Samba Season Research Articles

YIELD GAP ANALYSIS IN RICE: THANJAVUR DISTRICT

Yield gap was estimated for rice in Thanjavur district for three regions (old delta, new delta and coastal regions) and for dominant varieties only, covering 90 respondents during samba season for the year 1990-91. Yield gap I was highest in ADT 39 (9.2 kg per ha) followed by CO 43 and CR 1009 (679.6 kg). Yield Gap II was highest in CR 1009 (2011.7 kg) followed by CO 43 and ADT 39 (1506.35 kg).

MANAGEMENT OF RICE GALL MIDGE Orseolia oryzae (WOOD-MASON) WITH REFERENCE TO TIME OF PLANTING AND VARIETAL RESISTANCE

The incidence of rice gall midge was maximum when CO 40 was planted on 1st September during samba season and when IR 20 was planted on 16th September during thaladi season. The incidence was less when the plantings were made during August or October. Of the 41 varieties tested. IET 3231 was free from gallmidge Infestation while CR 1009. IR 20, Jaya, CO 25, CO 40 and Pankaj recorded 5.91. 9.13, 9.80, 13.22. 14.83 and 34.59% respectively.

Manurial Experiments on Rice 2. Effects of season and continuous green leaf manuring on yield

Rice growers of this Province, by traditional ex- perience resort to green leaf manuring with a view to obtain increased yields. Investigations to assess its effect were for some time past in progress in this and other provinces. Two schools of thought were developed, the one attributing the beneficial effect of green leaf manuring to Nitrogen and its influence on the biological reactions in the soil and the other laying stress on the physical effects of the organic matter and also the possible influence on the solubility of soil phosphates. However, the literature on the cumulative effects of green leaf manuring over long periods is scanty. Irrespective of the nature of its action, green leaf manuring is an accepted practice among farmers to increase rice vields. Twenty five years ago two experiments on continuous green leaf manuring were laid out at Palur and Manganallur. At Palur in one experiment on rice, green leaf was applied to alluvial soils. The rice was grown in the samba season (September-January) irrigated by a perennial spring channel of Gadilam river.