The Effect of Irrigation and Nitrogen Fertilization on the Soybean Seed Yield, With a Correlation to the Protein and Oil Concentration

Abstract

The paper presents the result of a triennial field experiment (2013‒15), aiming to determine the influence of irrigation, nitrogen fertilization, and cultivars, as well as their interactions on the yield and chemical properties of the soybean seeds. Four soybean cultivars (Lucija, Vita, Ika and Tena) of different maturity groups were investigate as a sub‐subplot factor (C). The main plot factor (A - irrigation) resulted in a statistically very significant (P≤0.01) seed yield in all three years, and it was found out by an analysis of variance. The subplot factor (B - nitrogen fertilization) had an impact on the grain yield depending on the research year, while sub‐subplot factor (C-cultivar) significantly affected all examined traits. The factor interactions and their significance varied by the research years. The seed yield achieved in 2013 (3883 kg ha-1) indicated a great importance of all factors’ interaction. The correlations between a seed yield and a protein and oil concentration were determined during the research.

Environment- and Genotype-Dependent Irrigation Effect on Soybean Grain Yield and Grain Quality

“…The current study period was characterized by a variability in meteorological conditions as a result of climate change, resulting in very demanding conditions for crop production in terms of available water for the plants. As expected and previously reported by many authors [13][14][15][16][17]21,27,28], the overall irrigation effect on soybean grain yield was positive but largely depended on the environmental conditions (Table 2). For example, the lack of a significant irrigation effect on the soybean grain yield in the extremely humid A1 growing season was expected because sufficient precipitation makes the irrigation redundant [11].…”

“…For example, the lack of a significant irrigation effect on the soybean grain yield in the extremely humid A1 growing season was expected because sufficient precipitation makes the irrigation redundant [11]. The positive effects of irrigation on the grain yield in the dry A3 growing season with significant differences between the deficit irrigation (A3B2) and the full irrigation treatments (A3B3) (Table 2) were also expected, and similar grain yield responses to irrigation treatments in dry growing conditions were earlier noted by many authors [11,15,16,19]. However, in this research, the irrigation effect on the soybean grain yield was unexpectedly absent in the extremely dry A2 growing season.…”

“…For example, Marković et al [18] noted a significant increase in the soybean yield in average climatic years within deficit irrigation (60-80% of the field water capacity, FWC), while full irrigation (80-100% of the FWC) significantly increased the grain yield compared to deficit irrigation only during the extremely warm and very dry growing conditions. In the same agro-ecological conditions, Galić Subašić et al [15] achieved the highest soybean yield under full irrigation, regardless of the weather conditions. A large number of studies have also examined the impact of irrigation on soybean grain quality.…”

“…As water shortages during this period can have a significant negative impact on yield [10][11][12], maintaining production at its present level or increasing it will require precise irrigation scheduling to increase the yield per unit 2 of 13 of irrigation water applied. The literature shows that not only the irrigation scheduling has an impact on the soybean yield [13][14][15][16][17] but different irrigation strategies as well. For example, Marković et al [18] noted a significant increase in the soybean yield in average climatic years within deficit irrigation (60-80% of the field water capacity, FWC), while full irrigation (80-100% of the FWC) significantly increased the grain yield compared to deficit irrigation only during the extremely warm and very dry growing conditions.…”