BIOMASS ALLOCATION AND UPTAKE EFFICIENCIES OF NITROGEN, PHOSPHORUS AND POTASSIUM BY CRYPTOMERIA JAPONICA (L.F.) D. DON VIS-À-VIS NITROGEN FERTIGATION

Abstract

Cryptomeria japonica seeds were sown in polybags (10 x 15 cm) with sterilized riverbed sand in first week of February 2012. Three to five seeds were sown in each polybag. Germinated seeds were thinned out to one seedling polybag^-1 after 3 weeks of their emergence and then treated weekly with ingestad pretreatment nutrient solution for 4 weeks. Pretreated seedlings were fertigated with the following nitrogen levels 0, 3.00, 6.00, 9.00, 12.00, 15.00, 18.00 and 21.00 mg dissolved in 25 mL of water along with fixed levels of P, K, Ca and Mg seedling^-1 week^-1 up to 28 weeks as recommended by Ingestad and Lund (1979). Biomass allocation increased significantly both in shoots and roots with the increase in level of nitrogen fertigation and seedling age. With 21 and 18 mg seedling^-1 of nitrogen fertigation, average shoot and rot dry weight increased about 3.8 and 3.0 times, respectively after 28 weeks compared to control but the effect of both treatment levels remained at par. Nitrogen, phosphorus and potassium content increased significantly with increase in nitrogen fertigation levels by 118%, 127.6% and 67.74%, respectively over control. Nitrogen, phosphorus and potassium uptake efficiencies first decreased followed by gradual increase with the increase in nitrogen fertigation level up to 21 mg seedling^-1. Contrary to this NUE, PUE and KUE decreased with increasing nitrogen fertigation level up to 21 mg seedling^-1.