PhD

Detailed studies were conducted in black pepper (var. Panniyur 1) from
1981 to 1985 at the Pepper Research Station, Panniyur and College of
Horticulture, Vellanikkara with a view to induce nutrient deficiency
symptoms by sand culture and to find out the relationships of foliar nutrients
with yield.
Deficiency symptoms of macro-nutrients except Ca and S were first
manifested on the older leaves while that of micro-nutrients on younger
leaves. Symptoms of N deficiency were expressed as uniform yellowing
followed by necrosis whereas purple to bronze yellowing with ash coloured
necrotic areas were the symptoms of P deficiency. Potassium deficiency
symptom was characterized by tip and marginal necrosis which later
progressed to the two-thirds distal portion of the lamina. Calcium deficiency
symptoms appeared as tiny brown necrotic spots on chlorotic area near
margins which later enlarged to form black necrotic areas. Visible symptom
of Mg deficiency was oval interveinal chlorotic area followed by black
necrotic patches. Sulphur deficiency was manifested as uniform yellowing
with brown necrotic spots. There was profound reduction in vegetative
growth due to deficiency of macronutrients. The reduction in shoot growth
and leaf area index was maximum in the case of deficiency of N (56 and 63%
respectively) followed by S (48 and 17% respectively). The reduction in root
growth was quite high due to deficiency of Ca (61%), P (45%) and N (39%).
Interveinal chlorosis was the initial symptom of deficiency of all micro-
nutrients. However, the symptoms were specific to the concerned nutrients.
Iron chlorosis was characterized by the presence of green bands along the
major veins whereas bronze yellow colour of the interveinal areas was the
specific symptom of Mn deficiency. Bronze colour of the entire lamina with
necrotic tips and margins were the symptoms of Cu deficiency. Zinc
deficiency was unique with little leaf and rosetting. Due to B deficiency, the
leaves became large, thick and brittle with orange yellow mottles on upper
surface and grey brown interveinal patches on lower surface. Unlike
macronutrients, there was no marked reduction in vegetative growth due to
deficiency of micro-nutrients except Fe and B which recorded 35 and 22 per
cent reduction respectively, in total dry matter production. Boron deficient
plants registered 18 per cent increase in leaf area index.
The growth of the vine was completely arrested at comparatively early
stage (4.5 months after treatment) due to S deficiency followed by N (6th
month), Fe (7th month), B (12th month), P (13th month) and Cu (14.5 months
after treatment). There was no cessation of growth in the case of deficiencies
of other nutrients.
Visual symptoms of deficiencies were concurred with a marked
reduction in the foliar levels of the concerned elements. Antagonistic effects
among K, Ca and Mg were also observed. In all other cases, deficiency of one
element failed to influence the foliar level of others. The deficiency symptoms
could be recovered by the application of the deficient nutrient element which
provided valid information for the confirmation of the deficiency symptoms.
The foliar levels of macro-nutrients except Ca registered two peaks, one
in June and the other in October while the lowest level was during April. The
nutrients namely Ca, Fe, Mn and Zn, in general showed a decreasing trend
from April to June and thereafter increased and reached maximum level in
December.
Highly significant positive correlations were showed by P, K, Ca and
Mg with yield. The critical level of S was found to be 0.15%. The ‘tentative
critical levels’ suggested for the other elements studied are as follows:
N - 2.1 to 2.4% P - 0.19 to 0.20%
K - 1.8 to 1.9% Ca- 2.8 to 2.9%
Mg - 0.5 to 0.6% Fe - 156 to 169 ppm
Mn - 77 to 88 ppm Zn- 30 to 32 ppm
The two most important nutrient elements which are highly essential
for the production of pepper could be identified as K and P in view of their
high direct and indirect effects on yield.