Comparing Ammonia Volatilization and Dry Matter Yield of Fertilized Crops with Nitrogen and Aluminosilicates.

The nitrogen loss by ammonia volatilization is one of the main factors for low efficiency of N-urea applied on the soil surface. The reduction of losses by volatilization can be obtained with the addition of aluminosilicates to the urea fertilizer. The objective of this study was to evaluate ammonia volatilization and dry matter yield of Zea mays and Brachiaria brizantha fertilized with nitrogen sources and with aluminosilicate addition. Two experiments were carried out: in green house with pots and in the field. Experimental design was a randomized blocks design with three and four replications, respectively. Treatments comprised: ammonium sulfate, ammonium nitrate, urea, urea mixed with an aluminium phyllosilicate and two species of heulandite, and control applied at the level of 100 kg ha^-1 of N on soil surface. Ammonia volatilized was captured by a foam absorber with politetrafluoroetilene. The reduction in ammonia losses by volatilization and the increased efficiency of N utilization when urea is used together with aluminosilicates was demonstrated in both green house and field experiments. These results indicate that aluminosilicates minerals are able to improve the efficiency of nitrogen use, contribute to increasing N uptake through the control of retention of ammonium ion.