PhD

A laboratory cum field experiment was conducted to study the effect of S
and B on the growth, yield and quality of sesame var. Thilarani and to standardize
the foliar diagnosis of these elements in Onattukara sandy loam soil. The study
included an incubation study and two field experiments. The treatments
comprising the different levels of S and B laid out in 42factorial RBD. The
treatments were T1(S0B0), T2(S0B1), T3(S0B2), T4(S0B3), T5(S1B0), T6(S1B1),
T7(S1B2), T8(S1B3), T9(S2B0), T10(S2B1), T11(S2B2), T12(S2B3), T13(S3B0),
T14(S3B1), T15(S3B2), T16(S3B3). The different levels of S were S0 (0 kg ha-1), S1
(7.5 kg ha-1), S2, (15 kg ha-1) and S3 (30 kg ha-1) and B0 (0 kg ha-1), B1(2.5 kg ha-
1), B2 (5 kg ha-1) and B3 (7.5 kg ha-1).
The incubation study was conducted at College of Agriculture, Vellayani
to understand the dissolution and release pattern of S and B from their sources
gypsum and borax respectively in Onattukara sandy soil.
The results revealed that the release of S and B was maximum at the 30th
DOI. Increasing levels of S and B has a positive influence on the S content of the
soil. T16 (S3B3) recorded the highest value at all the sampling stages for S whereas
in the case of B, the treatment combinations which received B at the highest levels
in combination with S3 or S2 showed the highest value.
The field experiments were laid out at ORARS, Kayamkulam in 42
factorial RBD having two replications using Thilarani as the test crop. It was
observed that application of S and B favourably influenced the yield and yield
attributes of sesame. T16 was found to be the treatment which gave the highest
grain yield and oil yield in both the years and was found to be on par with T14
(S3B1). S3 was the superior S level. As for the different levels of B, B1 can be
inferred as the best level.
The content of saturated fatty acids such as palmatic and stearic acid
showed a decreasing trend with increasing levels of S and B whereas the content
of the unsaturated fatty acids showed an increasing trend. The quality attributes of
oil such as acid value, iodine value and saponification value was also studied and
it was found that there is a decreasing trend with regard to acid and saponification
value and an increasing trend for iodine number. The grain protein content also
showed an increasing trend with the increase in rate of application of S and B.
Regarding the content and uptake of N, P, K, S, B, Fe, Mn, Cu and Zn, a
favourable influence for the different levels of S and B was recorded. Results
regarding the S and B use efficiency and their apparent recovery showed that with
increase in levels of S, an increasing trend was observed for S. In the case of B,
increase was noticed up to B1 (2.5 kg ha-1) and there after showed a decreasing
trend.
This positive influence was also reflected on the available nutrient status
of the soil such as organic carbon content, available N, P, K, S, B and DTPA
extractable micronutrients.
Correlation studies conducted to standardize the part and stage of sampling
for the foliar diagnosis of sesame showed petiole at 30 DAS and 20 DAS in the
case of S and B respectively. The same stages were found for the soil sampling
also for both the nutrients.
The critical nutrient level in the part standardised for these two nutrients
were standardized using the graphical method proposed by Cate and Nelson
(1965). In the case of S, it had been standardized as 0.088 per cent and for B, it
had been found to be 28 mg kg-1. The critical nutrient level in soil was also
estimated using the scatter diagram technique and was found to be 23 kg ha-1 at 30
DAS for S and 1.4 ppm at 20 DAS for B.
Hence the application of S @ 30 kg ha-1 and B @ 2.5 kg ha-1 could
faourably enhance growth of sesame with regard to the growth characters, yield
and yield attributes and the quality aspects. Moreover, analysis of the plant and
soil samples at the critical stages fixed for the respective nutrients will provide the
necessary data for the sustainable management of the crop in Onattukara sandy
loam soil.