Evaluation of soil test methods for available copper and its critical level in oat (Avena sativa L.)
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Date
2012
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CCSHAU
Abstract
In order to evaluate soil test methods for available copper and its critical level in oat (Avena
sativa L.), laboratory and a screen house experiment was conducted at CCS HAU, Hisar during the
year 2010-11.The results of the study revealed that the effect of copper application on the dry matter
yield of oat increased significantly and varied from 2.88 g pot-1 in control to 3.28, 3.76, 3.52
and 3.47 g pot-1 with application of Cu @ 5, 10, 15 and 20 mg Cu kg-1 soil. Maximum yield of 3.76 g
pot-1 was obtained with application of 10 mg Cu kg-1 soil. In oat plant, increasing level of Cu
application was found to increase Cu content and maximum Cu content of 12.53 mg kg-1 was recorded
with the application of 20 mg Cu kg-1 soil. The uptake of Cu by oat also increased significantly
from 19.12 μg pot-1 in control to 43.85 μg Cu pot-1 with increased level of Cu application upto
20 mg Cu kg-1 soil. Relationship between Bray per cent yield against DTPA-Cu in soil and Cu
concentration in plants indicated critical deficiency level of Cu in soil as 0.30 mg kg-1and for oat plant
it was 11.7 mg kg-1 which was statistically also at par. Post harvest of DTPA-extractable copper in soils
also increased with increasing level of Cu and maximum Cu content of 7.13 mg kg-1 was noticed with
the application of 20 mg Cu kg-1. Among different extractants, AAAc+EDTA at pH 4.6 gave high
amount of copper ranging from 1.00 to 4.19 mg kg-1 with the mean value of 2.62 mg kg -1
while 1N NH4OAc at pH 8.0 extractant gave low amount of copper which ranged from 0.02 to
0.09 mg kg-1 with a mean value of 0.05 mg kg-1.Extractants involving DTPA showed
maximum ability in extracting copper than rest of the extractants. Copper associated with
different fraction was found in the order of: RES > CFeOX > AFeOX > OM > EX > CARB > MnOX.
Extractable copper related negatively with pH and CaCO3, but the values were significantly for DTPACaCl
2 (pH 7.3), 0.1M HCL, 1N NH4OAc (pH 7.0), 0.02M EDTA and Citric Acid (1%). On the other
hand, it was significantly and positively related with that of organic carbon and clay content. Out of the
ten extractants, evaluated for plant available Cu, only DTPA-CaCl2 (pH 7.3), 1N NH4OAc (pH 8.0) and
AAAc+EDTA (pH 4.6) were correlated significantly with Cu uptake by oat crop. Among these three
extractants, 1N NH4OAc (pH 8.0) showed highest correlation (r = 0.593**) followed by AAAc+EDTA
(pH 4.6) and DTPA-CaCl2 (pH 7.3), thereby indicating that 1N NH4OAc (pH 8.0) extractant is also
equally good for predicting Cu availability for oat crop. On the basis of stepwise regression analysis,
the residual fraction was found to contribute very little whereas exchangeable and carbonate bound
fraction contribute maximum to the availability of Cu to oat plant.
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Biological phenomena, Marketing, Participation, Technological changes, Land resources, Markets, Research methods, Crops, Manpower, Productivity