Effect of Organic and Inorganic Nutrient Management on Productivity, Cost Economics and Energy Use Efficiency in Sesame

Field experiments were carried out to assess the soil physicochemical properties, yield, quality, energy use and profit analysis of sesame and under organic vis-à-vis conventional production systems for three consecutive seasons. The soil organic C, available N, P, K and micronutrients recorded a slight rise in the organic production system over three seasons. The mean total energy input expended in the production of sesame using organic inputs was much lower (3,586.9 MJ ha-1) compared to that with inorganic fertilizers (5,156.3 MJ ha-1). Manures/Fertilizers and diesel inputs dominated the total energy inputs for both the production systems. However, the energy output obtained was higher in the inorganic production system (12,000 MJ) than in organic production system (9,375 MJ). The cost of cultivation of sesame was Rs. 12807 ha-1 and Rs. 16413 ha-1 under inorganic and organic farming, respectively. Organic sesame yield was about 22 per cent less compared to inorganic production system. At least 40% price premium for organic sesame may be required to offset the higher cost of cultivation and low yields under organic production system compared with inorganic production system especially during initial years. Renewable energy input utilization was higher (66 %) in organic than in inorganic production systems (13%). Energy efficiency and productivity was higher in organic than inorganic sesame production system by 12 per cent and 10 per cent, respectively. Since, the organic production system is more energy efficient and it is recommended that sesame production under organic farming should be encouraged for environmental and economic sustainability.

Influence of Weather, Vector and Variety on Incidence of Yellow Leaf Disease in Sugarcane

Yellow leaf disease of sugarcane (Saccharum spp.) caused by the Sugarcane yellow leaf virus (SCYLV), vectored by aphids has attained epidemic proportions causing severe yield losses, ranging from 20 to 40 % in susceptible varieties. Yellow leaf spread by aphids depends on cultivar susceptibility as well as weather parameters and thus the present studies were conceptualized. The observations on meteorological parameters were taken from the observatory at the station. The data on incidence of vector(aphids) and yellow leaf disease were recorded at weekly interval during the entire crop growth period on three sugarcane varieties viz., 2005 A 128, 2001 A 63 and 2003 V 46. The data on vector and disease incidence was correlated with weather parameters. The aphid incidence on 2005 A 128 initiated (4.6 per leaf) at 30 SMW and gradually increased to 19.1 per leaf at 40 SMW. In the variety 2001 A 63, the aphid incidence was first observed (2.2 per leaf) at 27 SMW and reached the peak population of 19.1 per leaf at 38 SMW. The aphid incidence on 2003 V 46 initiated (2.1 per leaf) at 29 SMW and gradually increased to 18.1 per leaf at 42 SMW. With regard to yellow leaf disease the incidence was first observed (1.0 per cent) at 26 SMW and reached the peak (28.7 per cent) at 37 SMW in the variety 2005 A 128. In the variety 2001 A 63, the incidence of yellow leaf disease was 1.8 per cent at 26 SMW which later on increased up to 29.4 per cent by 46 SMW. The incidence of yellow leaf disease was 3.5 per cent at 28 SMW which later on increased up to 27.6 per cent by 44 SMW in the variety 2003 V 46.The observations on incidence of aphids and YLD in susceptible varieties revealed that aphids contribute significantly to the initial spread of YLD, from initial incidence of aphids and YLD in 29-30 SW up to 42-44 SMW when the aphids reach peak incidence and YLD also leaps to above 25 per cent. The aphid population exhibited positive correlation with maximum temperature (r2=0.62), minimum temperature (r2=0.55) and relative humidity I (r2=0.65), whereas, negative correlation with rainfall (r2=-0.63). The yellow leaf disease exhibited positive correlation with minimum temperature (r2=0.75) and relative humidity I (r2=0.67), whereas, negative correlation with rainfall (r2=-0.63). The leaf and aphid samples were collected at peak incidence of Yellow leaf disease and were tested and found positive for presence of virus using ELISA reader at 405 nm.