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Field experiments were conducted to compare the System of Rice Intensification (SRI) with the best management recommendations and farmers' practices of rice (Oryza sativa L.) production. The experimental variables included combinations of seedling number and age (10 day-old single vs. 20 day-old two seedlings per hill), spacing (25 x 25 cm vs. 20 x 15 cm), irrigation (intermittent irrigation vs. continuous flooding), and weed control (cono-weeding vs. manual weeding) treatments, besides farmers' practice (control). The trial was laid out in completely randomized factorial design, replicated thrice. Highest grain yield (4467 kg ha-1) and net returns (Rs 17745 ha-1) were obtained for the suite of best management practices (planting two 20 days-old seedlings hill-1 at 20 x15 cm + intermittent irrigation and cono-weeding). Yield under SRI management (planting 10 day-old single seedlings at 25 x 25 cm + intermittent irrigation and cono-weeding: 3326 kg ha-1) was lower than that of recommended practices (20 day-old two seedlings at 20 x15cm+continuous irrigation and hand weeding: 4310 kg ha-1) but was greater than that of farmers' practices (2643 kg ha-1). Planting 10 day-old single seedlings at 25 x 25 cm spacing had little impact on yield under the experimental conditions. Although intermittent irrigation and continuous flooding were statistically at par, cono-weeding reduced the labour required for weeding by 35 man-days ha-1 and labour cost by Rs 3125 ha-1. Farmers' participatory evaluation revealed that planting of one or two young seedlings hill-1 at specified spacing and employing conoweeding and intermittent irrigation are economically viable technologies. [ABSTRACT FROM AUTHOR]

Two field experiments were conducted on simultaneous growing and incorporation of daincha (Sesbania aculeata Pers.) in wet seeded rice in the humid tropics of Kerala, India. The objectives were to optimize the stage and method of incorporation of daincha, to evaluate N release pattern following green manure addition, and to assess its potential to supplement the nutrient requirement of rice crop, besides evaluating the cost effectiveness of in situ green manuring. Treatments consisted of two stages of incorporation of in situ grown daincha (20 and 30 days after sowing), three methods of incorporation (using cono weeder, spraying 2, 4-D at1.0 kg·ha-1, and spraying met sulfuron methyl at 5.0 g·ha-1), and two levels of N application (100 and 75% of the recommended N dose of 90 kg·ha-1). Wet sown rice without daincha, receiving 5 Mg·ha-1 farm yard manure and 90,45,45 kg N, P, and K ha-1 respectively, served as control. The experiment was laid out in a completely randomized factorial design during 2004 and 2005 and was replicated thrice. Incorporation of daincha at 30 days added about 14 Mg·ha-1 of organic matter, reduced weed population by 70% and supplemented about 25% of the N requirement of rice. Peak release of NH4+ - N from daincha coincided with panicle initiation stage of rice, signifying N availability at the most critical physiological stage (synchrony in the release of green manure held nutrients and nutrient uptake by the rice crop). Green manuring with intercropped daincha also enhanced rice yield by 544 kg·ha-1 and returns by Rs. 10220 ha-1, implying the potential of integrated nutrient management systems to augment crop productivity and profitability. [ABSTRACT FROM AUTHOR]

Papaya mealy bug, Paracoccus marginatus Williams and Granara de Willink (Hemiptera: Pseudococcidae) has a wide host range. In Kerala, during 2010 - 12 periods, 95 host plants were recorded belonging to 39 plant families. Highest number of host plants of P. marginatus was recorded under the family Euphorbiaceae. Heavy population build up was recorded on 44 host, moderate incidence on 27 plants and on 21 hosts, the infestation severity was low. Spatial distribution studies showed that the variance to mean ratio was the highest on Manihot esculenta Crantz (>100) and lowest on Phyllanthus amarus Schumach & Thonn. (0.63). Members of the same genus had variation in different indices owing to the plant architecture. [ABSTRACT FROM AUTHOR]