Subtropical India Research Articles

Effect on yield and juice quality of sugarcane following rice

Sugarcane is usually grown after paddy in tropical and subtropical India; this rotation is adopted when sugarcane is planted in October (autumn planting). Soil puddling is required for paddy, but puddling disturbs the soil structure and impedes development of roots beyond the puddled layer. Adverse effects on growth and yield of sugarcane are therefore expected, but contrary to such expectations, sustained or increased yields of cane after paddy have been observed (Alvarez & Snyder, 1984; Anon. 1984; Snyder el al. 1986). It appears that certain other soil factors overcome the harmful effects of adverse soil physical conditions. Therefore, the present study was undertaken to investigate such factors.

Effect of sowing date, population density and row spacing on growth and yield of opium poppy in north central subtropical India

SUMMARYOpium poppy (Papaver somniferum Linn.) was sown at three sowing dates (10, 25 November, 10 December), row spacings (15, 30, 45 cm) and population densities (6 × 105, 3 × 105, 1·5 × 105 plants/ha) in a split-plot design at Lucknow. Sowing on 10 November resulted in higher yields of opium, seed, total dry matter and morphine content. Delayed sowing, higher plant density and narrow spacing produced low yields with less morphine content. Decline in opium yield was associated with decrease in plant height, leaf area index, capsule size and number of capsules per plant. The crop sown on 10 November removed most N. N concentration and uptake also increased when the number of plants per unit area was decreased. The study suggests that to achieve maximum yields poppy should be sown in rows 30 cm apart on 10 November with 3 × 105 plants/ha.

Seed potato production in the sub-tropical plains of India

The complex problem of degeneration of seed stocks caused by several virus diseases has hitherto limited the production of potatoes in sub-tropical India. The reduction in yield by over 50% through the use of degenerated seed stocks necessitated development of seed areas in temperate climate in the hills of northern India, 2,000 meters above sea level.