Yield and Profitability of Tomato As Influenced by Integrated Application of Synthetic Fertilizer and Biogas Slurry

Biogas slurry, a by-product of biogas production generated from anaerobic digestion of animal waste and crop residues, is often considered a waste product. Being a cheap source of organic matter and plant nutrients, its application may improve soil fertility, and yield quality and quantity. Field experiments were conducted at Lahirirhat Farming System Research and Development site, Rangpur, Bangladesh, to assess effects of biogas slurry in combination with synthetic fertilizer on tomato (Solanum lycopersicum L.) yield and profitability. Treatments included: soil test-based fertilizer, synthetic fertilizer+cow dung manure @ 5 t∙ha−1, synthetic fertilizer+cow dung bioslurry @ 5 t∙ha−1, synthetic fertilizer+poultry manure @ 3 t∙ha−1, synthetic fertilizer+poultry bioslurry @ 3 t∙ha−1, and farmer practice. Fruit yield was higher for plants grown with synthetic fertilizer+cow dung bioslurry compared with other fertilizer treatments and the farmer practice. Application of synthetic fertilizer+poultry bioslurry resulted in the highest fruit yield; plants maintained with the farmer practice yielded the least. The highest gross return and gross margin were obtained from plants treated with synthetic fertilizer+cow dung bioslurry. Synthetic fertilizer+poultry bioslurry-treated plants returned the highest gross return and gross margin. Application of synthetic fertilizer in combination with bioslurry has potential in increasing tomato yield and economic return of farmers.