TITLE:
Evaluation of Tropical Legume Cover Crops for Copper Use Efficiency
AUTHORS:
Nand Kumar Fageria, Virupax Chanabasappa Baligar
KEYWORDS:
Root Length; Root and Shoot Dry Weight; Specific Root Length; Cu Use Efficiency
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.5 No.9,
April
4,
2014
ABSTRACT: Cover crops are
important components of cropping systems due to their role in improving soil
quality. Lack of adequate levels of soil micronutrients prevents the success of
cover crops in highly weathered tropical soils. A greenhouse experiment was
conducted with the objective to evaluate copper use efficiency of nine tropical
legume cover crops. The copper levels used were 0, 5, 10 and 20 mg Cu kg-1 of soil. Shoot dry weight, maximum root length and root dry weight
significantly increased in a quadratic fashion with increasing soil Cu levels
in the range of 0 to 20 mg kg-1 soil. Cu x cover crops interactions
for shoot dry weight, root dry weight, maximum root length and contribution of
root to the total dry weight were significant, indicating different responses
of cover crops with the variation in soil Cu levels. Overall, maximum shoot dry
weight was obtained with the application of 13 mg Cu kg-1. Similarly,
maximum root dry weight and maximum root length were obtained with the
application of 12 and 14 mg Cu kg-1 of soil. Root dry weight and
maximum root length were significantly and positively related to shoot dry
weight, indicating that a vigorous root system is important for improving
productivity of cover crops grown on Brazilian Oxisols, especially where
deficiency of micronutrients such as Cu exists. The Cu concentration in the
plant tissue decreased in a quadratic fashion whereas, Cu uptake increased with
increasing Cu application rate from 0 to 20 mg kg-1 soil. There was
a significant variation observed in Cu use efficiency among cover crop species.
Increasing applied Cu levels significantly increased soil pH and Mehlich 1
extractable soil Cu, Zn, Mn and Fe concentrations in the soil solution.