Bradyrhizobium spp. inoculation associated with nitrogen application enhances the quality of soybean seeds

Abstract

The physiological seed quality can be altered by nutritional management of the soybean crop, especially by the fertilization with nitrogen (N), which is a structural component of several organic compounds, including proteins, and has an important catalytic role in the activation of several enzymes. The aim of this research was to investigate the effects of sources and application rates of mineral N fertilizer associated with inoculation of Bradyrhizobium spp. on physiological quality of soybean seeds. The treatments were arranged in a completely randomized block design, in a 3 × 5 factorial arrangement [three N fertilizer sources (Bradyrhizobium spp. inoculation; Bradyrhizobium spp. inoculation + urea application; and, Bradyrhizobium spp. inoculation + ammonium sulfate application) and five N application rates (0, 50, 100, 150 and 200 kg N ha-1)], with four replicates. Nitrogen fertilizer was applied in topdressing at R2 stage when soybean plants were in full flowering. The quality parameters evaluated in soybean seeds were: 1,000-seed mass, seed protein content, germination, first germination count test, seedling emergence, emergence speed index, accelerated aging, electrical conductivity, vigor and viability of seeds by tetrazolium test. The application of 50 kg N ha-1 of mineral fertilizer (ammonium sulfate or urea) associated with the Bradyrhizobium spp. inoculation enhanced the physiological quality of soybean seeds, resulting in higher seed germination percentage and higher emergence and seedling emergence speed index. The application of ammonium sulfate or urea (50 kg N ha-1) at full flowering of soybean plants inoculated with Bradyrhizobium spp. can improve the physiological quality of soybean seeds.

Agronomic characteristics of soybean cultivars with late-season nitrogen application in supplementation to the inoculation of Bradyrhizobium spp.

“…The late N application rates did not significantly affect (p > 0.05) the agronomic traits, grain protein concentration, or soybean yield (Table 4). Similar results have been reported by Kaschuk et al (2016), Korber et al (2017), andZuffo et al (2021), who showed that N fertilization had no significant effect on the agronomic traits of soybeans. Canonical correlation analysis was used to verify the contribution of each dependent variable measured in the soybean plants as affected by late N application rates (Figure 4).…”

“…Late N application rates did not optimize the grain protein concentration or yield of soybeans (Figure 4). Some research has also shown that N fertilization has not improved the productive performance or the grain protein concentration of soybeans (Aratani et al, 2008;Fipke et al, 2016;Kaschuk et al, 2016;Korber et al, 2017;Zuffo et al, 2018, Zuffo et al, 2021.…”

Planting position and application of different doses of nitrogen at different times on cassava

“…Our results indicated that nitrogen treatment beyond 135 DAP, as described by Mattos and Bezerra (2003), can promote a better response under the tested conditions (Table 3). Nitrogen is responsible for several physiological and biochemical processes in plants (Zuffo et al, 2021) and is a structural constituent of chlorophyll, proteins, enzymes, and nucleic acids (Nunes-Nesi;Fernie;Stitt, 2010;Taiz et al, 2017). Thus, plants with adequate levels of N have a high chlorophyll content, which can increase Plant height (PHe), number of shoots (NS), stem diameter (SD), number of commercial roots (NCR), total production (TP), and collection index (CI).…”

“…Nitrogen is an essential nutrient and extremely important for plant growth (Taiz et al, 2017). It improves crop production and the uptake of other nutrients (Zuffo et al, 2021;Ullah et al, 2022). Crop productivity is associated with the management of fertilization; 146 kg of potassium (K), 123 kg of nitrogen (N), and 46 kg of calcium were extracted to produce approximately 25 tons of cassava roots per hectare Bezerra, 2003).…”

Side dressing nitrogen fertilization in soybean in association with inoculation

“…For this, investigations on mineral nitrogen in soybean seek to better understand the dynamics between BNF and additional supplementation with nitrogen. Among the various factors investigated, we found studies that associate nitrogen doses with sowing density (FERREIRA et al, 2016;WERNER et al, 2016); supplementary mineral nitrogen with its effects on oil and/or protein contents in grains (HAMAGUCHI et al, 2020;MOREIRA et al, 2017;PRUSIŃSKI, BATURO-CIEŚNIEWSKA, BOROWSKA, 2020;SZPUNAR-KROK et al, 2021); nitrogen supply with seed quality (ZUFFO et al, 2021); as well as those that investigate the dynamics of nitrogen absorption in the initial stages of soybean, in which the BNF is not yet meeting the requirements of the crop (CONCEIÇÃO et al, 2018); in addition to studies on the effects of fixed nitrogen in the subsequent crop (GOSS et al, 2002;ZUFFO et al, 2022); and studies on foliar nitrogen and their effects on carbon and oxidative metabolism (RODRIGUES et al, 2021). Bahry et al (2014) pointed out that, in some edaphoclimatic conditions, nitrogen from BNF is not enough to meet the requirements of the crop and its limitation may compromise the final productivity, evidencing that the application of nitrogen in the reproductive phase of soybean positively influences some yield components.…”