Effect of planting distance and nitrogen fertilizer on the yield and physiological traits of Pinto bean (Phaseolus vulgaris L.)

To investigate the influence of planting distance and nitrogen fertilizer levels on yield and yield components of common bean (Phaseolus vulgaris L.) cultivars, a study was conducted in 2021 at the educational and research farm of the Daikundi Higher Education Institute. Employing a Randomized Complete Block Design (RCBD) Split-Plot arrangement with 2 replications, the research examined 4 planting distances (10, 15, 20 and 25 cm) as the primary factor and 3 nitrogen fertilizer levels (0, 50 and 100 kg N/ha) as the secondary factor. The analysis revealed that the highest seed yield for common beans, averaging 1220 kg/ha, was obtained with a planting distance of 25 cm and a nitrogen application rate of 100 kg N/ha. Conversely, the lowest yield, averaging 773 kg/ha, was recorded at the narrowest planting distance of 10 cm without nitrogen fertilization. Agronomic and physiological traits, such as increased total dry matter and leaf relative water content, were observed to positively correlate with grain yield in pinto beans. In contrast, reduced planting row spacing adversely affected seed yield, harvest index, phonological stages and other common bean characteristics, particularly at seeding stage. However, the application of 100 kg N/ha significantly improved certain measured traits. Based on these findings, the study recommends a combined agronomic practice of applying 100 kg N/ha and maintaining a planting row distance of 25 cm for optimal management of common bean crops in the Nili center of Daikundi province.