Productivity enhancement in medicinal rice (Oryza sativa L.) njavara

Abstract

The present investigation on “Productivity enhancement in medicinal rice (Oryza sativa L.) cv. Njavara” was conducted at College of Agriculture, Vellayani for assessing the impact of silicon, modified NK ratios and reduced seed rate on the growth, lodging and yield and the economics of production of Njavara rice. The treatments consisted of three rates of silicon, viz, (S1)-0 kg, (S2)-50 kg and (S3) -100 kg Si02 ha-1.,three seed rates as (R1)-50 kg, (R2)-75 kg and R3- 100 kg ha-1 and three levels of K(modified N:K ratios) as K1- 40 kg(1:1),K2- 80 kg(1:2) and K3-120 kg(1:3) K20 ha-1.The experiment was laid out in split plot design with three replications. It includes 9 main plot treatments as combinations of silicon and seed rate (SR) and 3 sub plot treatments as the levels of K (modified N: K ratios). The results of the investigation are summarised below. Application of silicon influenced the growth attributes like plant height at 40DAS and at harvest, LAI at panicle initiation stage and culm strength at harvest stage. The other growth attributes like rooting depth, tillers m-2 and total biomass were not significantly influenced by silicon. Yield contributing characters like productive tillers m-2; spikelets panicle-1 and thousand grain weight were significantly influenced by silicon application. While silicon @100 kg ha-1 recorded significantly higher number of productive tillers m-2 and thousand grain weight, silicon @50 kg ha-1registered the highest number of spikelets panicle-1. The other yield contributing characters like grain weight panicle-1, filled grains panicle-1, sterility percentage, straw yield, grain yield and harvest index were not significantly influenced by silicon. Seed rate produced significant influence on growth attributes like plant height, LAI, total biomass and rooting depth. Seed @ 50 kg ha-1 produced the highest rooting depth and total biomass and seed @75 kg ha-1 produced highest plant height. Tillers m-2 and culm strength were not significantly influenced by seed rate. Yield attributes like number of productive tillers m-2, thousand grain weight, grain yield, straw yield and harvest index were significantly influenced by seed rate. While seed @100 kg ha-1produced significantly highest number of productive tillers m-2, thousand grain weight, grain yield, straw yield and harvest index were highest at seed @ 50 kg ha-1. Potassium (NK ratio) could not exert any significant influence on growth characters except plant height and number of tillers m-2, registering the superiority at K2 (N:K: 1:2). Number of productive tillers m-2 was the only yield contributing parameter significantly influenced by NK ratio ( K levels ) and the highest value was recorded by K3 (N:K: 1:3). Yield attributes like number of productive tillers m-2, grain yield, net income and B: C ratio varied significantly by interaction of treatments and s2 r3 k2 (S-50 kg ha-1, R-100 kg ha-1, NK 1:2 -80 kg ha-1) registered the highest grain yield. The highest net income and the highest B: C ratio of Rs 93120/- and 1.97 respectively were for s1r2k1. (S-0, R-75 , K-40 kg ha-1). Considering the general performance of the crop with regard to all the growth and yield parameters, the treatment receiving silicon @ 50 kg ha-1, seed @ 100 kg ha-1 and potassium @ 80 kg K2O ha-1(NK ratio 1:2) was found beneficial for Njavara rice.