NPK₉ =250:170:200 kg ha^-1.

Correlation Analysis: The mix matrix correlation analysis were based on the means of treatments which resulted higher values of correlation due to reduced variation within the treatments. The correlation analysis of trial conducted in 2023 revealed that all the parameters were positively associated with each other, however correlation pattern suggest that trait related to reproductive and vegetative growth imposed a combined effect to attain a better yield.  A strong positive correlation 0.710-0.91 was observed among PHM, NBP and MBW which exhibited a strong relation with GOT, FL, SCY and FS which indicate a strong correlation among growth yield and fiber quality attributes. While the correlation results of trial conducted during 2024 represented that growth, yield and fiber quality parameters were positively linked to each other. The correlation pattern suggested a strong correlation among PHM, MBW, GOT, FL, FU, FS and SCY (0.90-0.99). The correlation of second year trial demonstrated the improvement in boll development and growth attributes of cotton which improved the seed cotton yield and fiber performance as compared the first year of study. Contrastingly NBP showed a weak association with almost all the studied parameters (Table 7).

Table 7. Mix scatter plot of growth, yield and fiber quality attributes of cotton cultivated during 2023 and 2024

Whereas; PHM=Plant height at maturity, NBP= Number of bolls plant^-1, MBW=Mean boll weight (g), SCY=Seed cotton yield (kg ha^-1), GOT=Ginning out turn (%), FL=Fiber length (mm), FS=Fiber strength (g tex^-1), FU=Fiber uniformity (%)

DISCUSSION

 The application of NPK fertilizer coupled with TS significantly influenced the growth, yield and fiber quality of cotton which is validated by a second-year experiment. The contrasting result could also be attributed to other research factors as our research involved the nutrient management which is also correlated to the fluctuation in the cotton growth, physiology and yield (Gwathmey et al., 2010; Bekele, 2020). In our research nutrient management outperformed as emergence of cotton was optimum at a balanced fertilization of NPK (200:120:150 kg ha^-1). The findings are strongly aligned with the fact that balanced supply of nutrients during initial growth stages of crop plays a significant role during the early stages (Xiao and Yin, 2019; Nwachukwu et al., 2024). The findings revealed that reduced tillage significantly improved the number of sympodial branches plant^-1 which might be attributed due to improved soil moisture content and reduced disturbance of soil that also enhance soil quality (Singh et al., 2023). Furthermore, conservation tillage practices are widely reported to improve soil structure, increase OMC and microbial communities which facilitate a better nutrient efficiency and root development. The attained results strongly aligned with the findings of  Pendke et al. (2025). Additionally, reduced tillage also improves soil quality and the soil available nutrient resources for a better growth of cotton.

 The results of our study also revealed that balanced NPK (200:120:150 kg ha^-1) resulted in the maximum number of sympodial branches plant^-1 during both the years 2023 and 2024. Hence, application of balanced nutrition improves nutrient use efficiency (NUE), photosynthetic efficiency of crop and assimilate the partitioning of nutrient which promote the initiation and development of more sympodial branches in the cotton (Zhou et al., 2023; Alagarswamy et al.,  2024). The increase in sympodial branches likely to increase the fruit bearing branches that ultimately increase the number of bolls per plants which we observed during the both years of research under reduced tillage and balanced nutrient management. The findings of our research are consistent with Boincean and Dent (2019) who reported that more boll bearing branches appear after the application of balanced NPK. The tillage practices had non-significant effect on plant height, while balanced fertilization (200:120:150 kg ha^-1) again outperformed with a maximum plant height during both the experimental years. The higher plant height may be attributed to the higher uptake of N which is relatively a good source for vegetative growth of cotton and promote higher photosynthesis. The findings strongly agrees with the scientific fact that height of cotton plants increased with more balanced NPK fertilizers due to higher nutrient uptake and photosynthetic activity (Zhang et al., 2024). In contrasting tillage systems did not significantly affect the number of bolls plant^-1, mean weight of boll and weight of 100 cotton seeds in either year of the study. The lack of significance could be attributed to the difference in moisture and nutrient availability during the reproductive stage under conventional and reduced system. The literature also report that reduce tillage cutoff the moisture and nutrient at early growth stages which later on create a clear difference among the reproductive traits of cotton (Pearsons et al., 2023). Contrastingly there was a positive nutrient management effect on the number of bolls plant^-1 and the average weight of bolls. Among all the nutrient treatments, the highest no. of bolls and boll weight were associated with the balanced NPK (200:120:150 kg ha^-1) which possibly contributed to the yield increase. The highest number of bolls plant^-1 was recorded in 2024 which was likely due to the improved weather in 2024 compared to 2023. The higher number of bolls plant^-1 might be associated with the favorable thermo-moisture regime during the reproductive phase especially temperature near to the optimum range for cotton flowering and boll formation (28° to 32° C) and reduce stress which can improve viability of pollen, fertilization assimilate supply and the boll retention while reducing the boll shedding (Saini et al., 2023). These results strongly aligned with Pittelkow et al. (2015) who reported the positive influence of optimized weather conditions  on the improvement of length of cropping season. The improvement in reproductive phase leads to improve the seed weight which ends up with a better yield (Francaviglia et al., 2023). Among different tillage systems, seed cotton yield and ginning outturn were impacted with reduced tillage yielding better results than conventional tillage. These findings correspond with Mrabet et al. (2024), who attributed the increased yield under reduced tillage to better soil moisture contents, water holding capacity and improved OM. The results of our study revealed that changes in nutrient regimes in combination with reduced tillage resulted in different ginning outturns and fiber lengths (Zhou et al., 2026). The 200:120:150 kg ha^-1 NPK treatment had the highest ginning outturn with balanced fertilization improving ginning quality. The treatments with 200:120:150 and 250:170:200 kg ha^-1 NPK had the greatest fiber lengths, supporting Shah et al. (2022) statement of the role P in improving the fiber length by enhancing the energy metabolism of the fiber developing cells. Reduced tillage practices annually strengthened fiber with each year as reported by Wang et al. (2024) who stated that conservation tillage encourages further fiber strengthening and boll development. Each year, fiber strength improved, likely due to variations in climate and the influence of nutrients in the soil, as discussed by Ghaffar et al. (2020). In contrast, tillage practices impacted micronaire size and fiber uniformity. The strongest fibers were produced at a balanced NPK level (200:120:150 kg ha^-1) and at the highest fertilizer level (250:170:200 kg ha^-1) in the both growing seasons. These findings were aligned with the results of Boquet et al. (2004) and Bednarz et al. (2006) who also reported that proper management of fertilizers with optimum pairs of different nutrient give higher yield of any cropping system combining with conservation tillage practices.  The improvement in the growth, yield and fiber quality of cotton attributed to the significance of balanced nutrient supply which ensure that plant do not face any nutritional deficiency that can limit the growth of cotton and also improve the nutrient retention within plants (Ul-Allah et al., 2021; Iftikhar et al., 2025). The economic analysis also revealed that outperforming NPK treatment in combination with reduced tillage is economically feasible in developing countries like Pakistan, however the validity of economic returns has already reported by Vinayak et al. (2023) and Iqbal et al. (2025).

Conclusion: Results revealed that integration of reduced tillage with balanced NPK fertilization progressively enhanced crop productivity, fiber quality traits, and profit of cotton crop under arid climate. Conventional tillage produced 15-18% lower seed cotton yield as compared to reduced tillage during both seasons of the experiment. Among the fertilization regimes, 200:120:150 NPK kg ha^-1 was the most effective pair of NPK in producing highest seed cotton yield 2606-2656 kg ha^-1 by enhancing the yielding parameters such as no. of sympodial branches per plant, boll weight, ginning outturn, and improving fiber traits quality, strength, length, and uniformity. Highest net return US $: 1003.18 ha^-1 with the BCR of 2.3 were achieved with the combination of reduced tillage and 200:120:150 kg ha^-1 in comparison to all other NPK combinations. Therefore, based on the results of two growing seasons at the experimental site in Dera Ismail Khan which belong to arid region, it is concluded that reduced tillage and NPK (200:120:150 kg ha^-1) improved cotton productivity and it can be recommended for the agroecological conditions similar to the experimental site. However, addition multi location studies are required to validate the results of current funding. Future research and efforts should be aligned with the long term reduced tillage operations to improve soil health, crop productivity and food security under different agro-climatic conditions.

Funding: This research received no external funding. The study was conducted without any financial support from public, commercial funding agencies, however the consumables were provided by Agricultural Research Institute, Ratta Kulachi where both of the studies conducted.

Acknowledgements: The authors of this manuscript acknowledge the kind assistance, cooperation and encouragement of staff members of Research Institute, Ratta Kulachi Dera Ismail Khan and CCRI, Multan

Conflict of Interest: The authors of this manuscript declare that there is no conflict of interest

Author’s contributions: KU supervised and designed the study. RH executed the experiment, recorded data and initial draft. AAK and QA assisted in data curation and draft editing. All authors interpreted the data, critically revised the manuscript for important intellectual contents and approved the final version.

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