Agriculture Reference
In-Depth Information
all microelements decreased with increasing levels of B in the nutrient supply, and
exerted close connection to the growth response of radish plants. Moreover, Zn/Cu
ratio increased and ratio of Mn/Fe and Mn/Zn decreased, while Fe/Cu exerted
unpredictable trend with increasing B levels. Inoculation with biofertilisers (
Rhi-
zobium
strains) alone or combined with different levels of B increased significantly
the uptake of N, P, K, Fe, Mn, Zn and B by shoot and seeds of peanut in both
seasons as compared with the corresponding treatments without biofertilisers. The
highest values of N, P, K, Fe and Mn uptake by straw and seeds of peanut plants
were obtained by using (200 ppm of B +
Rhizobium
spp.) in two successive seasons,
while the highest values of Zn and B uptake by straw and seeds in both seasons were
obtained by using (300 ppm of B + inoculation with
Rhizobium
; Nadia et al.
2006
).
B interactions (synergism and/or antagonism) can affect plant nutrition under both
deficient and toxic levels (Tariq and Mott
2007
).
There is no significant effect on the residual Fe in the soil when using B fertiliser.
Results suggest that Zn and B fertilisers had no role in the changes of residual Fe
and Mn in the soil relative to the normal levels, and other factors are operative on
the accumulation of residual Fe and Mn in the soil relative to its normal levels. The
effect of Zn and B interaction on the residual Fe and Mn in the soil was insignificant
(Aref
2010
).
Our findings showed that different level of B applied to the groundnut plant
affect uptake of nutrients in an irregular fashion. Interactions between nutrients and
applied B indicted uptake of N, P, K, Mg, Mn, Zn and Fe are indirectly dependent
on increasing supply of B resulting in increasing NUE and NDS, but at a certain
level. Our recent observations suggested that at 1 kg ha
1
B level, NUE of
groundnut plant was higher in terms of absorption of mineral nutrients compared
to the 0.5 kg ha
1
B level. At the 2.0 kg ha
1
B level, groundnut varieties showed
decreases in nutrients uptake capacity, resulting in decreases in NUE. Increases in
supply of nutrients may affect nutrient uptake capacity of plants, which was
confirmed when levels of absorbed macro- and micronutrients in groundnut plants
at 2.0 kg ha
1
B supply were determined. At 0.5 and 1.0 kg ha
1
B, NDS in
groundnut plants was higher. NDS was improved in both varieties of groundnut at
1.0 kg ha
1
B supply. Higher levels of B might be exerting antagonist effects on
uptake of nutrients, which might be affecting NUE and NDS to groundnut plants.
Observations of nutrient uptake capacity of groundnut plants in all three conditions
(limiting, sufficient and toxic) strongly suggested that 1.0 kg ha
1
B improved NUE
and NDS in groundnut plants. Despite substantial literature, the mechanism of B
interaction with other nutrients still remains unclear and needs more investigation
in terms of improvement in NUE and NDS. NUE is usually studied for only one
nutrient and improving NUE for any one nutrient may affect the NUE of other
nutrients; this is still a question of interest.
