Betty, BastinDanish, TamulyKAU2019-11-212019-11-212011http://krishikosh.egranth.ac.in/handle/1/5810135935PGA field experiment was carried out to find out the best nutrient management system suited for sustainable rice production in black soils of Chittur, Palakkad district. The study also aimed to know the influence of zinc on the yield of rice in such soils. These black soils though fertile, the nutrient imbalances, as well as the poor physical condition may adversely affect the yield of crop. The soil selected for the study had a mean pH value of 6.4 and electrical conductivity of 0.1dSm-1. The organic carbon content was 0.74%. The status of available N, P and K were 310.5, 5.67 and 154.36 kg ha-1 respectively. It was found that, except for available P and B, all other soil nutrients were present either in the medium level or adequate. The field experiment consisted of eleven treatments and three replications each. The treatments were- Absolute control (T1), farmer’s practice (T2), recommendation of KAU (T3), Soil Test Laboratory recommendation of Kerala (T4), STCR recommendation (T5), STCR + FYM @ 5 t ha-1 (T6), T2 + zinc sulphate @ 25 kg ha-1 (T7), T3 + zinc sulphate @ 25 kg ha-1 (T8), T4 + zinc sulphate @ 25 kg ha-1 (T9), T5+ zinc sulphate @ 25 kg ha-1 (T10) and T6 + zinc sulphate @ 25 kg ha-1 (T11). Soil as well as plant nutrient status were recorded at critical growth stages viz, maximum tillering, panicle initiation, flowering and harvest stage for the content of N, P, K, Ca, Mg, S Na, Si, Fe, Mn, Zn, Cu and B. Biometric parameters such as the height of the plant, number of tillers and number of leaves at critical growth stages were also recorded. Simple correlation co-efficient were worked out for soil nutrients, plant nutrients, grain nutrient and uptake with yield. Among the available soil nutrients, N content was found to be highest followed by available K and P during different growth stages. Available Ca was higher than Mg during all the growth stages. Among micronutrients, available Zn reduced while B increased from maximum tillering to harvest. A sharp decline in soil Fe content was observed with the advancement of growth stages. Available Na increased while, Si remained almost uniform throughout the different growth stages. Among plant nutrients, the content of N decreased from maximum tillering stage to harvest. A higher concentration of Mg compared to Ca was observed during maximum tillering stage. The plant content of Fe showed a sharp decrease from maximum tillering to panicle initiation and thereafter increased. The range varied from 5000 mg kg-1 at maximum tillering stage to 3000 mg kg-1 towards the harvest stage. The plant content of Na increased from panicle initiation to harvest stage while, that of Si declined from flowering to harvest. The number of leaves and tillers were found to be significantly higher for STCR treatments (with or without FYM) and zinc sulphate at the flowering stage. The highest benefit cost ratio was obtained for T1 (absolute control). It was also observed that the yield of both grain and straw reduced on addition of ZnSO4. Positive and significant correlation was observed between uptake of almost all the nutrients with grain and straw yield except Ca, Cu and Si. The uptake of the major nutrients, N and K was found to be significantly and negatively correlated to the contents of Na and Ca in soil. This supports the fact that excess amount of basic cations are hindering the uptake of major nutrients. Prediction of yield based on content of soil, plant and yield attributes could not be obtained from the present study. It can be concluded that black soils of Chittur are fertile. But the productivity of these soils are constrained by factors like high content of basic cations such as calcium and sodium and subsequent low uptake of major nutrients. High plant content of Fe was also observed during the maximum tillering and panicle initiation stage. The content of Si in soil as well as uptake of Si by the crop was also comparatively less. So management practices have to be adopted to reduce the soil content of the basic cations as well as nutrient imbalances in soil and plants by drainage, leaching and incorporation of FYM, crop residues rice husk etc. the interaction between macro and micronutrients have to be examined in detail and further studies have to be conducted for sustainable rice production in these poonthalpadam (black) soils.ennullThesis