MSc

he study entitled “Nutrient scheduling for upland rice intercropped in
coconut” was undertaken during the period 2016-2018, at College of Agriculture,
Vellayani, Thiruvananthapuram, Kerala, with an objective of optimizing the
nutrient schedule for upland rice intercropped in coconut and to assess the impact
of foliar application of Zn and B on growth and yield.
The field experiment was carried out at Coconut research Station,
Balaramapuram, Thiruvananthapuram district, Kerala, during Kharif 2017 (June to
October 2017). The design adopted was randomized block design and the
treatments included four nutrient levels, viz., n1-60:30:30 kg NPK ha-1 , n2 -
70:30:35 kg NPK ha-1, n3-90:30:45 kg NPK ha-1 and n4-120:30:60 kg NPK ha-1 and
four different schedules of nutrient application viz., s1 - N in three equal splits (15
DAS, active tillering and panicle initiation stage) + K in two equal splits (15 DAS
and panicle initiation stage) and P as basal, s2 - N and K in three equal splits (15
DAS, active tillering and panicle initiation stage) and P as basal, s3 - s1 + zinc
sulphate (0.2 per cent) + sodium borate (0.04 per cent) as foliar spray at 45 DAS
and s4 - s2 + zinc sulphate (0.2 per cent) + sodium borate (0.04 per cent) as foliar
spray at 45 DAS. The variety used for the study was Prathyasa (MO-21).
Results of the experiment revealed that nutrient levels and schedule of
nutrient application had significant effect on growth parameters at harvest stage.
Among the nutrient levels, NPK @ 90:30:45 (n3) and 120:30:60 kg ha-1 (n4) and
among the schedule of application, the treatments with foliar spray of 0.2 per cent
zinc sulphate and 0.04 per cent sodium borate at 45 DAS (s3 and s4) recorded higher
number of tillers m-2, LAI at 40 and 60 DAS and dry matter production at harvest
stage.
The total chlorophyll content was the highest in n4 (NPK @ 120:30:60 kg
ha-1). Application of N in three equal splits, K in two equal splits and P as basal
along with the foliar spray of 0.2 per cent zinc sulphate and 0.04 per cent sodium
borate at 45 DAS (s3) recorded higher total chlorophyll content as well as
chlorophyll a and b content.
The treatment receiving higher levels of N and K i.e., NPK @ 120:30:60 kg
ha-1 (n4) and 90:30:45 kg ha-1 (n3) recorded higher crop growth rate and relative
growth rate. Among the schedule of nutrient application, the treatments with the
foliar spray of zinc sulphate and sodium borate at 45 DAS (s3 and s4) recorded
higher values.
Filled grains panicle-1, grain weight panicle-1 and sterility percentage were
significantly influenced by the nutrient levels. Higher values for yield attributes
were recorded in n3 (NPK @ 90:30:45 kg ha-1). Among the schedule of nutrient
application, treatments with foliar spray of 0.2 per cent zinc sulphate and 0.04 per
cent sodium borate at 45 DAS (s3 and s4) resulted in the better expression of yield
attributes.
The higher levels of N and K (n3 and n4) recorded higher N, P, K and Zn
uptake by crop. Among the schedule of nutrient application, higher values of N, P,
K, Zn and B uptake were registered in treatments with the foliar spray of 0.2 per
cent zinc sulphate and 0.04 per cent sodium borate at 45 DAS.
With the incremental dose of N and K, the organic carbon content,
available N, P and K status of post-harvest soil were found to increase. Available
N, P and K status of post-harvest soil was significantly influenced by the schedule
of nutrient application. However, available Zn and B status of the soil was found
non-significant.
Application of NPK @ 90:30:45 kg ha-1 (n3) recorded the highest grain yield
(3.00 t ha-1) and straw yield (4.15 t ha-1) and among the nutrient schedule, N in three
equal splits, K in two equal splits and P as basal along with foliar spray of 0.2 per
cent zinc sulphate and 0.04 per cent sodium borate at 45 DAS (s3) recorded the
highest grain yield. Interaction between nutrient levels and schedule of nutrient
application was found significant and the highest grain yield (3.25 t ha-1) was
recorded in n3s3 (NPK @ 90:30:45 kg ha-1 applied as N in three equal splits, P as
basal and K in two equal splits along with foliar spray of 0.2 per cent zinc sulphate
and 0.04 per cent sodium borate at 45 DAS).
The highest crude protein content was registered in n4 (NPK @ 120:30:60
kg ha-1). However, lower nutrient levels recorded higher starch content. Foliar
spray of 0.2 per cent zinc sulphate and 0.04 per cent sodium borate at 45 DAS
enhanced the crude protein and starch content of the grain.
Nutrient level n3 (NPK @ 90:30:45 kg ha-1) recorded the highest B: C ratio
(1.49) and net return (₹ 29, 978 ha-1). Among the nutrient schedule, net return and
B:C ratio were the highest in s3 (N in three equal splits, K in two equal splits and P
as basal along with foliar spray of 0.2 per cent ZnSO4 and 0.04 per cent sodium
borate at 45 DAS). Interaction effect was also found significant with the treatment
combination n3s3 recording the highest net return and B: C ratio of ₹ 35, 637 ha -1
and 1.57, respectively.
The leaf folder incidence was the lowest in n1 (NPK @ 60:30:30 kg ha-1)
and among the schedule of nutrient application, the treatments receiving half the
dose of K at 15 DAS (s1 and s3) recorded lower incidence of leaf folder.
From the results it was concluded that NPK @ 90:30:45 kg ha -1 applied as
N in three equal splits (15 DAS, active tillering and panicle initiation stage), P as
basal and K in two equal splits (15 DAS and panicle initiation stage) along with
foliar spray of 0.2 per cent zinc sulphate and 0.04 per cent sodium borate at 45 DAS
(n3s3) can be recommended for getting higher yield in upland rice intercropped in
coconut.