Effect of different plant geometry and canopy management practices on dry matter distribution and NPK uptake of Bt cotton under drip irrigation

Introduction

Cotton (Gossypium spp.) popularly known as white gold and is an important crop for the rural economy of India and livelihood of the Indian farming community. Presently India ranks first in area and second in production of cotton in the world (Anonymous, 2024). Cotton is an important cash crop of India occupying an area of 31.1 million ha with a production of 117.40 million bales, each weighing 217.72 kg (ICAC, COCPC meeting Report, 2024). The production and productivity of cotton can be increased by the introduction of high yielding varities coupled with optimum plant geometry and suitable canopy management practices like detopping and removal of monopodia and spraying of growth retardant like mepiquat chloride (Thokale et al., 2004) [24] . In addition to this, role of plant growth regulators is very important in maintaining proper ratio of vegetative and reproductive structures under excessive vegetative growth situations to obtain higher fruiting bodies contributing the higher dry matter per plant. Highest dry matter accumulation in plant observed in fruiting bodies might be attributed to the improvement in the assimilation of photosynthates under monopodia removal at 45-50 DAS and detopping at 100 cm plant height because of resources benefit compared to other treatments. This might be due to efficient utilization of moisture, nutrients and sunshine by cotton crop with proper aeration in the root zone, which enabled crop plants to explore their maximum potential in the absence of monopodial branches (i.e vegetative branches) as well as due to detopping practice, that enhance availability and uptake of nutrients to enhance photosynthesis and translocation of nutrients to reproductive parts thus increasing dry matter accumulation per plant. Similar results were recorded by Shwetha et al. (2009) [20] , Hallikeri et al. (2010) [11] , Kataria and Valu (2018) [15] , Chaudhari et al. (2021) [8] . Agriculture is by far the largest (81%) water consumer in India (WRI, 2007) [25] and hence more efficient use of water in agriculture needs to be the top most priority. Water input per unit irrigated area will have to be reduced in response to water scarcity and environmental concerns (INCID, 2006) [13] .

Materials and Methods

The present experiment was carried out in growing season kharif 2024-25 at Cotton research Unit Dr. Panjabrao Deshmukh Krushi Vidyapeeth, Akola, Maharashtra. The experimental site was located at 20.7039246 N and 77.0655831 E. The soil of experimental site was slightly saline in texture with pH (8.10), available nitrogen (214 kg ha -1 ), available phosphorus (16.80 kg ha -1 ) and available potassium (308 kg ha -1 ) during experimental study. The present experiment was laid out in Factorial Randomized Block Design with 12 treatment combination replicated thrice. The treatment detail was, factor I is different plant geometry viz., 90 cm x 15 cm (S 1 ), 90 cm x 30 cm (S 2 ) and 90 cm x 45 cm (S 3 ) and factor II is four canopy management treatment is used namely, Control (C 1 ), Monopodia removal of at 45-50 DAS and detopping at 100 cm plant height, Monopodia removal at 45-50 DAS and one spray of mepiquat chloride @ 25 g a.i. at 60-65 DAS (C 3 ) and Two spray of mepiquat chloride 25 g a.i. at 45-50 DAS and 60-65 DAS.

Effect of plant geometry

The plant geometry of 90 cm x 45 cm plant spacing recorded significantly higher dry matter distribution to different plant parts as well as total dry matter accumulation plant -1 over 90 cm x 15 cm and 90 cm x30 cm, at all the crop growth stages. Difference in dry matter production plant -1 among plant geometry, might be due to dry matter accumulation and distribution in different plant parts depend on photosynthetic ability of plant which in turn dependence on dry matter accumulation in leaves, stem, and reproductive parts, leaf area and leaf area index, Similar results were reported by Shwetha et al. (2009) [20] , Hallikeri et al. (2010) [11] , Kataria and Valu (2018) [15] , Dodiya et al. (2018) [10] and Chaudhari et al. (2021) [8] .

Result and Discussion

The results and discussion of the present study have been summarized under following heads:

A. Dry matter distribution per plant

Effect of canopy management practices

Accumulation of dry matter in different plant parts was significantly influenced by canopy management practices at all the dates of observations except, at 30 DAS for leaf, stem and fruiting bodies dry matter. At 60, 90 DAS, control treatment (C 1 ) recorded significantly higher dry matter accumulation of leaves (61.80 g and 101.41 g) and stem dry matter (53.77 and 88.57 g) over all the other treatments. However, treatment C 2 (Monopodia removal at 45-50 DAS and detopping at 100 cm plant height) showed significantly higher dry matter in terms of fruiting bodies (18.64 g and 148.03 g) over other treatments, which was followed by C 4 treatment (two spray of mepiquat chloride @ 25 g a.i. at 45-50 DAS and 60-65 DAS). At 120 DAS and at harvest, control treatment (C 1 ) showed superior over all the treatments in accumulation of highest dry matter of leaves and stem. However, among the other canopy management practices, treatment C 2 and C 3 shows significantly minimum dry matter of leaf and stem. This might be due to removal of monopodial branches at 60 DAS, which reduced the number of functional leaves well as stem compared to other treatments. Among the other treatments, C 2 (monopodia removal at 45-50 DAS and detopping at 100 cm plant height) recorded significantly highest dry matter of fruiting bodies, which was followed by treatment C 4 (two spray of mepiquat chloride @ 25 g a.i. at 45-50 DAS and 60-65 DAS) at 120 DAS and at harvest. Highest dry matter accumulation in fruiting bodies might be attributed to the improvement in the assimilation of photosynthates under monopodia removal at 45-50 DAS and detopping at 100 cm plant height because of resources benefit compared to other treatments. This might be due to efficient utilization of moisture, nutrients and sunshine by cotton crop with proper aeration in the root zone, which enabled crop plants to explore their maximum potential in the absence of monopodial branches (i.e vegetative branches) as well as due to detopping practice, that enhance availability and uptake of nutrients to enhance photosynthesis and translocation of nutrients to reproductive parts thus increasing dry matter accumulation per plant. Similar results were recorded by Shwetha et al. (2009) [20] , Hallikeri et al. (2010) [11] , Kataria and Valu (2018) [15] , Chaudhari et al. (2021) [8] .

Interaction

The data on dry matter distribution to different parts plant -1 of Bt. cotton was not influenced significantly due to the interaction effect between different plant geometry and different canopy management practices.

Nutrient Uptake Nitrogen uptake

Nitrogen uptake The data revealed that, the different plant gerometry on nitrogen uptake was influenced significantly among the treatments. The plant grometry 90 cm x 15 cm recorded highest nitrogen uptake (119.74 N kg ha -1 ), which was followed by 90 cm x 30 cm and 90 cm x 45 cm (104.09 and 93.39 N kg ha -1 ) it might be due to higher plant population in closer spacing. Among different canopy management practices, the maximum uptake of nitrogen recorded in C 2 treatment i.e. monopodia removal at 45-50 DAS and detopping at 100 cm plant height (119.20 N kg ha - ), followed by C 4 and C 2 , where biological yield was maximum. Minimum uptake of nitrogen (89.95 kg ha -1 ) by crop was recorded with control treatment (C 1 ), where no canopy management practices were done during experiment. It might be due high dry matter production and yield. Similar finding was reported by Norton et al. (2005) [17] .

Phosphorous uptake

Phosphorus uptake in different plant geometry was strongly influenced by Bt. Cotton hybrid. The highest phosphorus uptake (37.37 P kg ha -1 ) was reported in closer plant spacing of 90 cm x 15 cm (S 1 ) followed by wider plant spacing of 90 cm x 30 cm (S 2) and 90 cm x 45 cm (S 3 ) (31.62 and 28.28 P kg ha -1 ). It might be due to maximum plant population obtained in closer plant spacing. The phosphorus uptake by plant was influenced significantly due to different canopy management practices. The phosphorus by plant was significantly higher (37.37 P kg ha -1 ) under monopodia removal at 45-50 DAS and detopping at 100 cm plant height (C 2 ) than rest of treatments. However, which was followed by C 4 and C 3 treatment (Norton et al., 2005) [17] .

Potassium uptake

Among the different plant geometry, potassium uptake by plant was influenced significantly among the treatments. Significantly maximum potassium uptake by plant was recorded in closer plant spacing of 90 cm x 15 cm (88.88 K kg ha -1 ), as compared to wider plant spacing of 90 cm x 30 cm and 90 cm x 45 cm (77.26 and 71.23 K kg ha -1 ). The maximum uptake of potassium (87.97 K kg ha -1 ) by Bt cotton was found with treatment monopodia removal at 45-50 DAS and detopping at 100 cm plant height (C 2 ) over all the other treatments, which is followed by C 4 and C 3 treatment (83.72 and 76.02 K kg ha -1 ). Minimum uptake of potassium by crop (68.79 K kg ha -1 ) was recorded with control treatment, where no canopy management practices (Norton et al., 2005) [17] .

Conclusion

Based on above data, it could be concluded that plant spacing 90 cm x 15 cm had better dry matter production than 90 cm x 30 cm and 90 cm 45 c. under drip irrigation.

As well as canopy management practices like monopodial removal at 45-50 DAS detopping at 100 cm plant height had advantage to produce higher dry matter than no or other canopy management practices. In case of NPK uptake of plant 90 cm x 15 cm plant spacing observed higher NPK uptake than 90 cm x 30 cm and 90 cm x 45 cm. In canopy management practices monopodia removal at 45-50 DAS and detopping at 100 cm plant height (C 2 ) observed significantly highest available NPK than other canopy management practices.

Acknowledgement

AcknowledgementAuthors are thankful to Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola, all faculty of Agriculture, Government of India for supporting this research project to carry out this work. An expression of gratitude to Prof. Dr Sanjay Kakade for their guidance and support, as well as gave advice and suggestions.

References

1. Anonymous. Committee on Cotton Production and Consumption (COCPC) meeting held on 28.11.2024. 2024.
2. Anonymous. International Cotton Advisory Committee (ICAC): Rules and regulations. 2024.
3. Anonymous. All India Coordinated Cotton Improvement Project. Annual report. Coimbatore; 2017. p. 1-5.
4. Anusree G, Sakthivel N, Thiruvaran S, Balamurugan J. Effect of drip fertigation on growth, yield parameters and fertilizer use efficiency of irrigated cotton (Gossypium hirsutum L.) under high density planting system. Int J Curr Microbiol Appl Sci. 2020;9(7):24452453.
5. Bar-Yosef B. Advances in fertigation. Adv Agron. 1999;65:1-70.
6. Bhalerao PD, Gaikwad GS, Imade SR. Productivity and nutrient uptake of Bt cotton (Gossypium hirsutum L.) as influenced by precision in application of irrigation and fertilizer. Indian J Agron. 2011;56(2):150-153.
7. Cathey GW, Luckett K. Some effects of growth regulator chemicals on cotton earliness, yield and quality. In: Brown JM, editor. Proceedings of the Beltwide Cotton Production Research Conference. Memphis (TN): National Cotton Council of America; 1980. p. 45-45.
8. Chaudhari JH, Chauhan SA, Chaudhary MM. Effect of topping and nitrogen levels on growth, yield attributes and yield of Bt cotton under drip irrigation conditions. Pharma Innov J. 2021;10(10):1898-1902.
9. Dhillion GS, Chhabra KL, Punia SS. Effect of crop geometry and integrated nutrient management on fibre quality and nutrient uptake by cotton crop. J Cotton Res Dev. 2006;28:221-223.
10. Dodiya C. Effect of crop geometry, detopping and plant growth regulator on growth and yield of Bt cotton (Gossypium hirsutum L.). M.Sc. (Agri.) thesis. Anand: Anand Agricultural University; 2018.
11. Hallikeri SS, Halemani HL, Patil VC, Palled YB, Patil BC, Katageri IS. Effect of nitrogen levels, split application of nitrogen and detopping on seed cotton yield and fibre quality in Bt cotton. Karnataka J Agric Sci. 2010;23:418-422.
12. International Cotton Advisory Committee (ICAC). Cotton This Month. COCPC meeting. India; 2023 Jun 1.
13. Indian National Committee on Irrigation and Drainage (INCID). Drip irrigation: prospects and coverage in India. New Delhi: Ministry of Water Resources; 2006.
14. Kakade SU, Bhale VM, Deshmukh JP, Wadatkar S. Growth, nutrient uptake and seed cotton yield as influenced by split application of nutrients through fertigation in Bt cotton. Int J Curr Microbiol Appl Sci. 2017;6(9):2982-2990.
15. Kataria GK, Valu MG. Effect of detopping and growth retardant on physiological parameters and yield of Bt cotton (Gossypium hirsutum L.). J Cotton Res Dev. 2018;32(2):226-230.
16. Kaul A, Deol JS, Brar AS. Response of different Bt cotton (Gossypium hirsutum L.) hybrids to canopy modification practices. J Appl Nat Sci. 2016;8(3):11881197.
17. Norton LJ, Clark H, Borrego B, Ellsworth B. Evaluation of two plant growth regulators from LT Biosyn. Arizona Cotton Report. 2005 May;142-142.
18. Patel N, Rajput TBS. Simulation and modeling of water movement in potato (Solanum tuberosum L.). Indian J Agric Sci. 2011;81:25-32.
19. Rademacher W. Growth retardants: effects on gibberellin biosynthesis and other metabolic pathways. Annu Rev Plant Physiol Plant Mol Biol. 2000;51:501531.
20. Shwetha NS, Halepyati AS, Pujari BT. Effect of detopping, removal of monopodia and plant spacing on nutrient uptake, quality parameters and economics of Bt cotton (Gossypium hirsutum L.). Karnataka J Agric Sci. 2009;22(4):892-893.
21. Singh K, Singh H, Gumber RK, Rathore P. Studies on the seed cotton yield, growth and yield contributing characters of new Bt cotton hybrids under varied agronomic manipulations. In: World Cotton Research Conference on Technologies for Prosperity; 2011. p. 338-340.
22. Srinivasulu K, Hema KNV, Prasad SD, Rao KVK. Performance of cotton hybrids under different spacing and nitrogen levels in black cotton soils of coastal Andhra Pradesh. J Cotton Res Dev. 2006;20(1):99-101.
23. Thakare SS, Paslawar AN, Deshmukh JP, Kubde KJ, Saoji BV, Shingrup PV. Effect of fertigation levels and weed management practices on weed flora and seed cotton yield of Bt cotton. J Pharmacogn Phytochem. 2019;8(6):2237-2241.
24. Thokale JG, Raut RS, Mehetre SS. Effect of fertilizers and spacing on yield parameters of interspecific hybrid Phule 492 under summer irrigated condition. J Cotton Res Dev. 2004;18:167-171.
25. World Resources Institute (WRI). Annual report 20062007. Washington (DC): WRI; 2007.