Active root distribution zone of bell pepper (Capsicum annuum L.) under drip irrigation with and without mulches.

Cap<;icum is cultivated commercially in Tamil Nadu, KarnaLaka and Andhra Pradesh For etficient use 01 "aler drip irrigation is practiced widely in lighl lex­ lured soils \'here commercial crops are grown. Drip ilrighell pepper (var. California \Vonuer) in a gravelly sandy loam soil at Agricultural College FeIl·Ill. Raiendranagar during 1997-98. Roar <1eLi\-ity \ldS studicd in drip 0.8 and drip 0.6 irrigation treal­ mcnts in combination with and wilhout mulches (black. polylhclle and paddy husk) and in cOl1trol i.e., surraec irrigution (ul1mulched). In drip 0.8 and dnp 0.6 lrcallllCnls irrigations were gi\-en 111 the I'W/(:PI:, ralio or 0,1) 8nd 0.6. respcctively on alternate clays. In case or SIJrfaee ir 'galion treatl1lcnt thc crop was irri­ 1!ZIlCU I"hen lhe CPJ-: (Cwllldative pan cvapmalion) rCi.lcheu 40 1I11ll. l3Iaek rOI)'lhene mulch and organic mulch (raud)' husk.) \\ere spl"~ld on the surface after thc estahlishmcnt or the crop. The root activity was studied emplo) ing 32p soil injection leehnique (fiatt et al. 1953). fach plant \Ia" appli,ed wilh carrier Iree "adio aclivc 32r :'(,( 100 llei/piar:1 equally distribution in foul' holes ~Irounu (he plant in Ireatment combinations of 15 and 30 Clll lat­ eral uist.lm.:es anu 10,20 and 30 cm vertical depths in threc replk lions at 60 1),'\T. Th': planl '5all1p1cs werc colleelc'd after 7 days of 32p application for 32r assa) (lArA, '964) and the eoullts were recorded u\ing liquiu scintillation countcr. The COUllts obtained under various treatmcnl combinations were taken as the ba­ )is tll compulc the relative distribution of active roolS. In general, lhere was decreasc in per cellt aCLIve ['(lOIS \\ ith distance away from the plant Crable I). ~il1lilar rcsults wcre reponeJ by Malia Reddy f?/ Cli. (1988) in chilli crops. More roots near the plant \\,\;rc reported under drip irrigation III l!J oUlidnlll (R'I L. 1997-98), In drip 0.8 aclj\ e roots in the 'lii UCc' I~lyer. de­ creased with depth. Whc:rcds in dl'lp OJ) "'hcr" relatively less \\',ller \~i1, ,1Pll\i~ nWI'c loots \1 c:re round al 20 em depth (Ill idJIe lel\ n 1 eOIll pared II) '\11­ race and bottom la) ers. SII11I)',\!' 1'1 I ~ C'\rellcnc~ (11 Randall dnl! L.ocascio (I CJXX) with eUCllll1h,·£. I 111\­ ev~r, the cAlcndcd rool dcvclormc:nl it; d. ir I) 6 Clll1JJ nor cOlllpenS,lle lor redUCed \\ ~il~I' ,,\ Jll"hi'iil)' "nJ planl growth and the yield \\ CiS I clJl,ced a~ d C(lil,c'· quencc (though dk WlJL \\<1:, I',igh in ul'ip 0.6 comrared to urip II, lrcatment).