Field experiments were carried out during 1996-97 and 1997-98 to study the influence of biofertilizer with organic and inorganic sources of nitrogen on quality and yield of rice. Azospirillum plus 50 per cent of the inorganic N recorded more amylose, crude protein content and lower loss of gruel and increased the grain and straw yields. Azospirillum plus 100 per cent of the inorganic N resulted in significantly higher cooking time. Regarding organics sources, daincha incorporation @ 12 t ha^-1 recorded higher cooking time, total amylose content, crude protein content and the lowest loss of gruel and also increased the grain and straw yields.

Keywords : Rice, Azospirillum, inorganic nitrogen, daincha, rice grain quality, yield.

Total N demand in our country is about 8.2 million tonnes, as against the production of 6.8 million tonnes. Further, the projected deficit was 1.4 mt. So N requirement for the future has to be met from renewable source of nutrients like organics and biofertilizer. Among the organics, FYM and green manures are commonly used (Meelu and Morris, 1987). In single crop wetlands, the pre-season period of June-July is kept fallow. During this period about 200 mm of average rainfall is received. There is a possibility of raising green manure crop during this pre-season fallow period. Green manure incorporation can effectively substitute the inorganic nitrogen by 20-50 per cent (Alok kumar and Yadav, 1995). Hence, integrated N management becomes imperative tool to increase rice productivity and quality on a long term basis. The present investigation was aimed to study the biofertilizer plus inorganic and organic sources of N on quality and productivity of lowland rice in periyar-vaigai command areas.

MATERIALS AND METHODS :

Field experiments were carried out during kharif season of 1996-97 and 1997-98 with test crop CO 43 at Agricultural College and Research Institute, Madurai on sandy clay loam soil. The soil had organic carbon content 0.52 per cent , pH 7.6, EC 0.41 m. mhos cm^-1 and 202, 13.4 and 289.1 kg ha^-1 of available N, P₂O₅ and K₂0 respectively.

The experiment consisted of four main and six sub-treatments arranged in a split-plot design having three replications. The treatment details are

Main Plot : Organic sources of N.

M₁ - No organic manure (control)

M₂ - Farm yard manure (FYM) @ 12.5 t/ha

M₃ - Daincha (Sesbania aculeata) @ 12 t/ha

M₄ - Sunnhemp (Crotolaria juncia) @ 11t/ha

Sub Plot : Biofertilizer with inorganic sources of N.

S₁ - 50 per cent of the recommended N.

S₂ - 75 per cent of the recommended N.

S₃ - 100 per cent of the recommended N.

S₄ - Azospirillum + 50 per cent of the recommended N.

S₅ - Azospirillum + 75 per cent of the recommended N.

S₆ - Azospirillum + 100 per cent of the recommended N.

The recommended dose of fertilizer was 150:50:50 kg NPK ha^-1. Azospirillum inoculation was carried out as seed treatment (600 g ha^-1) seedling dip (1000 g ha^-1) and soil application (2000 g ha^-1). Daincha and sunnhemp were raised as pre-season crop using summer showers and at 45 days the green manure crops were incorporated 3 days before transplanting of rice. The quality and yield characters were recorded and presented.