Soil Fertility and Nutrient management (1+1)

Consumption of Nitrogen by plants

• Plants absorb the N mostly in nitrate (NO3-) form or in ammonical (NH4+) form by some plants. Plants usually absorb the N more during active growing period, but they do not always absorb it at the same rate. The amount of nitrogen absorbed is at a maximum when the plants are young and gradually declines as the plants age. Plants can absorb extra nitrogen when it is available and store it to be used later if needed.
• An oversupply of N generally produces dark green, succulent, vegetative growth. In such cases there will be a decline in seed production of grain crops, fruit production in tomatoes and some tree crops. In sugar beets, sugar content decreases and in and potatoes, tubers become watery. The negative effects of too much of N on growing plants can be lessened if the P and K supplies are adequate.
• The average utilization of applied N by crops is around 50 percent but with proper nitrogen management strategies the efficiency as high as 80 % or more can be increased. Low N use efficiency may be attributed to various losses such as Volatilization of Ammonia in alkaline soil, Denitrification of Nitrate ions in flodded soil, Leaching loss of Nitrates in coarse textured soil, soil erosion/run off and ammonium fixation in clay lattices.