Integrated nutrient approach on productivity enhancement of rice in oxyaquic fluent soils of Northern Kerala

Abstract

The experiment entitled “Integrated nutrient approach on productivity enhancement of rice in oxyaquic fluent soils of Northern Kerala” was conducted to study the effect of organic manures along with micronutrient mixtures on growth, yield, pest and disease incidence, nutrient uptake and economics of wetland rice in farmer’s field during virippu season 2017. The experiment was laid out in randomized block design with 12 treatments and 3 replications. The treatments were T1 - Farmer’s practice (FYM 5 t ha -1 + 18:18:18), T2 - Fertilizer recommendation on the STCR basis (75.6: 57.6: 37.35 kg ha -1 NPK), T3 - POP Recommendation of KAU (90:45:45 kg ha-1 NPK ), T4 - FYM (5t ha-1) + Neem cake (400 kg ha-1) + Groundnut cake (400 kg ha -1), T5 - T3 + Ayar (500 kg ha-1 as basal dose), T6 - T3 + Sampoorna (5g l-1 at 1-2 days before transplanting and 10 g l-1 at 50 DAT as foliar spray respectively), T7 - T4 + Ayar (500 kg ha-1 as basal dose), T8 - T4 + Sampoorna (5g l-1 at 1-2 days before transplanting and 10 g l-1 and at 50 DAT as foliar spray respectively), T9 - T5 + Si (100 kg ha-1 as calcium silicate), T10 - T6 + Si (100 kg ha-1 as calcium silicate), T11 - T7 + Si (100 kg ha-1 as calcium silicate) and T12 - T8 + Si (100 kg ha-1 as calcium silicate). The available N, P and K status of the experimental field ranged from low to medium and the secondary and micronutrients were in the sufficiency level. All the treatments were applied as per the technical programme. The results of the experiment showed that the growth and yield attributes such as plant height and number of tillers hill-1, number of panicles hill-1, filled grains panicle-1, test weight and lowest number of chaffy grains were significantly influenced by application of POP recommendation of KAU along with micronutrient mixtures viz. Sampoorna and Ayar. The treatment T9 (T5 + Si) recorded maximum grain yield which was on par with T6 (T3 + Sampoorna). Straw yield was maximum in T5 (T3 + Ayar) and was on par with T6. Higher harvest index was recorded in treatment T9 (T5 + Si). At harvest, the available N and P status of the soil were increased whereas the available K was decreased when compared to the initial soil nutrient status. Application of FYM + Neem cake + Groundnut cake along with Sampoorna

recorded higher soil available N and application of fertilizers based on POP recommendation of KAU along with Ayar recorded maximum soil available P content. Plant nutrient content viz. N, P, K, Ca, Mg, Fe, Mn, Zn, Cu and Si of both shoot and root were analyzed at maximum tillering, PI stage and at harvest. In the shoot, all the nutrients showed a declining trend from maximum tillering to PI except sulphur. The content of Fe showed sharp decrease from maximum tillering to harvest stage. The total uptake of nutrients showed a significant difference among treatments. Phosphorus uptake was maximum in treatment T10 and T6 recorded maximum K uptake. The treatment T9 recorded maximum uptake of nutrients such as Ca, Zn and Mn. T 5 recorded maximum Mg uptake. Application of FYM + Neem cake + Groundnut cake along with Sampoorna and silicon reduced the uptake of Fe. Correlation study revealed that plant nutrient content such as P, Ca, Mg, Cu and Si showed a positive relationship with yield at different critical growth stages. The treatment with POP Recommendation of KAU along with Sampoorna (T6) recorded maximum yield, gross return, net return and B:C ratio whereas, application of POP Recommendation of KAU along with Ayar and Si were also equally good with yield and ease of application. In general, the integrated use of organic and inorganic sources of nutrients along with secondary, micronutrients and Si not only increase the growth parameters and yield attributes but also increase the soil nutrient level and economics of wetland rice cultivation.