POTASSIUM DYNAMICS IN SOILS UNDER COTTON BASED CROPPING SYSTEM OF NORTH KARNATAKA
Loading...
Date
1999-08-30
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
UNIVERSITY OF AGRICULTURAL SCIENCES GKVK BANGALORE
Abstract
Seventy two soil samples from eigtJiteen prollles belonging to order Vertisol
under cotton based cropping system of Nortli Kamataka were collected to
investigate distribution of forms of potassium, K content in soil textural fractions, K
fixation and release characteristics and Quantity-Intensity ( Q/1 ) parameters of
potassium in these soils. The range in contents of various forms of potassium in the
soil profiles were 8.00 to 20.25 ppm, 102 to 285 ppm, 445 to 1125 ppm, 0.454 to
1.328 per cent, 0.523 to 1.460 per cent and 306 to 770 kg K2O ha-1 of water
soluble, exchangeable, non-exchangeable, lattice, total and available potassium,
respectively. The average contribution of water soluble, exchangeable,nonexchangeable
and lattice K to total soil K varied from 0.09 to 0.30, 1.21 to 3.33,
5.97 to 11.90 and 85.00 to 92.30 per cent, respectively. The potassium content in
coarse sand, fine sand, silt and clay ranged from 0.15 to 0.42 , 0.32 to 1.19, 0.46 to
1.33 and 0.63 to 1.65 per cent, respectively. The mean potassium contribution
from coarse sand, fine sand, silt and clay towards total soil K were 3.85,5.36,22.86
and 67.93 per cent, respectively. The K fixation capacity of surface soils varied
from 0.78 to 1.34 c.mol (p t-)kg-1. The per cent K fixation varied from 15.60 to
27.20. The cumulative K release, step-K and constant rate K values ranged from
537 to 1157, 400 to 747 and 13 to 44 ppm, respectively. The Q/I parameters
viz.,AReK ,Kl ,Kx, Kq ,PBCK and - G values ranged from 1.45 to 3.10(ML-1)
10-3 0.80 to 1.30, 0.50 to 0.76, 0.30 to 0.54 c.mol (p+) kg-1/ ( ML -1 ) and
3421 to 3871 cal. respectively. The soils under present study were high in
available and step-K. However, the crops may face deficiency of potassium due to
lower immediately available K( AReK ). Hence, K fertilization is necessary to
available K to cotton crop
Description
Keywords
null