Nitrogen and Zinc on Growth and Nutrient Concentrations in Leaf of Pummelo cv. Kao - thongdee (Citrus maxima (Burm.) Merr

Abstract

Pummelo (Citrus maxima) cultivar Kao-thongdee is an important fruit crop growing in  Pak  Panang   river   basin in  southern   part   of   Thailand. Deficiencies  of  nitrogen  and zinc   were   reported   as  a  main  problem  of  soil  fertility in this   pummelo   growing  area.  Growth   characteristics  of  air-layering  seedlings  of  pummelo   cultivar  Kao-thongdee  in  pots containing   both   nitrogen    and   zinc   deficient  soils were   studied   at  Centre  for   Scientific   and   Technological Equipments   of   Walailak Univesrity, Thasala district, Nakhon Si Thammarat province during May 2008 to October 2009. The experiment was  set  up  in  completely randomized   design   consisted  of  6  replications   and  4  treatments    namely   control,  calcium  nitrate,  zinc   sulphate and  calcium   combine   zinc sulphate. The objectives were to investigate growth and nutrient concentrations in leaf of pummelo. The  results   showed   that  the   calcium  nitrate and   calcium   combing   zinc   sulphate    treated    plants   had chlorophyll    concentrations    in   plant     leaves   at   43.6  and 50.8  mol,    nitrogen    concentrations   in   plant   leaves  at  2.21  and  2.10 %  dry    weight,  vegetative  flushes  at 31.0 and 30.5%, leaf  area   at   2,754  and 2,743 cm², leaves  dry weight at   194  and  193 g,  branches  and  stems   dry   weight  at 310 and  288  and  root   dry   weight  at  153  and  152  g,  respectively  significant    higher  than   the   control   and  zinc sulphate   treatments.  Zinc  concentration  on   the  plant  leaves   in   zinc   sulphate   treatment    at  78.2   mg/kg   had significant    higher    than    other   treatments.