Grain yield, efficiency and the allocation of foliar N applied to soybean canopies

Abstract

Soybean [Glycine max (L.) Merr.] grain yield is closely associated with the level of optimal nitrogen (N) supply, especially during the reproductive stages. Foliar fertilization with low rates of N have been considered as a strategy for furnishing additional N and enhancing grain yields. Field studies using 15 N tracer were conducted over two growing seasons to investigate the impact of foliar N fertilization on grain yield, plant N content, the amount of N derived from fertilizer (NDFF) and N recovery efficiency (NRE). Four foliar N rates (0, 1300, 2600 and 3900 g ha-1) were supplied by two equal split applications at the R1 and R3 stages. Foliar N fertilization of soybean canopies did not affect grain yield, grain N content, shoot N content nor plant N content. Total NDFF was increased from 0.7 to 2.0 kg ha-1 across the N rates. Nonetheless, NRE was unaffected by foliar N fertilization, which averaged 53 %. Soybean plants allocated the same amount of N fertilizer to both grains and shoots. No significant effects of low rate foliar N fertilization were registered on soybean grain yield nor plant N content, despite considerable N fertilizer recovery by plant organs.

Response of mungbean to foliar application of nitrogen and micronutrients during reproductive stages

“…In contrast, the lowest yield contributing characters and yield were recorded in T1 (control). Several studies (Hamayun et al, 2011;El-Azab, 2016;Oliveira et al, 2019;Bahadri et al, 2020) confirmed that foliar application of N and/or micronutrients increased grain yield in legumes that supported the present experimental results. The effect of variety on yield attributes and yield was significant (table 3).…”

Foliar nitrogen as stimulant fertilization alters carbon metabolism, reactive oxygen species scavenging, and enhances grain yield in a soybean–maize rotation

“…This was an important finding in this study as the concept of stimulant fertilization entails responses in otherwise well‐fertilized crop. Although the foliar application provides an input of N readily available for the soybean and maize plants, the amount supplied is not able to abruptly increase the crop nutrition (Moreira et al., 2017; Oliveira et al., 2019), especially of a highly required macronutrient, as is the case of N. However, the foliar fertilization, in addition to being able to prevent and/or correct nutritional stresses in periods of high requirement of nutrients, can also act as a stimulating fertilizer (Rosolem, 2002), helping the crops to activate plant metabolism, even for a short period of time. Therefore, in this research it is believed that the use of N applied to the leaves is not only an N supplementation for the plants, but also a way to stimulate plants to activate different metabolic processes and convert this metabolism into grain yield.…”

“…With increasing global demand for maize ( Zea mays L.) and soybean [ Glycine max (L.) Merr.] (OECD/FAO, 2020), many studies are evaluating the potential of foliar applications of nutrients to increase grain yield (Moreira et al., 2017; Oliveira et al., 2019). Foliar fertilization increase yields in different ways and can be used in a preventive, corrective, substitute, complementary, or supplementary manner during the reproductive stage, and as supplementary stimulant (Afifi et al., 2011; Cassim et al., 2020; Fageria et al., 2009; Oliveira et al., 2019; Rajaie & Tavakoly, 2018; Rosolem, 2002; Shehata et al., 2019).…”

Calcium and Boron Fertilization Improves Soybean Photosynthetic Efficiency and Grain Yield

“…Foliar fertilization is an alternative for nutritional management, mainly used as a nutritional supplement [ 1 ]. In soybean, foliar nutrient management was common during the reproductive period, when plants have high nutrient requirements due to the high transfer rates of nutrients and sugars for the formation of reproductive structures and, ultimately, grain production [ 2 , 3 , 4 , 5 ].…”