Effect of nursery application of sewage sludge oil yield and heavy metal contents and uptake by rice (ADT 36) in the main field.

A field experiment was conducted on the seedlings of rice ADT 36 to study the possibility of reducing the dose of-sewage sludge to be applied to the main field and also the contamination to the soil without sacrificing the grain and straw yields and nutrient and metal contents of rice crop. Seedlings were raised in two nursery plots-one without sludge application and another with sludge application @ 20 t ha(-1) (1.6 t/800 m(2)). The seedlings from both the treatments were transplanted separately. in the main plots receiving 0, 25, 75 and 100 per cent of recommended dose (120 : 50 : 50 kg NPK ha(-1)) of mineral fertilizer. The yields of grain and straw of the sludged seedlings receiving 75 per cent mineral fertilizer was on par with that of unsludged seedlings receiving 100 per cent mineral fertilizer. Similar influence was also observed with regard to the content and uptake of nutrients and heavy metals by the crop. No toxic effects of heavy metal contamination on soil or in grains were noticed in this study. Hence this method helps to reduce the mineral fertilizer requirement by 25 per cent and also avoid addition of heavy metals to the main field.