An Evaluation of Nitrogen and Phosphorous Efficiency in Sugar Beet Seed Bearing Plants

To assess the effects of different levels of nitrogen and phosphorous on yield and nutrient use efficiency of sugar beet (polygerm seed (Cv. 7233)), this study was carried out in 1999-2001 in Ardabil Agricultural Research Station (Alarough). The experiment contained two factors of: nitrogen in 4 levels (control, 100, 200 and 300 Kg N/ha) and phosphorous in 3 levels (control, 100 and 200 Kg P2O5/ha) in four replications based on a randomized complete block design. Each plot consisted of 8 rows each with a length of 10 meters and interspacing of 65 cm. During the study, Agronomic or Economic (AE), Physiological Efficiency (PE), Apparent Recovery Efficiency (ARE), and Mineral Nutrient Efficiency (MNE) were assessed. Results indicated no significant effects of nitrogen and phosphorous application on crude and saleable seed yield. But application of nitrogen significantly (<0.01) affected the standard and viable seed yield, in a way that control levels until 200 kg/ha had statistically the same viable standard seed yield with the further increase in nitrogen application up to 300 kg/ha leading to a significant decrease in seed yield to 833 kg/ha. Although phosphorous application led to a higher PE as compared with N application (1.269 kg/kg), but of each kilogram addition of phosphorous result in an increase in crude, saleable and viable standard seed yield of only 0.365, 0.590 and 0.460 kg, respectively. PE, as a result of phosphorous application (1.269 kg/kg) was higher than that of nitrogen (0.225 kg/kg), while ARE due to nitrogen application (77.3%) was greater than ARE due to phosphorous application (12.9%) by sixfold