ABSTRACT
The stabilization process necessary for leather tanning, in the leather industry, generates a great deal of collagenic solid waste, which is a likely pollutant. This solid waste has high nitrogen content, which suggests potential for agricultural use. To evaluate the feasibility of application of industrial leather waste as an N source for wheat and rice crops, a greenhouse experiment was conducted with five application rates of N from collagen (0, 225, 450, 675, and 900 mg kg-1) and three additional treatments (control, urea, and urea replenished in the second crop). The application of up to 675 mg kg-1 of N via collagen led to shoot dry matter production of wheat plants similar to application of mineral N fertilization, and increased wheat grain weight at all application rates studied (14 to 41 % higher than the application of mineral N). Collagen as a residual source provided N levels in the soil sufficient to obtain higher levels of rice grain weight (above 675 mg kg-1 of N via collagen), without leaf Cr contents being considered toxic. Collagen could be a good alternative for establishing the rice crop after wheat without yield losses and need for replacement of N fertilizers if applied at a rate corresponding to 675 mg kg-1 of N supplied through collagen.
waste; wet blue leather; nitrogen; Oryza sativa L; Triticum aestivum L
