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

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.

Evaluation of Remotely Piloted Aircraft for Agricultural Spraying in Corn Cultivation in the Brazilian Savannah

“…The average deposition significantly increased by 87.90% for the 15 L ha -1 treatments and by 46.70% for the 30 L ha -1 treatments compared to ground application. Further supporting these results, Hussain et al (2022) also evaluated the deposition in corn cultivation at different plant heights. They observed that the average droplet deposition values for RPA application at rates of 15 and 30 L ha -1 were not statistically different.…”

Evaluation of the deposition and distribution of spray droplets in citrus orchards by plant protection drones

“…The upper spray liquid effect of the knapsack electric sprayer was significantly lower than that of the plant protection drone. This is due to the lack of droplet-assisted diffusion device in the knapsack electric sprayer, and it takes some time for the liquid to reach the surface of the crop leaves from the nozzle, resulting in part of the liquid evaporating and drifting away, and reducing the surface coverage of the leaves ( Hussain et al., 2022a ; Hussain et al., 2022b ). At the same time, the spraying height of the knapsack electric sprayer in the actual application process depends on the operator, and the deposition effect is also closely related to the operator’s spraying method.…”

Optimizing Seed Rate and Herbicide Doses With or Without Adjuvant for Weed Control and Its Influence on Yield of Winter Wheat

“…This may be achievable by optimizing the efficacy of herbicides at a lower rate by including an adjuvant [31]. An adjuvant is a chemical that reduces the amount of energy and time required to absorb active substances and can reduce herbicide use by 75% without reducing yield or overall benefits for environmentally friendly weed control [5,[32][33][34]. Adjuvants entirely change the chemical composition of herbicides or even blanket the plant surface by maintaining the herbicide in contact with plant tissue, increasing herbicide absorption and binding capacity to kill the target plant while causing no damage to the genuine crop [35].…”