MSc.

The research programme entitled “Relative efficiency of soil and foliar applied
nutrients in irrigated rice of Palakkad” was conducted in the farmer’s field,
Thathamangalam, Palakkad during Mundakan season October 2011- February 2012 to
compare the efficacy of soil and foliar applied nutrients especially magnesium, zinc and
boron. The treatments included package of practices recommendation for rice manuring
(POP NPK+FYM), NPK alone as in the package of practices recommendation (POP
NPK), soil test based nutrient application +FYM, soil application of MgSO4 @ 40 & 80 kg
ha-1, ZnSO4 @ 20 & 30 kg ha-1, Borax @ 10 & 20 kg ha-1; foliar spray of MgSO4 @ 0.5 &
1%, ZnSO4 @ 0.5 & 1% and Borax @ 0.25 & 0.5% and an absolute control. Soil
application of Mg, Zn and B were done as basal and foliar application were given at 20
and 40 DAT of rice as per the treatments.
The growth characters of rice such as plant height, number of tillers, LAI and dry
matter production were significantly improved by the application of MgSO4, ZnSO4 and
borax along with POP NPK treatment. The application of POP NPK inclusive of FYM
also resulted in noticeable improvement in growth characters. The height, number of
tillers and dry matter production were low in the treatments which received soil test based
nutrient application. The foliar application of 1% MgSO4 resulted in higher number of
productive tillers. The higher level of borax either as soil application or as foliar spray had
depressing effect on crop growth characters. The application of MgSO4, ZnSO4 and borax
showed significant increase in chlorophyll content at 60 DAT.
MgSO4 application either as soil or as foliar spray has significantly influenced the
panicles/hill, spikelets/panicle and 1000 grain weight. Lower dose of Zn (either soil
applied or foliar) also positively influenced all the yield attributing characters. Borax at
lower level of foliar spray resulted in the highest percentage of filled grain. The
application of POP NPK +FYM positively influenced all the yield attributing characters.
The soil application of MgSO4 at 80 kg ha-1 or at 1% foliar spray resulted in an increased
yield over the POP NPK alone. With regard to zinc, foliar spray at the lower level of 0.5%
was significantly superior to its higher concentration (1%) or its soil application @ 20 or
30 kg ha-1. The soil application of borax at 10 kg ha-1 or foliar spray at 0.25%
concentration resulted in more than 7 t yield per ha. Higher dose of B (20 kg ha-1) either
as soil application or as 0.5% foliar spray was found to be not effective and reduced the
yield. Soil test based nutrient application together with FYM resulted in an almost 1 t less
grain yield than that of POP recommendation possibly due to the application of an
estimated lower N rate. Similar or higher BC ratios were observed for secondary or
micronutrients applied treatments than POP recommendation. The BC ratios were
markedly increased when these nutrients were foliar applied at desired concentrations.
The nutrient contents of rice plants were also influenced by the application of
MgSO4, ZnSO4 and borax along with POP NPK. The soil application of MgSO4 @ 80 kg
ha-1 and foliar spray @1% increased the content and uptake of Mg. The Zn content was
higher in 1% foliar spray of ZnSO4 and the application of ZnSO4 either as soil or as foliar
significantly influenced the uptake of Zn. In the case of B, the soil application of 10 kg
borax ha-1 recorded significantly higher B content and the foliar application of 0.25 %
borax improved the B uptake. A higher content of nutrients together with higher yield
contributed to the higher uptake of nutrients. The application of POP NPK+FYM also
recorded significantly high content of nutrients and uptake.
The application of MgSO4, ZnSO4 and borax along with POP NPK significantly
influenced the pH, EC, OC and available nutrients of soil after the experiment. The status
of available N and K2O remained almost constant after the experiment. But the P2O5
content got reduced. The application of ZnSO4 and borax increased the status of Zn and B
in soil. Available Mg was more or less similar after the experiment, compared to the
initial content.