Effect of source, level of K on chemical composition of potato leaves and tubers:
Nitrogen concentration in the potato leaves was lower than required limits of adequacy
(Router, 1991). The results indicated an increased N concentration in leaves with P and K
application. It increased from 3.55 g 100 g-1 in control treatment to 3.90 g 100 g-1 in P
treatment. It was 4.30 and 4.20 g 100 g-1 in treatments where K was applied at 150 kg ha-1
from SOP and MOP respectively (Table 2). The differences in leaf N concentration
between the applied K sources was non significant. A positive interaction between N and
K in plant system was observed with K application. The N contents in tubers increased
significantly with P application as it was 6% more in NP treatments as compared to alone
N applied tubers and it decreased with K treatment. The P concentration was positively
affected with K application and it remained unaffected in SOP treatment but in case of
MOP, the P concentration positively affected with applied K at both rates. The K
concentration increased with its application in leaves but in tubers it increased slightly.
Zinc concentration decreased in potato leaves as well as in tubers with K treatment. At
higher rate of applied K the Zn concentration was further suppressed in leaves with both
the sources of K and same trend was observed in case of potato tubers. This indicates
antagonistic effect of P and K on the Zn concentration in the plant system. There was no
difference in the nutrient concentration in plants treated with K by different methods.
Results of the study are pretty close to those reported by James et al., (1968).
Effect of source, level and method of K application on potato tuber yield: Pot