The Combined Effect of Drought Stress and Nitrogen Fertilization on Soybean

Abstract

Soybean is one of the most important crops worldwide; however, its production and produced seed quality are challenged by the increasingly reported drought waves because of its relative susceptibility to drought stress conditions. Nitrogen (N) is a major macronutrient that has distinctive influence on soybean, especially if applied in correct rates. Moreover, N has an additive importance under drought stress conditions. An experiment was carried out in Debrecen, Hungary in 2017, 2018, and 2019 to investigate the sole and the combined effects of N application under different irrigation regimes on soybean physiology, yield, and its components in addition to the quality of the produced yield. Results showed that the morpho-physiological traits, in addition to the yield component traits were influenced by both fertilization rates and irrigation regimes. Most importantly, high N rate is not recommended with the absence of drought conditions as, compared to low rate, it decreased flower and pod number per plant, plant height, and seed yield. On the other hand, high N rate enhanced most traits under drought stress conditions. 100-seed weight had the highest correlation with yield, followed by flower and pod number per plant, plant height, and Normalized Difference Vegetation Index (NDVI).

Effect of Deficit Irrigation and Reduced N Fertilization on Plant Growth, Root Morphology and Water Use Efficiency of Tomato Grown in Soilless Culture

“…This structural change in roots may have occurred due to reallocation of assimilates from shoot to root by plants under water stress, which resulted in decreased shoot growth and increased root system traits such as root length, root surface area, and root volume under reduced irrigation, as water is the main driver of resource allocation [28]. Moreover, N provided additive importance under water stress [29]. This could be because more photosynthetic products become conveyed to the root system under water stress, which improves root growth and nutrient and water absorption by enhancing root length, and finer root and deeper root spreading in the rootzone [30].…”

Effectiveness of a Complex Fertilisation Technology Applied to Zea mays, Assessed Based on Normalised Difference Vegetation Index (NDVI) from Terra Moderate Resolution Imaging Spectroradiometer (MODIS)

“…Higher values of NDVI, linked to fertilisation and observed during dry periods, were reported by other researchers in the context of maize [35] and wheat cultivation [36]. Moreover, positive effects of fertilisation with N on the values of NDVI related to soybean plants during dry periods were demonstrated by Basal and Szabó [37].…”

Nitrogen Uptake from Different Sources by Non-GMO Soybean Varieties

“…Literature reports indicate that drought is one of the factors which hinder soybean development and yielding [35]. Water shortages lead to reduced plant height [36], particularly when they occur at the stage of shoot formation. Newark [37] and El Kheir et al [38] have found that insufficient precipitation at this stage may reduce plant height by about 30% to 70% [39].…”