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A field experiment entitled “Enhancing grain yield and quality through soil
amelioration and foliar nutrition in rice (Oryza sativa L.) in Vaikom Kari soils” was
conducted in a farmer's field at Vechoor, during puncha season of 2020. The objectives
were to augment the yield and quality of rice in Vaikom Kari soils through soil amelioration
practices for managing soil acidity, and to supplement nutrition at panicle initiation stage
through foliar application of K and micronutrients.
The field experiment was laid out in Randomized Block Design. The effect of soil
amelioration on soil parameters and growth characters was assessed in simple RBD with
three treatments and fifteen replications. The treatments were: no dolomite (T1), application
of ordinary dolomite basally and at 30 DAS (T2) and application of granulated dolomite
basally and at 30 DAS (T3). The effect of soil amelioration and foliar nutrition on yield and
yield attributes, and plant nutrient content and uptake were analysed in factorial RBD with
two factors. Factor A consisted of three levels of dolomite application, D0, D1 and D2,
similar to treatments mentioned above (T1, T2, and T3), and factor B consisted of five levels
of foliar nutrition at PI stage: without foliar application (N0), foliar spray of 1% KNO3 (N1),
foliar spray of 1% K2SiO3 (N2), foliar spray of 1% KNO3 + 0.5% micronutrient solution
(N3) and foliar spray of 1% K2SiO3 + 0.5% micronutrient solution (N4). The medium
duration rice variety Uma (Mo 16) was used for the study.
Analysis of experimental results indicated that treatments had significant effect on
growth characters, yield and yield attributes, soil nutrient content, and plant nutrient content
and uptake in grain and straw as compared to control. Application of granulated dolomite
(D2) produced taller plants with higher LAI at PI and harvest stages, and the highest number
of tillers at both maximum tillering and PI stages. The same treatment recorded the highest
grain yield (6.79 t ha-1
), straw yield (8.78 t ha-1
), total dry matter production
(15.05 kg ha-1
), productive tillers (564.38 m-2
), total grains per panicle (85.93), thousand
grain weight (28.35 g), and percentage of filled grains (89.32%). Application of
1% KNO3 + 0.5% micronutrient solution at PI stage (N3) resulted in the highest grain yield
(6.76 t ha-1
) which was on par with all other treatments except the treatment without foliar
nutrition, and the highest straw yield (8.91 t ha-1
) and thousand grain weight (28.56 g) were
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obtained with application of 1% KNO3 alone at PI stage (N1). The interaction of soil
amelioration and foliar nutrition did not show any influence on yield and yield attributes.
Soil analysis was carried out at PI and harvest, and soil amelioration practices had
significant effect on pH, EC, OC and all available macro and micronutrient contents in the
soil except Zn and Cu. Available N and P contents in the soil at harvest stage were also not
influenced by the treatments. Addition of granulated dolomite (D2) significantly increased
available Ca and Mg contents and reduced S and Fe contents in the soil. Among various
treatments D2 recorded the highest soil pH, OC, available K, available Ca, available Mg
and available B at both PI and harvest stages and the highest N content at PI stage and the
lowest S and Na contents at harvest stages were observed in the same treatment. Treatment
without dolomite application recorded the highest EC, available S, Na, and available Fe at
both PI and harvest stages.
Plant nutrient contents and uptake were significantly influenced by soil
amelioration practices, foliar nutrition and by their interaction effects. Higher uptake of
nutrients such as N, P, K, Ca, Mg and S was observed on dolomite application along with
foliar nutrition. Plant nutrient content and uptake of nutrients varied among different
treatments.
The results obtained from the experiment revealed the significant influence of soil
amelioration practices, foliar nutrition and their interaction effect on growth and yield
attributes, soil pH, EC, OC, available nutrients and plant nutrient uptake in rice as compared
to control. Application of granulated dolomite basally and at 30 DAS was effective in
reducing soil acidity, thereby increasing the available nutrient content in soil, which
resulted in increased grain yield and quality. Foliar nutrition of 1% KNO3 or combined
spray of 1% KNO3 with 0.5% micronutrients at PI stage were found to be more effective
in enhancing grain yield and quality in rice in Vaikom Kari soils.