Abstract:
To find out the optimum N/P ratio (applied as basal or as basal and foliar application) for maximum yield of soybean crop under rainfed situations a field experiment was conducted during
kharif 2015. The experiment consists of 13 N/P fertilizer ratios and levels. Foliar application of nitrogen (N) was taken in the form of urea @ 2.00 % at initiation of flowering (i.e., in the treatment T
4) or at initiation of flowering and 15 days after first spray (i.e., in the treatments from T
5 to T
13). At 30 and 60 DAS, the treatment receiving N/P fertilizer ratio of 0.70 produced taller plants (24.55 and 64.67 cm) as compared to control (20.01 and 55.93 cm) and potassium level alone (21.59 and 58.63 cm) respectively. At 60 DAS, the treatment receiving N/P fertilizer ratio of 0.70 recorded higher leaf area plant
-1 (12.62 dm
2 plant
-1) as compared to control (6.82 dm
2 plant
-1) and potassium level alone (6.96 dm
2 plant
-1). The balance after the harvest of soybean was the highest (164.23 kg ha
-1) in treatment T4 receiving, while the lowest (88.07 kg ha
-1) balance was observed in treatment T5
i.e.N/P ratio of 0.70. However, the apparent gain or loss in the available nitrogen was to extent of 188.26 kg ha
-1 in treatment T5 receiving N/P ratio of 0.70. The maximum uptake of phosphorus (27.93 kg ha
5) was observed in treatment T6 receiving N/P ratio of 0.70. The expected phosphorus balance after the harvest of soybean was highest (91.33 kg ha
-1) in treatment T3.