Evaluation of droplet deposition and efficiency of 28-homobrassinolide sprayed with unmanned aerial spraying system and electric air-pressure knapsack sprayer over wheat field
Introduction
Wheat (Triticum aestivum L.) is a major cereal crop and contributes around 40 % of the world's food sources (Giraldo et al., 2019). Wheat grains are rich in calories and the primary source of dietary carbohydrates, proteins, sugar, fiber, and fat (Kumar et al., 2011). Wheat production is critical for global food security (Zou et al., 2018). According to (Erenstein et al., 2021), with the increasing demand for wheat, a 4 % decrease is estimated in global wheat farms (from 135 to 130 million) in 2030 due to limited resources such as diminishing fertile lands and agricultural water (Hawkesford et al., 2013). Furthermore, environmental stresses (biotic and abiotic) and extreme climatic conditions especially rising global temperature and changes in precipitation frequencies, also have a direct and indirect impact on the overall yield of crops (Daloz et al., 2021, Rosenzweig et al., 2014, Shen and Cao, 2012, Zhao et al., 2017). Abiotic factors such as heavy metals, salinity, drought, and extreme temperature are major yield-limiting factors (Zörb et al., 2019), which cause around 70 % of yield loss in major crops (Mantri et al., 2012). Estimation Based on the crop yield models has predicted the loss in agricultural productivity of major crops, including wheat, rice, and maize, which is a serious threat to food security (Tigchelaar et al., 2018). It is reported that wheat production is estimated to decrease by 6 % per °C in further global warming (Asseng et al., 2015). A decrease in wheat yield is due to the decrease in the duration of the wheat-growing season (Yang et al., 2014). In this situation, providing high grains production is a complex challenge that needs to be solved by multidisciplinary approaches in crop improvements (Zheng et al., 2011). Improving stomatal activity and photosynthesis increases the grains filling duration, which increases yield (Derkx et al., 2012, Dwivedi et al., 2018).
Plant growth regulators (PGRs) are extensively used to combat environmental factors, strengthen photosynthetic machinery and regulate senescence (Maghsoudi et al., 2020). Brassinolides (BRs) are the naturally occurring steroidal hormones involved in physiological functions, improve the plant tolerance against abiotic stresses (Naservafaei et al., 2021) and elevate reactive oxygen species (ROS) in high temperature and drought conditions to improve plant growth, yield and quality parameters in different crops (Fahad et al., 2016, Sharma et al., 2017, Sridhara et al., 2021). There is evidence that exogenously applied BRs have an ameliorative role in resistance against heavy metal stress, salinity stress and drought stress (Naveen et al., 2021, Nazir et al., 2021, Nazir et al., 2019). Furthermore, these phytohormones accelerate the photosynthesis rate, improve the antioxidant system, and intensify physio-biochemical attributes (Sanjari et al., 2019). Previous studies revealed the influence of BRs on morpho-physiological processes of different plants such as, stomatal movement, root morphology, protein synthesis, stem elongation, proline accumulation, photosynthesis, leaf exchange attributes, antioxidant system, cell viability, and osmoprotectant induction (Ahmad et al., 2018, Anjum et al., 2016, Krishna, 2003, Shahzad et al., 2018). Foliar application of BRs on flowering (anthesis) stage of wheat, increased period of physiological maturity, prolonged grains filling duration by controlling the sink functions and resulted in increased grain yield by 7.3 %, grain number per spike by 9.17 %, thousand-grain weight (TGW) by 6.62 % compared with control (CK) in wheat and rice (Saka et al., 2003). Moreover, foliar application of phytohormones also increased the number of spikes and spike length per plant, grains per spike, leaf area and grain yield under the salt stress and non-stress conditions (Lal et al., 2019).
28-Homobrassinolide (HBR) is an analogue of naturally occurring phytohormones that enhance the growth, yield, and quality traits and have a great role in photosynthetic traits, which leads to better grain filling, increase in photo-assimilate production and final yield (Yusuf et al. 2011). In literature, research showed that high-temperature stress and heavy metal down the regulation of PS II activity, HBR helps alleviate the effect of these stresses and leads to up-regulation of PS II activity (Hayat et al., 2010). Foliar application of HBR on tomatoes increased the chlorophyll, which increased the size, length, breadth, and fruit quality (Sridhara et al., 2021). However, the application of HBR on the wheat crop by different sprayers has not been studied.
The selection of high-efficiency spray equipment is a critical factor in achieving a better effect of agrochemicals (Yang et al., 2018). Electric air-pressure knapsack (EAP) and boom sprayers are commonly used in wheat fields. Although boom sprayers are helpful in spraying in large fields, because of driven by ground machinery, it has damaging effects on wheat plants and results in reduced yields, while EAPs are not suitable for large fields because of low working efficiency (Weicai et al., 2016). To improve the crop protection and efficiency of agrochemicals, unmanned aerial Spraying system (UASS) have been developed (Xiongkui et al., 2017). UASS as an emerging plant protection machinery, could not only improve the spraying efficiency of chemicals but also reduce the cost of wheat production. In order to reduce the chemical dosage and residue, the precise variable rate of pesticide spraying can be adjusted according to crop type (Lou et al., 2018, Wang et al., 2019a). The use of adjuvants in the spray composition increases the UASS spray efficiency, and chemical deposition by decreasing fine droplets and droplets winding spectra (Wang et al., 2018). Droplet deposition distribution and penetration depend on the size of the droplets; deposition of chemicals on the upper and lower canopy of the plant was increased with increasing droplet size at an extent of 185.09 μm volume median diameter (VMD) (Chen et al., 2020). The research community has shown interest in the droplet distribution efficiency of UASS and EAP by comparing the deposition of two sprayers. UASS had higher chemical deposition as compared to EAP, but less coverage rate and droplet density (Q. Xiao et al., 2020), and Wang et al. (2019b) concluded that spray deposition characterizations of the UASS were higher working efficiency and less losses to the ground as compared to EAP and boom sprayer. Another study revealed that spraying fungicide on heading stage, UASS had higher droplet distribution on the lower canopy of wheat as compared to manual sprayers, and the addition of adjuvant in UASS spray formulation showed better effect when chemical dosage reduced by 20 % as compared to EAP (Qin et al., 2018). Furthermore, application of weedicides in wheat field by UASS had more suppressive effects as compared to artificial sprayers (Zhang et al., 2020). Application of HBR by UASS on maize flowering stage had high deposition rate on plant leaves and resulted in high photosynthesis, grain filling rate and then higher yield in comparison with EAP (Hussain et al., 2022). The droplet distribution and penetration is characterized by the different spray volumes (SV). UASS with speed of 4.5 m s−1, 3.5 m height have 49.1–57.1 % more deposition than EAP (Xiao et al., 2019) and UASS working efficiency is 20 times higher than EAP. Chemical formulation of 10 L ha−1 with addition of adjuvant applied by UASS has better penetration in plant leaves (Wang et al., 2019b). UASS 15 L ha−1 had better results than EAP 300 L ha−1 spray volume when chemical dosage was same in both sprayers, while the same results were recorded in both sprayers when the chemical dosage was decreased by 20 % with the addition of adjuvants in UASS (Sarri et al., 2019). However, there are no reports of applying multiple dosages of HBR by different sprayers with various spray volumes during the wheat flowering stage.
In this research, we set different dosages of HBR and spray volumes for UASS and compared its effects with the EAP sprayer. We hypothesized that HBR applied by UASS would have better effects on wheat growth and development as compared to EAP sprayer. The objectives of this work were to: (1) compare the possible effects of HBR on wheat crop applied by UASS and EAP, (2) obtain the optimum dosage of HBR and spray volume for wheat crop applied by UASS, (3) evaluate the droplet deposition of EAP and spray volumes of UASS on different wheat canopies, (4) examine the effects UASS application of 20 % decreased HBR dosages than EAP.
Section snippets
Experimental site
A field trial was conducted in the years 2019 and 2020 at Jiyang research station of Shandong Academy of Agricultural Sciences (SAAS) (36°58′N, 116°58′E), Jinan, Shandong, China. The soil at the research station is sandy clay loam, and PH is 8.5. A soil depth of 0–40 cm contains 1.15 g kg−1 of total nitrogen, 42.8 mg kg−1 of available P, 138 mg kg−1 of available K, 15.6 g kg−1 of organic matter. The land used in the experiment was an annual rotation of maize-wheat, the last cultivated crop was
Characterization of droplets deposition
The droplet coverage percentage is an important parameter to evaluate spray effectiveness. WSP was used to estimate the droplet coverage rate from three different positions of wheat plants. Droplet coverage of EAP was higher on all wheat canopies than UASS treatments. The coverage rate of EAP sprayer was 84.48 %, 66.60 % higher than UASS 15 L ha−1 and UASS 30 L ha−1 on average plant canopies. Droplet coverage rates varied in different plant canopies. Flag leaf coverage rate was 8.82 %, 28.64 %
Discussion
Our results reveal the importance of HBR different dosages and spray volumes with two sprayers (UASS and EAP) on droplet deposition, growth and development of wheat. In this study, droplet coverage and droplet density were relatively lower in UASS applications as compared to EAP, especially in UASS 15 L ha−1 (Fig. 4A, B). Less spray volume had fewer droplets captured by the wheat head and flag leaf. Droplets density and coverage were lower on the lower plant canopy than on flag leaf and wheat
Conclusions
In this study, UASS and EAP sprayers were used to explore the possible effects of HBR dosages and spray volumes on the growth and development of the wheat crop. The main conclusions are as follows:
HBR applied by UASS 15 L ha−1 had the most significant deposition and deposition rate. Deposition of UASS was 44.41 %, 15.51 % higher than EAP and UASS 30 L ha−1, while the uniformity of droplet density, coverage and deposition in UASS was less as compared to EAP. UASS spray volume of 15 L ha−1 had
Author Contributions
W.T. and M.H. designed the experiments; M.H., Z.W. and Y.M. performed data curation and investigation; M.H., G.H. and Y.M. performed formal analysis; M.H. and W.T. wrote the paper; Z.W., Y.G., R.K., and L.D. reviewed the manuscript.
Compliance with Ethical Standards
This manuscript has not been published in whole or in part elsewhere and is not currently being considered for publication in another journal. All authors have been personally and actively involved in substantive work leading to the manuscript and hold themselves jointly and individually responsible for its content.
Ethical Approval
This article does not contain any studies with human participants or animals performed by any of the authors.
Informed Consent
Informed consent was obtained from all individual participants included in the study.
Data Availability Statement
The authors declare that data supporting the findings of this study are available on request from the corresponding author.
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
The authors thank the anonymous referees and the editor for their valuable comments and suggestions in improving this paper.
Funding
This work was supported by the National Key Research and Development Program of China (2017YFD0201300) and the Natural Science Foundation of China (31872850).
References (66)
- et al.
Direct and indirect impacts of climate change on wheat yield in the Indo-Gangetic plain in India
J. Agric. Food Res.
(2021) - et al.
Estimating the global number and distribution of maize and wheat farms
Glob. Food Sec.
(2021) - et al.
Spraying exogenous 6-benzyladenine and brassinolide at tasseling increases maize yield by enhancing source and sink capacity
F. Crop. Res.
(2017) - et al.
Effect of 28-homobrassinolide on photosynthesis, fluorescence and antioxidant system in the presence or absence of salinity and temperature in Vigna radiata
Environ. Exp. Bot.
(2010) - et al.
Strip rotary tillage with subsoiling increases winter wheat yield by alleviating leaf senescence and increasing grain filling
Crop J.
(2020) - et al.
Effect of phosphorus and potassium foliage application post-anthesis on grain filling and hormonal changes of wheat
F. Crop. Res.
(2017) - et al.
Spray droplet impaction outcomes for different plant species and spray formulations
Crop Prot.
(2017) - et al.
Interactive role of epibrassinolide and hydrogen peroxide in regulating stomatal physiology, root morphology, photosynthetic and growth traits in Solanum lycopersicum L. under nickel stress
Environ. Exp. Bot.
(2019) - et al.
Brassinosteroid and hydrogen peroxide improve photosynthetic machinery, stomatal movement, root morphology and cell viability and reduce Cu-triggered oxidative burst in tomato
Ecotoxicol. Environ. Saf.
(2021) - et al.
Role of 24-epibrassinolide (EBL) in mediating heavy metal and pesticide induced oxidative stress in plants: a review
Ecotoxicol. Environ. Saf.
(2018)
Tillage practices affect dry matter accumulation and grain yield in winter wheat in the North China Plain
Soil Tillage Res.
Application of homobrassinolide enhances growth, yield and quality of tomato
Saudi J. Biol. Sci.
Genetic gains in grain yield, net photosynthesis and stomatal conductance achieved in Henan Province of China between 1981 and 2008
F. Crop. Res.
Modification of osmolytes and antioxidant enzymes by 24-epibrassinolide in chickpea seedlings under mercury (Hg) toxicity
J. Plant Growth Regul.
Brassinolide application improves the drought tolerance in maize through modulation of enzymatic antioxidants and leaf gas exchange
J. Agron. Crop Sci.
Exogenously applied methyl jasmonate improves the drought tolerance in wheat imposed at early and late developmental stages
Acta Physiol. Plant.
Rising temperatures reduce global wheat production
Nat. Clim. Chang.
Effect of droplet size parameters on droplet deposition and drift of aerial spraying by using plant protection UAV
Agronomy
Identification of differentially Senescing mutants of wheat and impacts on yield, biomass and nitrogen Partitioning F
J. Integr. Plant Biol.
Induction of water deficit tolerance in wheat due to exogenous application of plant growth regulators: membrane stability, water relations and photosynthesis
Photosynthetica
Exogenously applied plant growth regulators enhance the morpho-physiological growth and yield of rice under high temperature
Front. Plant Sci.
Water-soluble food dye of Allura Red as a tracer to determine the spray deposition of pesticide on target crops
Pest Manag. Sci.
Worldwide research trends on wheat and barley: A bibliometric comparative analysis
Agronomy
Prospects of doubling global wheat yields
Food Energy Secur.
Carbonic anhydrase, photosynthesis, and seed yield in mustard plants treated with phytohormones
Photosynthetica
Control effect on cotton aphids of insecticides sprayed with unmanned aerial vehicles under different flight heights and spray volumes
Int. J. Precis. Agric. Aviat.
Comparison of droplet deposition, 28-Homobrassinolide dosage efficacy and working efficiency of the unmanned aerial vehicle and knapsack manual sprayer in the maize field
Agronomy
Brassinosteroid-mediated stress responses
J. Plant Growth Regul.
Nutritional contents and medicinal properties of wheat: a review
Life Sci. Med. Res.
Role of brassinolide in amelioration of salinity induced adverse effects on growth, yield attributes and yield of wheat
J. Pharmacogn. Phytochem.
Influence of the Downwash Wind Field of Plant Protection UAV on Droplet Deposition Distribution Characteristics at Different Flight Heights
Agronomy
Evaluation of an unmanned aerial vehicle as a new method of pesticide application for almond crop protection
Pest Manag. Sci.
Grain sink strength may be related to the poor grain filling of indica-japonica rice (Oryza sativa) hybrids
Physiol. Plant.
Cited by (6)
Comparative studies of knapsack, boom, and drone sprayers for weed management in soybean (Glycine max L.)
2024, Environmental ResearchEvaluation of the deposition and distribution of spray droplets in citrus orchards by plant protection drones
2023, Frontiers in Plant ScienceA REVIEW OF THE CURRENT UNMANNED AERIAL VEHICLE SPRAYER APPLICATIONS IN PRECISION AGRICULTURE
2023, Journal of the ASABE