A field experiment was conducted at Regional Agricultural Research Station, Jagtial, during rainy (kharif) and winter (rabr) seasons of 1996-97 to 1998-99 on red sandy-loam soils, to find out profitable and energy-efficient rice (Oryza sativa L.)-based cropping sequences among different cropping sequences, viz., rice-maize (Zea mays L.), rice-sunflower (Helianthus annuus L.), rice-groundnut (Arachis hypogaea L.), rice-blackgram (Phaseolus mungo L.), rice-greengram (Phaseolus radiatus L.), rice-soybean [Glycine m a (L.) Merr.], rice-ln- dian mustard [Brassica juncea (L.) Czernj. & Cosson] and rice-rice. Of the 8 cropping sequences, rice-rice, rice- maize and rice-sunflower cropping sequences gave significantly higher rice-equivalent yield (1 1,616, 11,553 and 10,868 kg/ha respectively) and gross returns (Rs 51,745, 51,464 and 48,2911ha respectively). Though field water supply was higher to rice-rice cropping sequence (2,800 mm), the water-use efficiency was lowest (4.15 kg/mm). Similarly, rice-rice cropping sequence also required higher energy input (75,036 MJIha) but the energy efficiency and energy productivity were lowest (4.2 and 155 g1MJ). However, net returns and benefit : cost ratio were higher with rice-maize (Rs 21,8841ha; 1.74) and rice-sunflower (Rs 21,3211ha; 1.79) cropping sequences. Similarly, these cropping sequences also recorded higher energy-use efficiency (6.4 and 5.1 respectively), en- ergy productivity (227 and 238 g1MJ respectively) and water-use efficiency (7.22 and 7.50 kglmm respectively) and were more sustainable than rice-rice and other rice-based cropping sequences.

A field experiment was conducted during rainy and winter seasons of 1994-95 to find out the optimum level and time of N application for late seeded rice under puddled condition. In kharif, there was significant increase in grain yield up to 80 kg N/ha while-in rabi, the crop responded up to 120 kg N/ha. Application of N in two splits at sowing / 10 days after sowing (DAS) and maximum tillering (45 DAS) gave yield similar to that of 3 or 4 splits in both kharif and rabiseasons. !n kharif under late sown conditions, short duration cultivar WGL 1801 1-1 5 (1 05 days) gave higher yield than long duration varieties Kavya (135 days) and Pothana (125 days) but during rabi season both the cultivars under test (IR - 64 : 125 days, Kalinga - 390 days) gave similar yield.

A field experiment was conducted for 4 years during 1992-93 to 1995-96 to evaluate the production efficiency of 6 winter season sunflower (Helianthus annuus L.) • based cropping systems. The sunflower yield equivalents were higher in sunflower. groundnut (Arachis hypogaea) - greengram (Phaseolus radiatuS L.) cropping system than sunflower - maize (Zea mays L.) - greengrarnj sunflower - sunflower - greengram sunflower- greengram - greengram; sunflower - blackgram (P. mungo L.) - greengram sunflower - sesame (Sesamum indicum L.) - greengram cropping system. The sunflower - groundnut - greengram cropping system was found to be stable (sustainable yield index 70%) with higher production efficiency and net returns compared to other cropping systems. In summer, the sunflower yield equivalents and sustainable yield index were higher in groundnut than that of other crops grown.

A field experiment was conducted during winter season of 1993-94 and 1994-95 to study the effect of time of fertilizer application on growth and yield of sunflower (Helianthus annuus L.). Plant height, dry matter, 1,000-seed weight and seed yield increased with application of N. Phosphorus application at sowing along with N improved the seed yield; however, there was no response to K or S when applied with N and P. There was a decrease in seed yield when half dose of P was given at sowing and remaining at buttoning stage. Delaying the N and P application up to buttoning stage decreased the seed yield compared with N applied in 3 equal splits-at sowing, buttoning and flowering stages.

A field experiment was conducted during 1991-92 to 1993-94 to evaluate the production efficiency of 7 rainy-season maize (Zea mays L.)-based cropping systems. The rainy-season maize grown after winter greengram (Phaseolus radiatus L.), pigeonpea [Cajanus cajan (L.) Millsp.], groundnut (Arachis hypogaea L.) and indian mustard [Brussica juncea (L.) Czernj. & Cosson] gave more grain yield (2.03-2.14 tonnes/ha) than that grown after winter maize. sunflower (Helianthus annuus L.) and blackgram (P. mungo L.). Maize-blackgram, maize-pigeonpea, maize-groundnut and maize-sunflower cropping systems pave higher maize-yield equivalent (5.53-5.97 tonnes/ha) than maize-greengram, maize-indian mustard and maize-maize cropping systems (2.99-3.64 tonnes/ha). The net return was higher in maize-blackgram (Rs 15 033/ha) cropping system, followed hy maize-pigeonpea (Rs 13 340/ha) and maize-sunflower (Rs 13 301/ha). The benefit : cost ratio was higher in maize-blackgram cropping system (2.68), followed by maize-sunflower (2.55), maize-pigeonpea (2.36) and maize-groundnut (2.08). The production efficiency was higher in maize-blackgram and maize-sunflower cropping systems (28.5 and 28.7 kg/ha/day respectively) than in maize-groundnut, maize-pigeonpea, maize-greengram. maize-maize and maize-indian mustard cropping systems.