Legume Genomics and Genetics 2024, Vol.15, No.6, 280-290 http://cropscipublisher.com/index.php/lgg 281 density significantly increased soybean seed yield by 22.8% compared to normal planting density (Xu et al., 2021). Conversely, low-density planting reduces competition among plants for resources such as water, nutrients, and light, which can improve individual plant growth and nodulation parameters (Luca et al., 2014). Moderate density strikes a balance between these two extremes, aiming to optimize both yield and resource use efficiency. Different planting densities can also affect the uniformity of plant distribution. Uniform plant spacing at high densities has been shown to reduce plant-to-plant variability and increase overall yield by 9.5% compared to non-uniform spacing (Xu et al., 2021). This highlights the importance of not just the number of plants but also their spatial arrangement in the field. 2.2 Methods of adjusting plant density Adjusting plant density in soybean cultivation can be achieved through various methods, primarily by altering the spacing between plants and rows. Row spacing is a critical factor; narrower rows can increase canopy closure and light interception, which are beneficial for photosynthesis and yield. For example, a study found that reducing row spacing to 15 cm improved yield structure parameters and chlorophyll fluorescence in soybean plants (Table 1) (Jańczak-Pieniążek et al., 2021). On the other hand, wider row spacing can reduce competition for resources but may lead to lower overall yield. Table 1 Effect of row spacing and sowing densityon seed yield and structural yield components of soybean (Adopted from Jańczak-Pieniążek et al., 2021) Factor Seedyield (tha-1) Number of pods per plant (pcs.) Number of seeds per plant (pcs.) Seed weight per plant (g) Thousand seeds weight (g) Row spacing (cm) (S) Sowing density (pcs/m-2) (D) 15 70 4.84a±0.54 27.6b±9.5 57.0c±10.6 8.23c±1.27 146a±18 90 4.95a±0.48 20.4ab±4.5 45.1ab±7.4 7.61c±0.97 173b±39 110 4.91a±0.42 19.9a±9.0 42.9a±8.7 6.01ab±1.05 142a±18 30 70 4.73a±0.48 24.6ab±8.6 50.8bc±9.6 7.82c±0.99 157a±23 90 4.874a±0.40 23.6ab±5.8 45.4ab±6.9 6.65b±0.80 148a±17 110 4.85a±0.35 18.5a±5.4 41.0a±9.0 5.75a±1.17 141a±12 15 - 4.90a±0.47 22.6a±8.5 48.3a±10.8 7.28b±1.43 154a±30 30 - 4.82a±0.41 22.2b±7.1 45.7a±9.3 6.74a±1.29 148a±19 - 70 4.78a±0.50 26.1b±9.0 53,9b±10.4 8.02c±1.13 151b±21 - 90 4.91a±0.43 22.0ab±5.3 45.2a±7.0 7.13b±1.00 161c±32 - 110 4.88a±0.38 19.2a±7.3 42.0a±8.7 5.88a±1.10 141a±15 Year (Y) 2017 4.51a±0.30 20.1a±4.2 42.64a±9.1 5.98a±1.35 140a±5 2018 5.33c±0.29 19.3a±5.8 42.9a±6.1 7.31b±0.92 173b±30 2019 4.74b±0.22 27.9b±9.4 55.5b±8.8 7.74b±1.22 140a±14 Mean 4.86±0.44 22.4±7.8 47.0±10.0 7.01±1.38 151±25 S ns ns ns ** ns D ns ** *** *** *** Y *** *** *** *** *** S×D ns ns ns ns *** S×Y ns ns ns ns ns D×Y ns ns ** ns ** S×D×Y ns ns ns ns * Table caption: The results are presented asmean values±standarddeviation.Different letters in the same column indicate significant differences p=0.05), according to ANOVA followed by Tukey'stest.*,**，*** and ns mean ≤005, ≤0.01, <0.001, and not signifiant, repectively (Adopted from Jańczak-Pieniążek et al., 2021) The spacing between individual plants within rows is another method to adjust plant density. Uniform spacing can minimize competition and improve resource use efficiency. Research has shown that uniform plant distribution significantly increases canopy light interception and dry matter accumulation, leading to higher yields (Xu et al., 2021). Factors influencing the choice of plant density and spacing include soil fertility, water availability, and the specific soybean genotype being cultivated. For instance, different genotypes may respond differently to plant density adjustments, with some showing significant yield increases at higher densities while others may not (Gan et al., 2002; Wang et al., 2024).
RkJQdWJsaXNoZXIy MjQ4ODYzNA==