Effect of establishment methods and nutrient management on physiological attributes and water-use efficiency of rice (Oryza sativa) in a sub-tropical climate
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A field experiment was conducted during the rainy (kharif) seasons of 2004 to 2008 in acid soils of sub-tropical Meghalaya, under rainfed condition, to evaluate the impact of crop-establishment methods and nutrient-management practices on growth and physiological parameters of rice (Oryza sativa L.). Three establishment methods, viz. system of rice intensification (SRI), integrated crop management (ICM) and conventional rice culture (CRC), were evaluated under 5 nutrient-management practices, viz. recommended dose of fertilizers (RDF) (80: 60: 40 N, P2O5, K2O kg/ha), farmyard manure (FYM) 10 t/ha, 50% RDF + FYM 10 t/ha, RDF + FYM 5 t/ha and control (no FYM or fertilizer). Seedlings of 10, 20 and 30 days age were transplanted at a spacing of 25 cm × 25 cm, 20 cm × 20 cm and 20 cm × 15 cm for SRI, ICM and CRC respectively. Pooled data of year 2007 and 2008 revealed that SRI method recorded higher values of growth parameters, viz. plant height, number of tillers/hill, number of leaves, dry-matter production and root growth, than ICM and CRC methods. Significantly higher root volume and root dry weight were recorded with SRI than ICM and CRC methods. Application of RDF + FYM 5 t/ha being at par with 50% RDF + FYM 10 t/ha showed relatively taller plants, higher numbers of tillers, leaves, dry matter, root volume and root dry weight/hill than the other nutrient-management practices. The rice crop matured earlier (135 days) under SRI rice culture than that under ICM (141 days) and CRC (148 days) methods. Photosynthetic rate (PR) and water-use efficiency (WUE) were significantly higher under SRI, whereas transpiration rate (TR) was higher under CRC. Rice culture under SRI recorded higher values of yield-attributing parameters, viz. number of panicles/hill and number of grains/panicle than ICM and CRC. However, the grain and straw yields were significantly more with ICM than that of CRC but were at par with, SRI methods. Integrated application of RDF + FYM 5 t/ha followed by 50% RDF + FYM 10 t/ha gave higher value of all the yield-attributing parameters and yield of rice compared to the control. The highest net returns were recorded under ICM rice culture and application of RDF + FYM 5 t/ha.
Photosynthetic rate, Nutrient management, Rice, Root volume, Water-use efficiency.