Field experiments were conducted during the summer season of 1994 and 1995 at Cotton Research Station, Srivilliputtur to study the effect of intercropping and foliar nutrition on the productivity of summer irrigated cotton. Cotton + blackgram raised in paired row system (2:1) produced higher mean seed cotton yield equivalent (1815 kg/ha), mean net return (Rs. 17,724/ha) and mean benefit cost ratio (1.96). Spraying DAP two per cent + KCI one per cent (1:1) solution was found more economical. Raising cotton + blackgram in paired row 2:1 ratio and spraying DAP two per cent + KCI one per cent (1:1) solution resulted in the highest net return of Rs. 20,225 and benefit cost ratio of 2.12.

Field experiments were conducted at Regional Research Station, Aruppukottai during the rabi seasons of 1998-99, 1999-2000 and 2000-2001 to study the effect of graded levels of phosphorus and foliar nutrition on short duration redgram in rainfed Vertisol. The pooled data revealed that application of 37.5 kg P2O2 ha-1 had recorded higher grain yield of 958 kg ha' with a net income of Rs.9338 ha-1 and B-C ratio of 2.32 than 12.5 kg P2O5 ha but on par with application of 25 kg P2O2 ha'. Foliar application of di-ammonium phosphate two per cent had improved the grain yield and income with high B-C ratio.

A two year field study on sunflower (Helianthus annuus L.) based inter cropping systems conducted at Regional Research Station, Aruppukottai revealed that planting of component crops at 3:1 ratio under replacement series was optimum for better growth, increased sunflower grain yield equivalent (1019 kg har') and higher net income (Rs. 6392 kg ha¹) with higher benefit cost ratio (2.69). The yield of sunflower component increased from 718.7 to 805.9 kg ha as planting row ratio gets widened from 2:1 to 4:1 ratio. The yield of intercrops reduced by 17.7 and 33.8 per cent in 3:1 ratio and 4:1 ratio as compared to 2:1 ratio. Among the intercropping systems, sunflower + sesame had recorded the highest mean grain yield equivalent (1082.6 kg ha), mean net income (Rs. 6942 kg ha) coupled with maximum benefit cost ratio (2.87) compared to other intercropping systems. The yield advantage in sunflower + sesame intercropping system was mainly due to efficient utilizaiton of water under rainfed situation.

Field experiments were conducted during rabi 1997-98 and 1999- 2000 at Regional Research Station Aruppukottai to find out the optimum time of sowing and suitable intercrops for coriander under rainfed vertisol condition. November first week was found to be the optimum time for the sowing of coriander sole crop where as October last week was for coriander intercropping system. Among the intercrops tested, onion was found suitable for intercropping with coriander under rainfed vertisol condition. November first week sown coriander sole crop had recorded higher yields, 143 and 103 kg/ba during 1997-98 and 1999-2000 respectively. During 1999- 2000, October last week sown intercropping system had produced more coriander yield equivalent (498 kg ha-1), higher gross income (Rs.7969/ha-1) and net income (Rs.4837/ha-1) with 2.31 and 1.109 as benefit- cost ratio and LER values. Among the intercropping systems followed, during 1999-2000, coriander + onion intercropping system in 1:1 ratio had recorded significantly the highest equivalent yield (871 kg ha-1), more gross income (Rs.11939/ha-1) and net income (Rs.943 9/ha-1) with a benefit cost ratio of 3.10.

Field experiments conducted at the Agricultural Research Station, Kovilpatti during rub seasons of 1993-94 and 1994-95 revealed that intercropping of cotton + black gram at 2:1 ratio reduced the weed density and dry matter. Mulching eitherwith subabul loppings or hajru straw 6 6 ha recorded significantly lower weed population and the dry matter accumulation than the unimulched control.