Dynamics of Macro and Micronutrients in Lowland Rice as Affected by the Continuous Adoption of STCR-IPNS Technology in Typic Haplustalf.
Subramanium Thiyageshwari, P. Murugesa Boopathi, and R. Natesan. Tamil Nadu Agricultural Univ, Lawley Rd, Coimbatore District, Coimbatore, India
Soil test based fertilizer recommendation (STCR) is gaining momentum in the near future as we aim at higher target yields, which leads to depletion of soil fertility. Application of inorganics alone cannot help achieve both productivity and to maintain soil fertility. With a view to monitor the changes in nutrient dynamics and rice productivity, a continuous experiment is being conducted at TNAU, Coimbatore since 1998 in an Alfisol of clay loam texture under lowland ecosystem by following STCR recommendations with Integrated Plant Nutrient Supply System (IPNS). The treatments imposed were: (i) blanket recommendation, (ii)STCR alone at 6 t ha-1 as target yield, (iii) STCR alone at 7 t ha-1 as target yield,(iv) STCR at 7 t ha-1 as target yield with IPNS and (v) Control. The treatments were non-replicated. For IPNS plots, Green manure @6.25 t ha-1 and Azospirillum @2 kg ha-1 were applied. The pre sowing soil samples were analysed for available N, P and K status. Based on the soil test values, the fertilizer doses were applied for the STCR treatments. The post harvest soil samples were analysed for KMnO4-N, Olsen's-P, NH4OAc-K and DTPA available micronutrients. The results indicated that blanket and STCR Inorganics alone treated plots showed a declining trend in KMnO4-N when compared to the initial available N status of 280 kg ha-1. The mining of ammonium acetate -K was obvious in all treatments. In the STCR-IPNS treatment, there was either a built up or maintenance in the available macro and micronutrients of the soil besides a higher response ratio thus indicating sustainability in yield.