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082			_a630 _bSIN/EF
100			_aSindhu P V
245			_aEffect of nutrient inter-relations on productivity of rice in lateritic soils
260			_aVellanikkara _bDepartment of Agronomy, College of Horticulture _c2002
502			_bMSc
520	3		_aThe effect of nutrient inter-relations on productivity of rice in latritic soils was investigated during the first crop season (Virippu) Or 1999-2000 at the Agricultural Research station, Mannuthy. The objective of the study was to arrive at the minimum level combination of applied elements for maximum productivity based on the interaction pattern between applied and native elements so as to develop a sustainable management system. Jyothi was used as the Fest variety to analyse the pattern of interacting influences of P, K, Ca and S at two levels each, among themselves as well as on the native elements. The results showed that treatments had significant beneficial influence on yield expression, causing 90 and 10% increases in yield over absolute control and the presently recommended package of practices. This indicated the necessity of including Ca and S in the nutrient management system. Decline in chlorophyll content and high levels of cell sap pH, together with excess contents of Fe and Zn appear to act as the supressors of yield expression. The latter influences are inherent in soil and are actually the net product of the balance between positive and negative effects of nutrients. A significant finding was that application of any element by itself was not a guarantee for its uptake, and was subject to the effect of other elements, and similarly, had direct or indirect influences on other elements. The positive influence of K and Ca at the maximum tillering and S at the panicle initiation stage, and negative influence of Fe and Mn at the panicle initiation stage pointed out to the need for phasic management of nutrients. The only element inhibiting Fe uptake had been Si, suggesting that the reversal of the process of laterisation holds the key to higher yields. Discriminatory transfer of individual elements between leaf blade and leaf sheath appeared to be an important regulatory factor in deciding yield expression. Highest yield resulted when blade-sheath ratio was maximum tillering and panicle initiation declined in respect of Ca, Fe and Mn and increased in respect of K and S. the study resulted in development of the broad base of a management technology for high productivity and sustainability. The components included keeping N at the present reconunended level, reducing P by 50%, increasing K by 100% and top dressing N using s containing fertilizers as well as moderate basal dressing with Ca.
700			_aMeera Menon V (Guide)
856			_uhttps://krishikosh.egranth.ac.in/handle/1/5810156280
942			_2ddc _cTH