Effect of Different Row Spacing and Sowing Density on Selected Photosynthesis Indices, Yield, and Quality of White Lupine Seeds

Abstract

The use of appropriate plant spacing in the canopy is an important and cost-free agrotechnical factor for increasing seed yield. Proper row spacing and sowing density are important in maintaining adequate plant light, ensuring good physiological processes, and influencing the nutritional status of plants. As a consequence, this leads to better plant productivity while maintaining economic profitability. A four-year field experiment with white lupine was conducted in 2016–2019 at the Experimental Station for Cultivation Assessment in Przecław in southeastern Poland. The factors of the experiment were different row spacing (15 and 30 cm) and sowing density (60, 75, and 90 pcs m−2). Row spacing and sowing density had no significant effect on the yield obtained, the number of pods per plant, and the weight of 1000 seeds of white lupine. There was also no effect of experimental factors on nodulation and chlorophyll fluorescence parameters (Fv/Fm, Fv/F0, PI, and RC/R). The use of wider row spacing (30 cm) and the lowest sowing density (60 pcs m−2) resulted in the highest chlorophyll content. For the LAI index, the highest value was found at a row spacing of 15 cm. However, lower plant density per unit area had an effect on increasing the number of seeds per pod and seed weight per plant, which was associated with better conditions for plant growth. It was shown that greater competition between lupine plants in the canopy increased the height of the first pod set without affecting their height.