Comparison of Droplet Deposition, 28-Homobrassinolide Dosage Efficacy and Working Efficiency of the Unmanned Aerial Vehicle and Knapsack Manual Sprayer in the Maize Field

Mujahid Hussain,Guanmin Huang,Rehana Kaousar,You Mo,Weiming Tan,Liusheng Duan,Zhao Wang

doi:10.3390/agronomy12020385

Abstract

Brassinolides (BRs) are naturally-occurring phytohormones, which are essentially important to improve the crop adoptive capacity to various stresses. Spray volume (SV) and agrochemical application methods are associated with chemical deposition and field efficiency. The objective of this study was to compare the possible effects of 28-Homobrassinolide (HBL) dosages 18, 22, and 30 mg a.i. ha−1 for unmanned aerial vehicle (UAV) sprayers (15 L ha−1 and 30 L ha−1) and 22 mg a.i. ha−1 for Knapsack manual sprayers (KMS) (450 L ha−1) at maize silking stage on droplets deposition distribution, photosynthetic parameters, grain filling process and yield. The results showed that the droplet deposition of UAV (15, 30 L ha−1) was 47.04%, 8.89% higher than KMS. However, the UAV sprayer had a poor droplet deposition distribution. HBL significantly increased the photosynthetic parameters, grain filling rate, and yield. A UAV spray volume of 15 L ha−1 with 22 mg a.i. ha−1 significantly increased grains yield by 4.16–5.64%, 7.5–12.09% compared to KMS and CK in both years. Considering the high efficiency of the UAV sprayer and better effects of HBL on final yield, spraying 22~30 mg a.i. ha−1 with UAV spray volume 15 L ha−1 at the silking stage could be a better strategy.

Highlights

Published: 3 February 2022Maize (Zea mays L.) is the most important cereal crop in the world
The coverage rate of Knapsack manual sprayers (KMS) was significantly higher than all unmanned aerial vehicle (UAV) treatments
The average droplet deposition density of KMS was significantly higher in the top, middle, bottom leaf positions than in UAV 15 L ha−1 and UAV 30 L ha−1 treatments

Summary

Introduction

Maize (Zea mays L.) is the most important cereal crop in the world. It is widely grown for food, feed and industrial purposes [1]. Whole maize grains are rich in digestible starch, proteins, fat, oil, vitamin A, B, and other minerals [3,4]. Demand for maize is increasing with an increase in its consumption [5]. Abiotic stresses, including extreme weather, temperature, and climate changes have been the main obstacles in crop production [6]. Proper agriculture practices should be adopted to increase plant resistance against environmental stress [7]

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