STUDY ON THE INFLUENCE OF IRRIGATION REGIMES AND FERTIGATION LEVELS ON SUGARCANE UNDER SUBSURFACE DRIP FERTIGATION SYSTEM

摘要

Field investigations were carried out at the central farm, Agricultural College andrnResearch Institute, Madurai, Tamil Nadu during 2008-09 and 2009-2010, to elicitrninformation on the influence of irrigation regimes and fertigation levels on sugarcanernunder subsurface drip fertigation system. The experiments were laid out in Split PlotrnDesign with three replications. The main plots treatment consisted of threernsubsurface drip irrigation regimes viz., 75 per cent Etc (I_1), 100 per cent Etc (I_2) andrn125 per cent Etc (I_3). The subplot treatment consisted of six fertigation levels viz., 75rnper cent RDF as commercial fertilizers (F_1), 100 per cent RDF as commercialrnfertilizers (F_2), 75 per cent RDF – 50 per cent commercial and 50 per cent waterrnsoluble fertilizers (WSF) (F_3),.rn100 per cent RDF – 50 per cent commercial and 50 per cent WSF (F_4), 75 per centrnRDF as WSF (F_5) and 100 per cent RDF as WSF (F_6).The sugarcane variety COrn86032 was used for this study. Subsurface drip irrigation was given once in 3 daysrnand fertigation was given once in 6 days.rnTiller production and number of millable canes were higher in drip irrigation at 125 perrncent Etc along with fertigation of 100 per cent RDF as WSF (I_3F_6) which wasrncomparable with 125 per cent Etc along with 75 per cent RDF as WSF (I_3F_5) in bothrnplant and ratoon crop. The combination of drip irrigation at 125 per cent Etc with 100rnper cent RDF as WSF registered higher cane and sugar yield but it was comparablernwith 125 per cent Etc along with 75 per cent RDF as WSF in both crops. Surfacernirrigation with soil application of fertilizers recorded lower cane and sugar yield whenrncompared to subsurface treatments. The subsurface drip irrigation regime of 125 perrncent Etc registered higher total water use followed by 100 per cent Etc and 75 perrncent Etc in plant and ratoon crops. The treatment combination of 75 per cent Etcrnalong with 100 per cent RDF as WSF (I_1F_6) recorded higher WUE and waterrnproductivity. Higher net return was recorded in 125 per cent Etc with 75 per cent RDFrnas water soluble fertilizers in plant crop however in ratoon crop, higher net return wasrnobserved in 125 per cent Etc with 100 per cent RDF as WSF. Higher BC ratio wasrnassociated with drip irrigation at 125 per cent Etc in combination with 100 per centrnRDF as commercial fertilizers followed by drip fertigation of 75 per cent RDF asrncommercial fertilizers at 125 per cent Etc in both crops.