Soybean Response to Seed Coating with Chitosan + Alginate/PEG and/or Inoculation

Wacław Jarecki

doi:10.3390/agronomy11091737

Abstract

Inoculated or coated soybean seeds are often sown in agricultural practice. These treatments play a different role depending on the chemical composition of the preparation. The aim of the field experiment was to demonstrate the effectiveness of the developed coating (chitosan + alginate/PEG) and commercial inoculant (HiStick® Soy) applied alone or in combination to soybean seeds. Uncoated (control) seeds were sown for comparison. The research was carried out in 2018–2020 using the cultivar ‘Mavka’. The experiment was located in Makowisko, Podkarpackie Province, Poland. Coating composition was developed in a laboratory belonging to the Łukasiewicz Research Network—Institute of Biopolymers and Chemical Fibers in Łódź, Poland. The main role of the coating is to protect soybean seeds from low temperatures. HiStick® Soy inoculant contains Bradyrhizobium japonicum bacteria which increase nodulation on the roots. The conducted research demonstrated that sowing only coated seeds was not very effective, because the suitable number of nodules had not developed on soybean roots. The application of the inoculant alone positively affected the assessed traits compared to control, however, plant population was lower than expected. The highest seed yield was obtained after sowing coated seeds in combination with the inoculant (4.32 t·ha−1) and only inoculated seeds (4.23 t·ha−1) compared to control (3.64 t·ha−1). The test of the novel seed-coating agent showed that it had an good effect and efficacy, but only in combination with the inoculation procedure.

Highlights

Legumes account for 14.5% of arable land worldwide, but only 1.5% in European agriculture
Seed inoculation is especially recommended when rhizobia are not present in the soil or exhibit low viability [2,9,11]
Hungria et al [22] demonstrated that symbiosis between the plant and rhizobia can be inhibited when preparations toxic to bacteria are used for seed dressing

Summary

Introduction

Legumes account for 14.5% of arable land worldwide, but only 1.5% in European agriculture. Hara [30] showed that tungsten and molybdenum compounds applied to soybean seeds improved plant health status in conditions of excess water in the soil. Many such solutions are already in practical use, others are still at the research stage. Evangelista et al [44] showed that polymer coating applied in conditions of excessive soil moisture decreased the vigor of soybean seeds. Such a relationship was not observed when

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