Enhancing grain yield and quality through soil amelioration and foliar nutrition in rice (Oryza sativa L.) in Vaikom kari soils

Abstract

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 116 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.