Productivity of upland rice (Oryza sativa L.) at diffrerent nk ratios and spacings

Abstract

Abstract: A field experiment on ‘Productivity of upland rice (Oryza sativa L.) at different NK ratios and spacings’ was conducted during Kharif, 2018 at the Instructional Farm, College of Agriculture, Vellayani to study the influence of different levels of N and K, their ratios and spacing on growth and yield of upland rice and to work out the economics of cultivation. The variety used for the experiment was Prathyasha (MO 21). The technical programme consisted of 12 treatment combinations with six NK levels and two spacings laid out in 6 x 2 factorial RBD. The treatments were NK levels ( L) (kg ha-1 at 2:1 and 2:1.5 ratios) l1: 60 kg N : 30 kg K2O (Control), l2 : 90 kg N : 45 kg K2O , l3 : 120 kg N : 60 kg K2O, l4: 60 kg N : 45 kg K2O, l5 : 90 kg N : 67.5 kg K2O, l6 : 120 kg N : 90 kg K2O. There were two spacings (S) viz s1 : 20 cm x 15 cm and s2 : 20 cm x 10 cm. Uniform dose of 30 kg ha-1 P2O5 was given to all plots. The crop was sown on 29 -05-2018 and harvested on 14-09-2019. The soil of the site was sandy clay loam with available NPK content of 250, 31.5 and 244 kg ha-1respectively. The treatment l3 (120 kg N: 60 kg K2O) produced the tallest plants and maximum DMP at harvest. The spacing s2 (20 cm x 10 cm) recorded maximum DMP at harvest.Tillers m-2 and LAI were significantly influenced by treatments and l6 (120 kg N: 90 kg K2O) produced maximum tillers m-2 and LAI. Among the spacings, s2 (20 cm x 10 cm) recorded maximum tillers m-2. Spacing did not significantly influence LAI. The yield attributes viz., number of productive tillers m-2 , length of panicle , grain yield and straw yield were favourably influenced by treatment l3 (120 kg N: 60 kg K2O) except weight of panicle for l6. The treatment l3 recorded maximum grain and straw yields of 3123 and 4030 kg ha-1 respectively and was on par with l6. Among spacing, s2 (20 cm x 10 cm) recorded maximum number of productive tillers m-2, grain and straw yields. Grain and straw yields were significantly influenced by the interaction and l3s2 recorded the highest grain yield and was on par with l2s2, l3s1, l6s1 and l6s2. With regard to straw yield, l3s2 recorded the highest straw yield and was on par with l3s1, l6s1 and l6s2. The results showed favourable influence of treatments on protein content of grain. The treatment l3 recorded maximum grain protein content of 5.51 per cent and was on par with treatment l6 (5.39 per cent). The lowest grain protein content was recorded by l1 The uptake of nutrients was profoundly influenced by the treatments. Increased uptake of nutrients was recorded at an NK level of 120 kg N: 60 kg K2O. The spacings did not significantly influence nutrient uptake. Increasing the levels of N, P and K increased the soil available nutrients. Application of NK at 120 kg N: 60 kg K2O significantly improved nutrient status of soil. The results of the economic analysis revealed that net income and BCR were maximum in plots supplied with 120 kg N: 60 kg K2O ha-1. Spacing (20 cm x 10 cm) significantly influenced net income. Based on this investigation, it can be concluded that application of 120 kg N: 60 kg K2O along with 30 kg P2O5 ha-1 and sowing in a spacing of 20 cm x 10 cm was found to favourably influence growth characters, yield attributing characters, yields and economics of upland rice and it was further noted that increasing N dose from 60 to 120 kg ha-1 significantly influenced the growth,yield attributes, yield and net income irrespective of K dose.