International Journal of Horticulture, 2017, Vol.7, No. 31, 288-298
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Absorption of sodium decreased increased with increasing levels of CaCO3 up to 14.9 per cent and increased
thereafter. It increased up to 20.4 per cent on own root and 14.4 on 110R. Dog Ridge roots tended to absorb more
Na up to 10 per cent CaCO3, while own root beyond that level. They were more efficient in restricting the
absorption of Na in the CaCO3 range of 10-20 per cent, while 110R roots at all levels. Both rootstocks were at par
in the absorption of Na in the range of 12-17 per cent (Figure 4). Thus the ability of restricting the absorption of
Na by rootstocks was dependent on the free calcium levels in soil.
Figure 4 Relationship of soil CaCO3 content with nutrient absorption index
3.5 Effect of exchangeable sodium percent in soil
ESP influenced the nutrient absorption on own root only. It influenced the absorption of N, P and K negatively but
Fe positively (Table 2). N absorption decreased steadily with increasing levels of ESP reaching null at 14.5 per
cent on own root and 15.5 on 110R, but increased up to 8 per cent, reducing thereafter, reaching null at 15 per cent
on Dog Ridge (Table 3). Own root were more efficient than the rootstocks up to 6.0 per cent, while Dog Ridge
beyond that (Figure 5). Reduction of N use efficiency could be due to denitrification and volatile losses caused by
poor drainage resulting from high levels of sodium in medium clay soils (Abrol et al., 1988).
Absorption of P decreased steadily with increasing levels of ESP up to 14.1 per cent on own root, but increased up
to 8.23 and 8.15 per cent respectively on Dog Ridge and 110R and reducing thereafter (Table 3). Own root were
more efficient in P absorption up to 7.0 per cent ESP. Dog Ridge was slightly more efficient than the rest between
10 1nd 14 per cent (Figure 5). Low P absorption was attributed to higher pH levels, since positive correlation
between PH and ESP was observed (Gupta et al., 1981).
Potassium absorption increased up to 4.89 and 7.76 per cent ESP respectively on own root and 110R and
reduced thereafter; but reduced up to 10.4 per cent on Dog Ridge increasing thereafter (Table 3). Own root were
more efficient than the rootstocks between 3.5 – 7.76 per cent ESP, while Dog Ridge beyond 11.5 (Figure 5).
Reduction in K absorption could be attributed to the antagonistic effect of Na on K (Fisarakis et al., 2005;
Shikhamany and Sharma, 2008).
